JP2009102461A - Conductive water-containing gel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive polymer gel which has a good light transmission property, can maintain good conductivity, even when exposed to an atmosphere comprising a lower temperature region than the freezing point of water, and can stably being produced in a simple working process without adding a gelling agent such as a surfactant or an alcohol. <P>SOLUTION: This conductive water-containing gel is characterized by comprising a polymer having at least side chains comprising nitroxide radical groups on a hydrophilic main chain, and water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive hydrogel formed from an organic radical polymer having a main chain that absorbs moisture or swells in water.

  Conventionally, as a conductive water-containing gel, for example, the following are known.

(1) Conductive polymer gels that can be suitably used for biomedical electrodes used for local bioelectric signal measurement and electrotherapy have been developed (see Patent Document 1). Specifically, regarding a conductive polymer gel containing a crosslinked synthetic polymer, water, a polyhydric alcohol and an electrolyte salt, it is prepared when the crosslinked synthetic polymer is in the range of 8 to 25% by mass. Further, it is described that the ratio of the polymer main chain contained in the gel is optimized, and a conductive hydrogel having high gel strength and high waist strength can be obtained.

(2) A conductive polymer gel that easily gels and has good conductivity and a method for producing the same, an actuator using the conductive polymer gel, an iontophoretic patch label, and a bioelectrode have been developed. (See Patent Document 2). Specifically, it contains water, poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid), a surfactant and / or an alcohol, and the water content is 66 mass% or more and 98 mass% or less. Since this gel has both electron conduction and ion conduction, its conductivity is not impaired even if it is exposed to an atmosphere with a temperature range below the freezing point of water. It is described.

(3) It is known that a solid film made of a gel-like polythiophene derivative in which a three-dimensional network is formed can be obtained by a production method in which a monomer is electropolymerized (see Non-Patent Document 1).

  However, the following problems remain in the conductive polymer gel and the method for producing the same in the above conventional example.

  The conductive polymer gel of (1) above contains an electrolyte, and since this electrolyte has a function of exhibiting conductivity, the conductivity is unstable when exposed to a temperature range below the freezing point of water. There is a concern that the conductivity may not be ensured. That is, it has been difficult for conventional conductive polymer gels to maintain good conductivity in a low temperature atmosphere below the freezing point of water.

  The conductive polymer gel (2) is exposed to an atmosphere having a temperature range below the freezing point of water due to the conductivity of poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid). Even if it falls into a serious situation, the electrical conductivity is not impaired, but the combination of poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid) and water only becomes a colloidal dispersion, and the gelling agent As described above, it cannot be gelled unless a surfactant and / or alcohol is added. In addition, poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid) is a black material, and therefore has poor light transmission and cannot be used for a transparent electrode.

  The conductive polymer gel (3) exhibits conductivity without containing an electrolyte, but the monomer polymerization and gelation need to be performed in the same process, which makes the process complicated and controllable. From the viewpoint, advanced technology is required.

  On the other hand, polymers obtained by polymerizing stable radical molecules have been conventionally synthesized as one of redox resins. Such polymers are represented by polymers of acrylates and styrene derivatives substituted by 2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter sometimes abbreviated as “TEMPO”). Shows oxidation catalyst ability to ketone, etc.

  The inventor of the present invention pays attention to the point that the organic electrode reaction via a stable radical occurs with high reversibility because the electrode reaction is generally one-electron transfer. It is applied as.

  For example, as an example of a charge storage material, paying attention to the power storage performance of a polymer using organic radicals in the side chain, a non-aqueous secondary battery comprising a positive electrode, a negative electrode, and an organic electrolyte using propylene carbonate, acetonitrile, etc. An example of application as an electrode active material was previously filed (see Patent Documents 3 to 10).

  However, these applications relate to development as a power storage material for a non-aqueous secondary battery, and stable conductivity in water has not been studied at all.

