CA2108552A1 - Method of processing neutral polyanilines in solvent and solvent mixtures - Google Patents

Abstract

This invention relates to a solution or plasticized composition comprising one or more polyanilines, and one or more solvents capable of dissolving said polyanilines.

Description

21~ 8 ~

~19q!HOD OF PROCB88ING Nl~UTRAI.
POLYANIL~:NE8 IN 80LVENq! AND I~OLVEN~I! MIXTIJREB

BACKGROUND OF THE INVENTION

l. Field of the Invention This invention relates to solutions of neutral 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, such as polyaniline. See for example, U.S. Patent Nos. 3,963,498; 4,025,463;
4,855,361; 4,798,685; 4,806,271; 4,822,638; 4,851,487;
4,798,685 and PCT WO89/01694.
Several solvents for neutral (undoped) polyaniline are known. For example, F. Wudl et al., J. Am. Chem.
Soc. 109 3677(198); U.S. Patent No. 4,913,867; A.
MacDiarmid, et al. PolYm. PreDrints, 30, 147 (1989); X.
Tang et al. Makroml. Chem. RaDid Commun., 9, 829-834;
A.&. Green and A.E. Woodhead, J. Chem. Soc. , 2388(1940); M. Angelopoulos, et al. Mol. Crvst. Li~.
CrYst. Bulietin. p 240 (1988) and M. Inoue et al.
Svnth. Met. 30, 199(1989).
S~MMARY OF THE INVENTION
One aspect of this invention relates to a solution and to a plasticized composition comprising one or more substituted or unsubstituted polyanilines; and one or more solvents capable of dissolving said polyaniline to some extent, capable of plasticizing said polyaniline or a combination thereo~. As used herein "solution" is .

... ...
~ ' ~

-. .

. .

~ ~ rj 2 2 a real solution or an ultra-fine dispersion having an average particle si~e of less than about 100 nanometers, and, as used herein, a "plasticized composition" is a poly~er or a polymer blend which is softened by incorporation of a liquid or low melting temperature solid 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 quinoid rings and imine (-N=) linkages. As used herein "neutral or undoped polyaniline" is characterized by an uncharged backbone and "polyaniline base" is a particular form of undoped polyaniline which contains at least one quinoid diimine linkage in the backbone.
Through use of the solution of this invention polyaniline can be conveniently processed into useful conductive articles of all shapes such as fibers, coatings, printings, 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 a graph showing the Hansen solubility Parameters of solvents and co-solvents for polyaniline base.
Figure 2 is a graph showing the Hansen Solubility Parameters relative to polyaniline base for solvents W O 92/18572 PC~r/US92/03022 , ~1 ~3 ~ ~ 5 2 and non-solvents.

DETAILED DESCRIPTION OF THE INVENTION
One essential ingredient of the solutions or plasticized compositions of this invention is a substituted or unsubstituted polyaniline such. Any form of substituted and unsubstituted polyaniline can be conveniently used in the practice of this invention such as those are characterized by different ratios of phenylene amine and quinone imine backbone segments, as for example leucoemeraldine, protoemeraldine, emeraldine, nigraniline and pernigraniline.
Preferred polyanilines are of the type derived from the polymerization of unsubstituted and substituted anilines of the Formula I:
rl 1~ R,;,, (~
wherein: ( Rl) 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; and R1 is the same or different at each occurrence and is selected:from the group consisting of boric acid, phosphinic acid, phosphoric acid, sulfinate salt, amido, carboxylic acid, hydroxyamino, phosphonic acid, halo, hydroxy, cyano, sulfinic acid, carboxylate salt, borate salt, phosphate salt, sulfonate, phosphinate salt, phosphonate salt, amino, sulfonic acid, nitro, amino, cyano, sulfate salt, deuterium or substituted or unsubstituted arylsulfinyl, alkoxycarbonyl, arylsulfonyl, alkylamido, dialkylamido, arylamido, SUBSTITUTE SHEET

.

:

.
.:
.

'~ X ~ S '~ ' diarylamido, alkylarylamido, 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 R2 groups together or any R1 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 ôptionally include one or more divalent nitrogen, sulfur, sulfinyl, ester, carbonyl, sulfonyl or oxygen atoms, wherein permissible substituents are one or more amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, arylamido, diarylamido, alkylarylamido, arylamino, sulfinic acid, diarylamino, alkylarylamino, phosphonic acid, sulfonic acid, phosphoric acid, boric acid, carboxylate salt, borate salt, sulfonate salt, phosphinate salt, phosphonate salt, hydroxylamino, quaternary ammonium salt, phosphate salt, sulfinate salt, phosphinic acid, sulfate salt, carboxylic acid, halo, nitro, cyano or epoxy moieties; Rl or R2 is an aliphatic moiety having repeat units of the formula:

( OCH2CH2) qOCH3, ( OCH2CH ( CH3 ) ) qOCH3 30(CH2)qCF3~ (CFz)qCF3 or (CH2)gCH3 wherein q is a positive whole number; and R2 is the same or different at each occurrence and is R1 substituents or hydrogen.
35Illustrative of the polyanilines useful in the : ; :

WO92/1~72 PCT/US92/03022 ~5~3 5 'J 2 practice of this invention are those of the Formula II:
S ~

(~)~
wherein:
R1 and R2 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 l 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 l.
Preferred for use in the practice of this invention are polyanilines of the above Formula II 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;
R1 is aryl, alkyl or alkoxy having from l 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, SUBSTlTUTE SHEE ~

.
: - , . - ~

.

