AU619521B2

AU619521B2 - Electrically conducting polymers with improved solubility

Info

Publication number: AU619521B2
Application number: AU29787/89A
Authority: AU
Inventors: Michael Feldhues; Gunther Kampf; Thomas Mecklenburg
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1988-02-13
Filing date: 1989-02-10
Publication date: 1992-01-30
Anticipated expiration: 2009-02-10
Also published as: DE3804523A1; NO890586L; DK62489D0; EP0328983A1; IL89245A; FI890623A0; NO890586D0; AU2978789A; FI890623A; IL89245A0; DK62489A; JPH01261471A; PT89689A; CN1017052B; CN1036019A

Description

a3 I" COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: 0 Ui

I

4 i ^*lia' 1 Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: HOECHST AKTIENGESELLSCHAFT Bruningstrasse, D-6230 Frankfurt/Main, Federal Republic of Germany.

MICHAEL FELDHUES, GUNTHER KAMPF and THOMAS MECKLENBURG.

EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: ELECTRICALLY CONDUCTING POLYMERS WITH IMPROVED SOLUBILITY The following statement is a full description of this invention, including the best method of performing it known to US 0 la HOECHST AKTIENGES9LLSCHAFT HOE 88/F 034 Dr. DA/gm Description Electrically conducting polymers with improved solubility It is known that heteroaromatics can be oxidatively poLymerized, for example, by anodic oxidation and in the process form electricaLLy conducting polymers which are of interest for electrical engineering, in semiconductor components, switches, screening materials, solar cells and as electrode materials in electrochemical syntheses and in reversible charge stores (cf. for example, IBM J.

:0 Res. Develop. 27, 330 (1983)).

oQo o 0 0o The crucial disadvantage of most conducting polymers known 0* 15 hitherto is that they are not fusible, cannot be processed 0 thermoplastically and, with few exceptions, are not soluble .o o in one of the usual organic solvents.

The few electrically conducting polymers which are par- 120 tially soluble in the doped state are not yet satisfactory in relation to their solubility, the long-term stability of the electrical conductivity, the thermal stability and "o the film-forming properties (cf. J. Chem. Soc., Chem.

Commun. 1985, 90 and Synthetic Metals 15, 169 (1986)).

000 Finally, solutions of electrically conducting polymers of substituted thiophenes are known which have been prepared by a process of chemically doping the dissolved neutral (undoped) polymers (cf. EP-A 203,438). However, these solutions have the disadvantage that conductive products prepared therefrom are inevitably contaminated with doping agent or reaction products thereof and adverse effects may occur in the envisaged applications.

Soluble, electrically conducting polymers which already substantially fulfill the said requirements have already also been proposed (cf. EP-A 257,573). The dipolar t- i 2 aprotic solvents described therein are, however, less well suited to some of the envisaged applications.

The object of the present invention was therefore to provide an electrically conducting material in pure form which is homogeneously soluble at least in some of the usual organic solvents and has good film-forming properties and a high thermal stability.

The invention therefore relates to an intrinsically electrically conducting polymer in the neutral (nonconducting) and oxidized (doped) form having structural units which are joined to each other by Linking in position 2 and/or position 5, composed, on the statistical average, of 15 o 0 I 60 to 100 mol-% of structural units which are derived from o 0 o at least one monomer of the formula (I) 0 0 0 on R1 R 2 a a1 wherein R represents a straight-chain or branched C 6

-C

3 0 -alkoxy group and R represents a hydrogen atom or a C 1

-C

3 0 -alkoxy group, "e n 0 to 40 mol-% of structural units which are derived from at least one monomer of the formula (II)

R

4

R

30

II),

R

3

R

6 wherein R and R denote, independently of each other, a hydrogen atom, a halogen atom, a C 1

-C

12 -alkyl group, alkoxyalkyl, arylmethyl, aryl, a C 1

-C

4 -alkoxy group or O(CH2CH20)nCH3, where n 1 to 4, or together with the carbon atoms joining them, form an aromatic ring, R and R denote, independently of each other, a hydrogen 4 i 4 _L 3 4 atom, or R together with R and the carbon atoms joining them or R together with R and the carbon atoms joining them in each case form an aromatic ring, X denotes an oxygen atom, a sulfur atom, an NH group, an N-alkyl group or an N-aryl group, 0 to 40 mol-% of structural units which are derived from at least one monomer of the formula (III) R7 R8 R9 R 1 0

R

11 H

H

o wherein S7 8 9 Soo0.15 R R R and R denote, independently of each other, a hydrogen atom, a C1-C12-alkyL group, an aryl group or a o0 o S-C3 0 -alkoxy group, Y and Z denote, independently of each other, an oxygen atom, a sulfur atom, an NH group, an N-alkyl group or 9 :°20 N-aryl group, o°0.0 R denotes an arylene group, a heteroarylene group or a conjugated system of the formula wherein p o is zero, 1, 2 or 3, 0 to 40 mol-% of structural units which are derived from at least one compound of the formula (IV) R 1 2

R

1 3

(IV

H(IV),

H

wherein R12 and R 13 denote, independently of each other, a hydrogen atom, a halogen atom, a C 1

-C

12 -alkyl group, a C1-C30alkoxy group, a C1-C12-acylamino group or a C1-C12-acyloxy group, 14 R denotes a halogen atom, a C1-C 12 -alkyL group, a

C

1

-C

3 0 -alkoxy group, a C 1

-C

12 -acylamino group, a C1-C12 acyl group or a C1-C12-acyloxy group, and X has the meaning specified above.

