JP2007262195A - Light-driven polymer actuator, method for producing light-driven polymer actuator, polyfunctional monomer, and polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-driven actuator whose structure is reversibly deformed by light stimulation and whose response speed has practical light response, flexibility and light weight and is driven silently, and its light-driven polymer A simple manufacturing method of an actuator and a good material used for manufacturing a light-driven polymer actuator are provided.
A light-driven polymer actuator includes a polymer that deforms in response to light stimulation, and is a monofunctional that has polymerizability in a light-driven polymer actuator that uses deformation of the polymer as an actuator. A copolymer comprising a monomer and a polyfunctional monomer having a plurality of photoresponsive groups that have a polymerizability and undergo structural change under light stimulation, the copolymer being used for light stimulation It deforms accordingly and has a function as an actuator.
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Description

  The present invention relates to a light-driven polymer actuator that is driven in response to light and a method for producing the same, a polyfunctional monomer that has a plurality of photoresponsive groups that have polymerizability and cause structural changes under light stimulation, And a polymer obtained by polymerizing the polyfunctional monomer and a polymerizable monofunctional monomer.

  Various actuators have been developed in the mechatronics field, and polymer actuators in particular have attracted a great deal of attention because of their flexibility, light weight, and silence during driving. Among them, the light-driven polymer actuator that drives in response to light can supply energy without contact, and does not require wiring for driving, and can avoid noise generated from electrical wiring. In particular, it is expected to be applied to micromachines and robots used in the medical / nursing care field and aerospace field.

As a polymer material driven by light, research on a photoresponsive gel has been actively conducted. For example, photodeformation by a polyacrylamide gel containing a leuco body of triphenylmethane that is photoionized (see Non-Patent Document 1), or a bending action by irradiating the polyacrylamide gel with CO ₂ infrared laser light (Non-Patent Document 2). Reference) is realized. In the former example, an ion dissociation reaction due to light occurs, and as a result, the osmotic pressure in the gel increases and swells. In the latter example, the penetration is based on the volume change of the gel due to heat generated by infrared laser light irradiation. This is due to pressure changes. In addition to polyacrylamide gels, polyimide gels containing azobenzene groups in the main chain as photoresponsive groups are also known (see Patent Document 1). However, such a light-responsive gel has a problem that a solvent is indispensable and cannot be used in a dry environment because the driving principle is based on the uptake and discharge of solvent molecules such as water based on changes in osmotic pressure.

  In addition, there has been reported an actuator that bends when a polymerizable liquid crystal composition composed of an azobenzene derivative is immersed in an organic solvent such as toluene and swelled and irradiated with light (see Non-Patent Document 3 and Patent Document 2). ). However, these actuators also have a problem that a solvent is indispensable and cannot be used in a dry environment.

  On the other hand, as a light-driven polymer actuator that can be used in a dry environment, polyethyl acrylate crosslinked with azobenzene (see Non-Patent Document 4) and a polyimide film containing azobenzene in the main chain (see Non-Patent Document 5) are known. It has been. Furthermore, a polyquinoline (see Non-Patent Document 7) containing a polyethyl acrylate (see Non-Patent Document 6) or a stilbene group as a photoresponsive group with spirobenzopyran as a crosslinking agent is also known. However, in any case, the amount of displacement is small, and it is considered that practical use is difficult (see Non-Patent Document 8).

  On the other hand, a liquid crystal elastomer has recently been reported. For example, it has been reported that a liquid crystal elastomer obtained by crosslinking a polymer having an azobenzene group in the side chain as a photoresponsive group in a liquid crystal alignment state exhibits a stretching behavior when irradiated with ultraviolet light (see Non-Patent Document 9). In addition, it is known that a polydomain liquid crystal elastomer obtained by crosslinking a polymerizable liquid crystal composition comprising an azobenzene derivative with light or heat can be bent in a free direction by irradiation with polarized light of ultraviolet light (see Non-Patent Document 10). .

However, the technique disclosed in the former Non-Patent Document 9 has a problem in that the response speed to light is very slow. In the latter technique disclosed in Non-Patent Document 10, the response is reduced with the film thickness, the function can be exhibited only as a thin film, and the operating temperature is limited only by driving in the liquid crystal temperature range. Has a problem in that. Accordingly, these liquid crystal elastomers still have problems in terms of performance in view of practical use.
Macromolecules, Vol. 19, p. 2476 (1986) J. et al. Chem. Phys. 102, 551 (1995) Adv. Mater. Journal, Volume 15, 201 (2003) Polymer, Vol. 21, 1175 (1982) Macromolecules, Volume 3, 349 (1970) Pure Appl. Chem. Magazine, Vol. 8, 357 (1973) Macromolecules, Vol. 18, 321 (1985) Development and application of shape memory polymer, CMC, Tokyo (1988) Phys. Rev. Lett. Journal, Vol. 87, 015501 (2001) Nature, Vol. 425, 145 (2003) JP-A-2005-23151 JP 2002-256031 A

  In view of the above circumstances, the present invention is a light-driven actuator that is reversibly deformed by light stimulation and has a practical light response, flexibility, and lightness in response speed, and is driven silently, It is an object of the present invention to provide a simple manufacturing method of the light-driven polymer actuator and a good material used for manufacturing the light-driven polymer actuator.

The optically driven actuator of the present invention that achieves the above object is as follows.
In a light-driven polymer actuator that includes a polymer that deforms in response to light stimulation and uses the deformation of the polymer as an actuator,
Comprising a copolymer formed by polymerizing a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that undergo structural changes upon light stimulation;
The copolymer is characterized by being deformed in response to light stimulation and having a function as an actuator.

  In the light-driven polymer actuator of the present invention, since the copolymer contains a plurality of photoresponsive groups at the cross-linked site, the structure is reversibly deformed by light stimulation, and the response speed has practical photoresponsiveness. Have. In addition, since the light-driven polymer actuator of the present invention is a polymer made of a copolymer, it has flexibility, is lightweight, and can be driven silently.