8 ~

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;
R2 is the same or different at each occurrence and is a alkyl or hydrogen;
x is an integer equal to or greater than l;
y is equal to or greater than 0, with the proviso that the ratio of x to y is greater than about l; 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 Formula II
in which:
n is an integer from 0 to l;
m is an integer from 3 to 4, with the proviso that the sum of n and m is egual to 4;
Rl 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 alXyl 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 substituents;
Rz is the same or different at each occurrence and is a hydrogen;
x is àn 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 . . ~ , :
- . : . :,~

:

W092/l8572 PCT/US92/03022 2 ~ r ~ 2 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;
Rl 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;
R2 is hydrogen;
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 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 and the required degree of processibility i.e. melt processibility, solution processibility and the like. The number of aniline repeat units is pre~erably at least about 20, more preferably, at least about 30 and most preferably - :. . ~ . : ., , : , - :~ - ~

wos2/l8s72 PCT/US92/03022 2 ~ 8 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 chemically by treating aniline with a suitable oxidizing agent such as a~monium persulfate (NH4) 2S20 in excess acid such as lM HCl or can be prepared electrochemically by the electrochemical oxidation of aniline in aqueous fluoroboric acid electrolyte on a platinum foil anode.
The second component of the solution or plasticized composition of this invention is an "effective solvent". As used herein, "an effective solvent" is a solvent which has a relative dielectric lS constant of equal to or greater than about 5 (preferably equal to or greater than about 6), and a dipole moment equal to or greater than about 3.5 x 10-3 Cm (preferably equal to or greater than about 5 x 10-3 Cm) other than dimethylformamide, N-methylpyrrolidone, pyridine, and dimethylsulfoxide which is capable of dissolving a polyaniline.
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. A~l. Polvm Sci. 14, 1755 (1970). This method is based upon the relative sound velocity (g~) 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 o~ suitable solvents is the solubility parameter of the liquid, also referred to as ~ ' '''''-, - : . , '~:
. .. ~
, : ,~ : -, ' '.. ~. "~', .,' ' ~ :

W O 92/18572 P~r/US92/03022 2 i'~ i3 ~
, the Hildebrand Parameter (d). Preferred solvents havea 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 (dt), from polar interactions (dp), and from hydrogen bonding interactions (dh) In this scheme (which is disclosed in HHandbook 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 interaction (dh) ("Hansen Parameters") by the relation dZ=dd2+dpZ Idh2 -~ For example, in order to judge the suitability of a solvent for polyaniline, we have empirically determined solubility parametQrs-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 d h 5 10.4 MPa d = 22.0 NPa If we define a quantity (r) as:

r= t4(17.4-dd)2 + (8.5-dp)2 + (10.4 -db)2]

where da~ dp and d~ are the Hansen ParaoQters for a ~ ' .

~.- : . .-~ . .
:~i - ;,,: ......... .
,.. : : : ;: ;: ~ . ~ .

W O 92~18S72 PC~r/US92/03022 prospective solvent for polyaniline base, then suitable solvents are those for which r is less than about 7 MPa , more preferably less than about 6 MPa , 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 300C 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 2S0C.
Particularly preferred solvents have boiling points of less than about 200C. More preferred solvents have boiling points of less than about 150C and most preferred solvents have boiling points of from about 40C to about 100C.
Illustrative of useful solvents are alkyl alkanesulfonates such as methyl methanesulfonate;
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, and the like; nitroalkanes such as nitromethane, and the like; amides such as dimethylformamide, dimethyl thioformamide, N,N-dimethylacetamide, N-methylpyrrolidone, oxazolidone, 2-methyl-3-oxazolidone, 1,3-dimethyltetrahydro-2-pyrimidone; lactams such as capyrlactam, caprolactam and the like; organophosphorus compounds such as hexamethylphosphoramide, diethylphosphate, triethylphosphite, trimethyphosphate and the like; glycols such as tetraethylene glycol and the like; organosulfur compounds such as sulfolane, .., .
~ . , ''' ~. .', . '' .

