JPH05310947A - Autodoped polymer - Google Patents

Abstract

PURPOSE:To provide an electrically conductive polymer dopable and dedopable quickly, capable of maintaining stable doped state for a long period compared to conventional electrically conductive polymers. CONSTITUTION:The objective autodoped polymer made up of many monomer units with 0.01-100mol% thereof having at least one Broensted acid group in the side chain, and capable of forming sigma-electron conjugated system along the main chain.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to the field of conductive polymers. More specifically, the present invention relates to self-doping polymers in which Bronsted acid groups are covalently attached to the polymer backbone.

[0002]

2. Description of the Related Art Conventionally, metal has been used as a conductive material. As a more recent attempt, a carbon-based polymer having a wide π-conjugated system has been attracting attention. Furthermore, in the 1980s, a polysilane compound soluble in a solvent and moldable was discovered, and a polymer compound containing a silicon atom was found to have conductivity based on a σ-conjugated system. It was As a typical example thereof, J. Oreg
anometal. Chem. , 300, 327 (19
86) relates to a polysilane in which all of the polymer main chains consist of silicon atoms.

These highly conductive polymers known in the art are typically rendered conductive by an acceptor or donor doping process. In acceptor doping, the acceptor oxidizes the polymer backbone and introduces a positive charge into the polymer chain. Similarly, donor doping reduces the polymer and introduces a negative charge into the polymer chain. It is these mobile positive or negative charges introduced into the polymer chain from the outside that induce the conductivity of the doping polymer. In addition, such "p-type" (oxidation) or "n-type" (reduction) doping results in substantially all electronic structure changes after doping, such as optical or infrared absorption spectra. Induce a change.

[0004]

That is, in all of the conventional doping methods, counter ions are derived from an external acceptor or donor function. During the electrochemical cycle between neutral and ionic states, counterions must enter and exit the polymer body. It is often the case that this solid-state diffusion of externally introduced counterions is the rate-limiting step in the circulation process. It is desirable to overcome this limitation in electrochemical or electrochromic doping and dedoping operations, thereby reducing response time. An object of the present invention is to provide a conductive polymer that can be rapidly doped and dedoped, and that can maintain a stable doping state for a long period of time as compared with the conductive polymers of the prior art.

[0005]

The above-mentioned problems consist of a large number of monomer units, 0.01 to 100 mol% of which have at least one Bronsted acid group in the side chain and along the main chain. The problem is solved by a polymer compound capable of forming a σ-electron conjugated system, particularly a polymer compound in which a monomer unit having at least one Bronsted acid group in its side chain is represented by formula (1).

[Chemical 2] However, Y ₁ , Y ₂ , Y ₃ and Y ₄ are hydrogen or -R-XM.
R is a linear or branched alkyl, ether, ester or amide component having 1 to 10 carbon atoms, X is a Bronsted acid anion, and M is a positive monovalent counterion when oxidized. It is an atom that occurs. That is, the excellent properties of the polymers of the present invention result from the finding that conductive polymers can be made in a "self-doping" state, that is, counterions that impart conductivity can be covalently bound to the polymer itself. Yes, as compared to prior art polymers, there is no need to externally introduce counterions,
The diffusion-controlled step in the solid state can also be improved.

In the present invention, the term "conductivity" means the ability to transfer a charge by passing an ionized atom or an electron, and the term "conductive compound" means a compound containing or joining mobile ions or electrons. , As well as compounds that can be oxidized to contain or add mobile ions or electrons. Self-doping means that physical properties can be made conductive without using a conventional doping technique of externally introducing ions, and in the self-doping polymer of the present invention, a potential counter ion is shared by side chains of the polymer. It is combined. Bronsted acid is used to refer to a chemical species that can act as one or more proton sources, ie, proton-donors. For example, McGraw-Hill's Dictionary of Chemistry and Technical Term (3rd edition, 1984), 220.
See page. Thus, examples of Bronsted acids include carboxylic acids, sulfonic acids, phosphoric acids. The Bronsted acid group is a Bronsted acid as defined above, an anion of the Bronsted acid (that is, when a proton is removed), or a Brene compound obtained by associating the Bronsted acid anion with a monovalent cationic counterion. Means a salt of the Stead acid. The monomer unit refers to a repeating structural unit of a polymer. The individual monomer units of a particular polymer may be the same as in a homopolymer or different as in a copolymer.