-4- The invention furthermore relates to a process for preparing the intrinsically electrically conducting polymer by oxidative chemical or electrochemical polymerization of at least one monomer of the formula optionally together with one or more comonomers of the formulae (II), (III) or (IV).

The polymers according to the invention contain structural units which are derived by linking at least one monomer of the formula below

R

1

R

2 iy~oap(I), 0 o 0 0 00a H H 15 in position 2 and/or position o 000 R being a straight-chain or branched C 6

-C

30 prefer- 0 o ably C 8

-C

22 and, in particular, C 10

-C

16 -aLkoxy group.

a 02 R 2 is, in particular, a hydrogen atom or a C 1

-C

3 0 preferably C 1

-C

22 and, in particular, C 6

-C

12 -akoxy group.

0 Examples of representatives of the formula are 3-hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene, 3-nonyoxythiophene, 3-decyloxythiophene, 3-undecyloxythiophene, 3-dodecyloxythiophene, 3-tetradecyoxythiophene, 3-pentadecyloxythiophene, 3-hexadecyloxythiophene, '00#0 3-octadecyloxythiophene, 3-eicosyloxythiophene, 3-docosyl- .0014: oxythiophene, 3-C2'-ethylhexyloxy)thiophene, trimethyLpentyLoxy)thiophene, 3,4-dihexyloxythiophene, 3,4-dioctyoxythiophene, 3,4-dinonyoxythiophene, 3,4didodecyloxythjophene, 3-methoxy-4-pentyloxythiophene, 3-hexyLoxy-4-methoxythiophene, 3-methoxy-4-nonyloxythiophene, 3-dodecyloxy-4-methoxythiophene, 3-docosyloxy-4methoxythiophene, 3-ethoxy-4-pentyoxythiophene, 3-ethoxy- 4-hexyloxythiophene, 3-butoxy-4-dodecyoxythiophene, 3-(2'-ethyhexyloxy)-4-methoxythiophene.

The polymers according to the invention contain preferably 8 to 150, in particular 11 to 100 structural units. The amount of the structural units which are derived from at i i 5 least one monomer of the formula is, on the statistical average, 60 to 100 mol-%, preferably 90 to 100 mol-% and, in particular 95 to 100 mol-%, based on the structural units present in the undoped polymer.

The monomers of the formulae (III) and (IV) are suitable as comonomers for the monomers of the formula For example, mention may be made here of compounds of the formula (II) o o o o 0 0 0 1 0 0 o o 0Q o o0o 0 00 20 00 0 o 0o a 00 0D 0 Rd R

)X

(II),

R

3

R

R and R being, independently of each other, a hydrogen atom, a halogen atom, a C 1

-C

12 preferably C 1

-C

4 -alkyL group, an alkoxyalkyl group, preferably alkoxymethyl, an arylmethyl group, preferably benzyl or thienylmethyl, an aryl group, preferably phenyl or thienyl, a C 1

-C

4 preferably C 1

-C

2 -alkoxy group or -0(CH 2

CH

2 0)nCH 3 where n 1 to 4, preferably 1 or 2, or form, together with the carbon atoms joining them, an aromatic ring, preferably a benzene, thiophene or pyrrole ring.

R

3 and R are, independently of each other, a hydrogen atom or in each case form an aromatic ring, preferably a 4 5 benzene, thiophene or pyrrole ring, with R or R together with the carbon atoms joining them.

0000 o 6 e f* X denotes an oxygen atom, a sulfur atom, an NH group, an N-alkyl group, preferably N-C 1

-C

4 -alkyl, or an N-aryl group, preferably N-phenyl.

Pyrrol, 3-chloropyrrole, 3-methylpyrrole, 3,4-dimethylpyrrole, N-methylpyrrole, thieno[3,2-b3pyrrol, carbazol, thiophene, 3-methylthiophene, 3-octylthiophene, 3,4-dimethyithiophene, 3,4-diethylthiophene, 3-(methoxyethoxymethyl)thiophene, 3-(methoxyethoxyethoxymethyl)thiophene, 3-methoxythiophene,

I

-6 -I 3-ethoxyth jophene, 3-propoxyth iophene, 3-butoxyth jophene, 3-(methoxyethoxy) thiophene, 3-(methoxyethoxyethoxy) th jophene, 3-methoxy-4-methyLth iophene, 3-ethoxy-4-methyLthiophene, 3-butoxy-4-methyL th iophene, 3-ethyL--4-methoxyth jophene, 3-butyL--4-methoxyth iophene, 3-dodecyL-4-methoxyth iophene, 3,4-dimethoxyth iophene and thieno[2,3-blthiophene, dithieno[3,2-b;2' ,3'-djthiophene, dlibenzothiophene, and isothianaphthene are suitable.

Furthermore, suitable as comonomers for monomers of the formula are those of the formula (III).

7. 8 7 9 8 "00 0 hyroe atm a\lC2,peea~ lC-~y rua 0 Y: and Z Rdndt Rn arex idenen tlym, f etmach otHr up 00 a 0- y hyroenao, C 1

-C

12 preeraly C4-C-Lkyola g-roup a '06 0- h n L 0 aryl preferab lypey rthey raC 1

C

0 ,pe an 1 standys gorup~, preferab N-C-C 4 alyLe, or an Naryl ~000@~ Lene, preferably thienyLene, furanyLene, pyrroLyLene or a system of the formula CCH=CH)p, where p 1, 2 or 3.