WO92/18572 PCT/US92/0~22 methyl sulfolane, dimethylsulfite, dimethylsulfone, dimethylsulfoxide, glycolsulfite, tetraethylsulfamide and the like; aliphatic and aromatic diamines and amines such as 2-picoline, 1-aminopiperidine, pyrrolidine, piperidine, morpholine, ethylamine, benzylamine, butylamine, ethylenediamine, piperazine, pyridine, indoline, toluidine, quinoline, aniline, ethylenediamine, N,N-dimethylethylenediamine, tetrahydrofurylamine, N,N-dimethylethylenediamine, 2-methoxyethylamine, 3-methoxypropylamine 1,2,3,4-tetrahydroisoquinoline,tributylamine, dimethylamine, diet~ylamine, dipropylamine, dibutylamine, allylmethylamine, amylamine, isopropylamine, cyclohexylamine, phenylethylamine, 2-methylbenzylamine, 2-(ethylamino)ethanol, isobutylamine, tert-butylamine, 1-(3-aminopropyl)-2-pipecoline, 2,3-cyclohexenopyridine, 2-(methylamino)pyridine, 6-methylindole and the like, and other organonitrogen compounds such as dime~hylhydrazine, tetramethylurea, 1,3-dimethyl-3-imidazolidinone, 4,4-dimethyl-2-imidazoline, 3,5-dimethylisoazole.
Ethers such as tetrahydrofuran, 1,3-dioxane, dimethoxyethane and 1,3-dioxolane are also useful solvents.
Nixtures of such organic solvents can also be used as for example mixtures of 2-ethylaminoethanol and tetrahydrofuran, 2-(ethylamino)ethanol and 1,4-dioxane, tributylamine and N-methylpyrolidone, and the like.
: 30 When employing mixtures of organic solvents or an excess of the Lewis base, an average set of Hansen - Parameters can be calculated using the technigues of matrix algebra. Suitable solvent mixtures are then preferably those whose average values of dd, ~, and dh lead to a value of r which is less than about 7 MPa .

., ,. . . - ~ . ~ .
" : ; .,, ~ ~ :
~ , .: . ~, ...
,:
:. , :: .. ..

~ 12 In addition to the essential polyaniline, and solvent, the solutions and plasticized composition of this invention can include other optional ingredients which either dissolve or do not dissolve in the solution and plasticized composition. 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 and include other conventional polymers as for example, polyacrylonitrile, polyvinyl chloride, polyvinylidine fluoride, polyvinylidine chloride, polyvinyl alcohol, poly(phenylene oxide), poly(styrene), poly(l,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], polypropylene, polyethylene, and the like other conductive polymers, such as conjugated bac~bone polymers as for example poly(phenylene sulfide), polyacetylene, polyphenylene, polythiophene and the like; and other materials such as qraphite; carbon blacks; metal conductors; reinforcing fibers and inert fillers (such as clays and glass) and the like.
The proportion of polymer and solvent in the solution or plasticized composition of this invention containing the substituted or unsubstituted polyaniline homopolymer or copolymer, is 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 minimum amount of solvent as a proportion of the amount of solution is not believed to be .. :: ,: . , : , . . .: ., : ... . , . :: :
; ;: .
... : : .. , , ., .. :
, , .
, ~ ' : .; .:. :
. . .

WO92/18572 P~/US92/03022 ~, 6J ~3 U r",1 ~"

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. The maximum amount of solvant is again not critical, but it is recognized that additional solvent will lower viscosity and thereby effect processibility.
Excess solvent will also lenghten drying ti~e.
Preferably, the solvent is present in sufficient amounts to lower the viscosity of the solution to less than about 10,000 centipoise or preferably to 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 in powderéd form to a suitable solvent - such as pyrrolidine, morpholine and the like in a mixing vessel using conventional mixing means as for example shaking, ultrasonics, stirring and the like.
In use, the solution or plasticized composition can be placed in the desired configuration. As the solvent is removed, the polyaniline solidifies forming solid polyaniline in the desired configuration.
Various methods are contemplated for using the solution of the present invention. The solvent can be removed from the solution through use of any ' - . ', ..

W O 92t18572 PC~r/US92tO3022 1~ ;3 r ~, 2 ` ~

conventional solvent removal method but is removed preferably by evaporation to form a solid polyaniline.
Alternatively, the solvent can be removed by extraction with an extractant in which the solvent is 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 exa~ple, by removing volatiles from the present solution or plasticized composition spread on a surface, films of any desired thickness can be prepared. Even 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 moIding 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 .

, .~ ~ ' .: ;,. - .

