|Publication number||WO1992011644 A1|
|Publication date||9 Jul 1992|
|Filing date||18 Dec 1991|
|Priority date||20 Dec 1990|
|Also published as||EP0563289A1|
|Publication number||PCT/1991/9570, PCT/US/1991/009570, PCT/US/1991/09570, PCT/US/91/009570, PCT/US/91/09570, PCT/US1991/009570, PCT/US1991/09570, PCT/US1991009570, PCT/US199109570, PCT/US91/009570, PCT/US91/09570, PCT/US91009570, PCT/US9109570, WO 1992/011644 A1, WO 1992011644 A1, WO 1992011644A1, WO 9211644 A1, WO 9211644A1, WO-A1-1992011644, WO-A1-9211644, WO1992/011644A1, WO1992011644 A1, WO1992011644A1, WO9211644 A1, WO9211644A1|
|Inventors||Chien-Chung Han, Ronald L. Elsenbaumer, Lawrence W. Shacklette, Granville G. Miller|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (7), Classifications (25), Legal Events (5)|
|External Links: Patentscope, Espacenet|
METHOD OF PROCESSING ELECTRICALLY
CONDUCTIVE POLYANILINES IN SOLVENT MIXTURES
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to solutions of
electrically conductive substituted or unsubstituted polyanilines and to methods of forming such solutions. Another aspect of this invention relates to a method of using such solutions to form polymer articles, such as films, printings, coatings and parts.
2. Prior Art
There has recently been an increased interest in the electrochemistry and electrical phenomena of polymeric systems. Recently, work has intensified with polymers having extended conjugation in at least one backbone chain.
One conjugated polymer system currently under study is polyaniline. Kobayashi, et al., J.
Electroanal, Chem., "Electrochemical Reactions
Concerned With Electrochromism of Polyaniline
Film-Coated Electrodes", 177 (1984) 281-291, describes various experiments in which spectro-electrochemical measurements of a polyaniline film coated electrode were made. French Patent No. 1,519,729; French Patent of Addition 94,536; U.K. Patent 1,216,549; "Direct Current Conductivity of Polyaniline Sulfate", M.
Donomedoff, F. Kautier - Cristojini, R. De Surville, M. Jozefowicz, L-T. Yu, and R. Buvet, J. Chim. Phys.
Phvsicohim. Brol. 68, 1055 (1971); "Continuous Current Conductivity of Macromolecular Materials", L-T. Yu, M. Jozefowicz, and R. Buvet, Chim. Macromol., 1 , 469
61970); "Polyaniline Based Filmogenic Organic
Conductive Polymers", D. LaBarre and M. Jozefowicz, C.R. Read. Sci., Ser. C. 269, 964 (1969); "Recently Discovered Properties of Semiconducting Polymers", M.
Jozefowicz, L-T. Yu, J. Perichon, and R. Buvet, J.
Polym. Sci. Part C, 22 1187-1195 (1969);
"Electrochemical Properties of Polyaniline Sulfates:, F. Cristojini, R. De Surville, and M. Jozefowicz, Cr.
Read. Sci., Ser. C. 268. 1346 (1979); "Electrochemical
Cells Using Protolytic Organic Semiconductors", R. De
Surville, M. Jozefowicz, L-T. Yu, J. Perichon, R.
Buvet, Electrochem. Ditn. , 13. 1451 (1986); "Oligomers and Polymers Produced by Oxidation of Aromatic Amines:,
R. De Surville, M. Jozefowicz, and R. Buvet, Ann. Chem.
(Paris), 2, 5 (1967); "Experimental Study of the Direct
Current Conductivity of Macromolecular Compounds:, L-T.
Yu, M. Borredon, N. Jozefowicz, G. Belorgey, and R.
Buvet, J. Polvm. Sci. Part C., 16, 2931 (1967);
"Conductivity and Chemical Properties of Oligomeric Polyaniline", M. Jozefowicz, L-T. Yu, G. Belorgey and R. Buvet, J. Polvm. Sci.. Part C. 16, 2943 (1967);
"Products of the Catalytic Oxidation of Aromatic
Amines", R. De Surville, M. Jozefowicz, and R. Buvet, Ann. Chem. (Paris), 2, 149 (1967); "Conductivity and Chemical Composition of Macromolecular Semiconductors", Rev. Gen. Electr., 75, 1014 (1966); "Relation Between the Chemical and Electrochemical Properties of
Macromolecular Semiconductors", M. Jozefowicz and L-T. Yu, Rec. Gen. Electr., 75, 1008 (1966); "Preparation, Chemical Properties, and Electrical Conductivity of Poly-N-Alkyl Anilines in the Solid State", D. Muller and M. Jozefowicz, Bull. Soc. Chem.. Fr. 4087 (1972).
U.S. Patent Nos. 3,963,498 and 4,025,463 describe oligomeric polyanilines and substituted polyanilines having not more than 8 aniline repeat units which are described as being soluble in certain organic solvents and which are described as being useful in the
formation of semi-conductor compositions having bulk electrical conductivities up to about 7 × 10-3 S/cm and, surface resistivities of 4 × 107 ohm/square.
European Patent No. 0017717 is an apparent improvement in the compositions of U.S. Patent Nos. 3,963,498 and 4,025,463 and states that the polyaniline can be formed into a latex composite through use of acetone solutions of the oligomers of polyaniline and suitable binder polymers.
U.S. Patent No. 4,855,361 describes a conductive polymer blend which comprises mixing a polyamide with a base-type polymer containing carbon nitrogen linkages, such as polyaniline, having a polyamide-like group covalently linked to the nitrogen atoms of the
base-type polymer. The conductive polymer blend is formed by first reacting a base-type non-conductive polymer containing carbon-nitrogen linkages, such as polyaniline, with a carbonyl anhydride, such as 3, 4, 3', 4'-benzophenone tetracarboxylic dianhydride to form a conductive polymer containing polyimide-like groups covalently linked to the nitrogen atoms of the
base-type polymer, mixing such conductive polymer with non-conductive polyamide in a suitable solvent,
removing the solvent, and forming a conductive
continuous phase blend of the polyamide and the
U.S. Patent No. 4,798,685 describes the production of base-type conductive polymers, particularly from the family of conductive polyaniline, by reacting a
base-group non-conductive polymer containing
carbon-nitrogen linkages, e.g. polyaniline,with an R+ donor compound, where R is an organic group, e.g.
methyl iodide, and forming an electrically conductive polymer in which the R groups are covalently linked to the nitrogen atoms of the polymer.
U.S. Patent No. 4,806,271 describes the production of base-type conductive polymers, particularly from the family of conductive polyaniline, by reacting a
base-type non-conductive polymer containing
carbon-nitrogen linkages e.g., polyaniline, with a cation donor compound, such as R2SO4, R'SO2Cl or
R"3SiCl, where R, R' and R" are alkyl or aryl, such as dimethyl sulfate or tosyl chloride, and forming an electrically conductive polymer in which the R groups of R2SO4, the R'SO2 groups of R'SO2Cl, or the R"3Si groups of R"3SiCl are covalently linked to the nitrogen atoms of the polymer.
U.S. Patent No. 4,822,638 describes a process for fabricating an electronic device on a non-conductive polymer substrate, particularly from the family of polyaniline, which comprises applying a covalent doping agent,such as an R+ donor compound, where R is an organic group, e.g., methyl iodide, to a preselected portion of a base-type non-conductive polymer substrate containing carbon-nitrogen linkages, and converting such preselected portion of the polymer substrate to an electrically conductive polymer portion, by covalent linkage of the R groups of such donor compound, to the nitrogen atoms of the non-conductive polymer substrate. Electronic devices, such as resistors, capacitors, inductors, printed circuits and the like, can be
provided by the invention process, in the form of light-weight polymers containing no metal,and which are stable and wherein the conductive portions are
U.S. Patent No. 4,851,487 describes the production of base-type conductive polymers, particularly from the family of conductive polyaniline, by reacting a
base-type non-conductive polymer containing
carbon-nitrogen linkages, e.g., polyaniline, with an anhydride such as R-SO2-O-SO2-R' ,R-CO-O-CO-R' or R-CO-O-SO2R or mixtures thereof, where R and R' are alkyl or aryl, e.g., tosylic anhydride or benzophenone tetracarboxylic dianhydride, and forming an
electrically conductive polymer in which the S02R and COR cfroups are covalently linked to the nitrogen atoms of the conductive polymer and the anion of the
conductive polymers is the RSO3- or R'CO2- group.
U.S. Patent No. 4,798,685 describes the production of base-type conductive polymers, particularly from the family of conductive polyaniline, by reacting a
base-type non-conductive polymer containing
carbon-nitrogen linkages, e.g., polyaniline, with an R+ donor compound, where R is an organic group, e.g., methyl iodide, and forming an electrically conductive polymer in which the R groups are covalently linked to the nitrogen atoms of the polymer.
PCT WO89/01694 describes various electrically conductive polyanilines doped with certain sulfonated dopants. These materials are disclosed as thermally stable and capable of being melt blended tθ4 form blends with other types of polymers.
SUMMARY OF THE INVENTION
One aspect of this invention relates to a
non-electrically conductive solution and to a
plasticized composition comprising one or more
substituted or unsubstituted polyanilines; one or more Lewis-base/dopant complexes, said Lewis base having pKa which is greater than that of said polyaniline and said dopant capable of doping said polyaniline to form electrically conductive polyaniline on release of said dopant from said complexes and one or more solvents capable of dissolving said complex and said polyaniline to some extent or capable of plasticizing said
polyaniline or a combination thereof. As used herein "solution" is a real solution or an ultra-fine
dispersion having an average particle size of less than about 100 manometers, and, used herein, a "plasticized composition" is a polymer or a polymer blend which is softened by incorporation of a liquid or low melting solid temperature generally to a level of more than about 1% by weight and less than about 20%. As used herein "polyaniline" is a polymer which is synthesized for example by the head-to-tail linkage of substituted or unsubstituted anilines, and, which depending on oxidation state, consists of phenyl rings and amine linkages (-NH- or -NR- where R is a substituent other than hydrogen) with varying amounts of guinoid rings and amine (-N=) linkages. As used herein "undoped polyaniline" is characterized by an uncharged backbone and "polyaniline base" is a particular form of undoped polyaniline which contains at least one quinoid diamine linkage in the backbone.