Japanese Patent No. 3437124 Japanese Patent No. 3983731 JP 2004-227945 A JP 2004-227946 A JP 2004-228008 A JP 2004-259618 A JP 2006-73239 A JP 2006-73241 A JP 2007-35375 A JP 2007-184227 A Synthetic Metals 99 (1999) 53-59

  In view of such circumstances, the present invention is capable of maintaining good conductivity even when exposed to an atmosphere having a temperature range below the freezing point of water, and is not limited to surfactants or alcohols. It is an object of the present invention to provide a conductive polymer gel with good light transmission, which does not require the addition of a gelling agent and can be stably produced by a simple work process.

  As a result of intensive studies to solve the above problems, the present inventors have found that a conductive water-containing gel containing a polymer having a hydrophilic main chain and at least a side chain composed of a nitroxide radical group is good. As a result, the present invention was completed.

  The first aspect of the present invention resides in a conductive hydrogel characterized in that a hydrophilic main chain contains at least a polymer having a side chain composed of a nitroxide radical group and water.

  The second aspect of the present invention is characterized in that the main chain of the polymer is a kind selected from the group consisting of polyacrylamide, polyether, polyvinyl ether, and copolymers thereof. It exists in the electroconductive water-containing gel of description.

  According to a third aspect of the present invention, the side chain composed of the nitroxide radical group is formed by substituting a cyclic nitroxide for the main chain of the polymer. The conductive water-containing gel.

  In a fourth aspect of the present invention, the cyclic nitroxide is 2,2,6,6-tetramethylpiperidine-1-oxyl (= TEMPO), 2,2,5,5-tetramethylpyrrolidine-1-oxyl ( (Hereinafter, abbreviated as PROXYL) or 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (hereinafter abbreviated as nitronyl nitroxide). It exists in the electroconductive water-containing gel of description.

  5th aspect of this invention exists in the electroconductive water-containing gel of any one of Claims 1-4 in which the principal chain of the said polymer contains a crosslinked structure.

  The sixth aspect of the present invention resides in the conductive hydrogel according to any one of claims 1 to 5, wherein a supporting electrolyte is contained together with the water.

  According to the present invention, even when exposed to an atmosphere having a temperature range below the freezing point of water, it is possible to maintain good conductivity, and a gelling agent such as a surfactant or alcohol can be used. It is possible to provide a conductive polymer gel that does not need to be added and can be stably produced by a simple work process.

  When the main chain of the polymer having a side chain composed of a nitroxide radical group contains a crosslinked structure, it is possible to arbitrarily increase the mechanical strength of the conductive hydrous gel.

  When the conductive hydrogel contains a supporting electrolyte, the conductive hydrogel can be provided with more excellent conductivity when exposed to an atmosphere having a temperature range higher than the freezing point of water.

  The polymer used in the present invention is an organic radical polymer having a hydrophilic main chain and having at least a side chain composed of a nitroxide radical group.

  Here, the main chain of the organic radical polymer may be any as long as it has hydrophilicity and can be gelled by incorporating moisture or a water-soluble electrolyte into the polymer chain.

  The main chain of the polymer having hydrophilicity here refers to a polymer chain having a high affinity for water. More specifically, it refers to a polymer chain that can be impregnated with 10% by mass or more of water and gelled by bringing a polymer alone consisting of a polymer chain as a main chain into contact with a large amount of water.

  Specifically, the main chain can be selected from the group consisting of polyacrylamide, polyether, polyvinyl ether, and copolymers thereof.

  Further, the main chain of the organic radical polymer may include a crosslinked structure. By including a crosslinked structure, it is possible to arbitrarily increase the mechanical strength of the conductive hydrogel.

  In the present invention, the main chain having a crosslinked structure means that the polymer compound has a structure in which a bond is formed between the molecules by a covalent bond or the like to form a three-dimensional polymer or network polymer. The polymer having a crosslinked structure of the present invention has a three-dimensional or network-like polymer structure formed at a certain distance between the crosslinking points depending on the ratio of the crosslinking points.