WO92/1857~ PCT/US92/03022 t ~ t , ~
of undoped neutral polymer. If the additional components are volatile, then foamed or expanded cellular forms of the polymer may be formed.
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 po~ymer remaining, individual particles or shapes of non-soluble components coated or impregnated with doped polymer will be formed.
The neutral polyaniline forming the article produced from the solution of this invention can be rendered conductive by doping. 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 homopolymers or polymers to form conductive or semi-conductive polymers, as for example, those described in detail in U.S. Patent Nos. 4,442,187 and 4,321,114, and PCT WO 90/10297 and PCT WO 89/1694, which are hereby incorporated by reference.
Illustrative of useful dopant species are oxidizing dopants such as AsFs, MoOCl~, MoCl5, PCl5, POCl3, PCl3, AlCl3, NO~ and NO2~ salts (such as NOBF~, NOPF6, NOSbF6, NOAsF6, NOCH3CO2, NO2BF~, NO2PF6, NO2AsF6, NO2SbF6, and NO2(CF3SO2), HClO~, HNO3, H2SO~, benzoylperoxide, S03 , Br2, (FSO3) 2 ~ ZnCl2~ FSO3H, and Fe(III) salts (such as Fe(BF~) 3, FeBr3, Fe( CH3S03) 3, Fe(ClO~)3, FeCl3, Fe(OTs)3, and Fe(CF3SO3)3 which give rise to doped polymers , . .
`; ;~
:

WO92/18572 PCT/US92/0~22 ,, 5h~ 16 containing dopant ions such as NO3-, C~3SO3-, AlCl~-,BF4-, ZnCl~~, PCl~-, PF6-, AsF6-, SbF6-, CF3SO3-, ClO~-, OTs~, SO3 2, C6H5CO2-, CH3SO3-, FSO3-, and FeCl~~, and Cu(II) salts such as CuCl2 which may give dopant anions such as Cl- or CuCl3-.
Illustrative of other dopants are protonic acid dopants. Such dopants include inorganic acids, such as hydrofluoric acid, hydriodic acid, inorganic phosphorus acids such as phosphoric acid and the like, nitric acid, boric acid, inorganic sulfur acids such as sulfuric acid and the like. Such dopants also include organic a~ids such as 1-anthracene sulfonic acid, oxalic acid, 9-anthracene sulfonic acid, tartaric acid, 2-phenanthrene sulfonic acid, malonic acid, 3-phenanthrene sulfonic acid, succinic acid, 9-phenanthrene sulfonic acid, glutaric acid, adipic acid, trifluoromethane sulfonic acid, pimelic acid, perflourooctyl sulfonic acid, azelaic acid, perfluorooctyl carboxylic acid, sebacic acid, octyl sulfonic acid, phthalic acid, dodecyl sul~onic acid, isophthalic, cetyl sulfonic acid, terephthalic, toluene sulfonic acid, methyl phosphinic acid, dimethyl phosphinic acid, phenyl phosphonic acid, dodecylbenzene sulfonic acid, naphthalene sulfonic ~: 25 acid, benzene disulfonic acid, benzene sulfonic acid, 1,3-benzene disulfonic acid, 2,5-dihydroxy-ll4-benzene disulfonic acid, camphor sulfinic acid, naphthalene trisulfonic acid, ethylbenzene sulfonic acid, ethane sulfonic acid 1,5-naphthalene disulfonic acid, nickel phthalocyanine tetrasulfonic acid, phenyl phosphonic acid, diphenyl phosphinic acid, phenyl phosphinic acid, ortho boric acid, 3-sulfopropyl acrylate, meta boric acid, 3-sulfopropyl methacrylate, sulfamic acid, 5-sulfosalicyclic acid, trion (4,5-dihydroxy-1, 3-benzene disulfonic acid), vinyl sulfonic acid, ~, - : ~' `' . `", ', W O 92~18572 P~r/US92/03022 .
r t arsenic acid, arsenous acid, arsinic acid, arsonic acid, sulfanilic acid, 4-sulfophthalic acid, sulfoacetic acid, methyl phosphinic acid, phenylphosphonic acid, methyl phosphonic acid, methyl orange, sulfonated polystyrene, hydroboxofluoric acid, orthophosphoric acid, pyroboric acid, sulfonated poly(2-vinyl naphthalene), naphthol yellow, naphthol blue black, 1,2-naphthoquinone-4-sulfonic acid, naphthylazoxine S, l-octane sulfonic acid, pyrophosphoric acid, metaphosphoric acid, orthophosphorous acid, t-hutyl 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, 1,8-dihydroxynaphthalene-3-6-disulfonic acid, 3,6-dihydroxynaphthalene-2,7-disulfonic acid, 4,5-dihydroxynaphthalene-2,7-disulfonic acid, 6,7-dihydroxy-2-naphthalene sulfonic acid, l-naphthalene phosphoric acid, l-naphthalene sulfonic acid, 1-naphthalene-5,~-dinitro-8-hydroxy, 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 benzenephosphoric 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 suIfonic acid, l-naphthalene-7-hydroxy sulfonic acid, l-naphthalene-3-hydroxy sulfonic acid, 2-napthalene-1-hydroxy sulfonic acid, 4-phenylamino benzene sulfonic acid, 2,6-naphthalene disulfonic acid, 1,5-naphthalQne disulfonic acid, dinonylnaphthalene . - . : .
. . .
. .: , :. . :