Another aspect of this invention relates to a method of forming a conductive article or forming a polymer coated substrate from the solution or
plasticized composition of this invention which
comprises the steps of:
(a) forming a non-electrically conductive
solution or plasticized composition comprising one or more substituted or unsubstituted polyanilines; one or more Lewis-base/dopant complexes, said Lewis base having pKa which is greater than that of said
polyaniline; and said dopant capable of doping said polyaniline to form electrically conductive polyaniline on release of said dopant from said complexes and one or more solvents capable of dissolving said complexes and said polyanilines to some extent or capable of plasticizing said polyaniline or a combination thereof;
(b) placing all or a portion of said non-electrically conductive solution or plasticized composition onto a substrate or into the shape of an article; and
(c) removing all or a portion of said solvent and said Lewis base from said solution or plasticized composition to form a solidified, doped electrically conductive polyaniline having the configuration of said article or a substrate coated with said electrically conductive polyaniline.
Yet another aspect of this invention relates to an article of manufacture formed through use of the solution and process of this invention.
Still another aspect of this invention relates to a process of dissolving a substituted polyaniline or an unsubstituted polyaniline doped with a dopant or a combination thereof to render it electrically
conductive which comprises the steps of mixing said polyaniline to a liquid or molten Lewis base having a basicity greater than the basicity of said polyaniline as determined by relative pka's, said Lewis base being capable of complexing with said dopant in said polymer to form a Lewis-base/dopant complex and undoped
polyaniline and a solvent for said complex and undoped polyaniline to form a solution of said complex and said undoped polyaniline in said solvent, and/or to form a polyaniline containing said complex which is
plasticized by said solvent. Through use of this invention polyaniline can be conveniently processed into useful conductive articles of all shapes such as fibers, coatings, films and the like using conventional solution or plasticized polymer techniques.
BRIEF DESCRIPTION OF THE INVENTION
The invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and accompanying drawings in which:
Figure 1 shows ultraviolet-visible-near-infrared spectra of sulfonated polyaniline complexed with triethylamine, tripropylamine and tributylamine in methanol.
Figure 2 shows ultraviolet-visible-near infrared spectra of sulfonated polyaniline complexed with tri-n-propyl amine in methanol and ethanol, and tri-n-butylamine in ethanol.
Figure 3 shows an
ultraviolet-visible-near-infrared spectrum of
sulfonated polyaniline complexed with tri-n-propyl amine in methanol as a thin coating on a
Figure 4 shows a graph showing the Hansen
Solubility Parameters of solvents and co-solvents for polyaniline base.
Figure 5 is a graph showing the Hansen Solubility Parameters relative to polyaniline base for solvents and non-solvents.
DETAILED DESCRIPTION OF THE INVENTION
The non-electrically conductive solutions or plasticized compositions of this invention comprise three essential ingredients. One essential ingredient is a substituted or unsubstituted polyaniline which is capable of being doped with a suitable dopant to become electrically conductive to at least about 10-10 Scm-1 as measured by the co-linear four-probe method.
Any form of substituted and unsubstituted
polyaniline can be conveniently used in the practice of this invention. Illustrative of useful forms are those described in Green, A.G. and Woodhead, A.E., CXVII Aniline-black and Allied Compounds, Part I", J. Chem. Soc., 101, pp1117 (1912) and Kobayashi, et al.,
"Electrochemical Reactions...of Polyaniline Film-Coated Electrodes", J. Electroanal. Chem., 177. pp. 281-91 (1984) and in Shacklette, L.W. et al. "Structure and Properties of Polyaniline as Modeled, by Single-Crystal Oligomers", J. Chem Phys., 88. 3955 (1988), which are hereby incorporated by reference. For example,
unsubstituted or substituted polyaniline, useful forms of which are characterized by different ratios of phenylene amine and quinone amine backbone segments, include leucoemeraldine, protoemeraldine, emeraldine, nigraniline and pernigraniline.
In the preferred embodiments of this invention, polyanilines for use in the invention are homopolymers and σopolymers of the type derived from the
polymerization of unsubstituted and substituted
anilines of the Formula I:
n is an integer from 0 to 5;
m is an integer from 0 to 5, with the proviso that the sum of n and m is equal to 5;
R2 is the same or different at each occurrence and is R3 substituents or hydrogen; and
R3 is the same or different at each occurrence and is selected from the group consisting of boric acid, phosphinic acid, phosphoric acid, sulfinate, amido, carboxylic acid, hydroxyamino, phosphonic acid, halo, hydroxy, cyano, sulfinic acid, carboxylate, borate, phosphate, sulfonate, phosphinate, phosphonate, sulfonic acid, nitro, amino, cyano, deuterium or substituted or unsubstituted arylsulfinyl,
alkoxycarbonyl, arylsulfonyl, alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, alkylamino, dialkylamino, alkylarylamino, arylamino, diarylamino, aryl, alkynyl, alkylsulfinyl, aryloxyalkyl,
alkylsulfinylalkyl, alkoxyalkyl, alkoxyaryl,
alkylsulfonyl, arylthio, alkylsulfonylalkyl, or
alkylsilane or any two R3 groups together or any R3 group together with any R2 group may form a substituted or unsubstituted alkylene, alkynylene, or alkenylene chain completing a 3, 4, 5, 6, 7, 8, 9 or 10 membered aromatic, heteroaromatic, heteroalicyclic or alicyclic ring, which ring may optionally include one or more divalent nitrogen, sulfur, sulfinyl, ester, carbonyl, sulfonyl or oxygen atoms, wherein permissible
substituents are one or more amino, alkylamino,
dialkylamino, arylamino, sulfinic acid, diarylamino, alkylarylamino, phosphonic acid, sulfonic acid,
phosphoric acid, boric acid, carboxylate, borate, sulfonate, phosphinate, phosphonate, hydroxylamino, quaternary ammonium, phosphate, sulfinate, phosphinic acid, sulfate, carboxylic acid, halo, nitro, cyano or epoxy moieties; or R3 is a divalent organic moiety bonded to the same or a different substituted or
unsubstituted aniline moiety or R3 is an aliphatic moiety having repeat units of the formula:
wherein q is a positive whole number. Illustrative of the polyanilines useful in the practice of this invention are those of the Formulas II to V:
R2, and R3 are as describe above;
n and m are the same or different at each occurrence and are integers from 0 to 4, with the proviso that the sum of n and m is 4; and
y and x are the same or different at each occurrence and are integers equal to or greater than 0, with the proviso that the sum of x and y is greater than 0, preferably x is an integer equal to or greater than about 1 and/or the ratio of x to y is greater than or equal to about 0.5; and
z is an integer equal to or greater than 1.
The following listing of substituted and unsubstituted anilines are illustrative of those which can be used to prepare polymers and copolymers useful in the practice of this invention.
2- (Methylamino) aniline4-Benzylaniline
2- (Dimethylamino) aniline4-Aminoaniline
N-Methyl anilineN-Methyl 2,4-Dimethylaniline
N-Propyl anilineN-Propyl m-Toluidine
m-Toluidine 2, 5-Dibutylaniline
4-Amino carbazoleN-(p-Amino phenyl) aniline
Exemplary of useful R2 groups are hydrogen, methyl, ethyl, isopropyl, butyl, isobutyl, hexyl, octyl, benzyl, and the like.
Illustrative of useful R3 groups are hydrogen, alkyl such as methyl, ethyl, octyl, nonyl, tert-butyl, neopentyl, isopropyl, sec-butyl, dodecyl and the like, alkenyl such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 1-heptenyl, 1-octenyl and the like; alkoxy such as propoxy, butoxy, methoxy, isopropoxy, pentoxy, nonoxy, ethyoxy, octoxy, and the like; cycloalkenyl such as cyclohexenyl, cyclopentenyl and the like;
alkanoyl such as butanoyl, pentanoyl, octanoyl, ethanoyl, propanoyl and the like; alkylsulfinyl, alkylsulfonyl, alkylthio, arylsulfonyl, arylsulfonyl, and the like, such as butylthio, neopentylthio, methylsulfinyl, benzylsulfinyl, phenylsulfinyl, propylthio, octylthio, nonylsulfonyl, octylsulfonyl, methylthio, isopropylthio, phenylsulfonyl,
methylsulfonyl, nonylthio, phenylthio, ethylthio. benzylthio, phenethylthio, sec-butylthio, naphthylthio and the like; alkoxycarbonyl such as methoxycarbonyl, ethoxyethyl, ethoxycarbonyl, butoxycarbonyl and the like; cycloalkyl such as cyclohexyl, cyclopentyl, cyclooctyl, cycloheptyl and the like; alkoxyalkyl such as methoxymethyl, ethoxymethyl, butoxymethyl,
propoxyethyl, pentoxybutyl and the like; aryloxyalkyl and aryloxyaryl such as phenoxyphenyl, phenoxymethyl and the like; and various substituted alkyl and aryl groups such as 1-hydroxybutyl, 1-aminobutyl,
l-hydroxylpropyl, 1-hydroxypentyl, 1-hydroxyoctyl, 1-hydroxyethyl, 2-nitroethyl, trifluoromethyl,
3,4-epoxybutyl, cyanomethyl, 3-chloropropyl,
4-nitrophenyl, 3-cyanophenyl, and the like; acid groups such as sulfonic acid, carboxylic acid and the like; organic radicals substituted with acid groups and salts thereof such as alkoxy, alkoxyalkyl, alkylamino, arylamino, alkyl or aryl groups substituted with various acid groups such as phosphonic acid, phosphinic acid, sulfinate, sulfonic acid, sulfinic acid,
phosphoric acid, boric acid, or carboxylic acid groups such as ethylsulfonic acid, propylsulfonic acid, butylsulfonic acid, phenylsulfonic acid, and the corresponding phosphoric acid, boric acid, sulfonic acid, carboxylic acid, sulfinate, sulfinic acid, phosphonic acid, and phosphinic acid; and amino, alkylamino, dialkylamino, arylamino, diarylamino, or alkylarylamino groups such as amino, methylamino, ethylmethylamino, ethylamino, dimethylamino,
phenylamino, diphenylamino, methylphenylamino and the like.