  The method for producing a polymer having a crosslinked structure is not particularly limited, and can be produced, for example, by copolymerizing a monomer that forms a hydrophilic main chain after the polymerization reaction and at least one polyfunctional monomer. .

  As the polyfunctional monomer, a monomer having two or more, for example, about 2 to 4 polymerization sites with a monomer that forms a hydrophilic main chain after the polymerization reaction is used. Examples of the functional group that can be copolymerized with a monomer that forms a hydrophilic main chain after the polymerization reaction include an ethylene double bond. Specific examples of the polyfunctional monomer include polyfunctional vinyl monomers such as divinylbenzene, polyfunctional acrylate, and polyfunctional methacrylate.

  In order to constitute the side chain substituent of the organic radical polymer that can be used in the present invention, a radical compound that repeats stable redox in water can be used, and any radical compound that performs stable one-electron transfer in water can be used. Any can be used, and examples include cyclic nitroxide radicals.

  Cyclic nitroxide radicals are formed by substituting cyclic nitroxides into the main chain, more specifically 2,2,6,6-tetramethylpiperidine-1-oxyl (= TEMPO), 2,2,5,5- List those formed by substituting tetramethylpyrrolidine-1-oxyl (= PROXYL) or 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (= nitronyl nitroxide) Can do.

  Further, the radical compound may be a compound that becomes a precursor of the radical compound, that is, a compound that is oxidized or reduced by an electrode reaction or the like to become a radical state. In this case, an oxidation or reduction reaction such as an electrode reaction after the gel is formed. The radical site may be generated by

  The number average molecular weight of the organic radical polymer that can be used in the present invention is not particularly limited as long as it swells in water but does not dissolve, but is preferably 500 or more and 500,000 or less.

  The conductive hydrogel of the present invention contains such an organic radical polymer and water, and is gelled by incorporating at least a part of water into the main chain of the polymer.

  When the conductive hydrous gel of the present invention is used, it is preferable that the weight change of the organic radical polymer before and after hydration is in a range that does not involve a large volume change during swelling. Specifically, it is preferably 0.1% by mass or more and 1000% by mass or less, and more preferably 10% by mass or more and 50% by mass or less.

  Moreover, the electroconductive water-containing gel of the present invention may contain a supporting electrolyte together with water. By containing the supporting electrolyte, when exposed to an atmosphere having a temperature range higher than the freezing point of water, it is possible to provide further excellent conductivity. The concentration in the case of containing the supporting electrolyte is not particularly limited as long as it dissolves in water, but is preferably 0.01 to 10 mol / l.

  The electrolyte salt that can be used as the supporting electrolyte in the present invention may be an electrolyte salt known in the art, such as sodium chloride, potassium chloride, calcium chloride, ammonium chloride, iron chloride, aluminum chloride, zinc chloride, nickel chloride, Examples thereof include sodium sulfate, potassium sulfate, calcium sulfate, ammonium sulfate, iron sulfate, aluminum sulfate, zinc sulfate, and nickel sulfate.

  Hereinafter, although the detail of this invention is concretely demonstrated by a synthesis example and an Example, this invention is not limited to these Examples.

<Synthesis of polymer>
[Production Example 1]
(Production Example 1-1) Synthesis of N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide

  2.5 g (15.9 mmol) of 4-amino-2,2,6,6-tetramethylpiperidine are reacted with 1.29 ml (15.9 mmol) of acrylic chloride in benzene. After stirring at room temperature for 2 hours, the precipitated solid was recovered and subjected to recrystallization purification to obtain 1.38 g of N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide as crystals on a white plate. 41%).

  The NMR measurement data, mass spectrometry, and elemental analysis results of the obtained N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 6.30 (d, 1H, J = 1.5 Hz), 6.09-6.04 (q, 1H), 5.63 (d, 1H , J = 11.6 Hz), 5.40 (s, 1H), 4.36 (m, 1H), 1.92 (d, 1H, J = 12.5 Hz), 1.27 (s, 6H), 1.13 (s, 6H), 0.95 (t, 2H, J = 12.2 Hz)

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 164.7, 131.3, 126.0, 50.9, 45.2, 42.7, 35.1, 28.6.