Here, the polyfunctional monomer is preferably a polyfunctional monomer represented by the following general formula (I).
Formula (I)

(In the formula, P ¹ and P ² each independently represent a polymerizable group, L ¹ , L ^2m and L ³ each independently represent a divalent linking group, and R ¹ and R ^2m each independently And m represents an integer of 1 to 4.)
According to the polyfunctional monomer represented by the general formula (I), R ¹ and R ^2m each independently exhibit photoresponsiveness, so that responsiveness to light can be enhanced.

  The photoresponsive group is preferably an azobenzene group.

  An azobenzene group usually exists as a thermodynamically stable trans isomer, but becomes a cis isomer by irradiating the azobenzene group with ultraviolet light, and returns to the trans isomer again by irradiating the azobenzene group with visible light. It is a photoisomerization group. Therefore, by using an azobenzene group as a photoisomerization group, it is easy to cause a photoisomerization reaction, and extremely high photoresponsiveness can be obtained.

Here, the monofunctional monomer is preferably a monofunctional monomer represented by the following general formula (II).
Formula (II)

(Wherein P ³ represents a polymerizable group, L ⁴ represents a divalent linking group, M represents a mesogenic group, and o represents 0 or 1)
According to the monofunctional monomer represented by the general formula (II), addition polymerization is facilitated. Moreover, this monofunctional monomer can enhance the orientation of the polymer by having a mesogenic group.

In the general formula (I),
P ¹ and P ² are preferably each independently a polymerizable group represented by the following general formula (III).
Formula (III)

(In the formula, Z ¹ represents a single bond, an oxygen atom, or —O—CH ₂ —, Z ² represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and Z ³ represents a single bond, -CO- or -O- is represented.)
Further, in the above general formula (I), P ¹ and P ^2, it is particularly preferred independently an acryloyl group or a methacryloyl group.

  According to this polyfunctional monomer, an acryloyl group or a methacryloyl group has a particularly high addition polymerizability, so that it becomes easy to produce a light-driven polymer actuator.

Here, the first manufacturing method of the optically driven actuator of the present invention that achieves the above object is as follows.
In a method of manufacturing a light-driven polymer actuator that includes a polymer that deforms in response to light stimulation and uses the deformation of the polymer as an actuator.
Applying a composition comprising a monofunctional monomer having a polymerizability and a polyfunctional monomer having a plurality of photoresponsive groups having a polymerizability and causing a structural change upon light stimulation;
And a step of polymerizing the composition.

  According to the first method for producing a light-driven polymer actuator of the present invention, polymerization does not start immediately after the composition is applied onto the substrate, but polymerization is initiated by stimulation with light or heat. Therefore, it is excellent in processability and easy to handle, and a light-driven polymer actuator can be easily produced.

Here, the second manufacturing method of the light-driven actuator of the present invention that achieves the above object includes a polymer that deforms in response to light stimulation, and uses the deformation of the polymer as an actuator. In the manufacturing method of the type polymer actuator,
Injecting a composition comprising a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a plurality of photoresponsive groups having a polymerizable property and undergoing a structural change upon light stimulation; ,
And a step of polymerizing the composition.

  Also in the second method for producing a light-driven polymer actuator of the present invention, polymerization does not start immediately after the composition is injected between a pair of substrates, but polymerization is initiated by stimulation of light or heat. Therefore, it is excellent in processability and easy to handle, and a light-driven polymer actuator can be easily produced.

Here, the polyfunctional monomer is preferably a polyfunctional monomer represented by the following general formula (IV).
Formula (IV)

(In the formula, P ¹ and P ² each independently represent a polymerizable group, and L ¹ , L ² and L ³ each independently represent a divalent linking group. In the formula, the azobenzene group is a substituent. May be included.)
According to this polyfunctional monomer, since it has a plurality of azobenzene groups, the photoresponsiveness of the light-driven polymer actuator becomes extremely high.

In the general formula (IV),
P ¹ and P ² are each independently an acryloyl group or a methacryloyl group,
L ¹ , L ² , and L ³ are each independently a divalent alkylene group having 1 to 20 carbon atoms, a divalent alkenylene group having 1 to 20 carbon atoms, or a divalent alkynylene group having 1 to 20 carbon atoms. It is a divalent linking group comprising a group, —O—, —S—, —NH—, —COO—, —OCO—, —CONH—, —NHCO—, or a combination thereof.

  According to such a polyfunctional monomer, the physical properties of the light-driven polymer actuator can be appropriately controlled.

Here, in the general formula (IV),
L ² is an alkylene group having 1 to 20 carbon atoms, an oxyalkyleneoxy group having 1 to 20 carbon atoms, a carbonyloxyalkyleneoxycarbonyl group having 1 to 20 carbon atoms, or an oxycarbonylalkylenecarbonyloxy group having 1 to 20 carbon atoms. It is preferably a group.

  Such a polyfunctional monomer can also appropriately control the physical properties of the light-driven polymer actuator.

  Here, the copolymer is preferably a polymer composed of a copolymer of a polyfunctional monomer represented by the general formula (IV) and a monofunctional monomer represented by the general formula (II).

  This polymer can function as a polymer with improved photoresponsiveness.

  According to the present invention, a light-driven actuator whose structure is reversibly deformed by light stimulation and whose response speed has practical light responsiveness, flexibility, and light weight and is driven silently, and its light driving It is possible to provide a simple method for manufacturing a type polymer actuator and a good material used for manufacturing a light-driven type polymer actuator.

  Embodiments of the present invention will be described below.

  The light-driven polymer actuator of the present invention is obtained by polymerizing a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that undergo structural changes upon stimulation of light. It is characterized by providing the copolymer which consists of. In the copolymer, the main chain and the main chain of the polymer are cross-linked by the polymerization of the polyfunctional monomer. In addition, the light-driven polymer actuator can improve the response to light by including a plurality of photoresponsive groups at the cross-linked site.