In particular, 1,2-di(2-thienyL)ethene, 1,2-di (3-methylthien-2-yL )ethene, 1,2-di C2-furanyL)ethene, 1-(2-furanyL)- 2-(2-thienyL)ethene, 1,4-di (2-thienyL)buta-1,3-diene, 1,4-di(2-thienyL)benzene, 2,5-li (2-thieriyL)thiophene (terthienyL), 2,5-di (2-thienyL)pyrroLe, 2,2'-dithiophene, 3,3' -dimethyL-2,2 '-bithiophene, 3,3'-dimethoxy-2,21'-bi thiophene, 3,41-dimethoxy-2,2 '-bithiophene, 4,4'-dimethoxy- 2,2 '-bithiophene, 3,3'-dihexyLoxy-2,2 '-bi thiophene, 4,4' didodecyLoxy-2,2 '-bithiophene, and 3-dodecyLoxy-4'-methoxy-2, 2 '-bi th jophene are suitable.

The amount of the structural units which are derived from monomers of the formula (II) is, on the statistical average, 0 to 40 mol-Z, preferably 0 to 10 mol-%. The structural units derived from monomers of the formula (II) are present, on the statistical average, in an amount of 0 to 40 mol-%, preferabLy 0 to 10 mol-%.

Furthermore, the terminal groups of the poLymers according to the invention can be formed from structural units of the monomers of the formula (IV) which may be added to the monomers of formula to modify the degree of polymerization and the physical properties.

0g 0 00 0 040 0 0 00 0 0 00 00 C 00 C Q-0.

0 0 c 0 oC 0 0o 0 0' 4 15

R

1 2

R

1 3 rx

(IV)

C 12 13 R and R are, independently of each other, a hydrogen atom, a halogen atom, preferably chlorine or bromine, a 020 C 1

-C

1 2 preferably C 1

-C

4 -aLkyL group, a C 1

-C

30 pre ferably C 1

-C

12 -akoxy group, a C 1

-C

12 -acyLamino group, preferably acetylamino, or a C 1

-C

12 -acyLoxy group, preferably acetyloxy.

R 14is a halogen atom, preferably chlorine or bromine, a

C

1

-C

12 preferably C 1

-C

4 -aLky group, a Cl-C 3 0 preferably C 1

-C

12 -alkoxy group, a C 1

-C

12 -acyamino group, preferably acetylamino, a C 1

-C

12 -acyL group, preferably acetyl, or a C 1

-C

12 -acyoxy group, preferably acetyloxy.

X has the meaning specified above.

Examples of compounds of the formula (IV) are 2-bromothiophene, 2-chlorothiophene, 2-methylthiophene, 2-dodecylthiophene, 2-methoxythiophene, 2-hexyloxythiophene, 2-dodecyloxythiophene, 2-acetylaminothiophene, 2-bromo-3methoxythiophene, 2-bromo-4-methoxythiophene, 2-chLoro-3methylthiophene, 2,3-dimethylthiophene, 2,4-dimethylthiophene, 2,3-dimethoxythiophene, 2,4-dimethoxythiophene, 3-methoxy-2-methyLthiophene, 3-hexyloxy-2-methyLthiophene, 2-methoxy-3-methylthiophene, 4-methoxy-2-methylthiophene, 8 2-acetyamino-3-methoxythiophene, 2-acetyamino-4-methoxythiophene, 2,3,4-trimethylthiophene, 3,4-dimethyL-2methoxythiophene, 2,4-dimethyl-3-methoxythiophene, 3,4dimethyL-2-dodecyloxythiophene, 3,4-dimethoxy-2-methyLthiophene, 2,3,4-trimethoxythiophene, 2-acety-3,4-dimethoxythiophene, 2-bromopyrroLe, 2-chLoropyrrole, 2-acetylpyrrole, 2-chLoro-3-methyLpyrrole, 2-bromo-3,4-dimethytypyrrole, 2-methyLfuran, 2-methoxyfuran, and 2,3,4-trimethyfuran.

Owing to the substitution in position 2, the compounds of the formula (IV) have a chain-terminating action. As a rule, the proportion of them is 0 to 40 mol-%, preferably a U* less than 10 mol-%.

0'4 o a0 a o a 15 The above comonomers of the formulae (III) and (IV) q can also be used in mixtures with each other. The preparation of the monomers of formula and of the comonomers of the formulae (III) and (IV) is known from S270 the prior art or is described in the German Patent AppLication P 3,804,522.2.

In the oxidized form, the soluble, electrically conducting polymers contain a appropriate number of anions to compensate for the positive charges. These are preferably the anions *a of the conducting salt or of the oxidizing agent which o q was used in the preparation process. As examples of suitable anions, mention may be made here of: BF 4

PF

6 PO AsF 6 SbCL6, SO4 HS04-, alkyL S0 3 perfluoroalkyl-S03-, aryl-S0 3

CL-,

13-, FeCL 4 FeE(CN) 6 3 If the thermal stability is dispensed with, CL047, 104-, and N0 3 are also suitable. According to the invention, BF 4

PF

6

CF

3 S0 3 and p-toluenesulfonate are preferred. Mixtures of the above-mentioned anions introduced into the polymer may also be present. The number of these anions based on the number of the monomer units is for the most part 10 to preferably 15 to 4.L; I i i io 000 0 00 00 0 00 00 0 0c 0 0 0I 0* 0.00 o 0.