Also illustrative of useful R3 groups are divalent moieties derived from any two R3 groups or a R3 group with any R2 group such as moieties of the formula:
different at each occurrence and is hydrogen or alkyl, as for example (CH2)4, (CH2)3-, (CH=CH-CH=CH)-,
[-CH2-CH(CH3)-CH2]-and -(CH2)5, such moieties which optionally include heteroatoms of oxygen, nitrogen, ester, sulfonyl, carbonyl, sulfinyl, and/or sulfur such as -CH2SCH2 CH2NHCH2-, -SCH2NHCH2-, -O-CH2-S-CH2-,
-CH2S(O2)CH2-, -O(CH2)2O-, -CH2S(O)CH2-, -OC(O) CH2CH2-, -CH2C(O)CH2- and -CH2-O-CH2- to form heterocyclic amino compounds such as tetrahydronaphthylamine,
dihydrobenzopyranamine, dihydrobenzofuranamine, dihydrobenzoparaoxazineamine,
dihydrobenzoxazoleamine and the like. Exemplary of useful R3 groups are divalent alkenylene chains
containing 1 to about 3 unsaturated bonds such as divalent 1,3-butadiene and like moieties which may also include one or more divalent oxygen, nitrogen,
sulfinyl, sulfonyl, carbonyl, ester, and/or sulfur groups which form such compounds as benzodiazineamine, benzodiazoleamine, benzotriazepineamine,
benzoxazineamine, naphthaleneamine, benzopyranamine, benzothiazineamine, anthraceneamine,
benzothiopheneamine, benzothiodiazoleamine, and the like.
Preferred for use in the practice of this
invention are polyanilines of the above Formulas II to V in which:
n is an integer from 0 to about 2;
m is an integer from 2 to 4, with the proviso that the sum of n and m is equal to 4;
R2 is the same or different at each occurrence and is a R3 substituent or hydrogen;
R3 is aryl, alkyl or alkoxy having from 1 to about 30 carbon atoms, cyano, halo, sulfonic acid, carboxylic acid, boric acid, borate, phosphoric acid, phosphate, phosphonic acid, phosphonate, phosphinic acid,
phosphinate, sulfinic acid, sulfinate, carboxylate, sulfonate, amino, alkylamino, dialkylamino, arylamino, hydroxy, diarylamino, alkylarylamino, or alkyl, aryl or alkoxy substituted with phosphonic acid, phosphate, phosphoric acid, borate, sulfonate, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, carboxylate, hydroxy, alkoxy, phosphonate, boric acid, alkyl, phosphinic acid, phosphonate, phosphinate, carboxylic acid or sulfonic acid substituents;
x is an integer equal to or greater than 1;
y is equal to or greater than 0,
with the proviso that the ratio of x to y is greater than about 1; and
z is an integer equal to or greater than about 5. Particularly preferred for use in the practice of this invention are polyanilines of the above Formulas in which:
n is an integer from 0 to 1;
m is an integer from 3 to 4, with the proviso that the sum of n and m is equal to 4;
R2 is the same or different at each occurrence and is a R3 subsituent or hydrogen; R3 is aryl, alkyl or alkoxy having from 1 to about 20 carbon atoms, sulfonic acid, halo, carboxylic acid, amino, carboxylate, alkylamino, phosphonate,
dialkylamino, arylamino, phosphonic acid, boric acid, phosphate, phosphoric acid, borate, diarylamino, alkylyarylamino or alkyl or aryl substituted with carboxylic acid, phosphoric acid, boric acid,
phosphate, phosphonic acid, borate, sulfonate, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, carboxylate, halo, phosphonate, or sulfonic acid
x is an integer equal to or greater than 2;
y is equal to or greater than 0, with the proviso that the ratio of x to y is greater than about 2; and z is an integer equal to or greater than about 5. Amongst the particularly preferred embodiments, most preferred for use in the practice of this
invention are polyanilines of the above Formulas III or V in which:
n is an integer from 0 to 1;
m is an integer from 3 to 4, with the proviso that the sum of n and m is equal to 4;
R2 is hydrogen;
R3 is aryl, alkyl or alkoxy from 1 to about 15 carbon atoms, amino, alkylamino, dialkylamino,
arylamino, diarylamino, alkylarylamino, halo, sulfonic acid, sulfonate, carboxylic acid, carboxylate, or alkyl or aryl substituted with one or more sulfonic acid, carboxylate, amino, alkylamino, dialkylamino,
arylamino, diarylamino, halo, alkylarylamino, sulfate, sulfonic acid, or carboxylic acid substituents;
x is an integer equal to or greater than 2;
y is equal to or greater than 1, with the proviso that the ratio of x to y is equal to or greater than about 2; and
z is an integer equal to or greater than about 5. In the most preferred embodiments of this
invention, the polyaniline is derived from
unsubstituted aniline, alkoxy, alkyl, or sulfonic acid substituted aniline or copolymers thereof.
In general, the number of aniline repeat units is not critical and may vary widely. The greater the number of aniline repeat units the greater the
viscosity and molecular weight of the polyaniline. In those applications where a polyaniline of lower
molecular weight and viscosity is required, such material may be used, and in those applications where a polyaniline of high molecular weight and viscosity is required, then such material can be used. The number of aniline repeat units is preferably at least about 10. The upper limit can vary widely depending on the desired viscosity and molecular weight. In the more preferred embodiments of the invention, the number of aniline repeat units is at least about 20, and in the particularly preferred embodiments, the number of repeat units is at least about 30. Amongst the
particularly preferred embodiments, most preferred are those embodiments in which the number of repeat units is at least about 40.
Useful polyanilines can be prepared through use of chemical and electrochemical synthetic procedures. For example, one form of polyaniline can be prepared by treating aniline with ammonium persulfate (NH4)2S2OB in excess 1M HCl. This powdered form of polyaniline is blue green in color. After methanol washing and air drying this material exhibits a conductivity of 10 S/cm. This conductive form of polyaniline can be treated with ammonium hydroxide in ethanol to form a non-conductive form of polyaniline which is dark blue in color and which has a conductivity equal to or greater than of about 10-10S/cm. Other chemical
procedures for preparation of various chemical forms of polyaniline are described in detail in Green et al. described above.
Useful forms of polyaniline can also be prepared electrochemically. For example, useful forms of polyaniline can be prepared by the electrochemical oxidation of aniline in aqueous fluoroboric acid electrolyte on a platinum foil anode.
Other chemical and electrochemical syntheses and transformations of the conductive form of polyaniline may be discovered and are presently contemplated as being useful. Moreover, additional forms or types of polyaniline may be elucidated in the future.
Accordingly, no limitation to the syntheses,
transformation, or structures herein described or postulated is intended beyond the limitations of the appended claims.
The second essential ingredient of the solution or plasticized composition of this invention is a Lewis base/dopant complex. The purpose of the dopant
component of the complex is to dope the polyaniline and render it electrically conductive on release of the dopant from the complex and/or removal of the solvent and/or Lewis base from the solution or composition.
While we do not wish to be bound by any theory, it is believed that such dopant solute is derived from a compound, which upon addition to the polyaniline, ionizes the polymer via oxidative electron transfer or protonation with co-committent formation of a dopant solute species to form a charge transfer complex with polyaniline. The complex has a conductivity equal to or greater than about 10-10 ohm-1cm-1, preferably equal to or greater than about 10-6ohm-1cm-1, more preferably equal to or greater than about 10-2ohm-1cm-1 and most preferably equal to or greater than about 10-1ohm-1cm-1.
Dopants for use in the practice of this invention can vary widely and can be such materials which are known in the art for use in doping conjugated backbone polymers to form conductive or semiconductive polymers, as for example, those described in detail in U.S.
Patent Nos. 4,442,187 and 4,321,114 which are hereby incorporated by reference. Illustrative of useful dopant species are oxidizing dopants. Oxidizing dopants are well known in the conductive polymer art, and any of such known oxidizing dopants can be used. Illustrative of useful oxidizing dopants are AsF5, MoOCl4, MoCl5, PCI5, POCl3, PCl3, AlCl3, NO+ and NO2 + salts (such as NOBF4, NOPF6, NOSbF6, NOAsF6, NOCH3CO2, NO2BF4, NO2PF6, NO2AsF6, NO2SbF6, and NO2CF3SO2) , HClO4, HNO3, H2SO4, benzoylperoxide, SO3, Br2, (FSO3)2, ZnCl2, FSO3H, and Fe(III) salts (such as Fe(BF4)3, FeBr3,
Fe(CH3SO3)3, Fe(ClO4)3, FeCl3, Fe(OTs)3, and Fe(CF3SO3)3 which give rise to doped polymers containing dopant solutes such as NO3-, CH3SO3-, AlCl4-,BF4-, ZnCl4-, PCl4-, PF6-, AsF6-, SbF6-, CF3SO3-, CIO4-, OTs-, SO3-, C6H5CO2-, CH3SO3-, FSO3-, and FeCl4-. Other useful oxidizing dopants include electrolyte salts such as LiClO4,LiBF4, LiAsF6, NaPF6, Bu4NClO4, Bu4NOTs, Bu4NCF3SO3, LiCF3SO3, AgOTs, and the like. Preferred oxidizing dopants for use in the practice of this invention are oxidizing dopants selected from the group consisting of MoOCl4, MoCl5, and Fe (III) salts such as Fe(ClO4)3, FeCl3,
FeBr3, and Fe(CF3SO3)3, and particularly preferred oxidizing dopants for use in the practice of this invention are dopants selected from the group
consisting of MoOCl4, MoCl5, and FeCl3. Amongst these particularly preferred embodiments, most preferred oxidizing dopants are those embodiments in which the oxidizing dopant is FeCl3.
Illustrative of still other dopants are protonic acid dopants. Such dopants include inorganic acids, such as hydrofluoric acid hydriodic acid, hydrochloric acid, phosphoric acid, nitric acid, boric acid, sulfuric acid, and the like.
Illustrative of still other useful dopants are protonic acids and derivatives thereof such as those containing anionic moieties of the formula:
R1(PO3-)r(PO2-R1)r(PO3H-)r(BO-2)r(SO3)r(CO2-)r(BO2H-)r and having one or more cationic moieties selected from the group consisting of:
R1 is the same or different at each occurrence and is an organic radical or an amino group;
s is a positive integer equal to or greater than 1, preferably from 1 to about 8;
M is a species having a positive charge equal to s; and
r is the same or different at each occurrence and is 0 or a positive integer equal to or greater than 1, with the proviso that at least one of r is other than 0.