..~

WO9~/18572 PCT/US92/03022 .;

~io~5 3Z 18 sulfonic acid, phenylboronic acid, 1,2-benzene boronic acid sulfonic acid, and 1,3-naphthalene-7-hydroxy disulfonic acid.
The amount of dopant included in the complex is 5 not critical and may vary widely. In general, sufficient dopant is included in the complex such that an amount of dopant is released from the complex on removal of the Lewis based and/or solvent from the complex and/or from the solution and/or composition 10 such that the polyaniline is doped the desired extent, usually an amount such that the polyaniline is doped to a conductivity of at least about 10-1 ohm~1cm~1. The upper level o~ conductivity is not critical and will usually depend on the type of aniline polymer employed.
15 In general, the highest level of conductivity obtained is provided without unduly adversely affecting the environmental stability of the polymer. Preferably the amount of dopant employed is sufficient to provide a conductivity of at least about 1O~5Ohm~1cm~l, more 20 preferably of from about lO~~ohm~~cm~1 to about 10+2ohm~lcm~~ and most preferably about lO~lohm~lcm~l to about 10~2ohm~lcm~1.
Examples of articles formed from non-soluble components and the present polymer solutions include 25 conductive polymer coated-housings for sensitive electronic equipment (microprocessors), infrared and microwave absorbing shields, flexible electrically conducting connectors, conductive bearings, motor or generator brushes and semiconducting junctions t 30 photoconductors, conductive traces or ground planes for electronic devices, antistatic materials for packaging electronic components, carpet fibers, tiles, or coatings for floors in computer rooms and antistatic spray finishers for plastics, and thin, optically 35 transparent antistatic finishes for C~T screens, . . .... .
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..

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aircraft, auto windows and the like.
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 H~0, 50g of aniline (0.54 mole) and 172g p-toluene sulfonic acid (0.90 mole) was added, dropwise at 15C, a solution of ammonium persulfate (153.4g in 336.5 ml X20) over a period of 40 minutes. Then the reaction was allowed to continue at 15C 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 130C 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 thi8 material was 1 Scm~1 as measured by the co-linear four-probe method. The conductivity of the moisture-saturated pellet was 20 Scm~l The yield was 78g. The intrinsic viscosity (in H2SO~, at 25C) was 0.66 dl/g. Elemental analysis of the dried green powder gave:
C:64.37(Wt%)H:4.86% N:8.59%
S:8.40%0:13.51%
Moisture: less than 0.8 wt%
~L
Poly(anilinium tosylate) tl3g) obtained from Example 1 was suspended in water at room temperature and nuetralized with excess sodium carbonate (Na2CO3). The suspension was then filtered ` . ~ ' t .

WO92~18572 PCT/US92/03022 .
,~ ~ Q g v ~ 2 and the cake was dried to yield a blue-black powder of polyaniline base.

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 A) Nomenclature ~1) d is the Hildebrand Parameter (units: MPa) and is related to the Hansen Parameters (dt, dp, dh) as follows:

d2=dt2=dd2+dp2+dh2 (2) dd is the contribution from dispersion interactions.

(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:

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dd = 18.5 MPa dp = 4.1 MPa dh = 7.4 MPa d = (dd2 + dp2 + dh2) = 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.

15 A series of potential solvents with significant polar and hydrogen bonding contributions were tested with undoped polyaniline base which had been synthesized as in Example 2. Solvents which were demonstrated to dissolve undoped polyaniline are shown in Table 1 below and in Figure 1.

:

WO~Z/~857Z PCT/US92/03022 3ia ~ 22 $ABLE 1 Observed Solvents For Unsubstituted Undoped Polyaniline Base S
Biquid BP(C) gw e m d Morpholine 129200.0 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 10 Pyrrolidine 88 - - 5.3 N-methyl pyrrolidone 204 - 32.0 - 23.7 Dimethylsulfoxide189 79.0 46.5 13.3 26.4 Dimethylformamide158 68.0 37.0 11.2 24.1 Dimethylhydrazine 63 - - - 19.8 15 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 20 2-Pyrrolidone 245 - - 7.7 28.4 Dimethylacetamide165 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 Hexamethyl Phosphoramide235 - 30.0 17.6 23.2 m-Cresol 203 - 11.8 - 22.7 Benzyl alcohol 206 - 13.0 5.5 23.5 8enzylamine 185 - - - -2-~ethoxyethylamine 90 "-" means that the data is not available.
The parameters listed in Table 1 are as follows: "B.P.~ is the boiling point in C; "gw" is the relative sound velocity in paper wetted by the - ' ',' - ; '.~
.~

W092/18572 2 i ~ 3 ~ PCT/US92/0~22 solvent (water = 100) which is a measure of hydrogen bonding capability; "e" is the dielectric constant relative to the permittivity of free space teO = 8.854 x 10-12 F/m); "m" is the dipole moment in 10-30 Cm, and "d" is the Hildebrand (solubility) parameter in MPa It was noted that in cases where it was known, the hydrogen bonding parameter, g~, was equal to or greater than 68, and the dipole moment was equal to or greater than 4.7 x 10-3 Cm. 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 by group additive techniques for the given solvent.