00 0) 00 9 The polymers according to the invention are prepared by oxidative polymerization, preferably by eLectrochemicaL anodic polymerization of monomers.

The polymers according to the invention may be prepared, for example, by the action of electron acceptors on the monomers of the formula optionally together with comionomers of the formulae (III) and SuitabLe oxidizing agents which at the saie time also act as doping agents for the polynomers are, for example, 12, AsF 5 SbCL 5 MoCL5, FeCL 3 Fe(CL0 4 3 Fe(BF 4 3 Fe(CF 3

SO

3 3 Fe(lI) p-toluenesulfonate and NO and N02' salts such as

NOBF

4

NOPF

6 NOAsF 6 NOSbF 6

NOCF

3

SO

3

NO

2

BF

4

NO

2

PF

6 and aryldiazonium salts, such as, for example, benzenedia- 115 zonium tetrafluoroborate.

The molar ratio of oxidizing agent to monomer is for the most part 2:1 to 5:1. If a solution is employed, the concentration of the oxidizing agent is, in gen- 20 eral, between 0.1 and 1.5 mol per dm 3 of solvent.

To modify the properties of the conducting polymers produced, the presence of a further inert salt during the polymerization may be of advantage since the anions contained in said salt may be incorporated into the conduct- S ing polymer. Mention may be made here, for example, of tetrafluoroborates, hexafluorophosphates, hexafluoroarsenates, hexafluoroantimonates, hexachLoroantimonates, hydrogen sulfates, perfluoroalkysufonates, p-toluene sulfonates and perchlorates. At the same time, tetrafluoroborates, hexafluorophosphates and trifluoro-methanesulfonates are preferred. Mixtures of these salts may also be used. In addition to the alkaline-earth-metat cations and H in particular, the alkali-metal cations, preferably Li+ and Na are suitable as cations for the salts. Cations of the type R 4 N or R 4 P wherein the radicals R in each case denote, independently of each other, hydrogen, C 1

-C

12 alkyl radicals, cycoaiphatic or aromatic radicals are found to be particularly beneficial. The ratio of the 00 0 0, QU 00 0~n 0000 00404 10 anion equivalents added via the salt to the anion equivalents added via the oxidizing agent is 0.1 to 100.

The chemical polymerization may be carried out in the gas phase or in the liquid phase of the monomer and also in an emulsion or suspension. In most cases it is, however, advantageous to use an aprotic organic solvent for the monomer, such as, for example, acetonitrile, nitromethane, propylene carbonate, sulfolane, dichloromethane, chloroform, and tetrahydrofuran. It is not necessary, but of advantage, if the oxidizing agent is also soluble in the solvent.

0 0 o A variant of the chemical polymerization process is to o a 15 dissolve or suspend the oxidizing agent in a polymer matrix and to add the monomer via the gas phase. The poly- S o merization then takes place on and in the polymer matrix.

Most soluble, film-forming homo- and copolymers, such as, for example, polyvinyl acetate, polyvinyl alcohol, polyo 20 methyl methacrylate, and ethyLene/vinyl acetate copolymers o 0 o are suitable as matrix polymers. The content of oxidizing agent in the matrix polymers is usually 5 to 50 by weight.

The chemical polymerization is preferably carried out at room temperature. The temperature may, however, also be varied in a fairly large range which is limited in the downward direction by the solidification point and in the upward direction by the boiling point or decomposition point of one of the components and is for the most part in the range from -60 to 80 0 C, preferably -20 to 50 0

C.

The greatest yields are, in general, achieved with a temperature of -10 to 40 0

C.

Particularly advantageous is the elactrochemical preparation of the polymers according to the invention by anodic polymerization of the monomers of the formula optionally together with comonomers of the formulae (II), (III) or (IV) in an electrolyte solvent in the presence of a conducting salt.

A i 1~14~r~- Llll~ 11 The anode is composed of one of the usual materials which are stable under the conditions of anodic polymerization, preferably of noble metals, in particular, platinum and gold, or carbon, in particular pyrolytic carbon. In addition to the i-ode material, the surface and geometry of the anode used is of importance since these determine to a considerable extent the degree of polymerization and consequently the properties of the products produced. Thus, it is of advantage to choose a form of electrode which offers a large surface with many cavities. For the purpose according to the invention anodes which, owing to their geometry, enclose a large internal volume, such as, for example, gridtype, sponge-type, fabric-type, honeycomb-type and felt-type forms in whose cavities good deposition of the products 15 formed is possible are found to be particularly suitable.

Examples of this are single-layer and multi-layer grids of platinum or platinum/rhodium alloys, hard and soft felts, and also single-layer and multi-layer carbon fiber fabrics.

Preferably an arrangement of the anodes with parallel align- 20 ment to the cathode is chosen. If two such anodes are used, they are situated at the same distance in front and behind the cathode.