The R1 group may vary widely and can be amino, a substituted or unsubstituted aliphatic radical such as alkyl, alkylamino, dialkylamino, nitroalkyl, haloalkyl and the like, or a substituted or unsubstituted
aromatic radical such as phenyl, halophenyl,
nitrophenyl, anthracyl, naphthyl, indanyl, phenylamino, diphenylamino, phenanthryl and the like, or a substituted or unsubstituted- heteroaromatic or
heteroalicyclic radical such as piperidyl, pyrrolidyl, benzofuryl, benzothienyl, benzopyranyl, carbazoyl, imidazolyl, isoxazolyl and the like. R1 may also be a polymeric or oligomeric radical such as a polymer having recurring pendant phenyl groups in the polymeric backbone substituted with sulfonic acid and derivatives thereof; such as salts; phosphoric acid and derivatives thereof; such as salts; phosphonic acid and derivatives thereof; such as salts; sulfinic acid and derivatives thereof; such as salts; carboxylic acid and derivatives thereof; such as salts; boric acid and derivatives thereof; such as salts; or phosphonic acid and
derivatives thereof; such as salts; moieties such as sulfonated or phosphonated polystyrene,
poly(a-vinyl naphthalene), poly(vinyl benzoate), poly(benzyl methacrylate) and the like. In the
particularly preferred embodiments of the invention, R1 is an aromatic radical and in the most preferred embodiments R1 is substituted or unsubstituted phenyl or naphthyl. The nature of the M+s group may vary widely. For example, M+s may be be a non-metal cation such as Bu4N+, H+, NO+, NO2 +, NH4 + and the like, or may be a metal cation such as Na+, Li+, Ag+, Ba+2, Co+3, Al+3, Fe+3 and the like.
Preferred for use in the practice of this
invention are organic acid dopants, more preferably protonized forms of those having anionic portions of the formulas:
R1(P03-)r(PO2-R1)r(PO3H-)r(BO-2)r(SO3)r(CO2-)r(BO2H-)r where R1 and r are as described above.
More preferred for use in the practice of this invention are acids or acid derivatives thereof of the formula:
R6(BO2M2)s (PO3M2)f(SO3M)c(CO2M)d or
M is a metal or hydrogen or other non-metal cation;
c is 0, 1, 2, 3 or 4;
d is 0, 1 or 2;
e is 0, 1 or 2;
f is 0, 1 or 2;
g is 0, 1 or 2 with the proviso that at least one of c, d, f and g is other than 0; and
R6 is nitro, phosphonate, phosphonic acid,
sulfinate, sulfinic acid, sulfate, quaternary ammonium, cyano, hydroxy, halo, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, alkoxy or substituted or unsubstituted aryl or alkyl having from 1 to about 30 carbon atoms wherein permissible
substituents include perhaloalkyl, phenyl, alkoxy, halo, cyano, amino, phosphate, alkylamino,
dialkylamino, arylamino, diarylamino, borate,
alkylarylamino, haloalkyl, hydroxy, sulfonic acid, sulfonate, phosphoric acid, boric acid, sulfinate, sulfinic acid, carboxylic acid, nitro, carboxylate and the like, or R6 together may form an alkylene or alkenylene chain completing aromatic, heteroaromatic, alicyclic or heteroalicyclic ring system which chain may optionally include one or more oxygen, nitrogen, ester, sulfur, carbonyl or a combination thereof and/or which chain be unsubstituted or substituted with one or more halo, sulfate, hydroxy, amino, alkylamino, dialkylamino, alkyl, arylamino, diarylamino,
alkylarylamino, boric acid, nitro, cyano, sulfinate, phosphoric acid, sulfinic acid, alkoxy, phosphate, carboxylate, phosphonic acid, phosphonate,
sulfonate,borate, sulfonic acid or carboxylic acid groups, or R6 is a moiety of the formula:
q is a positive whole number from 1 to about 10; and
In the more preferred embodiments of this
invention, useful dopants are acid or acid derivatives of the formula:
R6(BO2M2), (PO3M2)f (SO3M)e (CO2M)d or
M is the same or different at each occurrence and is a metal or hydrogen or other non-metal cation;
c is 0, 1, 2 or 3;
d is 0 or 1;
e is 0 or 1;
f is 0 or l;
g is 0 or 1, with the proviso that at least one of c, d, f or g is other than 0;
Re is halo, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, hydroxy, phenyl, haloalkyl, perhaloalkyl, cyano, nitro, alkoxy, phosphonate, phosphonic acid, sulfinic acid or
sulfinate substituted or unsubstituted phenyl or alkyl wherein permissible substituents are selected from the group consisting of alkyl, halo, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, hydroxy, phenyl, haloalkyl, perhaloalkyl, cyano, nitro, alkoxy, boric acid, borate, phosphonate, phosphonic acid, carboxylate, sulfonate, phosphate, sulfonic acid, carboxylic acid, phosphoric acid, sulfinic acid or sulfinate or Re may form an unsubstituted or
substituted alkylene or alkenylene chain completing a naphthalene, anthracene or phenanthracene fused ring system wherein permissible substituents are one or more halo, amino, alkylamino, dialkylamino, arylamino, alkyl, diarylamino, alkylaryl, amino, hydroxy, phenyl, haloalkyl, perhaloalkyl, cyano, nitro, alkoxy, boric acid, borate, hydroxy, phosphonate, phosphonic acid, carboxylate, sulfonate, alkoxy, phosphate, sulfonic acid, carboxylic acid, phosphoric acid, sulfinic acid or sulfinate substituted or unsubstituted phenyl; and
M is a cation such as NO+, NO2 +, Fe(III), H+,
Pb(IV), Ce(IV), Al(III), Sr(IV), Cr(VI), Mn(VII),
Co(III), Au(III), Os(VIII), Na(I), Li(I), K(I) or Bu4N(I).
In the most preferred embodiments of this
invention, useful dopants are acids or acid derivatives of the formula:
c is 1, 2 or 3;
d and e are the same or different and are 0 or 1;
R6 is alkyl, phenyl, biphenyl, fluoro, amino, alkylamino, phosphate, phosphoric acid, borate, boric acid, dialkylamino, arylamino, diarylamino,
alkylarylamino, alkyl substituted with one or more fluoro, sulfonic acid, phosphate, phosphoric acid, borate, boric acid, sulfonate, alkoxy, carboxylate, hydroxy, nitro, cyano, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, or carboxylic acid groups, or phenyl or biphenyl substituted with one or more alkyl, fluoro, alkoxy, fluoroalkyl,
perfluoroalkyl, sulfonic acid, sulfonate, amino,
alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, carboxylate, phosphate, phosphoric acid, borate, boric acid,hydroxy, nitro, cyano, or carboxylic groups or Re may form an unsubstituted or substituted alkylene or alkenylene chain completing a naphthalene, anthracene or phenanthracene fused system which may be substituted with one or more alkyl, alkoxy, fluoro, fluoroalkyl, phosphate, phosphoric acid, borate, boric acid, sulfonic acid,
perfluoroalkyl, sulfonate, carboxylic acid,
carboxylate, hydroxy, nitro or cyano groups; and
M is a cation
The following is a listing of dopants which are useful in the practice of the most preferred
embodiments of this invention for formation of the dopant solute.
1-anthracene sulfonic acid,
9-anthracene sulfonic acid,
2-phenanthracene sulfonic acid,
3-phenanthracene sulfonic acid,
9-phenanthracene sulfonic acid,
perflouro octylsulfonic acid
perfluoro octylcarboxylic acid
toluenesulfonic Acid (TsOH),
dodecylbenzene sulfonic acid,
naphthalene sulfonic acid,
benzene disulfonic acid,
benzene sulfonic acid,
1,3-benzene disulfonic acid,
2,5-dihydroxy-1,4-benzene disulfonic acid, camphor sulfinic acid naphthalene trisulfonic acid
dodecylbenzene sulfonic acid,
ethane sulfonic acid
1,5-naphthalene disulfonic acid,
nickel phthalocyanine tetrasulfonic acid,
phenyl phosphonic acid,
poly(vinyl sulfonic acid),
tiron (4,5-dihydroxy-1,3-benzene disulfonic acid), vinyl sulfonic acid,
sulfonated poly(a-vinyl naphthalene),
naphthol blue black,
1-octane sulfonic acid,
t-butyl phosphonic acid,
ethyl phosphonic acid,
butyl phosphonic acid,
1,2-benzene disulfonic acid,
4-octylbenzene sulfonic acid,
2-mesitylene sulfonic acid,
2, 6-naphthalene disulfonic acid,
2-naphthalene sulfonic acid,
1,3,6-naphthalene trisulfonic acid,
1,3,7-naphthalene trisulfonic acid,
sulfonazo III acid, biphenyl disulfonic acid,
biphenyl sulfonic acid,
3,6-dihydroxynaphthalene-2,7-disulfonic acid, 4,5-dihydroxynaphthalene-2,7-disulfonic acid,
6,7-dihydroxy-2-naphthalene sulfonic acid,
1-naphthalene phosphoric acid,
1-naphthalene sulfonic acid,
1-naphthalene-5,7-dinitro-8-hydroxy sulfonic acid 1-naphthalene-4-hydroxy sulfonic acid,
4-bromo benzene sulfonic acid,
4-hydroxy-5-isopropyl-2-methyl benzene sulfonic acid
3,4-diamino benzene sulfonic acid
1,3,5-benzene trisulfonic acid,
2-methyl-5-isopropyl benzene sulfonic acid,
3,4-dinitro benzene sulfonic acid,
2-methoxy benzene sulfonic acid,
1-naphthalene-5-hydroxy sulfonic acid,
1-naphthalene-7-hydroxy sulfonic acid,
1-naphthalene-3-hydroxy sulfonic acid,
2-napthalene-1-hydroxy sulfonic acid,
4-phenylamino benzene sulfonic acid,
1,6-naphthalene disulfonic acid,
1,5-naphthalene disulfonic acid,
1,3-naphthalene-7-hydroxy disulfonic acid, and
The amount of dopant is not critical and may vary widely. In general, sufficient dopant is included in the complex such that on release of the dopant from the complex and removal of the Lewis base and/or solvent from the composition or solution, the polyaniline is doped to a conductivity of at least about 10-10
ohm-1cm-1. The upper level of conductivity is not critical and will usually depend on the type of aniline polymer employed. In general, the highest level of conductivity obtained is provided without unduly adversely affecting the environmental stability of the polymer. In the preferred embodiments of the
invention, the amount of dopant employed is sufficient to provide a conductivity of at least about 10-6ohm-1cm-1 and in the particularly preferred embodiments is sufficient to provide a conductivity of from about 10-4ohm-1cm-1 to about 10+2ohm-1cm-1. Amongst these
particularly preferred embodiments, most preferred are those embodiments in which unsubstituted polyaniline is employed and in which sufficient dopant is employed to provide a conductivity of at least about 10-1ohm-1cm to about 10+2ohm-1cm-1. Amounts sufficient to provide a conductivity from about 10°ohm-1cm-1 to about 10+2ohm-1cm-1 usually are the amounts of choice.