The polymers of the present invention may be copolymers or homopolymers and have a backbone structure that provides a sigma electron conjugated system. An example of such a polymer backbone is polysilane composed of silicon-silicon bonds. More specifically, an alkyl group, an aryl group,
It is composed of a monomer unit having an aralkyl group and a derivative thereof in a side chain, and 0.01 to 100 mol% of the unit has at least one Bronsted acid group in the side chain and has a σ electron conjugated system along the main chain. It is a polysilane.

That is, in applications requiring high conductivity, it is usually at least 10 mol%, typically 50 to 10 mol%.
Replace 0 mol% of the monomer units. For semiconductor applications, it is common to replace less than 10 mole percent monomer units, and sometimes as little as 0.1-0.01 mole percent. Therefore, in both the homopolymers and copolymers of the present invention, it is necessary that 0.01 to 100 mol% of the polymer is a monomer unit having at least one Bronsted acid group in the side chain.

In a preferred embodiment, the present invention comprises an electrically neutral polymer given by formula (1). In order for the polymer to be conductive, it must be oxidized to remove the M component, yielding a polymer containing a zwitterionic structure.

In a preferred embodiment, for example, M may be H, Na, Li or K, and X may be CO ₂ , S.
It is preferably O ₃ or HPO ₃ , where R is a straight chain alkylene or ether group [ie — (CH ₂ ) _x — or —
(CH ₂ ) _y O (CH ₂ ) _Z − (where _x and ( _Y +
2) is 1-10. )]. In a particularly preferred embodiment, M is H, Li or Na, X is CO ₂ or SO ₃ , and R is a linear alkylene having 2 to 6 carbon atoms.

To dedope the zwitterionic form of the polymer, charge may be provided in the opposite direction to that used in the doping (alternatively, a mild reducing agent may be used as discussed above). ). The M component is moved in a polymer X ^- to neutralize the counterion. Thus, the dedoping process is as fast as the doping process.

Equation (2) represents the oxidation and reduction of the above polymers, ie the transition between the electrically neutral and the conductive zwitterionic form.

[Chemical 3] When X is CO _2, the electrochemical conversion of the above pH1~
It depends strongly pH in a range of 6 [pKa when in formula (1) X-CO ₂ and M-H is about 5. On the other hand, X is S
When O ₃ , the above electrochemical reaction is pH independent over a much wider pH range of about 1 to 14 [pKa for X-SO ₃ and MH in formula (1) is about 1]. ].
That is, the sulfonic acid derivative is charged at virtually any pH and the carboxylic acid derivative is charged only at the lower pH. Thus, by changing the pH of the polymer solution, adjusting the conductivity of the carboxylic acid derivative is easier than adjusting the conductivity of the corresponding sulfonic acid derivative. That is, the selection of a particular Bronsted acid component depends on the particular application.

The conductivity of these self-doping polymers is at least 10 ^-6 S / cm, preferably 10 ^-3 S / cm or more, more preferably 1 S / cm or more. In addition, the chain length is 100 to 10 monomer units,
The range of 000 is desirable, especially 1,000 to 10,000
A high molecular weight of 0 is preferred.

In the present invention, the method for introducing a Bronsted acid group into the polymer may be to polymerize or copolymerize a monomer having a Bronsted acid group, or to formula (1)
In, a polymer or copolymer of monomer units having no Bronsted acid group may be prepared, and then the Bronsted acid group may be introduced. It is within the skill of the art to incorporate Bronsted acid groups into a monomer or polymer.

As an example, as shown in the formula (3), N-bromosuccinamide (NBS) can be used to convert an alkyl group into a halogenated alkyl during monomer synthesis or on a polymer side chain.