  Mass (m / z): [M + 1]: found, 211; calcd, 211.

  Elemental Analysis Found: C, 62.9; H, 9.5; N, 11.1%. Calcd: C, 63.9; H, 9.7; N, 11.7%

(Production Example 1-2) Synthesis of poly (N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide)

  N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide 100 mg (0.47 mmol) in ethanol azobisisobutyronitrile (abbreviated as AIBN) 3.8 mg (24 μmol) Was stirred at 70 ° C. for 2 hours to obtain poly (N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide) as a colorless transparent solid 83 mg (yield 83%). It was.

(Production Example 1-3) Synthesis of poly (N- (2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl) -acrylamide)

  100 mg of poly (N- (2,2,6,6-tetramethylpiperidin-4-yl) -acrylamide) was stirred in 246 mg of 3 equivalents of m-chloroperbenzoic acid (abbreviated as mCPBA) in acetone for 24 hours. did. An orange solid was collected and washed with methanol. The obtained polymer had a number average molecular weight of 38000 (polystyrene conversion) and a degree of dispersion (weight average molecular weight / number average molecular weight) of 2.2. (Yield 80 mg, Yield 80%) Quantitative generation of radicals was confirmed by ESR measurement and SQUID magnetization measurement.

[Production Example 2]
(Production Example 2-1) Synthesis of 4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl

4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl 2.57 g (14.9 mmol), sodium carbonate 944 mg (8.92 mmol), bis (1,5-cyclooctadiene) diiridium ( I) 103 mg (141 μmol) of dichloride (= [Ir (cod) Cl] ₂ ) was stirred in toluene under an argon atmosphere, and 2.8 ml (29.2 mmol) of vinyl acetate was further added and reacted at 90 ° C. for 5 hours. It was. After ether extraction and column purification using chloroform, 1.44 g (yield 49%) of 4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl was obtained.

  The NMR measurement data, mass analysis, and elemental analysis results of the resulting 4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 6.44 (dd, 1H, J = 8.7, 7.7 Hz), 4.47 (d, 1H, J = 5.0 Hz), 4 .19 (m, 2H), 1.68 (t, 2H, J = 12.1 Hz), 1.33 (s, 6H), 1.30 (s, 6H).

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 150, 88.0, 58.5, 44.0, 20.3.

  Mass (m / z): [M]: found, 198; calcd, 198.

  Elemental Analysis Found: C, 66.2; H, 9.9; N, 7.0%. Calcd: C, 67.0; H, 9.7; N, 7.1%

(Production Example 2-2) Synthesis of poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl)

  4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl 97.0 g (489 mmol) in 550 ml of dichloromethane solvent and 1.23 ml (9.8 mmol) of boron trifluoride diethyl ether complex as an initiator The reaction was carried out at −20 ° C. for 20 hours. After being dispersed and washed in methanol, poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) was obtained by drying under reduced pressure at 50 ° C. for 12 hours (yield 92.6 g, Yield 96%).

[Production Example 3]
(Production Example 3-1) Synthesis of 4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl

  Epichlorohydrin 2.5 ml (30 mmol) 84 mg (239 μmol) sodium tetrabutylammonium hydrogensulfate is added to 4 ml of 50% by mass aqueous sodium hydroxide solution and stirred. Further, 1.03 g (5.98 mmol) of 4-hydroxy-2,2,6,6 tetramethylpiperidine-1-oxyl is added and reacted at room temperature for 12 hours. After ether extraction and column purification using ether / hexane mixed solvent (mixing volume ratio = 1/1), 1.14 g of 4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (yield) 84%).