The second component of the Lewis base/dopant complex is a Lewis base. The Lewis base has several essential characteristics. The base has a pKa greater than that of the polyaniline in the solution or the composition; and is capable of complexing with the dopant for the electrically conductive polyaniline to form a dopant/Lewis base complex which is soluble in the solvent to some extent. The pKa of the Lewis base is greater than the pKa of the neutral (undoped) form of the polyaniline. The pKa for the conjugate acid of the neutral form of the polyaniline with n=4, m=0, x=2, y=1 and z>1 in Formula III is estimated to be in the range of 5.4 ± 0.4. The pKa of the conjugate acid of the Lewis base component of the solution is then
preferably greater than about 5.4, more preferably greater than about 6, and most preferably greater than about 9.
The Lewis base may be a solid or a liquid but is such that it can be removed from the complex releasing the dopant to dope the polyaniline, and preferably is removable from the solution or the composition. Lewis base can be removed from the complex by any suitable means as for example chemical reaction, extraction, evaporation and the like.
The Lewis base is preferably relatively volatile which enhances the quality of conductive polyaniline articles formed from the solution or plasticized composition. As used herein "volatile" means that the Lewis base can be volatilized from the composition or solution when subjected to heat and has a
volatilization temperature such as a boiling point, a sublimation point and the like equal to or less than about 300°C under use conditions, preferably at
atmospheric or autogenous pressure. The lower limit to the volatilization temperature is not critical as long as the base can be easily handled under use conditions. The volatilization temperature of the Lewis base may vary and is preferably less than about 250ºC, more preferably from about 30 to about 150° and most
preferably from about 35 to about 100°.
In the preferred embodiments of the invention, the Lewis base is a liquid under use conditions. This aids in a removal of the Lewis base from the composition or solution when they are used to form the article or coatings.
Illustrative of suitable Lewis bases are primary, secondary and tertiary aromatic and aliphatic amines, phosphine compounds, amides, phosphoroamides and polymers containing amine or phosphine functional groups such as morpholine, 4-amino morpholine,
2-picoline, methylamine, pyridine, piperidine,
ethylamine, 4-picoline, pyrrolidone, 2-oxazolidone, 2-imidazolidone, triphenylamine, benzylamine. diethylmethylamine, allylmethylamine, aniline,
dibutylamine, triethylamine, dibenzylethylamine, piperazine, diethylamine, diisopropylamine,
diphenylmethylamine, dipropylamine, triisobutylamine, tripropylamine, cyclohexylamine, 2-(ethylamino) ethanol, ethanolamine, 2-(aminomethyL)pyridine,
1-(3-amino-propyl)-2-picoline, 1,1-dimethylhydrazine, propylamine, amylamine, butylamine, ethylenediamine, N,N-dimethylethylenediamine,
N,N'-dimethyl-ethylenediamine, tetrahydrofurfurylamine, 1,2,3,4-tetrahydroisoquinoline, trimethylphosphine triethylphosphine and the like.
In the preferred embodiments of the invention, the Lewis base of choice is selected from the group
consisting of amines, amides, and phosphoramides. More preferred Lewis bases are primary, secondary and tertiary aliphatic amines, diamines, pyridine and amides. Such liquid Lewis bases as amides, diamines, amines and pyridine are preferred because they are strong enough bases to complex with the dopant; and because they are liquid at room temperature and are relatively volatile (boiling point of from about 30° to about 200°) and can be easily and completely removed on casting of the solution or composition in the desired form to form the desired solid electrically conductive articles or coated substrates. Most preferred amines, diamines, pyridine, and amides include piperdine, pyrrolidine, 2-picoline, benzylamine,
3-picoline, N,N'-dimethylethylene diamine,
N,N-dimethylethylene diamine, ethylenediamine,
morpholine, 2-pyrrolidone, 2-oxazolidone,
tetrahydrofurfurylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, dimethylamine. diethylamine, dipropylamine,. dibutylamine, methylamine, ethylamine, propylamine, butylamine, amylamine,
pyridine, isopropylamine, cyclohexylamine,
2-(ethylamino) ethanol, isobutylamine, tert-butylamine and the like.
The amount of Lewis base may vary widely but is usually at least an amount which is sufficient to complex with all or a portion of the dopant in the electrically conductive polyaniline. The amount of Lewis base used may vary widely and depends to a significant extent on the amount of dopant and
polyaniline. In general, the greater the amount of dopant and polyaniline, the greater the amount of Lewis base required to de-dope the polyaniline and to form the dopant/Lewis base complex to the desired extent; conversely, the smaller the amount of dopant and polyaniline the smaller the amount of Lewis base required to complex the dopant. In general, the amount of Lewis base is at least about 25 mole percent based on total moles of polymer repeat units. In the
preferred embodiments of the invention, the amount of Lewis base is at least about 50 mole percent based on the total moles of polymer repeat units, and in the more preferred embodiments of the invention, the amount of Lewis base is more than 100 mole percent based on the total moles of polymer repeat units. The upper limit to the amount of Lewis base is not critical but excess Lewis base will function in part as a solvent or plasticizer for the Lewis-base/dopant complex and the polyaniline, and the solubility parameters of the excess base must be taken in combination with those of any additional solvents.
The third component of the solution of this invention is a polar organic or inorganic solvent which is capable of dissolving neutral polyaniline and the Lewis-base/acid-dopant complex to form the solution of this invention. As used herein, "a polar organic or inorganic solvent" is a solvent which has a relative dielectric constant of equal to or greater than about 5, and a dipole moment equal to or greater than about 3.5 × 10-30 Cm. Preferred solvents are those solvents with dielectric constants equal to or greater than about 6 and dipole moments equal to or greater than about 5 × 10-30 Cm.
Preferred solvents have a relatively strong hydrogen bonding capability. The degree of hydrogen bonding capability can be assessed by a variety of techniques. One method which we find to be most predictive of suitable solvents for the present invention is that Craver, J. Appl. Polvm Sci. 14. 1755 (1970). This method is based upon the relative sound velocity (gw) in paper wetted by the solvent, where water is arbitrarily assigned a value of 100. By this measure, suitable solvents are those which have a hydrogen bonding capability greater than about 50, and more preferably greater than about 60.
Another useful measure of suitable solvents are the solubility parameter of the liquid, also referred to as the Hildebrand Parameter (d) . Preferred solvents have a Hildebrand Parameter which lies in the range of from about 17 to about 29, more preferably in the range of from about 18 to about 26, and most preferably in the range of from about 19 to about 25.
An even more useful measure of suitable solvents is based on dividing the Hildebrand Parameter of the liquid into separate contributions from dispersion (dd), from polar interactions (dp), and from hydrogen bonding interactions (dh) In this scheme (which is disclosed in "Handbook of Solubility Parameters and Other Cohesion Parameters", .by Allan F.M. Barton (CRC Press, 1983) pp 141-162, 94-110) the Hildebrand
Parameter is related to the contribution from
dispersion (dd), polar interactions (dp) and hydrogen bonding (dn) ("Hansen Parameters") by the relation d2=dd 2+dp 2+dh 2
For example, in order to judge the suitability of a solvent for polyaniline, we have empirically determined solubility parameters for the neutral base form of polyaniline which contains approximately a 50/50 ratio of amine to imine nitrogen linkages as follows: d d - 17.4 MPa
d p = 8.5 MPa
dh = 10.4 MPa
d = 22.0 MPa If we define a quantity (r) as:
r= [4(17.4-dd)2 + (8.5-dp)2 + (10.4 -dh)2] where dd, dp and dh are the Hansen Parameters for a prospective solvent for polyaniline base, then suitable solvents are those for which r is less than about 7, more preferably less than about 6, and most preferably less than about 5 MPa.
Solvents for use in the practice of this invention are volatile. As used herein, a "volatile" solvent is a liquid which has a boiling point of equal to or less than about 300ºC under use condition, preferably at atmospheric or autogenous pressure. The lower limit to the boiling point is not critical provided that the solvent is in the liquid state under use conditions. In the preferred embodiments of the invention the boiling point of the solvent is less than about 250°C. Particularly preferred solvents have boiling points of less than about 200°C. More preferred solvents have boiling points of less than about 150°C and most preferred solvents have boiling points of from about 40°C to about 100ºC.
Illustrative of useful solvents are alkyl
alkanesulfonates such as methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate; nitriles such as acetonitrile,
propionitrile, butyronitrile, benzonitrile, and the like; aromatic solvents such as nitrobenzene, benzene, toluene and the like; carbonates such as propylene carbonate, dimethyl carbonate, ethylene carbonate and the like; nitroalkanes such as nitromethane,
nitroethane, nitropropane, and the like; amides such as dimethyl formamide, dimethyl thioformamide, diethyl formamide, N,N-dimethylacetamide,
pyrrolidone, 2-methyl-3-oxazolidone, 1,3-dim *ethyl tetrahydro-2-pyrimidone, lactams, caprolactam and the like; organophosphorus compounds such as hexamethyl phosphoramide, diethylphosphate, triethylphosphite, trimethyphosphate and the like; glycols such as
tetraethylene glycol and the like; organosulfur
compounds such as sulfolane, methyl sulfolane, dimethyl sulfone, dimethyl sulfoxide, glycol sulfite,
tetraethylsulfamide and the like; amines such as pyrrolidine, piperidine, morpholine, ethylamine, benzylamine, butylamine, propylamine, ethylenediamine, propylene diamine, piperazine, pyridine, indoline, picoline, toluidine, quinoline, aniline and the like; and other organonitrogen compounds such as
1,3-dimethyl-3-imidazolidinone, 4,4-dimethyl-2-imidazoline, 3,5-dimethylisoazole, 1-(3-aminopropyl)-2-pipecoline, 2-(ethylamino)ethanol, 2,3-cyclohexenopyridine, 2-(methylamino)pyridine, 6-methylindole and the like. Ethers such as
tetrahydrofuran, 1,3-dioxane, dimethoxyethane and 1,3 dioxolane.
Mixtures of such organic solvents can also be used as for example mixtures of N-methyl pyrrolidinone and pyrrolidine or tetrahydrofuran and
2- (ethylamino) ethanol. When employing mixtures of organic solvents or an excess of the Lewis base, an average set of Hansen Parameters can be calculated using the techniques of matrix algebra. Suitable solvent mixtures are then preferably those whose average values of dd, dp, and dh lead to a value of r which is less than about 7 MPa.
In addition to the essential polyaniline,
Lewis-base/dopant complex and liquid to dissolve or plasticize the neutral polyaniline and
Lewis-base/acid-dopant complex, the solutions of this invention can include other optional ingredients which either dissolve or do not dissolve in the solution.