[Chemical 4] The halide can then be treated with sodium cyanide / sodium hydroxide or sodium sulfite and then hydrolyzed to the carvone or sulfone Bronsted acid, respectively. This reaction is shown in formula (4).

[Chemical 5]

An example of a method for synthesizing a Bronsted acid having an ether bond group is shown in formula (5).

[Chemical 6]

The synthesis of the polymers of the present invention is described in R.S. Waist et al. Polym Sci. , Polym. Let
t. Ed. , 23, 469 (1985), a reductive coupling reaction with an alkali metal is general. In addition, for example, J. F. ACS Symp. Ser. , 360, 89 (1
Dehydrogenative coupling reaction with transition metals as described in H. 988). Sakurai et al. Am. Cle
m. Soc. , 111,7641 (1989), anionic polymerization of masked disilanes, K .; ACS Sym such as Matizawazeusky
p. Ser. , 360, 78 (1988), and reductive coupling reaction by electrochemistry are known, but are not particularly limited.

The polymers of the present invention offer unique advantages over conventional conductive polymers used as electrodes in electrochemical cells. Since the counterion is covalently attached to the polymer, battery capacity is not limited by electrolyte concentration or solubility. This means that in optimized batteries the total electrolyte and solvent can be significantly reduced and the energy density of the batteries thus obtained can be increased.

Self-doping facilitates kinetic ion transport and allows for rapid charging, discharging and fast electrochromic switching. Electrodes made with the polymers of this invention can be made from these polymers or conventional substrates coated with these polymers. Conventional substrates include, for example, indium tin oxide coated glass, platinum, nickel, palladium or any other suitable electrode material. When used as an electrode, the internal self-doping of the polymer is expressed by the formula (2)
Results in a transition represented by.

The self-doping polymers of the present invention also provide unique advantages over conventional conductive polymers for long-term performance in various device applications where the dopant ions are not constantly mobile. Examples of such applications are Schottky diodes, field effect transistors and the like. In self-doping polymers, the dopant ions are covalently attached to the polymer chain, thus eliminating the ion diffusion problem.

[0021]

The preferred embodiments of the present invention are described below, but these are for the purpose of illustration and not limitation of the present invention.

Example 1 In a nitrogen atmosphere of 500 ml of dry THF solvent, while stirring 330 g of P- (chlorohexyl) phenyltrichlorosilane at 25 ° C., 500 ml of 2.0 M methylmagnesium chloride-ether solution was added. It dripped at 0.0 hours. After filtering the obtained reaction product and removing the solvent by applying the filtrate to an evaporator,
Distillation gave 155 g of the product methyl, P- (chlorohexyl) phenyldichlorosilane. 50% yield,
The purity was 99% or more by gas chromatography. ¹ H-nuclear magnetic resonance spectrum (measured in CDCl ₃ solution), NMR
¹ H (CDCl ₃ ) δ1.05 (3H, —CH ₃ );
δ 1.30 (8H, —CH ₂ —); δ 2.60 (2H,
_{-CH 2 -Ph); δ3.40 (2H} , -CH 2 -C
1); δ 7.20-7.70 (4H, Ph).

Next, 23 g of sodium was added under a nitrogen atmosphere in 500 ml of a dry toluene solvent, heat was applied so that toluene in the system was refluxed, and the mixture was vigorously stirred to disperse sodium. To this system, methyl, P- (chlorohexyl) phenyldichlorosilane 1
Polymerization was carried out by dropwise adding 55 g over 1.5 hours. Then, a slurry solution of 2.47 g of sodium hydrogen carbonate and 24.7 ml of 2-propanol was added to the reaction mixture, and 1000 ml of water was further added to deactivate the remaining active sodium. The obtained reaction mixture was extracted with toluene, the obtained organic phase was dried, and then reprecipitated once with a toluene / 2-propanol mixed solvent to give poly {methyl, P- (chlorohexyl). ) Phenylsilane}, 24 g was obtained. Yield 20%.