  In addition, a polymer generally refers to a polymer having a molecular weight of 10,000 or more, and a compound having a molecular weight of 1000 to 10,000 (less than) is treated as a quasi-polymer. Also, those having a degree of polymerization of about 2 to 20 are called oligomers and are usually distinguished from polymers (Iwanami Rikagaku Dictionary 3rd edition supplement edition, edited by Tamamichi Bunichi et al., Page 449, Iwanami Shoten, 1982). ). In the present invention, the polymer in the light-driven polymer actuator means a quasi-polymer having a molecular weight of 1000 or more and a polymerization degree of 20 or more, preferably a molecular weight of 5000 or more, or a polymerization degree. The molecular weight is 10,000 or more, or the degree of polymerization is 100 or more. Also, it is composed only of a copolymer obtained by polymerizing the above-mentioned monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that cause structural changes upon light stimulation. It may be a mixture with other low molecular compounds or high molecular compounds, and may be a mixture with inorganic particles as required.

  Here, the photoresponsive group is, for example, a group that causes at least one of a photoisomerization reaction, a photodimerization reaction, and a photolysis reaction by light irradiation. The photoresponsive group is particularly preferably a unit composed of a group that undergoes a photoisomerization reaction by light irradiation from the viewpoint of reversibility. Specifically, an azobenzene group can be mentioned as a particularly preferred example.

Examples of the polyfunctional monomer containing a plurality of photoresponsive groups preferably used in the present invention include polyfunctional monomers represented by the following general formula (I). In the general formula (I), P ¹ and P ² each independently represent a polymerizable group. As the polymerizable group, a polymerizable group capable of addition polymerization reaction is preferable. Specific examples include acryloyl group, methacryloyl group, glycidyl group, vinyl group, vinyloxy group, oxetanyl group and the like, among which acryloyl group and methacryloyl group are particularly preferable. L ¹ , L ^2m , and L ³ each independently represent a divalent linking group, a C 1-20 divalent alkylene group, a C 1-20 divalent alkenylene group, a carbon number 1 A divalent linkage comprising 20 divalent alkynylene groups, -O-, -S-, -NH-, -NY-, -COO-, -OCO-, -CONH-, -NHCO-, or combinations thereof Groups are preferred. As for L ¹ and L ³ , an alkyleneoxy group having 1 to 20 carbon atoms, an oxyalkyleneoxy group having 1 to 20 carbon atoms, an oxyalkyleneoxycarbonyl group having 1 to 20 carbon atoms, and an oxyalkylenecarbonyl having 1 to 20 carbon atoms An oxy group etc. can be mentioned as a particularly preferable example. For L ^2m , an alkylene group having 1 to 20 carbon atoms, an oxyalkyleneoxy group having 1 to 20 carbon atoms, a carbonyloxyalkyleneoxycarbonyl group having 1 to 20 carbon atoms, or an oxycarbonylalkylene having 1 to 20 carbon atoms A carbonyloxy group can be mentioned as a particularly preferred example. R ¹ and R ^2m each independently represent the above-described photoresponsive group. m represents an integer of 1 to 4, and is preferably 1 or 2.

Here, the polyfunctional monomer represented by the general formula (I) is particularly preferably a polyfunctional monomer represented by the following general formula (III).
Formula (III)

In the general formula (III), the description of P ¹ , P ² , L ¹ , L ³ , R ¹ , R ^2m , l, n is the same as that in the general formula (I). Regarding L ² , an alkylene group having 1 to 20 carbon atoms, an oxyalkyleneoxy group having 1 to 20 carbon atoms, a carbonyloxyalkyleneoxycarbonyl group having 1 to 20 carbon atoms, and an oxycarbonylalkylenecarbonyloxy group having 1 to 20 carbon atoms Can be mentioned as preferred examples, and —CH ₂ — and —CH ₂ CH ₂ — can be mentioned as particularly preferred examples.

  Specific examples of the polyfunctional monomer containing a plurality of photoresponsive groups used in the present invention are given below. However, the polyfunctional monomer of the present invention is not limited to these.

The polyfunctional monomer containing a plurality of photoresponsive groups represented by the general formula (III) of the present invention can be produced, for example, by the following method.
Scheme 1

(In the formula, P ¹ , P ² , L ¹ , L ² and L ³ have the same meanings as described above. Q represents an appropriate leaving group. L ¹¹ and L ¹² are bonded by reaction to form L ^1. And L ³¹ and L ³² are groups bonded to each other by reaction to form L ^3. )
A compound represented by the general formula (I-IV) is obtained by diazo coupling of the compound represented by the general formula (II) with the compound represented by the general formula (I-II) and the general formula (I-III). Convert. In this reaction, preferred examples of L ¹¹ and L ³¹ include divalent linking groups such as —O—, —S—, and —NH—. Regarding diazo coupling, a compound represented by formula (II) is allowed to react with sodium nitrite in the presence of an acid to form a diazonium salt, and then in the presence of a base, formula (I-II), and A general diazo coupling method for coupling with a compound represented by the formula (I-III) can be employed. The acid used is preferably hydrochloric acid, and the base used can be any base such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, or an organic base such as triethylamine, but sodium hydroxide, potassium hydroxide. Non-bases such as are preferred. Next, the compound represented by the general formula (IV) or the general formula (I-VI) is condensed in the presence of a base, and a plurality of azobenzene groups are used as the target photoresponsive unit represented by the general formula (III). Can be synthesized. Here, Q represents a leaving group, and preferred leaving groups include a mesyl group, a tosyl group, and a halogeno group. L ¹² and L ³² are each a substituent that forms a divalent linking group L ¹ or L ³ by binding to L ¹¹ or L ^31, and preferred examples include an alkylene group, an oxyalkylene group, and an iminoalkylene group. Can be mentioned. As the base to be used, a non-base such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate or an organic base such as triethylamine can be adopted, but a non-base such as sodium carbonate and potassium carbonate is particularly preferred. It is also preferable from the viewpoint of accelerating the reaction to add a small amount of sodium iodide, potassium iodide or the like as required.

