JP2008115347A - Photoinduced rotation method, light-driven rotor, power transmission system and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoinduced rotation method converting light energy to rotational energy. <P>SOLUTION: The photoinduced rotation method of the present invention, in one embodiment, includes irradiating a first active light and a second active light to a crosslinked liquid crystal polymer molded product, in which a photochromic molecule reversibly isomerizable by irradiation of the first and second active light is introduced, so as to be locally isomerized, and rotating the crosslinked liquid crystal polymer molded product by inducing shape change of the molded product. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light-induced rotation method, a light-driven rotor, and a power transmission system and a power transmission device including the light-driven rotor.

  Liquid crystal polymers are highly functional materials that have both anisotropy based on liquid crystallinity and moldability of polymers, but they have only been put to practical use in a few fields, and in a wider range of fields. Practical use is expected. The group of the present inventors has recently been able to bend a crosslinked liquid crystal polymer molded body by irradiation with a first actinic ray in a molded body composed of a crosslinked liquid crystal polymer incorporating photochromic molecules, It was found that the crosslinked liquid crystal polymer molded product can be restored to its original form by irradiation with actinic rays (Patent Document 1). In other words, it was reported that light energy can be converted to mechanical energy in crosslinked liquid crystal polymer moldings. If this phenomenon is used, wiring for energy transmission becomes unnecessary, and it becomes possible to bend a molded body such as a film only by irradiating a laser beam from a distance. For this reason, it can be expected to be applied to various light-driven motion materials such as an unprecedented small and light optical micromachine.

Although this is not an example of using liquid crystal polymer materials and light energy, as a polymer material that converts external stimuli into mechanical energy, there is a technology that induces rotation of the polymer material using water and a polar solvent. It has been proposed (Non-Patent Document 1). Non-patent document 2 will be described later.
JP 2005-255805 A Okuzaki, H. et al J. Polym. Sci. Part B: Polym. Phys. 1996, 34, 1747-1749 "Modeling examples", [online], D-MEC Corporation, [searched on November 9, 2006], Internet (http://www.d-mec.co.jp/products/acculas/acculas_zoukei.html)

  In the development of application to light-driven motion materials, development of other motion modes is expected in addition to the motion mode of the light bending-restoration response.

  The present invention has been made in view of the above-described background, and an object thereof is to provide a light-induced rotation method capable of converting light energy into rotational energy, a light-driven rotor, and a power transmission system including the same. And providing a power transmission device.

  In the photoinduced rotation method according to the present invention, the photochromic molecule isomerism is introduced into a crosslinked liquid crystal polymer molded product into which a photochromic molecule that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray is introduced. The cross-linked liquid crystal polymer molded body is rotated by irradiating the first actinic ray and the second actinic light so as to cause localization and inducing a shape change of the cross-linked liquid crystal polymer molded body. It is something to be made. In the photoinduced rotation method according to the present invention, the orientation change of mesogens is enhanced by isomerization of photochromic molecules in a material having a liquid crystal structure having both orientation and fluidity and a crosslinking structure that easily propagates the orientation change. Can efficiently propagate to the polymer skeleton. As a result, it is possible to induce an anisotropic and mechanical response of the crosslinked liquid crystal polymer molded body and convert it into a rotational motion.

  The light-driven rotor according to the present invention contains a photochromic molecule that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray, and the first actinic ray and the second actinic ray. It comprises a crosslinked liquid crystal polymer molded body that exhibits rotational behavior in response to light irradiation. In the present invention, photochromic molecules are introduced into a liquid crystal structure having both orientation and fluidity and a crosslinked liquid crystal polymer having a crosslinked structure that easily propagates orientation changes, so light energy can be converted into rotational energy. A light-driven rotor can be provided.

  A power transmission system according to the present invention includes the light-driven rotor and a light source that irradiates the light-driven rotor with the first active light beam and the second active light beam.

  A power transmission device according to the present invention includes the light-driven rotor and a power transmission member that moves in conjunction with the light-driven rotor.

  According to the present invention, there is an excellent effect that it is possible to provide a light-induced rotation method capable of converting light energy into rotational energy, a light-driven rotor, a power transmission system and a power transmission device including the same. .

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. It goes without saying that other embodiments may also belong to the category of the present invention as long as they meet the spirit of the present invention.

  The light-driven rotator according to the present invention contains a photochromic molecule that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray, and the first actinic ray and the second actinic ray. A crosslinked liquid crystal polymer molded body that exhibits rotational behavior in response to the irradiation is provided. Examples of the optimal form of the crosslinked liquid crystal polymer molded body include films and sheets. In the present specification, the “light-driven rotor” refers to a member that can convert light energy into rotational energy that is mechanical energy.