The weight average molecular weight (Mw) of the polysilane compound thus obtained was measured by GPC and found to be 12,000. Further, the results of instrumental analysis of this polysilane compound are shown below. NMR ¹ H (CDCl ₃ ) δ 0.65 (3H,
_{-CH 3); δ0.90 (8H,} -CH 2 -); δ2.
_{20 (2H, -CH 2 -Ph)} ; δ3.00 (2H, -
_{CH 2 -Cl); δ6.80-7.30 (4H} , Ph) Elemental analysis _{(C 13 H 17 Si 1 Cl} 1) n theory C, 66.0; H, 7.2; Si, 11.
8; Cl, 15.0 measured value C, 67.0; H, 6.7; Si, 11.
3; Cl, 15.0

28.4 g (0.2 mol) of Na ₂ SO ₃
To 1 liter of a THF / water-1: 1 mixed solution of poly {methyl, P- (chlorohexyl) phenylsilane},
23.9 g were added and the reaction mixture was heated to reflux at 70 ° C. for 45 hours. The resulting mixture was evaporated to dryness.
The resulting solid is a mixture of the desired poly {methyl, P- (sodium hexyl sulfonate) phenylsilane} and an excess of sodium sulfite impurity, and the solid is dissolved in acetone and filtered to remove sodium sulfite. Was removed, and acetone was evaporated to obtain poly {methyl, P- (sodium hexylsulfonate) phenylsilane}.

The analytical values were as follows: NMR ¹ H (CDCl ₃ ) δ 0.65 (3H, -C
_{H 3); δ1.20-1.50 (8H,} -CH 2 -);
_{δ2.30 (2H, -CH 2 -Ph)} ; δ4.80-
_{4.90 (2H, -CH 2 -Cl)} ; δ6.80-7.
At 30 (4H, Ph) IR (KBr, νcm ⁻¹ , Na ₂ SO ₃ peak is subtracted), it is considered to be due to —SO ₃ Na. 1242
S, 1210S, 1177S, 1056S were observed.

The electric conductivity was obtained by casting a polymer film on a glass substrate to which all contacts were previously attached. It was measured by the standard 4-terminal method. Poly {methyl, P
-(Sodium hexyl sulfonate) phenylsilane}
Had an electric conductivity of about 1 S / cm. Upon further exposure to silicon, the electrical conductivity of poly {methyl, P- (sodium hexyl sulfonate) phenylsilane} is about 1
It rose to 0 S / cm.

Example 2 500 ml of a 2.0 M methylmagnesium chloride-ether solution was stirred while stirring 316 g of P- (chloropentyl) phenyltrichlorosilane at 25 ° C. in a nitrogen atmosphere of 500 ml of dry THF solvent. It dripped at 0.0 hours. After filtering the obtained reaction product and removing the solvent by applying the filtrate to an evaporator,
Distillation gave 154 g of the product methyl, P- (chloropentyl) phenyldichlorosilane. The yield is 52%,
The purity was 99% or more by gas chromatography. ¹ H-nuclear magnetic resonance spectrum (measured in CDCl ₃ solution), NMR
¹ H (CDCl ₃ ) δ1.05 (3H, —CH ₃ );
δ1.28 (6H, —CH ₂ —); δ2.59 (2H,
_{-CH 2 -Ph); δ3.38 (2H} , -CH 2 -C
1); δ7.18-7.69 (4H, Ph).

Next, 23 g of sodium was added to 500 ml of a dry toluene solvent in a nitrogen atmosphere, and heat was applied so that toluene in the system was refluxed. By vigorous stirring, sodium was dispersed. Methyl, P- (chloropentyl) phenyldichlorosilane 1 was added to this system.
Polymerization was carried out by dropwise adding 48 g over 1.5 hours. Then, a slurry solution of 2.47 g of sodium hydrogen carbonate and 24.7 ml of 2-propanol was added to the reaction mixture, and 1000 ml of water was further added to deactivate the remaining active sodium. The obtained reaction mixture was extracted with toluene, the obtained organic phase was dried, and then reprecipitated once with a toluene / 2-propanol mixed solvent to obtain poly {methyl, P- (chloropentyl). ) Phenylsilane}, 25 g was obtained. Yield 22%.