  The monofunctional monomer suitably used in the present invention is preferably a monofunctional monomer represented by the general formula (II).

In the general formula (II), P ³ represents a polymerizable group, and a polymerizable group capable of addition polymerization reaction is preferable. Specific examples include acryloyl group, methacryloyl group, glycidyl group, vinyl group, vinyloxy group, oxetanyl group and the like, among which acryloyl group and methacryloyl group are particularly preferable. L ⁴ represents a divalent linking group, and is a divalent alkylene group having 1 to 20 carbon atoms, a divalent alkenylene group having 1 to 20 carbon atoms, a divalent alkynylene group having 1 to 20 carbon atoms, —O A divalent linking group consisting of-, -S-, -NH-, -NY-, -COO-, -OCO-, -CONH-, -NHCO-, or a combination thereof is preferred M is a mesogenic group, The main skeleton of liquid crystal molecules contributing to the formation of rigid liquid crystals is shown. Examples of mesogenic groups are described in, for example, “Flushage Kristal in Table II”, VEB Deutsche Verlag fur Grundstoff Industries, Leipzig, (1984), pages 7-18. The mesogen group is classified into a mesogen group used for a rod-like liquid crystal and a mesogen group used for a disc-like liquid crystal, and is preferably a mesogen group generally used for a rod-like liquid crystal. Among these, a mesogen group represented by the following general formula (IV) is particularly preferable.
Formula (IV)

In the formula, ring A, ring B and ring C represent a cyclic group having 5 to 10 ring members, and represent a benzene ring, cyclohexane ring, piperidine ring, pyridine ring, pyrimidine ring, dioxane ring, thiophene ring or naphthalene ring, A benzene ring and a cyclohexane ring are particularly preferred. Ring A, Ring B, and Ring C may each have a substituent on the ring, and the substituent includes an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and 1 to 1 carbon atoms. 20 alkoxycarbonyl groups, C1-20 alkyloxycarbonyl groups, cyano groups, halogeno groups and the like are preferable, C1-6 alkyl groups, C1-6 alkoxy groups, C1-6 carbon atoms. Particularly preferred are an alkoxycarbonyl group, an aalkyloxycarbonyl group having 1 to 6 carbon atoms, a cyano group, a fluoro group, a bromo group and the like. When the rings A, B, and C have a substituent on the ring, the substituents on the ring may be connected to each other to form a ring. X or _{Y p} is, independently, a single _{bond, -CH 2 CH 2 -, -} CH = CH -, - C≡C -, - C≡C-C≡C -, - COO -, - OCO _{-, - O -, - CH} 2 O -, - OCH 2 -, - N = N -, - CH = N -, - N-C = H -, - C = C-CO -, - CO-C = C— represents a single bond, —COO—, —OCO—, —C═C—CO—, and —CO—C═C—.
o represents 0 or 1, but is preferably 1.

  Specific examples of the monofunctional monomer used in the present invention are given below. However, the monofunctional monomer of the present invention is not limited to these.

  In the copolymer constituting the light-driven polymer actuator of the present invention, the total amount of the polyfunctional monomer containing a plurality of photoresponsive groups is 50 with respect to the total amount of the copolymer components from the viewpoint of drive response. % By weight or less is preferable, and 30% by weight or less is more preferable. The total amount of the monofunctional monomer is preferably 50% by weight or more, more preferably 70% by weight or more, based on the total amount of the copolymer constituent components, from the viewpoint of drive response. In addition to the polyfunctional monomer and the monofunctional monomer, the constituent component of the copolymer may contain an additive such as a crosslinking agent as necessary. Each of the monofunctional monomer and the polyfunctional monomer may be one kind or plural. Specifically, the crosslinking agent is a compound having a plurality of polymerizable groups, and can be appropriately selected depending on the monomer used. Specific examples of the acrylate include trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

The copolymer constituting the light-driven polymer actuator of the present invention is a polyfunctional compound having a plurality of photoresponsive groups that have the above-mentioned monofunctional monomer and the above-described polymerizability and cause structural changes upon light stimulation. It can be obtained by polymerizing a composition containing a functional monomer.
A general polymerization method can be used for the polymerization reaction, although it varies depending on the polymerizable group and properties of the monofunctional monomer and the polyfunctional monomer. For example, various known polymerization methods using heat or electromagnetic waves can be employed for the polymerization, but radical polymerization using an azo polymerization initiator or a photopolymerization initiator, or cationic polymerization using a photoacid generator is particularly preferred. For the polymerization reaction, a method of dissolving the composition in a solvent and reacting with a solution or a method of reacting by applying the composition on a substrate or injecting the composition between substrates is employed. A method of reacting by coating on a substrate or injecting a composition between a pair of substrates is preferable.

  In the light-driven polymer actuator of the present invention, the photoresponsive group present in the copolymer obtained by polymerizing a monofunctional monomer and a polyfunctional monomer may or may not be oriented in the polymer. Which one is selected depends on the usage form of the actuator. For example, when a material that selectively bends or stretches only in one direction is required, it is preferable that the photoresponsive groups are uniaxially arranged in the polymer layer. In addition, when a material that can be bent or stretched in a free direction is required, it is preferable that the photoresponsive group is not oriented in the polymer layer.

  Below, the example of the manufacturing method of the copolymer which comprises the optically driven polymer actuator of this invention is demonstrated in detail.

  FIG. 1 is a flowchart showing an embodiment of a first method for producing a light-driven polymer actuator of the present invention.

  As a first step, a composition comprising a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that undergo structural changes upon receiving light stimulation is formed on a substrate. Apply (step S100).