The nature of such optional ingredients can vary widely, and include those materials which are known to those of skill in the art for inclusion in polymer articles. In the case of dissolvable components, materials may be present which alter the physical or mechanical properties of either the solution or the articles eventually cast from the solution. Examples of such materials include salts such as, for example, LiCl, LiBr, LiCF3SO3, KCF3(CF2)2SO3, and the like which may be included to provide dopant counterions for the polyaniline or which may improve the solubility of the polyaniline or other additional conventional polymers. These other conventional polymers which may be present include, for example, polycarbonate, polyacrylonitrile, polyvinyl chloride, polyvinylidene fluoride,
polyvinylidine chloride, polyvinyl alcohol,
polyethylene oxide, polystyrene, nylon, cellulose poly(1,4-cyclohexylidene dimethylene terephthalate), poly(phenylene sulfide), poly(ethylene terephthalate), poly(4-aminobutyric acid), poly(hexamethylene
adipamide), poly(p-phenylene terephthalamide),
poly[methane bis(4-phenyl) carbonate], sulfonated polystyrene, sulfonated poly(2-methyl styrene),
sulfonated poly(4-phenyl styrene), sulfonated
poly(a-vinyl naphthalene), sulfonated poly(benzyl methacrylate, poly(acetate butyrate), polypropylene, polyethylene, cellulose acetate, polyphenylene oxide, polyvinyl acetate, and the like. In the case of nonsoluble fourth components, materials may be present which either fill or form a substrate for the
conductive polymer cast from the solution. These fourth components include other conductive polymers, such as conjugated backbone polymers as for example poly(phenylene sulfide), polyacetylene, polyphenylene, polythiophene and the like which may become conductive upon doping, graphite, carbon blacks, metal conductors, reinforcing fibers and inert fillers (such as clays and glass).
The proportion of polymer and solvent in the solution or plasticized composition of this invention containing the substituted or unsubstituted polyaniline homopolymer or copolymer, the Lewis base/dopant complex and the organic solvent are not critical and can vary widely, such that the composition varies from a
solution to a plasticized composition. However, the following guidelines are believed important for
achieving solutions and plasticized compositions
particularly useful in the present invention. In general, the amount of solvent as a proportion of the amount of solution is not believed to be critical, since any amount as a liquid will form at least a viscous gel or a plasticized composition with the polymer. These viscous gel embodiments of the
invention are particularly useful for silk screening conductive circuitry and for applying thick film coatings on substrates. For other applications, it may be preferred, however, to use sufficient liquid solvent to lower the viscosity of the gel, composition or solution to a point where it flows at least
sufficiently to conform to a container shape or mold in a reasonably short period of time, e.g., in 30 minutes or less. Preferably, the solvent is present in
sufficient amounts to lower the viscosity of the solution to less than about 10,000 centipoise or preferably from about 1 to about 1000 centipoise.
The method of forming the solutions or plasticized compositions of this invention is not critical and can vary widely. For example, one preferred method of forming the present composition or solution containing the substituted or unsubstituted polyaniline is to add the polyaniline doped with a suitable dopant such as toluene sulfonic acid and a suitable Lewis base such as piperdine or pyrrolidine to a suitable solvent such as N-methyl pyrrolidone in a mixing vessel. All or a portion of the Lewis base complexes with the acid dopant of the conductive polyaniline forming the Lewis base/acid complex and neutral undoped polyaniline base. The complex and the neutral polyaniline then dissolve in the liquid. As used herein, "to complex" means to form an association or ionic bond such as a conjugate acid base pair between the Lewis base and the dopant for the electrically conductive polyaniline. In use, the solution or plasticized composition can be placed in the desired configuration. As the liquid and the Lewis base are removed, the complex decomposes
releasing the dopant which then dopes the polyaniline forming the doped electrically conductive solid polyaniline in the desired configuration.
Another preferred method is to react,
simultaneously, the undoped polymer, the dopant and the Lewis base in a suitable solvent. Thus, for example, by introducing polyaniline as a solid powder such a polyaniline of the Formula III, in which y≥ 1, ×≥ 1 and z≥ 1 , or a mixture of a polyaniline Formula III x=0,y≥ 1 and z ≥ 1, (pernigraniline form) and a polyaniline of the Formula IV (leuco form), a suitable Lewis base, such as propylamine, morpholine or
pyrrolidine and a acid dopant such as toluene sulfonic acid, dodecyl benzene sulfonic acid or naphthalene disulfonic acid as a solid into a mixing vessel
containing N-methylpyrrolidone as a solvent, a solution of the polyaniline and dopant/Lewis-base complex is quickly formed, from which conductive polymer can be cast.
Similarly, undoped polyaniline in the leuco form of Formula IV can be added to a suitable mixing vessel with a suitable solvent such as N-methylpyrrolidone, a suitable Lewis base such as pyrrolidine or piperidine and a suitable oxidizing dopant such as NOSbF6, FeCl3 or mixture of an acid and oxygen and an oxidizing agent such as toluenesulfonic acid and oxygen to form the solution or composition of this invention from which the conductive polyaniline can be cast. The conditions of mixing are not critical, provided that sufficient dopant is used to dope the desired quantity of
polyaniline and sufficient Lewis base is employed to complex the dopant to the desired extent, and
sufficient solvent is used to reduce the viscosity of the solution to manageable levels. An alternate technique of preparing the solution of this invention containing the doped polymer is to mix first the polyaniline, the Lewis base and the solvent, thereafter add the dopant to the solution, if the dopant is soluble in the solvent, or to form a two phase system if the dopant is insoluble. Thus, for example, undoped polyaniline base is admixed with a soluble solvent, such as N-methylpyrrolidone and a Lewis base such as propylamine, morpholine or pyrrolidine, the addition of a suitable dopant to this suspension, such as toluene sulfonic acid, causes the Lewis base and the dopant to complex. Even if the dopant is insoluble in the solvent, it will still go into the solution, provided that the complexed dopant and base is soluble in the solvent.
Various methods are contemplated for using the solution of the present invention. The Lewis base and the solvent can be removed from the solution through use of any conventional solvent removal method but is removed preferably by evaporation to form a conductive polyaniline. Alternatively, the Lewis base solvent can be removed by extraction with an extractant in which the Lewis base and the solvent are substantially more soluble than the doped polymer.
As will be appreciated by those skilled in polymer processing, the ability to form polymer articles by removing a solvent from a solution or plasticized composition enables one to prepare articles of a wide variety of shapes and sizes. Thus, for example, by removing volatiles from the present solution or
plasticized composition spread on a surface, films of any desired thickness can be prepared. Extremely thin films can be prepared which are substantially
transparent. By extruding the solution or plasticized composition through a die, fibers or films can be made. Similarly, by removing volatiles from the solution or plasticized composition in a mold of various shapes, shaped articles conforming in shape to the mold can be prepared. It will be appreciated that some shrinkage might occur between the solution or plasticized
composition in its last flowable state to the final article, but such shrinkage is conventionally accounted for in molding polymers from solution. It is also contemplated that, once a solution or plasticized composition is formed, a partial or substantial removal of solvent will occur prior to placing the solution or plasticized composition on a surface or in a mold, with the final removal of solvent occurring on the surface or in the mold. It is contemplated that, if additional soluble components are introduced into the solution, they will, unless also volatile, be present in the formed article . If the additional component is a non-volatile liquid, then the removal of volatile components may leave a new liquid or plasticized form of doped conducting polymer or undoped neutral polymer. If the additional components are volatile, then foamed or expanded cellular forms of the polymer may be
In the event that the fourth or additional
non-soluble components are present (or suspended) in the solution, the doped polymer will form around, or be filled with, the insoluble material. If, for example, the additional components are glass fibers, depending on the relative amounts of fibers and doped polymer, the removal of the solvent will cause either the
polymer to be fiber-filled, or the fibers to be polymer coated or impregnated, or some intermediate composite of fibers and doped polymer to be formed. In the case of systems wherein the amount of non-soluble component greatly exceeds the doped polymer remaining, individual particles or shapes of non-soluble components coated or impregnated with doped polymer will be formed.
Examples of articles formed from non-soluble components and the present polymer solutions include conductive polymer coated-housings for sensitive electronic equipment (microprocessors), infrared and microwave absorbing shields, flexible electrical conducting connectors, conductive bearings, brushes and semiconducting photoconductor junctions, antistatic materials for packaging electronic components, carpet fibers, tiles, or waxes for floors in computer rooms and antistatic spray finishers for plastics, and thin, optically transparent antistatic finishes for CRT screens, aircraft, auto windows and the like.
A third application for the present polymer solutions is in the doping of other materials, and especially other conjugated backbone polymers which could also be doped by the electron-acceptor dopant alone. Such doping may occur as a part of the process of casting the polymer solution onto the second polymer article, but may also be accomplished without,
necessarily, casting the conductive polymer from the solution.
The following specific examples are
present to illustrate the invention and are not to be construed as limitations thereon.
To a solution containing 1770ml of H2O, 50g of aniline (0.54 mole) and 172g p-toluene sulfonic acid (0.90 mole) was added, dropwise at 15°C, a solution of ammonium persulfate (153.4g in 336.5 ml H2O) over a period of 40 minutes. Then the reaction was allowed to continue at 15°C for a 0.5 hours. The resultant solid precipitate was collected and washed with 6 L of an aqueous toluene sulfonic acid solution (10 wt%) and then by 3 L of methanol. The resultant blue-black solid was dried in air for 25 hrs and dried at 130°C for 3 hrs. under dynamic vacuum to give poly(anilinium tosylate) as a green powder. The conductivity of the dried and pressed pellet formed from this material was 1 Scm-1 as measured by the co-linear four-probe method. The conductivity of the moisture-saturated pellet was 20 Scm-1.
The yield was 78g. The intrinsic viscosity (in H2SO4, at 25°C) was 0.66 dl/g. Elemental analysis of the dried green powder gave:
C:64.37(Wt%) H:4.86% N:8.59%
Moisture: less than 0.8 wt%
Poly(anilinium tosylate) (13g) obtained from Example 1 was suspended in 270ml of fuming sulfuric acid and stirred for 10 hrs. The resultant solution was then added dropwise to 2700 ml of methanol to precipitate the sulfonated polyaniline. The resultant sulfonated-polyaniline was collected by filtration, washed with 4 L of methanol, and then dried under dynamic vacuum for 15 hrs. The yield was 11g. The conductivity of a pellet formed from this material was measured (by a co-linear four-probe method) and was 0.05-0.1 Scm-1. Elemental analysis gave:
C:52.81%, H:4.13%, N:10.07%, 0:17.50%, S:10.84%
A series of experiments were carried out to determine the effect of the Lewis base on the solubility of the Lewis base/acid dopant complex and the polyaniline. In these experiments, a 3 mg sample of the polyaniline sulfonate of Example 2 was mixed with 0.2 ml of amine and 0.8 ml of a polar organic solvent, and the solubility of the solids were
evaluated. The results are set forth in the following Tables 1 and 2. In the Tables, the abbreviations have the following meanings: a) "VS" means very soluble.
b) "S" means soluble.
c) "SS" means slightly soluble.
d) "I" means insoluble.