0 0 04 0 o o 00a 0049 r a s o ad 0 00 00 0 00 0r The cathode is composed of one of the usual electrode materials, such as, for example, platinum, gold, nickel, copper, silve.r, graphite or glassy carbon, preferably of stainless steel. It may be used in the form of plates, metal sheets or grids and is, in general, arranged parallel to the anode. If two cathodes are used, they are situated at the same distance in front of and behind the anode. In order to prevent a short circuit, the cathode may be separated from the anode by means of a spacer which is composed, for example, of an inert plastic grid.

In order to make the deposition of the soluble, electrically conducting polymers according to the invention on the anode possible in good yield, in contrast to the usual electrolysis conditions, there must be no fairly vigorous stirring and no fairly vigorous flow. The 12 otherwise diffusion-controlled mass transport of the monomers to the anode may be assisted by intermittent stirring of the electrolyte or by slow continuous or intermittent flow of the electrolyte or slow continuous or intermittent movement of the electrodes. The chosen velocity of flow of the electrolyte relative to the anode is, in general, less than 1 cm/s. The voluminous anodes described above which enclose a large space element of the electrolyte promote the mass transfer as a consequence of the short diffusion paths and may make it possible to conduct the reaction completely without stirring or flow.

The electrochemical polymerization of the monomers or of o 15 the monomer mixtures is carried out in one of the usual electrolyte solvent systems which must be stable under o the conditions of the electrochemical polymerization and have an adequate solubility for monomer and conducting salt. Preferably, use is made of dipolar aprotic sol- 20 vents, such as, for example, acetonitrile, benzonitrile, Spropylene carbonate, nitromethane and sulfur dioxide, and also mixtures of these solvents, optionally also with o"o other solvents which are stable under the conditions of the electrochemical polymerization, such as, for example, dimethylformamide, N-methylpyrrolidinone, dimethyl sulfoxide, dichloromethane and tetrahydrofuran. An addition of less than five percent of a polar protic solvent, such as water, methanol or the acid on which the conducting salt is based may sometimes be of advantage.

As conducting salts which promote charge transport during the electrochemical polymerization and whose anions are incorporated in the polymers and may affect the properties thereof, such as thermostability solubility and electrical conductivity, use is made of the compounds which are usual per se. Mention may be made here, for example, of tetrafluoroborates, hexafluorophosphates, hexafluoroarsenates, hexafluoroantimonates, hexachloroantimonates, hydrogensulfates, perfluoroalkylsulfonates, p-toluene ;uc 13 suLfonates, and perchLorates. At the same time, tetrafLuoroborates, hexafluorophosphates and trifluoromethanesulfonates are preferred. Mixtures of these conducting salts may also be used.

Suitable cations for the conducting salts are, in addition to the aLkaline-earth-metal cations and H in particular the alkali-metal cations, preferably Li+ and Na+. Cations of the type R 4 N or R 4 P wherein the radicals R in each case denote, independently of each other, hydrogen, C 1

-C

12 alkyl radicals, cycloaliphatic or aromatic radicals, are found to be particularly beneficial. The quantity of conj ducting salt is, in general, between 0.01 and 1 mol, pre- Sferably 0.05 and 0.5 mol per dm of solvent.

S The concentration of monomer, which is important for the degree of polymerization of the polymers according to the invention, is 0.01 to 5 mol, preferably 0.05 to 1 mol of monomer per dm 3 of electrolyte solvent. In comonomer ,e 20 mixtures, the proportion of the monomers according to formula is, in general, greater than 60 mol-%, S preferably greater than 80 mol-% and, in particular, S, greater than 95 mol-%, based on the total quantity of monomers.

The electrochemical polymerization is preferably carried out at room temperature. The temperature may, however, S also be varied in a rather large range which is limited in the downward direction by the solidification point and in the upward direction by the boiling point of the electrolyte solvent system and is, for the most part, in the range from -60 to 80 0 C, preferably -20 to 50 0 C. The greatest yields are achieved, in general, at a temperature of -10 to 400C.

The electrolysis time depends on the electrolyte system used, the particular electrolysis conditions and, in particular, the quantity of monomers used. Usually, the electrolysis time is 1 to 12 hours, preferably 2 to 8 hours.

Ui 14 The electrochemical polymerization may be carried out in the usual cells or electrolysis apparatuses. Simple electrolysis apparatuses, for example, comprising an undivided cell, two or more electrodes and an external current-voltage source are very suitable. However, divided ceLLs with membranes or ion exchanger membranes or those with reference electrodes for determining the potential precisely may also oe used. The measurement of the current consumption is expedient since this makes it possible to estimate the quantity of monomer already consumed. An electrolysis apparatus in which the cathode is flatly formed at the bottom and the anode is fed in the S form of a strip with constant advance through the elec- Strolyte or rotates in the form of a cylinder only partly immersed in the electrolyte makes it possible to conduct 0 4 the process continuously.

0a 0 Any direct current voltage source which supplies a sufficiently high electrical voltage is suitable as currentvoltage source for operating the electrolytic cell in a e which the process according to the invention is carried out. Normally, the electrochemical polymerization is run 6" with a voltage of 0.1 to 100 V, preferably in the range from 1.5 to 30 V. Values in the range from 0.0002 to mA/cm preferably in the range from 0.001 to 10 mA/cm of specific anode surface have been found to be beneficial and advantageous for the current density.