  This first step will be described in further detail as follows.

  As the substrate, a glass substrate, a silicon substrate, a metal substrate, various polymer films, an elastomer, or the like can be used. The substrate may be subjected to orientation treatment as necessary. For the alignment treatment, methods generally used in the field of liquid crystals and polymers can be employed. Specifically, for example, an alignment film such as polyimide or polyvinyl alcohol is disposed on the substrate and a rubbing treatment is applied to the alignment film, or a photo-alignment film made of cinnamoyl polymer or azo polymer is disposed. Thus, a method of performing photo-alignment treatment, a method of performing vertical alignment treatment using a quaternary ammonium salt on the substrate, and the like can be employed. Furthermore, from the viewpoint of continuous production, a drum or a band may be used as the substrate.

  As the solvent of the coating solution, a known solvent that can dissolve or disperse the monomer component for constituting the copolymer can be used. Specific examples of the solvent include halogen solvents such as chloroform and dichloromethane, ketone solvents such as methyl ethyl ketone and cyclohexanone, amide solvents such as dimethylformamide and dimethylacetamide, and chloroform, methyl ethyl ketone, cyclohexanone and dimethylacetamide are preferable. Particularly preferred are chloroform, methyl ethyl ketone, and dimethylacetamide. Moreover, you may use combining these solvents.

  The optimum amount of the solvent added is determined within a range that does not impair the applicability, but the solid content concentration is preferably in the range of 1 to 75% in the coating solvent, and in the range of 5 to 50%. Is particularly preferred.

  If necessary, additives such as a polymerization initiator, a polymerization inhibitor, a photosensitizer, and a coating aid may be added to the coating solution. Regarding the polymerization initiator, a known polymerization initiator can be appropriately selected according to the polymerizable molecule having a photoresponsive group and the polymerization method.

  Specifically, an azo polymerization initiator, a cationic photopolymerization initiator, a radical photopolymerization initiator, or the like can be employed.

  Examples of the azo polymerization initiator include V-30, V-40, V-59, V-65, V-70, V-601, VAm-110, and VAm-111 (all manufactured by Wako Pure Chemical Industries). Can be adopted. As a cationic photopolymerization initiator, WPI-113 (manufactured by Wako Pure Chemical Industries), Irgacure 250 (manufactured by Ciba Specialty Chemicals), or the like can be employed. As the radical photopolymerization initiator, Irgacure 651, Irgacure 907, Irgacure 784, Irgacure Oxe 01 (all manufactured by Ciba Specialty Chemicals) and the like can be employed.

  As the polymerization inhibitor, for example, known hydroquinone polymerization inhibitors, hindered phenol polymerization inhibitors, and the like can be used. As the hydroquinone polymerization inhibitor, hydroquinone monomethyl ether, DOHQ (manufactured by Wako Pure Chemical Industries), DHHQ (manufactured by Wako Pure Chemical Industries, Ltd.) and the like can be employed. As the hindered phenol polymerization inhibitor, Irganox 1010, Irganox 1035, Irganox 1076 (all manufactured by Ciba Specialty Chemicals) and the like can be employed.

  The photosensitizer is used for combined use with a photopolymerization initiator, and can be appropriately selected according to the photopolymerization initiator and the wavelength of light. Specific examples include diethylthioxanthone, isopropylthioxanthone, Darocur EHA (manufactured by Ciba Specialty Chemicals), Darocur EDB (manufactured by Ciba Specialty Chemicals), and the like.

  With respect to the coating aid, for example, a known surfactant or high viscosity agent can be used to improve coating properties.

  The optimum amount of the solvent added is determined within a range that does not impair the applicability, but the concentration of the polymer is preferably in the range of 1 to 75% in the coating solvent, and in the range of 5 to 50%. It is particularly preferred.

  As the coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, print coating method, etc. may be used. it can.

  Subsequently, the composition is dried. A known drying method can be used for drying. Specifically, room temperature drying, warming drying, blow drying, and reduced pressure drying are mentioned, and these may be combined.

  Next, as a second step, the composition is polymerized (step S101).

  This second step will be described in further detail as follows.

  First, the monomer of the composition is polymerized to form a copolymer of a polyfunctional monomer containing a plurality of photoresponsive groups and a monofunctional monomer. Various known polymerization methods using heat or electromagnetic waves can be employed for the polymerization, but radical polymerization using an azo polymerization initiator or a photopolymerization initiator, and cationic polymerization using a photoacid generator are particularly preferred.

  In the case of thermal polymerization, the appropriate heating temperature depends on the polymerization initiator used. When the coated material exhibits liquid crystallinity, it is preferable to polymerize at a temperature higher than the temperature at which the liquid crystal is exhibited. For this purpose, an appropriate heating temperature and polymerization initiator are employed.

  In the case of photopolymerization, a known light source can be used without limitation, but a light source suitable for the photopolymerization initiator used is preferable. The wavelength of the light source is 220 nm to 740 nm, although it depends on the type of photoresponsive group and the photopolymerization initiator. When employing an azobenzene group as the photoresponsive group, specifically, a light source having a longer wave than 450 nm is preferable, and a wavelength of 520 nm to 600 nm is preferably used. When the composition exhibits liquid crystallinity, the polymerization is preferably performed at a temperature higher than the temperature at which the liquid crystal is exhibited. The polymerization reaction is preferably performed in a nitrogen atmosphere.

  The copolymer obtained as a result of the above can be peeled off from the substrate (drum, band) as necessary to obtain the copolymer of the present invention.

  In addition, when using as an actuator by the form integrated with a board | substrate, it can be used without peeling off the obtained copolymer from a board | substrate.

  Below, the example of another manufacturing method of the copolymer which comprises the optically driven polymer actuator of this invention is demonstrated.

  FIG. 2 is a flowchart showing an embodiment of the second manufacturing method of the optically driven polymer actuator of the present invention.