Amine Water Methanol
pyridine VS S SS triethylamine VS VS SS tripropylamine VS VS S tri (isooctyl) amine SS VS VS pyridine SS I I triethylamine SS I I tripropylamine S SS I tri (isooctyl) amine VS VS i
Dimethylformamide VS VS
Dimethylsulfoxide VS VS
N-Methylpyrrolidone VS S
Acetonitrile S S
Nitromethane S I
Methylene Chloride SS S
Acetone SS S
Tetrahydrofuran I S
Nitrobenzene I VS
Chloroform I S
Cyclohexanone I SS
Chlorobenzene I I
Ethylacetate I I
Petroleum Ether I I The solubility of the tested sulfonated
polyaniline/amine complexes is greatly affected by the amines used for complexation. By employing selected amines, the sulfonated-polyaniline is
solution-processible in a broad range of solvent media, such as water, methanol, ethanol, 1-propanol,
1-butanol, 1-octanol, dimethylformamide,
dimethylsulfoxide, N-methyl pyrrolidone, acetonitrile, nitromethane, ethylene chloride, acetone,
tetrahydrofuran, nitrobenzene, chloroform,
cyclohexanone and the like.
Figure 1 shows ultraviolet-visible-near infrared (UV-VIS-NIR) spectra of three different amine-complexed sulfonated-polyanilines (triethylamine, tripropylamine, tributylamine). Although these three samples have different dissolution characteristics (see Tables 1 and 2), they showed no differences in their UV-VIS-NIR absorption characteristics in methanol. Figure 2 shows that solvents also had little effect on the spectra. EXAMPLE 4
The solutions prepared in Example 3 can be used to prepare sulfonated polyaniline coatings on plastic films. The initially coated film was originally blue and non-conductive and was made conductive by
evaporation of the complexed amine. During the
evaporation process, the color of the coated film turned more and more green, with a continued
conductivity increase as determined using the
four-in-line probe method. Although thermal treatment was not always required for the evaporation process, it helped shorten the processing time.
UV-VIS-NIR spectroscopy was found to be a very useful analytical tool for characterization of the sulfonated-polyaniline coating prepared from the tripropylamine-complexed form and evaporated at room temperature. The spectrum is recorded in Figure 3.
The change in the UV-VIS-NIR absorption pattern
revealed the change in color of the polyaniline
sulfonate coating. The emergence of a new
near-infrared absorption with a peak between 800 and 1100 nm (depending on the degree of elimination of the complexed amine) indicated the formation of the
conductive state. EXAMPLE 5
Poly(anilinium tosylate) prepared in Example 1 was suspended in N-methylpyrrolidone (NMP) as an insoluble green powder. An equivalent amount of tripropylamine was then added as a complexation agent for the dopant (i.e. toluene sulfonic acid) . The green solid turned blue as soon as the amine was added, and then became soluble, giving a deep blue particle-free solution.
The intrinsic viscosity of the polyaniline in the solution was 0.53 dl/g which was comparable to that obtained for this polymer in a concentrated sulfuric acid solution (0.55 dl/g). This result indicated that the above poly(anilinium tosylate) solution was a true solution.
Poly(anilinium tosylate) coatings on various substrates have been successfully prepared from the above solution. Although the coatings were originally blue and non-conductive, they turned green and
conductive after the complexed amine was volatilized away.
Poly(anilinium tosylate) (2g) obtained in Example 1 was dissolved in 150 ml of N-methylpyrrolidone (NMP) containing 2 ml of tripropylamine (NPr3). The
resultant solution was filtered with a glass sintered filter to remove trace amounts of insoluble particles. The filtered solution was then slowly evaporated in a flat-bottom dish at 60 to 70ºC under dynamic vacuum. A free standing film 120 microns thick was obtained. The conductivity of this film was 0.005-0.01 Scm-1 using the four-in-line probe method, which is at least 5 orders of magnitude higher than that of the undoped polyaniline film.
The conductivity of this film can be further increased by either heating or re-doping to accelerate the removal of the complexed amine. The conductivity was 0.56 Scm-1 after re-doping for 2 days with a 20 wt% toluene sulfonic acid aqueous solution. The
conductivity was 3 Scm-1 after redoping with 1 N HCl for 1 hr. EXAMPLE 7
A series of experiments were carried out to assess the solubility of various doped polyanilines in
N-methyl pyrrolidone (NMP) and a mixture of NMP and tri-n-propyl amine (NPr3) using the procedure of
Examples 5 and 6. Poly(anilinium tosylate) was
prepared by the procedure described in Example l.
Poly(anilinium dihydrogen phosphate) and poly(anilinium trifluoromethanesulfonate) were prepared by the
procedure of Example 1, except that toluene sulfonic acid was replaced with phosphoric acid and
trifluoromethanesulfonic acid, respectively.
Poly(anilinium methanesulfonate), poly(anilinium benzene disulfonate), poly(anilinium polystyrene sulfonate) were prepared from poly(anilinium tosylate) by anion exchange with aqueous solutions of methane sulfonic acid, poly(styrene sulfonic acid) and
benzenedisulfonic acid, respectively. Poly(anilinium chloride) was prepared according to the procedure described by A. MacDiarmid et al.. Synthetic Metals. Vol 13, p 193 (1986). The solubility of these
polyanilines was evaluated in NMP and NPr3. The results are set forth in the following Table 3.
In Table 3, the abbreviations have the following meanings:
(a) "I" means insoluble,
(b) "S" means soluble, and
(c) "VS" means very soluble TABLE 3
Doped Polyaniline Solubility
NMP NMP/NPr3 poly(anilinium tosylate) I VS poly(anilinium dihydrogen phosphate) I S poly(anilinium-trifluoromethanesulfonate I S poly(anilinium methanesulfonate) I VS poly(anilinium benzenedisulfonate) I VS poly(anilinium polystyrenesulfonate) I S poly(anilinium chloride) I S
A conducting polymer gel of poly(anilinium
tosylate) can be prepared by dissolving 3.75 g of poly(anilinium tosylate) obtained in Example 1 in a solvent mixture containing 35 ml of N-methylpyrrolidone and 3.3 ml of tripropylamine. The resultant blue solution is then heated at 100°C for half an hour. A viscous gel was formed after the solution was cooled to room temperature. By drawing this conducting polymer gel, a green, conductive, polymer fiber was obtained after the amine was removed by evaporation.
This conducting polymer gel will also be useful for making other conducting polymer articles such as, conductive molded articles, compression molded sheets, and the like.
Calculations were carried out to suggest suitable solvents for use with unsubstituted undoped polyaniline using group additive contributions for determining individual components of the Hildebrand Parameter (d). In the representations of Hansen, the following nomenclature is used
(1) d is the Hildebrand Parameter (units: MPa) and is related to the Hansen Parameters (dd, dp, dh) as follows: d2=dt 2=dd 2+dp 2+dh 2
(2) dd is the contribution from dispersion
(3) dp is the contribution from polar interactions.
(4) dh is the contribution from hydrogen bonding interactions.
These components of d can be estimated from tabulated group molar attraction contributions from dispersion interactions (Fd), polar interactions (Fp) and from the cohesive hydrogen bonding energy (Uh). This analysis led to the estimate for the solubility parameter of the undoped (base) form of polyaniline given below: dd = 18.5 MPa
dp = 4.1 MPa
dh = 7.4 MPa
d = (dd 2 + dp 2 + dh 2) = 20.3 MPa Estimate of the Hildebrand Parameter based on group contributions to the heat of vaporization gave d = 23.8 MPa . Solvents which dissolve or swell undoped
polyaniline will be those whose own solubility
parameters are close to those of the polymer. Polar solvents with relatively strong hydrogen bonding are generally good solvents.
A series of potential solvents with significant polar and hydrogen bonding contributions were tested with polyaniline which had been synthesized as in
Example 1 and then undoped (neutralized) by treatment with an aqueous solution of sodium carbonate. Solvents which were demonstrated to dissolve undoped polyaniline are shown in Table 4 below and in Figure 4.
Observed Solvents For Unsubstituted
Undoped Polyaniline Base
Liquid BP(°C) gw e m d
Morpholine 129 200 .0 7.3 5.0 22.1
Piperidine 106 89 .0 5.8 4.0 19.3
Pyridine 115 80 .0 12.3 7.3 21.7
Pyrrolidine 88 - - 5.3 -
N-methyl pyrrolidone 204 - 32.0 - 23.7
Dimethylsulfoxide 189 79 .0 46.5 13.3 26.4
Dimethylformamide 158 68 .0 37.0 11.2 24.1
Dimethylhydrazine 63 - - - 19.8
Propylamine 48.5 - 5.3 4.7 19.7
Butylamine 78 - 5.3 4.7 18.6
Picoline 129 - 9.8 6.3 20.9
Aniline 182 94, .0 6.9 5.0 22.6
Quinoline 114 - 9.0 7.6 22.0
2-Pyrrolidone 245 - - 7.7 28.4
Dimethylacetamide 165 87. .0 38.0 12.7 22.7
Tetramethylurea 177 - 23.1 ' 13.0 21.7
Ethylene Diamine 117 - 12.9 6.6 25.3
Phosphoramide 235 - 30.0 17.6 23.2 m-Cresol 203 - 11.8 - 22.7
Benzyl alcohol 206 - 13.0 5.5 23.5
Benzylamine 185 - - - -
"-" means that the data is not available. The parameters listed in Table 4 are as follows: "B.P." is the boiling point in °C; "gw" is the relative sound velocity in paper wetted by the solvent (water = 100) which is a measure of hydrogen bonding capability; "e" is the dielectric constant relative to the
permittivity of free space (e0 = 8.854 × 10-12 F/m); "m" is the dipole moment in 10-30 Cm, and "d" is the Hildebrand (solubility) parameter in MPa . The data were used to establish an empirical measure of the solubility parameters which characterize the
interactions of undoped polyaniline according to a method developed by Hansen. Values of the Hansen parameters for the solvents used were taken from
"Handbook of Solubility Parameters and other Cohesive Parameters" by A.F.M. Barton (CRC Press, 1983). When multiple literature sources were found with widely differing Hansen parameter values, those sets of values were taken which were the closest to those
theoretically predicted for the given solvent. B) Hansen's Method for Solubility Parametier:
(1) In this method, the polymer is characterized as having a "solubility sphere" in a three dimensional space defined by the coordinates dd, dp, dh. The center point of the solubility sphere is (d, d,d'p,d, h) and the radius of the sphere is R.