To isolate and purify the soluble polymers, the crude pro- 30 ducts of the chemical or electrochemical polymerization (possibly together with the anode which serves as carrier) are freed from conducting salts, monomers and adhering contaminants by washing with solvents in which the respective polymers are insoluble, such as water, methanol, ethanol, possibly acetonitrile and pentane. The prepurified products (possibly with the carrier) are then digested in a solvent in which the conducting polymers according to the invention are soluble. Any contaminants suspended in the solution are then separated off by means of known 15 methods, such as filtration, centrifuging and decanting, and the pure polymers are then obtained by evaporation of the solvent. Yields of about 50 to 80% are possible using the process according to the invention.

In contrast to the electrically conducting polymers in powder or film form which are obtained by chemical or electrochemical oxidation of substituted thiophene derivatives, the polymers according to the invention are completely and reversibly soluble in many organic solvents in particular even in the oxidized, i.e. electrically conducting form with a degree of doping of at Least 10% and differ from the conducting polymers hitherto known in their structure, their o.properties and also in their possible uses.

o 449 SSuitable solvents for the polymers according to the invention are the usual organic solvents or solvent mixtures o which have a Hansen p value of Less than 8.5 (cal/ccm) 2 and a Hansen 6 H value of less than 6.5 (cal/ccm)1/2 as o 20 Hansen solvent parameters (cf. Barton, Handbook of Solubility Parameters and other Cohesion Parameters, CRC Press, o" 1983, pages 153-161), such as toluene, xylene, tetrahydroo a naphthaline, chlorobenzene, dichloromethane, chloroform, 1, 2-dichloroethane, 1,1,1-trichloroethane, trichloroethene, tetrachloroethene, diethyl ether, diisopropyl ether, tert- .ooo butyl methyl ether, tetrahydrofuran, 2-methyltetrahydro- 0446 furan, methyl ethyl ketone, diethyl ketone, methyl isobutyl 0 ketone, diisopropyL ketone, diisobutyl ketone, diethylamine, diisopropylamine, butyl acetate, preferably toluene, o-xylene, dichloromethane, tert-butyl methyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, methyl isobutyl ketone and diisobutyl ketone. In the case of solvent mixtures, which may also contain nonsolvents, the resulting values should be calculated in the manner specified in the literature. Preferably, solvents or solvent mixtures are used whose S value is less than 5.5 (cal/ccm) 1 2 and whose SHvalue P 1/2 is less than 5.0 (cal/ccm) The values of a few suitable solvents are given below (the values are listed in Barton, 1;

;'T

16 Handbook of Solubility Parameters and other Cohesion Parameters, CRC Press, 1983, pages 153-161): S (cal/ccm) 1 /2 -H (cal/ccm) 1 2 Toluene 0.7 o-Xylene 0.5 Dichloromethane 3.1 1,1,1-Trichloroethane 2.1 Diethyl ether 1.4 Tetrahydrofuran 2.8 3.9 Methyl isobutyl ketone 3.0 Diisobutyl ketone 1.8 SButyl acetate 1.8 3.1 o Depending on the solvent, at Least 0.1 g, preferably at o0 Least 1.0 g of electrically conductinq polymers may be oo cm 3 dissolved in 100 cm of solvent.

The electrical conductivity of the soluble polymers is -4 -3 to 100 S/cm, preferably 10 to 10 S/cm.

0 a"o The UV/VIS/NIR spectrum of the polymers shows an intensive absorption in the range from 400 to 3200 nm, in particular in the range from 500 to 1800 nm. The thermal stability of the polymers according to the invention is high.

This is shown, for example, by the fact that a reduction of a 00 the weight by 10 occurs only at temperatures above 200 C.

o 4 The particular properties which distinguish the polymers according to the invention from the known conducting polymers make it possible to use them also for applications for which a solubility and consequently processability is necessary or of advantage. Mention may be made here of the addition to commercially available polymers or the application of electrically conducting layers, optionally of a defined thickness, to conducting and non-conducting materials. This process can facilitate or simplify the production of catalysts, electrical switches, semiconductor components, solar cells, screening materials, camouflage paints, panel heating conductors, special

C

17 electrodes and in particular, of conducting and antistatic foils and fibers.

The invention is explained in more detail by the examples below. Unless otherwise mentioned, the parts and percentages specified in the examples relate to the weight. The specific conductivity was determined by means of fourpoint measurement on moldings. The thermal decomposition behavior was determined by differential thermogravimetry (DTG) and differential scanning calorimetry (DSC). The purified polymers obtained in the examples were soluble in tetrahydrofuran at 25 0 C to an extent of more than 3 1.0 g per 100 cm Solutions in tetrahydrofuran exhibited an intense absorption between 500 and 1,800 nm in the S .15 UV/VIS/NIR spectrum. The average molar mass (weight 2> average) of the polymers according to the invention were determined by gel permeation chromatography (GPC) against polystyrene as a standard using the neutral (undoped) form which was obtained, for example, by electrochemical reduction at a platinum cathode at 0.3 V (against Ag/AgCl).