  The NMR measurement data, mass spectrometry, and elemental analysis results of the resulting 4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 3.71 (dd, 1H, J = 11.3, 3.0 Hz), 3.64 (m, 1H), 3.40 (dd, 1H , J = 11.3, 5.8 Hz), 3.11 (m, 1H), 2.77 (t, 1H, J = 4.6 Hz), 2.58 (dd, 1H, J = 5.2) 2.7 Hz), 1.92 (m, 2H), 1.44 (q, 2H, J = 12.2 Hz), 1.14 (s, 6H).

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 71.1, 68.9, 58.9, 50.9, 44.5, 44.3, 32.0, 20.5.

  Mass (m / z): [M]: found, 228; calcd, 228.

  Elemental Analysis Found: C, 62.9; H, 9.5; N, 6.2%. Calcd: C, 63.1; H, 9.7; N, 6.1%

(Production Example 3-2) Synthesis of poly ((2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl) -glycidyl ether)

  4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl 228 mg (1.00 mmol) in tetrahydrofuran (= THF) tert-butoxy potassium (= t-BuOK) 5.6 mg (0.05 mmol) ) As a polymerization initiator, reacted at 60 ° C. in a nitrogen atmosphere for 24 hours, purified by reprecipitation into diethyl ether, and then converted into poly ((2,2,6,6-tetramethylpiperidine-1-oxyl) as an orange powder. -4-yl) -glycidyl ether) was obtained. The obtained polymer had a number average molecular weight of 3600 (polystyrene conversion) and a dispersity (weight average molecular weight / number average molecular weight) of 1.4 (yield 150 mg, yield 66%).

[Production Example 4]
(Production Example 4-1) Synthesis of 4-vinylbenzaldehyde

  2.70 g (7.58 mmol) of methyltriphenylphosphine bromide are stirred with 1.24 g of potassium carbonate in THF in an ice bath to form an ylide. Terephthalaldehyde (1.00 g, 7.46 mmol) was added, and the mixture was stirred at room temperature for 12 hours. Chloroform extraction and column purification using a hexane / chloroform mixed solvent (mixing volume ratio = 1/2) yielded 531 mg (yield 54%) of 4-vinylbenzaldehyde.

  The NMR measurement data and mass spectrometry result of the obtained 4-vinylbenzaldehyde are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 9.94 (s, 1H), 7.78 (d, 2H, J = 8.5 Hz), 7.61 (d, 2H, J = 8) .5Hz), 6.76 (dd, 4H, J = 10.7, 17.5 Hz), 5.86 (d, 1H, J = 17.4 Hz), 5.38 (d, 1H, J = 1.11. 0 Hz).

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 191.1, 142.9, 135.5, 135.3, 129.6, 126.3, 117.0.

  Mass (m / z): [M]: found, 132; calcd, 132.

(Production Example 4-2) Synthesis of 4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine-1,3-diol

  4-vinylbenzaldehyde 3.11 g (23.5 mmol) was added in water and methanol mixed solvent, sodium acetate 2.12 g (25.8 mmol) and bishydroxylammonium sulfate salt 6.36 g (25.8 mmol) were added, and 24 hours. Stir. After completion of the reaction, the solvent was removed, the solid was washed with water, and 4.92 g of 4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine-1,3-diol (80% yield). )

  The NMR measurement data, mass spectrometry, and elemental analysis results of the obtained 4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine-1,3-diol are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 7.48 (q, 4H, J = 27.7, 4.0 Hz), 6.76 (dd, 1H, J = 10.6, 17. 7 Hz), 5.84 (d, 1 H, J = 18.0 Hz), 5.22 (d, 1 H, J = 10.7 Hz), 4.64 (s, 1 H), 1.15 (s, 6 H) .

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 165.0, 145.3, 139.8, 131.5, 128.3, 115.8, 93.3, 69.3, 37.5 , 32.3, 27.0, 19.7.

  Mass (m / z): [M + 1]: found, 263; calcd, 263.