(2) An interaction distance for a given solvent is then defined as: r=[4(dd-d'd)2 + (dp-d'p)2 + (dh-d'h)2]
(3) The polymer should be soluble in a given solvent when r<R.
C. Hansen Method with Polyaniline and Various Solvents (1) The following values of the Hansen Parameters (all in units of MPa ) were determined for polyaniline by sampling Hansen Space (i.e., the range of possible values for dd, dp and dh) with the series of solvents in Table 5.
The following Table 5 sets forth the Hansen Parameters of various liquids which have been shown to be solvents for unsubstituted and undoped polyaniline base.
Hansen Parameters of Solvents For Unsubstituted
Undooed Polyaniline Base
Liquid dd dp dh r
Morpholine 16.0 11.4 10.1 4.0
Piperidine 16.2 8.7 5.8 5.2
Pyridine 17.6 10.1 7.7 3.2
Dimethylsulfoxide 18.4 16.4 10.2 8.2
N-methylpyrrolidone 16.5 10.4 13.5 4.1
Dimethylformamide 17.4 13.7 11.3 5.3
Dimethylhydrazine 15.3 5.9 11.0 5.0
Propylamine 17.0 4.9 8.6 4.1
Butylamine 16.2 4.9 8.0 4.9
Picoline 18.2 7.8 6.8 4.0
Aniline 19.4 5.1 10.0 5.3
Quinoline 19.4 7.0 7.6 5.1
2-Pyrrolidone 19.4 17.4 11.3 9.8
Dimethylacetamide 16.8 11.5 10.2 3.2
Tetramethylurea 16.8 8.2 11.1 1.4
Ethylene Diamine 16.6 8.8 17.0 6.8
Phosphoramide 18.3 8.6 11.3 2.0 m-Cresol 18.7 4.8 13.5 5.5
Benzylalcohol 18.5 4.9 13.9 5.5 The average values of the Parameters, dd, dp and dh, in Table 5 determine the approximate center of the solubility sphere (d'd, d'p, d'h) and the span of r values determine the approximate radius.
(i) N-methylpyrrolidone (NMP) : dd=16.5, dp=10.4, dh=13.5
r=[4(16.5-17.4)2 + (10.4-8.5)2 + (13.5-10.4)2] = 4.1
Since r<R, N-methylpyrrolidone is predicted and was found to be a solvent.
(ii) Methanol: dd=11.60, dp=13.0, dh=24 r=[4(16-17.4)2 + (13-8.5)2 + (24-10.4)2] = 18.4 Since r»R, methanol should be a nonsolvent which was observed.
(ii) Methyl Ethyl Ketone (MEK) : dd=14.1, dp=9.3, dh=9.5 r=[4(14.1-17.4)2 + (9.3-8.5)2 + (9.5-10.4)2] = 6.7
Since r>R, methylethylketone should not be a solvent. It was found in accordance with the
prediction that although mehhylethylketone swells undoped polyaniline it does not dissolve it to a noticeable degree. (iv) Piperidine: dd=16.2, dp=8.7, dh=9.5
r=[4(16.2-17.4)2 + (8.7-8.5)2 + (5.8-10.4)2] = 5.2
Since r<R, piperidine should be a solvent which was observed.
A number of prospective solvents were examined and found to be non-solvents for undoped polyaniline.
These non-solvents are summarized in the following Table 6 along with the predicted interaction distance (r) of the Hansen Method. TABLE 6
Non-Solvents of Polyaniline Tosylate and Polyaniline Base Non-Solvents
Non-Solvent gw mp d dd
Acetonitrile -1 11.2 24.4 15.3
Dipropylamine - - 16.3 14.0
Triethylamine - 2.2 15.3 14.6
Tributylamine - 2.3 15.9 15.1
Diisopropylamine - - 15.2 13.8
Cyclohexanone 38.0 9.3 20.2 17.7
Methylene Chloride - 5.0 20.2 13.4
Chloroform - 6.2 18.7 11.0
Methylethylketone 31.0 9.0 19.3 14.1
Tetrahydrofuran 32.0 5.4 18.5 13.3
1,4-Dioxane 46.0 0.0 19.8 18.3
1,3-Dioxolane - - 23.2 14.8
Diethyl Ether 24.0 3.8 15.6 14.4
Methanol 72.0 5.7 29.7 11.6
Ethanol 38.0 5.6 26.1 12.6
Acetone 29.0 9.1 19.7 13.0
Water 100.0 6.1 47.9 12.3
N-Ethylaniline - - 21.5 17.1
4-Butylaniline - - 20.4 16.9
Toluene 27.0 1.2 18.2 17.9
Hexane 24.0 0.3 14.9 14.9
Nitrobenzene - 14.1 22.5 17.6
Ethyl Acetate 29.0 6.0 18.2 13.4 TABLE 6 (Cont'd.
Non-Solvents of Polyaniline Tosylate
and Polyaniline Base Non-Solvent
Non-Solvent dp dh r
Acetonitrile 18.0 6.1 11.2
Dipropylamine 6.2 5.8 8.5
Triethylamine 3.7 1.9 11.3
Tributylamine 2.8 4.0 9.7
Diisopropylamine 6.2 2.0 11.3
Cyclohexanone 8.9 5.1 5.3
Methylene Chloride 11.7 9.6 8.7
Chloroform 13.7 6.3 14.4
Methylethylketone 9.3 9.5 6.7
Tetrahydrofuran 11.0 6.7 9.3
1,4-Dioxane 1.3 7.4 8.0
1,3-Dioxolane 11.3 13.9 6.9
Diethyl Ether 2.9 5.1 9.8
Methanol 13.0 24.0 18.4
Ethanol 11.2 20.0 13.8
Acetone 9.8 11.0 8.9
Water 31.3 34.2 34.5
N-ethylaniline 10.5 7.7 3.4
4-butylaniline 9.1 6.6 4.0
Toluene 1.1 2.1 11.2
Hexane 0.0 0.0 14.3
Nitrobenzene 14.0 0.0 11.8
Ethyl Acetate 8.6 8.9 8.1
1 "-" denotes that the data is not available.
The Hansen Parameters of these non-solvents are graphically compared to those for the solvents of
Example 10 in Figure 5. The majority of non-solvents in Table 6 have as expected, r>R (R_6 from Example 10); however, there are also a few exceptions. Such
exceptions are frequently seen and can stem from inaccurately known Hansen Parameters. Reference to Table 4 reveals that solvents of polyaniline possess hydrogen bonding parameters , gw, in cases where they are known, that are greater than 68. The only
non-solvents with gw > 68 in Table 6 are methanol and water which both have r » R and are not expected to be solvents. EXAMPLE 12
Various amines were evaluated for their ability to dissolve the poly(anilinium tosylate) prepared in
Example 1. The experiments were conducted by mixing 2 mg of poly(anilinium tosylate) with 1 ml of amine. The results are set forth in the following Table 7.
In Table 7, the abbreviations are defined as follows:
(a) "VS" is very soluble.
(b) "S" is soluble.
(c) "SS" is slightly soluble.
(d) "I" is insoluble.
Amine Liquid Solubility triethylamine I tripropylamine I tributylamine I triisobutylamine I pyridine I
2- (methylamino)pyridine SS
1-(3-aminopropyl)-2-pipecoline S quinoline I isoquinoline I tetrahydroisoquinoline SS tetrahydroquinoline I imidazole S aniline I
N-methylaniline I diethylamine I dipropylamine I diisopropylamine I dibutylamine I diisobutylamine I dipentylamine I
2-(Ethylamino)ethanol S TABLE 7 CON'TD
Amine Liquid Solubility ethylenediamine S
1,1,3,3-tetramethyl urea I
Doped polyaniline powder was prepared as in
Example 1 and dissolved as in Example 12. The
following Table 8 indicates the correlations found for solvents of polyaniline tosylate between the physical parameters: Boiling Point (B.P.), Hydrogen Bonding (gw), Dielectric Constant (e), Dipole Moment (m), Hildebrand Parameter (d), and pKa.
Single Solvents for Polyaniline Tosylate
Solvent B.P. gw e mp d pKa Morpholine 129 200.0 7.3 5. 0 22.1 8. 3 Pyrrolidine 88 - 5.3 - 11.3
Piperidine 106 89.0 5.8 4. 0 19.3 11.1
Propylamine 48.5 - 5. 3 4.7 18.2 10.8 Butylamine 78 5.3 4.7 17.7 10.8 2-Pyrrolidone 245 - - 28.4 -
Ethylenediamine 117 12.9 6. 6 25.3 10.1 Hexamethylphosphoramide 235 30. 0 17.6 23.2 -
Benzylamine 185 - - - - 9.3
2-(methylamino)pyridine 201 - - - 2-Picoline 129 - 9.8 6.3 20.9
4-Picoline 145 - - 8.6 - 6.0
Imidazole 256 - - - - 7.1
1,1-Dimethylhydrazine 64 - - - 19.8 -
Tetrahydrofurfurylamine 154 - - Tetrahydroisoquiniline 233 - - -
1-Aminopiperidine 150 - - -
2-(ethylamino)ethanol 170 - -
"-" indicates that the data is not available.
These solvents were moderately polar with a dipole moment, mp, equal to or greater than 4.0 × 10-30 Cm and were all characterized by relatively high basicity (pK. > 6).
Using the procedure of Example 3, some Lewis base mixtures were able to dissolve poly(anilinium
tosylate), although neither of the components of the mixture were able to dissolve it by themselves. The results are set forth in the following Table 9. In Table 9, the abbreviations have the following means:
(a) "S" is soluble
(b) "VS" is very soluble
(c) "SS" is slightly soluble
Two Component Solvent Systems For Doped Polyaniline Amine Mixture solubility
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|International Classification||C08G73/00, C08L79/00, D06M13/335, D06M13/285, D06M13/282, D06M13/35, D06M13/352, D06M13/288, D06M13/51, D06M13/244, D06M15/37, D06M13/07, D06M13/256, D06M13/152, D06M13/322, H01B1/12, D06M13/292, D06M13/02, D06M13/248, C08G73/02, D06M13/325|
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