  As a first step, a composition comprising a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that undergo structural changes upon light stimulation is paired with a pair of substrates. Inject in between (step S200).

  This first step will be described in further detail as follows.

  As a method of injecting between a pair of substrates, a general method such as a dispenser method or a bell jar method is adopted. Additives such as a polymerization initiator, a polymerization inhibitor, a photosensitizer, and a coating aid may be added to the composition. These explanations are as described above.

  Next, as a second step, the composition is polymerized (step S201).

  That is, the injected monomer is polymerized to form a copolymer of a polyfunctional monomer and a monofunctional monomer. The polymerization is the same as described above.

  Even through these steps, the optically driven polymer actuator of the present invention is manufactured.

  The copolymer obtained as a result of the above can be peeled off from the substrate as necessary to obtain a polymer comprising the copolymer of the present invention.

  The copolymer obtained as described above is disposed in the drive unit, provided with a light irradiation unit and a light waveguide unit for light driving, and the light irradiated from the light irradiation unit is guided to the drive unit, and the light drive type of the present invention One form of polymer actuator can be manufactured. As a light source of the light irradiation unit, a commonly used light source, for example, a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, a mercury xenon lamp, a carbon arc lamp, various lasers (eg, semiconductor laser) , Helium neon laser, argon ion laser, helium cadmium laser, YAG laser), light emitting diode, cathode ray tube, and the like. The light irradiation preferably has a configuration capable of irradiating the drive unit with light of two different wavelengths as required for reversible operation. In addition, a configuration in which heating by light or heat is used using a heater or light is also preferable.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
(Example 1)
Synthetic crosslinking agent C-1 of crosslinking agent C-1

  First, 87.8 mL of concentrated hydrochloric acid and 25 g of 4,4′-methylenedianiline (manufactured by Aldrich) were added to 25.8 mL of water under ice-cooling, and 21.7 g of sodium nitrite was added to 30.4 mL with stirring. An aqueous solution dissolved in water was added dropwise to prepare a diazonium salt reaction solution.

  Subsequently, 29.6 g of phenol and 68 g of sodium hydroxide were added to 680 mL of water and stirred under ice-cooling, and the previously prepared diazonium salt reaction solution was added dropwise. After reacting for 4 hours, a small amount of hydrochloric acid was added and suction filtration was performed. The obtained precipitate was washed with water and purified by silica gel chromatography (eluent: hexane / ethyl acetate = 1/1) to obtain 36 g of bis (4- (4-hydroxyphenylazophenyl) methane.

Next, to 100 mL of dimethylacetamide, 10 g of the bis (4- (4-hydroxyphenylazophenyl) methane obtained above, 13.3 g of 4-acryloxybutyl mesylate, 8.3 g of potassium carbonate, and a catalytic amount of Irgacure 1010 was added, and the mixture was reacted for 24 hours at 70 ° C. Water was added to the reaction mixture, and the mixture was extracted with dichloromethane, and the organic layer was washed with an aqueous ammonium chloride solution and saturated brine, and then dried over magnesium sulfate. After evaporation under reduced pressure, the residue was purified by silica gel chromatography (eluent: dichloromethane / ethyl acetate = 3/1) to obtain 6.0 g of the intended crosslinking agent C-1.
(Example 2)
Crosslinking agent C-2 Synthetic crosslinking agent C-2

  First, 25 g of 4,4′-ethylenedianiline (manufactured by Aldrich) was added to 203.6 mL of 1N hydrochloric acid under ice cooling, and 17.1 g of sodium nitrite was dissolved in 40.8 mL of water while stirring. The aqueous solution was added dropwise, and 406.5 mL of methanol was added to prepare a diazonium salt reaction solution.

  Subsequently, a reaction solution obtained by adding 23.3 g of phenol and 26.3 g of potassium hydroxide to 81.7 mL of methanol was added dropwise to the previously prepared diazonium salt reaction solution. After reacting for 4 hours, a small amount of hydrochloric acid was added and suction filtration was performed. The obtained precipitate was washed with 1N hydrochloric acid, ethyl acetate and water to obtain 58.8 g of 1,2-bis (4- (4-hydroxyphenylazophenyl) ethane.

Next, to 100 mL of dimethylacetamide, 10 g of 1,2-bis (4- (4-hydroxyphenylazophenyl) ethane obtained above, 13.3 g of 4-acryloxybutyl mesylate, 8.3 g of potassium carbonate, And a catalytic amount of Irgacure 1010 were added and reacted for 24 hours at 70 ° C. Water was added to the reaction solution, extracted with dichloromethane, and the organic layer was washed with 1N-hydrochloric acid and saturated aqueous sodium hydrogen carbonate solution, and then with magnesium sulfate. After the solvent was distilled off under reduced pressure, the residue was purified by silica gel chromatography (eluent: dichloromethane / ethyl acetate = 20/1) to obtain 7.0 g of the desired crosslinking agent C-2.
Example 3
Crosslinking agent C-3 Synthetic crosslinking agent C-3

  First, 24.6 mL of concentrated hydrochloric acid, 10 g of 4,4′-diaminostilbene hydrochloride (manufactured by Aldrich) was added to 7.23 mL of water under ice-cooling, and 6.1 g of sodium nitrite was added while stirring. An aqueous solution dissolved in 5 mL of water was added dropwise to prepare a diazonium salt reaction solution.

  Subsequently, 8.3 g of phenol and 18.8 g of sodium hydroxide were added to 188 mL of water and stirred under ice-cooling, and the previously prepared diazonium salt reaction solution was added dropwise. After reacting for 4 hours, a small amount of hydrochloric acid was added and suction filtration was performed. The obtained precipitate was washed with water to obtain 14.4 g of bis (4- (4-hydroxyphenylazophenyl) methane.