With respect to the polysilane compound thus obtained, the weight average molecular weight (Mw) was 13,000 as a result of measuring the molecular weight using GPC. Further, the results of instrumental analysis of this polysilane compound are shown below. NMR ¹ H (CDCl ₃ ) δ 0.65 (3H, -C
_{H 3); δ0.88 (6H,} -CH 2 -); δ2.18
_{(2H, -CH 2 -Ph);} δ2.99 (2H, -CH
_{2 -Cl); δ6.78-7.29 (4H,} Ph) Elemental analysis _{(C 12 H 17 Si 1 Cl} 1) n theory C, 64.1; H, 7.6; Si, 12.
5; Cl, 15.8 measured value C, 63.9; H, 7.7; Si, 12.
7; Cl, 15.7

28.4 g (0.2 mol) of Na ₂ SO ₃
Of the above poly {methyl, P- (chloropentyl) phenylsilane} into 1 liter of a THF / water-1: 1 mixed solution of
22.5 g was added and the reaction mixture was heated to reflux at 70 ° C. for 45 hours. The resulting mixture was evaporated to dryness.
The resulting solid is a mixture of the desired poly {methyl, P- (sodium pentyl sulfonate) phenylsilane} and an excess of sodium sulfite impurity, and the solid is dissolved in acetone and filtered to remove sodium sulfite. Was removed, and acetone was further evaporated to obtain poly {methyl, P- (sodium pentylsulfonate) phenylsilane}.

The analytical values were as follows: NMR ¹ H (CDCl ₃ ) δ 0.65 (3H, -C
_{H 3); δ1.19-1.49 (6H,} -CH 2 -);
δ 2.29 (2H, -CH ₂ -Ph); δ 4.79-
_{4.88 (2H, -CH 2 -Cl)} ; δ6.79-7.
28 (4H, Ph) IR (KBr, νcm ⁻¹ , Na ₂ SO ₃ peak is subtracted) and it is considered to be due to —SO ₃ Na. 1242
S, 1210S, 1177S, 1056S were observed.

As the electric conductivity, a polymer film cast on a glass substrate to which all contacts were previously attached was used. It was measured by the standard 4-terminal method. Poly {methyl, P
-(Sodium pentylsulfonate) phenylsilane}
Had an electric conductivity of about 1 S / cm. Upon further exposure to silicon, the electrical conductivity of poly {methyl, P- (sodium pentylsulfonate) phenylsilane} is about 1
It rose to 0 S / cm.

[0034]

The polymers of this invention have at least about 10 ^-6.
A conductivity of about S / cm can be exhibited. Self-doping polymers are used as electrodes in electrochemical cells, as conductive layers in electrochromic displays, field effect transistors, Schottky diodes, etc.
Alternatively, highly conductive polymers that exhibit rapid doping kinetics can be used in many applications where it is desirable.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Tomozawa 2-24-25 Tamagawa, Ota-ku, Tokyo Showa Denko K.K.

Claims (4)

[Claims] 1. A self-polymerization system comprising a large number of monomer units, 0.01 to 100 mol% of which have at least one Bronsted acid group in the side chain, and which can form a σ-electron conjugated system along the main chain. Doping polymer. 2. The self-doping polymer according to claim 1, wherein the monomer unit having a Bronsted acid group in its side chain has the formula (1). [Chemical 1] However, Y ₁ , Y ₂ , Y ₃ and Y ₄ are hydrogen or -R-XM.
R is a linear or branched alkyl, ether, ester or amide component having 1 to 10 carbon atoms, X is a Bronsted acid anion, and M is a positive monovalent counterion when oxidized. It is an atom that occurs. 3. Y ₁ , Y ₂ , Y ₃ and Y ₄ are hydrogen, R is a straight chain alkyl or ether group having 1 to 10 carbon atoms, X is CO ₂ or SO ₃ . M is H, Li,
The polymer compound according to claim 2, which is Na or K. 4. The polymer compound according to claim 3, wherein R is a linear alkyl group having 2 to 4 carbon atoms, and M is H, Li or Na.