Example 1 4.34 parts of tetraethylammonium tetrafluoroborate, 4.53 parts of 3-nonyloxythiophene and 200 parts of acetonitrile were introduced into an undivided electrolysis cell having a cooling jacket. The cathode comprised a V2A steel metal sheet 60 mm Long and 55 mm wide. A carbon felt (weight per unit area 0.4 kg/m specific surface (BET) approx.

m 2 60 mm long, 55 mm wide and 4 mm thick was used as anode. The anode was mounted parallel to the cathode at a distance of 2 cm and separated by means of a polypropylene grid spacer. At an electrolysis temperature of 200C and an anode current of 100 mA, a cell voltage of 3 to 6 V was obtained. After half of the theoretically required amount of current, the polymer-loaded anode was replaced by a new one and the electrolysis was stopped after the theoretical amount of current had been consumed. After drying, the anodes loaded with crude product were placed in a bath containing hexane and

I

18 digested there several times for a prolonged time. After drying, the carbon felts loaded with the polymers were digested in a bath containing tetrahydrofuran until the polymers had almost completely gone into solution. The solution was filtered through a glass filter crucible of the pore size G3 and the filtrate was evaporated to dryness in a rotary evaporator. The crude product was comminuted mechanically, washed with water, dried, washed with pentane and again dried. 1.52 parts of a solid with a bluish-black gloss were obtained. The elementary analysis yielded the following values: 64.3% C, 8.4% H, 13.8% S, 5.4% F. A powder molding of the ground product had a specific conductivity of 4.8 x 10 S/cm. In the DTG, a weight loss of less than 10% was observed up to S 15 2200C. The GPC of the undoped form revealed an average molar mass of approx, 4,500.

Example 2 4.34 parts of tetraethylmmonium tetrafluoroborate, 5.36 parts of 3-dodecyloxythiophene and 200 parts of acetonitrile were introduced into an undivided electrolysis cell having a cooling jacket. The cathode comprised a V2A steel metal sheet 60 mm long and 55 mm wide. A platinum metal sheet 60 mm long and 55 mm wide was used as anode. At an electrolysis temperature of 200C and an anode current of 50 mA, a cell voltage of 3 to 6 V was obtained. After a quarter of the theoretically required amount of current had been consumed, the polymer deposited on the anode was separated mechanically and the anode reused. This process was repeated until the theoretically required amount of current had been consumed. The crude product collected was comminuted mechanically, washed with water, dried, washed with pentane and acetonitrile and dried again. The product was taken up in tetrahydrofuran, filtered through a glass filter crucible of the pore size G3 and the filtrate was evaporated to dryness in a rotary evaporator. 1.88 parts of a solid with a bluish-black gloss were obtained. The elementary analysis yielded the following values: 65.7% C, 9.0% H; 11.1% S, ~I c 19 5.3% F. A powder molding of the ground product had a specific conductivity of 1.5 x 10 2 S/cm. In the DTG, a weight loss of Less than 10% was observed up to 255 0

C.

The DSC exhibited a maximum at 350 0 C (130 The GPC of the undoped form revealed an average molar mass of approx. 5,400.

Example 3 4.34 parts of tetraethylammonium tetrafluoroborate, 5.93 parts of 3-tetradecyloxythiophene and 200 parts of acetonitrile were introduced into an undivided electrolysis o, cell having a cooling jacket. The cathode comprised a V2A steel metal sheet 60 mm long and 55 mm wide. A platinum metal sheet 60 mm long and 55 mm wide was used as 00 S°o 15 anode. At an electrolysis temperature of 200C and an o* anode current of 50 mA, a cell voltage of 3 to 6 V was obtained. After a quarter of the theoretically required o 00 amount of current had been consumed, the polymer deposited on the anode was separated off mechanically and the anode 20 was reused. This process was repeated until the theoretio0~ o cally required amount of current had been consumed. The crude product collected was comminuted mechanically, °0 washed with water, dried, washed with pentane and acetonitrile and again dried. The crude product was taken up in tetrahydrofuran, filtered through a glass filter crucible of the pore size G3 and the filtrate was evaporated i to dryness in a rotary evaporator. 2.04 parts of a solid with a bluish-black gloss were obtained. The elementary analysis yielded the following values: 67.5% C, 10.0% H, 10.1% S, 4.8% F. A powder molding of the ground product -2 had a specific conductivity of 1.0 x 10 2 S/cm.

Example 4 parts of iron(III) chloride (anhydrous) were dissolved in 100 parts of acetonitrile. 1.0 parts of 3-dodecyloxythiophene were added while stirring. After stirring for 6 hours at room temperature, the polymer was completely precipitated, and it was filtered off and washed with acetonitrile. The crude product was taken up in THF, i I I_ ii 20 filtered through a glass filter crucible of the pore size G3 and the filtrate was evaporated to dryness in a rotary evaporator. The residue was washed with pentane and water and dried. 0.7 parts of of solid with a bluish-black gloss were obtained. The elementary analysis yielded the following values: 61.4% C, 8.1% H, 9.9% S, 10.1% Cl, 4.4% Fe and on the GPC (of the undoped form) the polymers consist to an extent of over 90% of 10-40 monomer units.

A powder molding of the ground product had a conductivity of 4 x 10 4 S/cm. In the DTG, a weight Loss of less than 10% was observed up to 2000C.

oa Examples 5-9 S4.34 parts of tetraethylammonium tetrafluoroborate, the 0o 3-alkoxythiophene and 200 parts of acetonitrile were in- 0oo0 o troduced into an undivided electrolysis cell having a cooling jacket. The cathode comprised a V2A steel metal sheet 60 mm Long and 55 mm wide. An 8-layer grid 60 mm long and 55 mm wide of platinum/rhodium (95:5) wire with I 20 a diameter of 0.07 mm was used as anode. At an electrolysis 0 00 Stemperature of 200C and an anode current of 100 mA, a cell voltage of 3 to 6 V was obtained. After the theoretical amount of current had been consumed, the polymer deposited on the anode was dissolved off the anode with dichloromethane. The solution was filtered through a glass filter crucible of the porn size G3 and the filtrate was evaporated to dryness in a rotary evaporator. The crude product was comminuted mechanically, washed with water, dried, digested with acetonitrile and hexane, then 30 filtered off and dried.