Next, to 60 mL of dimethylacetamide, 10 g of 1,2-bis (4- (4-hydroxyphenylazophenyl) methane obtained above, 13.3 g of 4-acryloxybutyl mesylate, 8.3 g of potassium carbonate, And a catalytic amount of Irgacure 1010 were added and reacted for 24 hours at 70 ° C. Water was added to the reaction solution, extracted with dichloromethane, and the organic layer was washed with 0.5N hydrochloric acid, saturated aqueous bicarbonate solution, and water, After drying with magnesium sulfate, the solvent was distilled off under reduced pressure, and the residue was washed with methanol and hot water to obtain 8.3 g of the intended crosslinking agent C-3.
Example 4
Production of copolymer 1
First, a coating solution having the following composition was prepared, filtered with a micro filter (DISMIC-13 PTFE 0.45 mm: manufactured by ADVANTEC), and then with a 180 μm-thick Teflon (registered trademark) tape on a nitroflon film AS ONE. The solution was poured into a 3 cm × 3 cm square frame, and the solvent was evaporated at room temperature for about 12 hours and dried.

Next, ultraviolet light emitted from an ultraviolet irradiator (EXECURE 3000, manufactured by HOYA CANDEO OPTRONICS) at 125 ° C. in a nitrogen atmosphere is irradiated through an O-54 cut filter (manufactured by HOYA) at an intensity of 50 mW / cm ² (560 nm). Thus, a crosslinked film having a thickness of 27 μm was prepared.

  FIG. 3 is a diagram showing an evaluation experiment of optical response of the optically driven polymer actuator in Example 4 of the present invention.

  FIG. 3 (a) shows a state before ultraviolet irradiation. One end of the light-driven polymer actuator 1 is fixed to the end of the upper surface of the mounting table 2 with a stopper 3. The stopper 3 is made of a material that blocks light.

  This light-driven polymer actuator 1 was irradiated onto a cross-linked film obtained by converting ultraviolet light emitted from an ultraviolet irradiator (EXECURE 3000, manufactured by HOYA CANDEO OPTRONICS) into linearly polarized light through a polarizing plate.

  FIG. 3B shows a state after ultraviolet irradiation. As shown in FIG. 3B, it was confirmed to be driven by light.

The composition of the coating solution is as follows.
Cross-linking agent C-1 10 mg
Monofunctional monomer M-1 90mg
Radical polymerization initiator Irg-784 2mg
(Ciba Specialty Chemicals)
Cationic photopolymerization initiator W113 2mg
(Wako Pure Chemical)
Chloroform 1mL

Monofunctional monomer M-1
(Example 5)
Production of copolymer 2
First, a polyimide liquid crystal alignment film (SE-150) was applied, and the following composition was poured into a cell in which a pair of rubbed glass substrates were prepared using a 40 μm double-sided tape as a spacer, and heated at 150 ° C. for 1 hour. Thus, a crosslinked film having a thickness of 26 μm was formed.

  Next, the obtained crosslinked film was irradiated with ultraviolet light emitted from an ultraviolet irradiator (EXECULE 3000, manufactured by HOYA CANDEO OPTRONICS), and its light driving behavior was confirmed.

The monomer composition is as follows.
Cross-linking agent C-2 30mg
Monofunctional monomer M-2 3mg
Azo polymerization initiator V-40 1mg
(Wako Pure Chemicals)

Monofunctional monomer M-2
(Example 6)
Production of copolymer 3
First, the following composition was injected into a cell prepared using a double-sided tape having a glass substrate of 40 μm as a spacer and heated at 150 ° C. for 1 hour to form a 27 μm thick crosslinked film.

  Next, the ultraviolet light emitted from the ultraviolet irradiator (EXECULE 3000, manufactured by HOYA CANDEO OPTRONICS) was irradiated to the crosslinked film obtained by converting the linearly polarized light through the polarizing plate, and the light driving behavior was confirmed.

The monomer composition is as follows.
Cross-linking agent C-2 30mg
Monofunctional monomer M-3 3mg
Azo polymerization initiator V-40 1mg
(Wako Pure Chemicals)

Monofunctional monomer M-3
(Example 7)
Production of copolymer 4
First, a polyimide liquid crystal alignment film (SE-150) was applied, and the following composition was poured into a cell in which a pair of rubbed glass substrates were prepared using a 40 μm double-sided tape as a spacer, and heated at 150 ° C. for 1 hour. Thus, a crosslinked film having a thickness of 26 μm was formed.

  Next, the obtained crosslinked film was irradiated with ultraviolet light emitted from an ultraviolet irradiator (EXECULE 3000, manufactured by HOYA CANDEO OPTRONICS), and its light driving behavior was confirmed.

The monomer composition is as follows.
Cross-linking agent C-2 30mg
Monofunctional monomer M-4 3mg
Azo polymerization initiator V-40 1mg
(Wako Pure Chemicals)

Monofunctional monomer M-4
(Comparative Example 1)
Production of comparative copolymer 1
The following composition is injected into a cell in which a polyimide liquid crystal alignment film (SE-150) is applied and a pair of rubbed glass substrates is prepared using a 40 μm double-sided tape as a spacer, and heated at 90 ° C. for 1 hour to form molecules. An oriented crosslinked film having a thickness of 28 μm was prepared.

The monomer composition is as follows.
Cross-linking agent D-1 30 mg
Monofunctional monomer M-4 3mg
Azo polymerization initiator V-40 1mg
(Wako Pure Chemicals)
Cross-linking agent D-1

(Comparative Example 2)
Comparative copolymer production 2
The following composition was injected into a cell prepared by applying a polyimide liquid crystal alignment film (SE-150) and rubbing a pair of glass substrates using a 40 μm double-sided tape as a spacer, and heated at 100 ° C. for 1 hour to form molecules. An oriented crosslinked film having a thickness of 25 μm was prepared.