  Elemental Analysis Found: C, 49.1; H, 5.7; N, 8.9%. Calcd: C, 49.5; H, 6.1; N, 8.9%

(Production Example 4-3) Synthesis of 1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine

  3,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine-1,3-diol (3.00 g, 11.4 mmol) in dimethylformamide (= DMF) 89 g (57.2 mmol) and 8.6-g (57.2 mmol) of tert-butyldimethylsilyl chloride (abbreviated as TBDMS-Cl) were added, and the mixture was stirred at 50 ° C. under an argon atmosphere for 12 hours. After extraction with chloroform and column purification with hexane, 1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine 3 Obtained .81 g (68% yield).

  NMR measurement data, mass spectrometry, and element of the resulting 1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine The analysis results are shown below.

¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 7.37 (s, 4H), 6.76 (dd, 4H, J = 17.7, 11.1 Hz), 5.79 (d, 1H , J = 17.7 Hz), 5.29 (d, 2H, J = 11.0 Hz), 4.63 (s, 1H), 1.20 (s, 12H), 0.83 (s, 18H) , -0.04 (s, 6H), -0.82 (s, 6H).

¹³ C-NMR (500 MHz, CDCl ₃ ) δ (ppm): 137.2, 137.0, 130.9, 125.4, 113.2, 93.9, 24.8, 26.3, 17.9 , 17.2, -3.8, -5.04.

  Mass (m / z): [M]: calcd, 489; found, 490.

Elemental Analysis Found: C, 66.3; H, 10.0; N, 5.7%. _{Calcd for C 27 H 52 N 2} O 2 Si 2: C, 66.1; H, 10.3; N, 5.7%

(Production Example 4-4) 1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine-acrylamide copolymer Composition

  1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine 100 mg (204 μmol) and acrylamide 10 mg (136 μmol) in THF solvent Medium AIBN (2.7 mg, 17 μmol) was used as an initiator, and the mixture was stirred at 70 ° C. for 12 hours. 1,3-bis- (t-butyl-dimethylsiloxy) -4,4,5,5-tetramethyl-2- (4-vinylphenyl) -imidazolidine as white powder after reprecipitation purification into diethyl ether Acrylamide copolymer was obtained. The polymer obtained had a number average molecular weight of 8600 (polystyrene conversion) and a dispersity (weight average molecular weight / number average molecular weight) of 1.5 (yield 84 mg, yield 76%).

(Production Example 4-5) Synthesis of Nitronyl Nitroxide-Substituted Polystyrene-Polyacrylamide Copolymer

100 mg (310 μmol) of the precursor polymer was stirred with 202 mg (775 μmol) of tetra (n-butyl) ammonium fluoride (= n-Bu ₄ NF) in THF at room temperature for 24 hours. Subsequently, a saturated solution of sodium periodate was added, the mixture was further stirred for 30 minutes, extracted with dichloromethane, and purified by reprecipitation into water to obtain a nitronyl nitroxide substituted polystyrene-polyacrylamide copolymer. The polymer obtained had a number average molecular weight of 8600 (polystyrene conversion) and a dispersity (weight average molecular weight / number average molecular weight) of 1.6 (yield 36 mg, 81%).
The quantitative generation of radicals was confirmed by ESR measurement and SQUID magnetization measurement.

<Creation of gel film>
(Example 1)
To 100 mg of the polymer synthesized in Production Example 1, 1 ml of acetonitrile was added and dissolved (dispersed) by stirring in a 50 ° C. atmosphere for 5 hours to prepare a polymer solution. By applying 1 ml of this solution using a gold electrode as a substrate, a synthesized polymer thin film was formed with a thickness of 23 μm. Furthermore, a thin film is sandwiched by placing a gold electrode on the thin film, and a gel film is created by impregnating each with pure water or 0.5 M saline to obtain a conductive water-containing gel with good light transmission. It was.

(Example 2)
A thin film of the synthesized polymer was formed to a thickness of 20 μm by operating in the same manner as in Example 1 except that the polymer synthesized in Production Example 2 was used. Furthermore, a thin film is sandwiched by placing a gold electrode on the thin film, and a gel film is created by impregnating each with pure water or 0.5 M saline to obtain a conductive water-containing gel with good light transmission. It was.