Monomer Weight Weight of Electrical taken product conductivity 3-Octyloxythiophene 4.24 parts 0.17 parts 2 x 10 3 S/cm 3-Decyloxythiophene 4.80 parts 1.10 parts 3 x 10 3 S/cm 3-Undecyloxythiophene 5.08 parts 0.51 parts 3 x 10 3 S/cm 3-TridecyLoxythiophene 5.44 parts 1.10 parts 2 x 10 S/cm 3-PentadecyLoxythiophene 6.21 parts 0.28 parts 1 x 10-3 S/cm 3-Pentadecyloxythiophene 6.21 parts 0.28 parts 1 x 10 S/cm 21 The poLymers are s3 tubLe, inter alia, in dlichioromethane, tetrahydrofuran and toluene in the oxidic (doped) form.

a0 0 00 0 00d 00

Claims

2. An intrinsically electrically conducting polymer as claimed in claim 1, which is composed, on the statistical average, of 90 to 100 mol% of structural units which are derived from a monomer of the formula
3. An intrinsically electrically conducting polymer as claimed in claim wherein the polymer is completely soluble at 25C0 in the oxidized form in an organic O.s-Ct% A. A) 44 I 44 24 solvent which has a s value of less than I/2P (cal/ccm) 1 2 and a 8H value of Less than (cal/ccm) 1 2 as Hansen solvent parameters and solu- tions can be obtained which have a content of at least 0.1 g of the polymer in 100 cm 3 of the solvent at 250C.
4. An intrinsically electrically conducting polymer as claimed in claim 1, wherein solutions can be obtained at 25°C which have a concentration of at least 1 g of the polymer in 100 cm 3 of an organic solvent which has a s value of less than 5.5 (cal/ccm)1/2 and a P 1/2 g value of Less than 5.0 (cal/ccm) as Hansen soL- H vent parameters. An intrinsically electrically conddcting polymer as claimed in claim 1, which is composed of eight to 150 structural units.
6. An intrinsically electrically conducting polymer as claimed in claim 1, wherein at least one of the two end groups is composed of a structural unit which is derived from compounds of the formula (IV) R 12 R 13 (IV), wherein R 12 and R 13 are, independently of each other, a hydro- gen atom, a halogen atom, a C 1 -C 12 -alkyl group or a C1-C1 2 -a koxy group, R 14 is a halogen atom, a C 1 -C 12 -acyl group, a C 1 -C 12 -acyloxy group or a C 1 -C 12 -alkoxy group, and X has the meaning specified in claim 1.
7. An intrinsically electrically conducting polymer as claimed in claim 1, wherein R1 in formula is a straight-chain or branched C13-C22-alkoxy group and R 2 is a hydrogen atom. _1~1~ 04 0 0 00 4 *0 0 00 0 0n 400 6' 0 40 0 0 04
8. A process for preparing the intrinsically electrically conducting polymer as claimed in claim 1 by oxidative polymerization of at least one monomer of the formula optionally together with one or more comonomers of the formulae (III) or (IV).
9. The process as claimed in claim 7, wherein a chemical oxidizing agent is used. 3+ The process as claimed in claim 7, wherein an Fe salt is used as oxidizing agent in the presence of a further salt selected from the serieS compriSing tetrafluoroborates, hexafluorophosphates and trifluoromethanesulfonates.
11. The process as claimed in claim 7, wherein an Fe 3 salt dissolved or suspended in a polymer matrix is used as oxidizing agent and the monomer is brought into contact with the oxidizing agent via the gas phase.
12. The process as claimed in claim 7, wherein the poly- merization is carried out electrochemically by anodic oxidation in an electrolytic solvent in the presence of a conducting salt.
13. The process as claimed in claim 7, wherein the anode in the electrochemical polymerization is composed of a noble metal or carbon and has a grid, sponge, fabric, honeycomb or felt structure.
14. The process as claimed in claim 7, wherein tetrafluoro- borates, hexafluorophosphates or trifluoromethane- sulfonates are used as conducting salt in the electro- chemical polymerization. The use of the intrinsically electrically conducting polymer as claimed in claim 1 for adding to plastics and also for coating electrically conducting or 0000 0 0 '-I 26 nonconducting materials in order to produce cata- lysts, electricaL switches, semiconductor components, soLar cells, screening materials, camouflage paints, paneL heating conductors, special electrodes, and also antistatic foils or fibers. DATED THIS 9th day of February, 1989 4, 140 4.144 14 00 C 14 0 04 0 00 0 404 14.4 14 14 14.4 0 nO 0 0 0 14.14 ~S 14' 0 0 14 14 O 0 04 0 6 (140 O 140 ao 0 14 4444 4114 14 HOECHST AKTIENGESELLSCHAFT EDWD. WATERS SONS, PATENT ATTORNEYS, 50 QUEEN STREET, MELBOURNE. VIC. 3000.