The monomer composition is as follows.
Cross-linking agent D-1 30 mg
Monofunctional monomer M-3 3mg
Azo polymerization initiator V-40 1mg
(Wako Pure Chemicals)
Here, with respect to the crosslinked films shown in the examples and comparative examples of the present invention, the responsiveness to the light driving behavior of the crosslinked films obtained from the ultraviolet light emitted from the ultraviolet irradiator (EXECURE 3000, manufactured by HOYA CANDEO OPTRONICS). Are summarized in Table 1. As is clear from this result, it was revealed that the crosslinked film composed of the copolymer of the present invention exhibited a light bending behavior at room temperature and improved its responsiveness.

  As described above, according to the present invention, a light-driven actuator that has a structure that is reversibly deformed by light stimulation and that has a practical response speed, flexibility, and lightness, and that is driven silently. It is possible to provide a simple manufacturing method of the light-driven polymer actuator and a good material used for manufacturing the light-driven polymer actuator.

  The light-driven actuator according to the present invention includes, for example, active forceps, endoscopes, artificial muscles, drug delivery systems, bio-elements, bio-elements, aerospace robots, artificial mimics in the medical / nursing field. It can be applied to a driving unit such as a satellite. Furthermore, in general equipment, it can be used for a drive unit of a digital camera, a mobile phone, a micropump, a tactile display, a non-contact inspection equipment, and the like.

It is a flowchart which shows one Embodiment of the 1st manufacturing method of the optically driven polymer actuator of this invention. It is a flowchart which shows one Embodiment of the 2nd manufacturing method of the optically driven polymer actuator of this invention. It is a figure which shows the evaluation experiment of the photoresponsiveness of the optically driven polymer actuator in Example 3 of this invention.

Explanation of symbols

1 Light-driven polymer actuator 2 Mounting table 3 Stopper

Claims (14)

In a light-driven polymer actuator that includes a polymer that deforms in response to light stimulation and uses the deformation of the polymer as an actuator,
Comprising a copolymer formed by polymerizing a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a polymerizable property and a plurality of photoresponsive groups that undergo structural changes upon light stimulation;
The light-driven polymer actuator, wherein the copolymer is deformed in response to light stimulation and has a function as an actuator. The light-driven polymer actuator according to claim 1, wherein the polyfunctional monomer is a polyfunctional monomer represented by the following general formula (I).
Formula (I)

(In the formula, P ¹ and P ² each independently represent a polymerizable group, L ¹ , L ^2m and L ³ each independently represent a divalent linking group, and R ¹ and R ^2m each independently And m represents an integer of 1 to 4.)   The light-driven polymer actuator according to claim 1, wherein the photoresponsive group is an azobenzene group. 4. The light-driven polymer actuator according to claim 1, wherein the monofunctional monomer is a monofunctional monomer represented by the following general formula (II). 5.
Formula (II)

(Wherein P ³ represents a polymerizable group, L ⁴ represents a divalent linking group, M represents a mesogenic group, and o represents 0 or 1) In the general formula (I),
5. The light-driven polymer according to claim 2, wherein P ¹ and P ² are each independently a polymerizable group represented by the following general formula (III): Actuator.
Formula (III)

(In the formula, Z ¹ represents a single bond, an oxygen atom, or —O—CH ₂ —, Z ² represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and Z ³ represents a single bond, -CO- or -O- is represented.) In the general formula (I),
5. The light-driven polymer actuator according to claim ² , wherein each of P ¹ and P ² is independently an acryloyl group or a methacryloyl group. In a method for producing a light-driven polymer actuator comprising a polymer that deforms in response to light stimulation, and using the deformation of the polymer as an actuator,
Applying a composition comprising a monofunctional monomer having a polymerizability and a polyfunctional monomer having a plurality of photoresponsive groups having a polymerizability and causing a structural change upon light stimulation;
A process for polymerizing the composition, and a method for producing a light-driven polymer actuator. In a method for producing a light-driven polymer actuator comprising a polymer that deforms in response to light stimulation, and using the deformation of the polymer as an actuator,
Injecting a composition comprising a monofunctional monomer having a polymerizable property and a polyfunctional monomer having a plurality of photoresponsive groups having a polymerizable property and undergoing a structural change upon light stimulation; ,
A process for polymerizing the composition, and a method for producing a light-driven polymer actuator. The polyfunctional monomer represented by the following general formula (IV).
Formula (IV)

(In the formula, P ¹ and P ² each independently represent a polymerizable group, and L ¹ , L ² and L ³ each independently represent a divalent linking group. In the formula, the azobenzene group is a substituent. May be included.) In the general formula (IV),
The polyfunctional monomer according to claim 9, wherein P ¹ and P ² are each independently a polymerizable group represented by the general formula (III). In the general formula (IV),
The polyfunctional monomer according to claim 9, wherein P ¹ and P ² are each independently an acryloyl group or a methacryloyl group. In the general formula (IV),
P ¹ and P ² are each independently an acryloyl group or a methacryloyl group,
L ¹ , L ² , and L ³ are each independently a divalent alkylene group having 1 to 20 carbon atoms, a divalent alkenylene group having 1 to 20 carbon atoms, or a divalent alkynylene group having 1 to 20 carbon atoms. A divalent linking group comprising a group, -O-, -S-, -NH-, -COO-, -OCO-, -CONH-, -NHCO-, or a combination thereof. 9. The multifunctional monomer according to 9. In the general formula (IV),
L ² is an alkylene group having 1 to 20 carbon atoms, an oxyalkyleneoxy group having 1 to 20 carbon atoms, a carbonyloxyalkyleneoxycarbonyl group having 1 to 20 carbon atoms, or an oxycarbonylalkylenecarbonyloxy group having 1 to 20 carbon atoms. The polyfunctional monomer according to claim 9, wherein the polyfunctional monomer is a group.   A polymer comprising a copolymer of the polyfunctional monomer according to any one of claims 9 to 13 and the monofunctional monomer represented by the general formula (II) according to claim 4.

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