B) Hansen's Method for Solubilit~ Parameter:

(l) In this method, the polymer is characterized as having a "solubility sphere" in a three dimensional space defined by the coordinates da~ dp, dh. The center point of the solubility sphere is (2d'd,d'p,d'h) and the radius of the sphere is R.

(2) An interaction distance for a given solvent is defined as:

r=t4(dd-d~d)2 + (dp-d'p)2 + (dh-d",)2]

(3) The polymer should be soluble in a given solvent .

... . I

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WO92/18572 P~T/US9Z/03022 -, r' ~ ~

when r~R.

C! Hansen Method with Polvaniline 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 1.

(i) d'd=17.4 (ii) d,p=8.5 (iii) dh=10.4 (iv) R=6 (v) d=22.0 The following Table 2 sets forth the Hansen Parameters of various liquids which have been shown to be solvents for unsubstituted and undoped polyaniline base.

WO~2/18572 PCT/US92/03022 ~ ~ sJ v ~ ` 2 Table 2 Hansen Parameters of Solvents For Unsubstituted Undo~ed Polvaniline Base Liguid d~ d~ d~_ r Morpholine 16.0 11.410.1 4.0 Piperidine 16.2 8.7 5.8 5.2 Pyridine 17.6 10.1 7.7 3.2 Dimethylsulfoxide 1~.416.4 10.2 8.2 N-methylpyrrolidone 16.510.4 13.5 4.1 Dimethylformamide 17.413.7 11.3 5.3 Dimethylhydrazine lS.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 5.110.0 5.3 Quinoline 19.4 7.0 7.6 5.1 2-Pyrrolidone 19.4 17.411.3 9.8 Dimethylacetamide 16.811.5 10.2 3.2 Tetramethylurea16.8 8.211.1 1.4 Ethylene Diamine 16.6 8.8 17.0 6.8 ~examethyl Phosphoramide 18.3 8.6 11.3 2.0 m-Cresol 18.7 4.813.5 5.5 Benzylalcohol 18.5 4.913.9 5.5 The average values of the Parameters, dd, dp and dh, in Table 2 determine the approximate center of the solubility sphere (2d d, dp, d b) and the span of r values determine the approximate radius.

(2) Examples:

(i) Methano~:

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:,, ~ ; ' WO92/lB572 PCT/VS92/03022 3 r~; ~3~

~6 dd=ll.60, dp=13.0, dh=24.0 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) Methvl Ethyl Ketone (MEK!:

dd=14 .1, dp=9.3, dh=9.5 t4(14.1 17.4) + (9.3-8 5) 2 + ( 9 5 1 0 A ) 2 Since r>R, methylethylketone should not be a solvent. It was found in accordance with the prediction that although methylethylXetone swells undoped polyaniline it does not dissolve it to a noticeable degree.

(il) Pi~eridine:

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 3 along with the predicted interaction distance ~r) of the Hansen Method.

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2 ~

Non-Solvents of PolYaniline Tosvlate and Polyaniline Base Non-Solvents Non-Solvent _ _ ar _m~ d d~
Acetonitrile 11.2 24.4 15.3 Dipropylamine - - 16.3 14.0 Triethylamine - 2.2 15.3 14.6 Tributylamine - 2.3 lS.9 15.1 Diisopropylamine - - 15.2 13.8 Cyclohexanone38.0 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 Ether24.0 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 lO0.0 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 Acetate29.0 6.0 18.2 13.4 2-(Ethylamino)ethanol -1,3-Dioxane In the Table, "-" denotes that the data is not available.