(Example 3)
A thin film of the synthesized polymer was formed to a thickness of 22 μm by operating in the same manner as in Example 1 except that the polymer synthesized in Production Example 3 and THF was used as the solvent of the solution. Furthermore, a thin film is sandwiched by placing a gold electrode on the thin film, and a gel film is created by impregnating each with pure water or 0.5 M saline to obtain a conductive water-containing gel with good light transmission. It was.

Example 4
A thin film of the synthesized polymer was formed to a thickness of 20 μm by operating in the same manner as in Example 1 except that the polymer synthesized in Production Example 4 was used. Furthermore, a thin film is sandwiched by placing a gold electrode on the thin film, and a gel film is created by impregnating each with pure water or 0.5 M saline to obtain a conductive water-containing gel with good light transmission. It was.

<Measurement of electrical conductivity>
(Test Example 1)
For each of the gel membranes impregnated with pure water or 0.5 M saline prepared in Example 1, the electrical conductivity was measured by an alternating current impedance method using a PGATAT30 analyzer manufactured by AUTOLAB.

The conductivity of the gel membrane impregnated with pure water is 2 × 10 ⁻⁸ Scm ⁻¹ , and the conductivity of the gel membrane impregnated with 0.5 M saline is 5 × 10 ⁻⁸ Scm ^−1. Conductivity.

(Test Example 2)
The polymer synthesized in Example 2 was prepared by performing the same operation as in Test Example 1 except that the gel film prepared in Example 2 and impregnated with pure water or 0.5 M saline was used. The electrical conductivity of the gel was measured.

The conductivity of the sample impregnated with pure water is 3 × 10 ⁻⁸ Scm ⁻¹ , and the conductivity of the gel membrane impregnated with 0.5 M saline is 2 × 10 ⁻⁷ Scm ^−1. It showed conductivity.

(Test Example 3)
The polymer synthesized in Example 3 by performing the same operation as in Test Example 1 except that the gel membrane prepared in Example 3 and impregnated with pure water or 0.5 M saline was used. The electrical conductivity of the hydrous gel was measured.

The conductivity of the sample impregnated with pure water is 4 × 10 ⁻⁵ Scm ⁻¹ , and the conductivity of the gel membrane impregnated with 0.5 M saline is 2 × 10 ⁻⁶ Scm ^−1. It showed conductivity.

(Test Example 4)
The polymer synthesized in Example 4 was prepared by performing the same operation as in Test Example 1 except that the gel film prepared in Example 4 and impregnated with pure water or 0.5 M saline was used. The electrical conductivity of the gel was measured.

The conductivity of the sample impregnated with pure water is 7 × 10 ⁻⁷ Scm ⁻¹ , and the conductivity of the gel membrane impregnated with 0.5 M saline is 3 × 10 ⁻⁶ Scm ^−1. It showed conductivity.

Claims (6)

A conductive hydrogel comprising a polymer having at least a side chain composed of a nitroxide radical group in a hydrophilic main chain and water. The conductive water-containing gel according to claim 1, wherein the main chain of the polymer is one selected from the group consisting of polyacrylamide, polyether, polyvinyl ether, and copolymers thereof. The conductive hydrous gel according to claim 1 or 2, wherein the side chain composed of the nitroxide radical group is formed by substituting cyclic nitroxide for the main chain of the polymer. The cyclic nitroxide is 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,5,5-tetramethylpyrrolidine-1-oxyl, or 4,4,5,5-tetramethylimidazoline- The conductive hydrogel according to claim 3, which is 1-oxyl-3-oxide. The conductive water-containing gel according to any one of claims 1 to 4, wherein the main chain of the polymer contains a crosslinked structure. The conductive water-containing gel according to any one of claims 1 to 5, further comprising a supporting electrolyte together with the water.