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;~ 2 TABLE 3 ~cont'd) Non-Solvent d~_ dh r Acetonitrile18.0 6.1 11.2 Dipropylamine6.2 5.8 8.5 Triethylamine3.7 1.9 11.3 Tributylamine2.8 4.0 9.7 Diisopropylamine 6.2 2.0 11. 3 Cyclohexanone8.9 5.1 5.3 lo Methylene Chloride 11.7 9.6 ~.7 Chloroform 13.7 6.3 14.4 Methylethylketone 9.3 9.5 6.7 Tetrahydrofuran11.0 6.7 9.3 1,4-Dioxane 1.3 7.4 8.0 1,3-Dioxolane11.3 13.9 6.9 Diethyl Ether2.9 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-ethylaniline10.5 7.7 3.4 4-butylaniline9.1 6.6 4.0 Toluene 1.1 2~1 11.2 Hexane 0.0 0.0 14O3 Nitrobenzene14.0 0.0 11.8 Ethyl Acetate8.6 8.9 8.1 1,3-Dioxane - - -~-(Ethylamino)ethanol -In the table, "-" denotes that the data is not available.
The Hansen Parameters of these non-solvents are graphically compared to those for the solvents of Example 4 in Figure 2. The majority of non-solvents in Table 3 have as expected,~ r>R (R_6 from Example 4);
however, there are also a few exceptions. Such exceptions are frequently seen and can stem from inaccurately known Hansen Parameters. Refexence to Table 1 reveals that solvents of polyaniline possess hydrogen bonding parameters , g~, in cases where they are known, that are greater than 68. The only non-solvents with g~ > 68 in Table 3 are methanol and water which both have r ~> R and are not expected to be solvents.

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~ 3~ w Doped polyaniline tosylate was prepared as in Example l. Undoped polyaniline base was prepared as in Example 2. A few milligrams of these powdered polyanilines were added to 2 ml of the prospective solvents and solvent mixtures listed below in Table 4.

lO sOlubility of Polyaniline Base (PAni Base) and Polyaniline Tosylate (PAni tosylate) in Selected Solvents Solvent Solubility for Solubility for PAni Base PAni Tosvlate -l,3-Dioxane l,4-Dioxane 20 Tetrahydrofuran (THF) 2-Ethylaminoethanol (EAE) i s EAE/l,3-Dioxane ss EA~/l/4-Dioxane ss EAE/THF s . s In the Table, "i~ is insoluble; "s" is soluble;
and "ss" is slightly soluble.

The results obtained with 2-ethylaminoethanol in combination with selected ethers demonstrated that polyaniline base can be soluble in mixtures of solvents even when it in insoluble in the neat constituents.

: .

W092/~8572 PCT/US92/03022 ~ .., ,~
i~la^~2 Undoped polyaniline in its base form was dissolved in dimethylformamide (DMFI and filtered to give a deep blue solution. Likewise polyaniline base was dissolved in pyrrolidine to give a deep blue solution. Phenyl hydrazine was added to each solution in an amount sufficient to render the solutions very light yellow and pale brown, respectively, indicating thereby that the polyaniline base had been reduced in each case to its leuco form (poly(phenylene amine), Formula IV). No clouding or precipitate was observed after 48 hours of standing which demonstrated t~at the leuco form is also at least equivalently soluble in these solvents.

Several pieces of polyethylene terephthalate film (5 inches x 4 inches) were coated with a 1.5 wt%
solution of neutral polyaniline base in pyrrolidine by a transfer coating technigue. In this technique, polyaniline solution was homogeneously laid down on the plastic films by a metal screen roller which contained hundreds of regularly engraved cells per sguare inch.
~;~ The coated films were blue and nonconductive. After doping with an acid dopant solution, the films turned green and conductive.
When p-toluene sulfonic acid was used as the dopant, the surface resistances, measured by a disc probe (Xeithley 610S), of these films ranged from 106 to 107 ohm/sq. When dodecylbenzenesulfonic acid was used, the surface resistance ranged from 107 to lOa ohm/sq.

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Claims (9)

WHAT IS CLAIMED IS:

1. A solution or plasticized composition comprising:
(a) a substituted or unsubstituted polyaniline;
and (b) a solvent which has a relative dielectric constant equal to or greater than 5, and a dipole moment equal to or greater than about 3.5x10-30Cm, said solvent other than dimethylformamide, N-methylpyrrolidone, pyridine and dimethylsulfoxide.

2. A solution to claim 1 wherein said polyaniline is a homopolymer or copolymer comprising a substituted or unsubstituted polyaniline of the type derived from polymerizing an aniline of the formula:

wherein:
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 5; and R1 is phosphinic acid, phosphonic acid, sulfonic acid, boric acid, phosphoric acid, amino, sulfonate, borate, hydroxy, phosphonate, phosphinate, phosphate, sulfinic acid, nitro, sulfinate, carboxylic acid, halo, carboxylate, cyano, deuterium, or substituted or unsubstituted alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, alkynyl, dialkylamine, arylamino, diarylamino, alkylarylamino, aryloxy, hydroxy, alkylthioalkyl, alkylaryl, arylalkyl, aryloxy, amino, alkylthioalkyl, alkylaryl, arylalkyl, alkylsufinyl, alkoxyalkyl, alkylsulfonyl, aryl, arylthio, arylsulfinyl, alkoxycarbonyl, alkylsilane, or arylsulfonyl, wherein permissible substituents are one or more amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, phosphonic acid, sulfonic acid, boric acid, sulfinic acid, sulfinate, phosphoric acid, sulfonate, borate, carboxylate, phosphonate, phosphate, carboxylic acid, halo, nitro, hydroxy, cyano or epoxy moieties; or any two R1 substituents or any one R1 substituent and R2 substituent taken together may form substituted or unsubstitued alkylene, alkynylene or alkenylene chain completing a 3, 4, 5, 6, 7, 8, 9 or 10 membered aromatic, heteroalicyclic, heteroaromatic or alicyclic carbon ring, which ring may optionally include one or more divalent ester, carbonyl, nitrogen, sulfur, sulfinyl, sulfonyl or oxygen wherein permissible substituents are one or more amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylamino, phosphonic acid, sulfonic acid, boric acid, sulfinic acid, sulfinate, phosphoric acid, sulfonate, borate, carboxylate, phosphonate, phosphate, carboxylic acid, halo, nitro, hydroxy, cyano or epoxy moieties, or R1 or R2 is an aliphatic moiety having repeat units of the formula:

(OCH2CH2)q O-CH3, (OCH2CH(CH3))qO-CH3, (CH2)qCF3, (CF2)qCF3 or (CH2)q CH3 wherein q is a positive whole number; and R2 is the same or different at each occurrence and is R1 substituents or hydrogen.

3. A solution according to claim 2 wherein said homopolymer or copolymer is of the formula II:

wherein:
x is an integer equal to or greater than 1;
y is equal to or greater than 1, with the proviso that the ratio of x to y is greater than abut 0.5;
z is an integer equal to or greater than about 1;
n is an integer from 0 to 3;
m is an integer from 1 to 4, with the proviso that the sum of n and m is 4;
R1 is the same or different at each occurrence and is alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, amino, alkylamino, dialkylamino, arylamino, diarylamino, alkylarylaminoalkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, alkylsulfinyl, alkoxyalkyl, alkylsulfonyl, aryl, arythio, arylsulfinyl, alkoxycarbonyl, phosphinic acid, phosphonic acid, alkylsilyl, boric acid, arylsulfonyl, carboxylic acid, halo, hydroxy, phosphate, sulfonate, phosphonate, borate, phosphinate, carboxylate, nitro, cyano, sulfonic acid, phosphoric acid or aryl, alkyl or alkoxy substituted with one or more sulfonic acid, carboxylic acid, sulfinate, phosphoric acid, boric acid, sulfinic acid, halogen, nitro, cyano, epoxy, hydroxy, sulfonate, phosphate, phosphonate, phosphinic acid, phosphinate, carboxylate, phosphonic acid or borate substituents; or any two R1 groups or any one R1 group and R2 group together may form a substituted or unsubstituted alkylene or alkenylene chain completing a 3, 5, 5, 6, 7, 8, 9 or 10 membered heteroaromatic, heteroalicyclic, aromatic or alicyclic carbon ring, which chain may optionally include one or more divalent nitrogen, ester, carbonyl, sulfur, sulfinyl, sulfonyl or oxygen group wherein permissible substituents are one or more sulfonic acid, carboxylic acid, sulfinate, phosphoric acid, boric acid, sulfinic acid, halogen, nitro, cyano, epoxy, hydroxy, sulfonate, phosphate, phosphonate, phosphinic acid, phosphinate, carboxylate, phosphonic acid or borate substituents; and R2 is the same of different at each occurrence and is alkyl.

4. A solution according to claim 3 wherein m is from about 3 to about 4 and n is 0 or 1.

5. A solution according to claim 4 wherein R1 is the same or different at each occurrence and is alkyl or alkoxy having from 1 to about 30 carbon atoms and R2 is hydrogen.

6. A solution according to claim 5 wherein n is 0.

7. A solution according to claim 6 wherein z is equal to or greater than about S and x is equal to or greater than about 2, with the proviso that the ratio of x to y is at least about 2.

8. A solution according to claim 6 wherein said solvent has a volatilization temperature equal to or less than about 250°C at 760mm of Hg; a hydrogen bonding capability (gw) of greater than about 50; net Hansen parameters which satisfy the condition that the expression [4(dd-17.4)2 + (dp-8.5)2 + (dh-10.4)2] is less than about 7 MPa.

9. A solution according to claim 8 wherein said solvent is selected from the group consisting of dimethylacetamide, dimethylpropionamide, 2-pyrrolidone, capryl lactams, caprolactam, piperidine, morpholine, ethylene diamine, N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine, quinoline, 2-picoline, 4-picoline, butylamine,propylamine, aniline, 2,3-cyclohexenopyridine, 1-(3-aminopropyl)-2-picoline, tetrahydrofurfurylamine, 1,2,3,4-tetrahydroisoquinoline, dimethylhydrazine, hexamethylphosphoramide, 1,1,3,3-tetramethyl urea, m-cresol, benzylamine, benzyl alcohol, 2-methyoxy ethylamine, and 3-methoxy propylamine.