  The cross-linked liquid crystal polymer according to the present invention may be either a main chain polymer liquid crystal or a side chain polymer liquid crystal, but there is a domain region that is an alignable region of the mesogen, which is a hard core part directly involved in the alignment of the liquid crystal. However, the polymer skeleton must form a three-dimensional network structure. As a result, the oriented mesogen is gently restrained in the polymer matrix, and the movement of the polymer skeleton is strongly correlated with the orientation of the mesogen. The cross-linked structure is more preferably a structure in which orientational order is maintained over a long distance.

  The crosslinked liquid crystal polymer can be obtained by a copolymer obtained from a monofunctional polymerizable monomer and a crosslinked polymerizable monomer copolymerized therewith. As a method for obtaining a copolymer, a known method can be used, but a method in which a mixture containing a monofunctional polymerizable monomer and a crosslinkable monomer is copolymerized under a condition in which the mesogen is oriented is used. Is convenient and advantageous. As a specific example, by using a reaction vessel having an orientation surface formed on the inner surface, a monomer mixture is photopolymerized or thermally polymerized using an in-situ polymerization method or the like. The method of making it copolymerize is mentioned. According to this method, the copolymer molecules are generated in a state of being oriented in a specific direction by the action of the oriented surface. Examples of the orientation treatment include a method in which a polyimide layer is formed on the inner surface of the reaction vessel and this is rubbed in a specific direction, and an electric field / magnetic field is applied. As another method of copolymerization, there can be mentioned a method in which a linear or weakly cross-linked liquid crystal polymer is prepared and a cross-linking reaction is performed while orienting mesogens by stress.

  The polymerization ratio between the monofunctional polymerizable monomer and the crosslinkable monomer is determined in consideration of the desired domain size and crosslink density. The domain size is preferably larger than 0.5 μm. When the domain size is small, the polymer skeleton has a structure similar to the relationship between chromophores and polymer segments in non-liquid crystal films, and the orientation of mesogens changes in each domain, giving the entire film even if the polymer skeleton is deformed. This is because the influence is reduced. In such a case, the orientation change does not lead to a mechanical response, and the rotation of the crosslinked liquid crystal polymer molded body is less likely to be induced. The cross-linked liquid crystal polymer molded product is not limited to those composed of the cross-linked liquid crystal polymer itself, and appropriate additives are included as long as the properties of the target cross-linked liquid crystal polymer molded product are not impaired. Also good.

  Examples of the polymerizable group include a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyloxy group, a vinyl group, and an epoxy group. Acrylamide groups are preferred. As the crosslinkable monomer, a bifunctional monomer or a polyfunctional monomer represented by a trifunctional monomer or the like can be used. Known polymerization initiators can be used.

  As a method for obtaining a cross-linked liquid crystal polymer molded body, a method in which a polymerization reaction is performed using a reaction vessel that also serves as a mold using a casting polymerization method, and the resulting copolymer is simultaneously molded is used. Is preferred. According to such a casting polymerization method, it is very easy to apply the above-described preferred alignment treatment method.

  The introduction site of the photochromic molecule may be either the polymer main chain or the polymer side chain, but is more preferably introduced into the mesogen site. This is because by introducing it into the mesogen site, the molecular structure change accompanying the isomerization of the photochromic molecule can be effectively converted into the orientation change of the mesogen in the domain region. By adopting a cross-linked structure, the orientation change of the mesogen is propagated to the polymer skeleton with high efficiency, and the anisotropic and mechanical response of the cross-linked liquid crystal polymer molded body is induced and converted into rotational motion. It becomes possible.

The photochromic molecule is not particularly limited, and known ones can be used. Examples include azobenzene and stilbene structures that undergo trans-cis isomerization, spiropyran and diallyl structures that can undergo ring-opening and ring-closing photoisomerization, and the like. Among them, azobenzene represented by the following formula (1) is particularly preferable because the wavelength of the first actinic ray is different from the wavelength of the second actinic ray and the intermolecular distance changes greatly upon isomerization. be able to.
Although azobenzene depends on a substituent bonded to the azobenzene skeleton, the first actinic ray is about 300 to 400 nm (hereinafter simply referred to as “ultraviolet light”), and the second actinic ray is about 500 to 650 nm. (Hereinafter simply referred to as “visible light”). As shown in the above formula (1), when azobenzene is irradiated with ultraviolet light, it is isomerized from a rod-shaped trans form to a bent cis form. When this isomerized cis form is irradiated with visible light, it returns to the original trans form.

  When azobenzene is introduced into the crosslinked liquid crystal polymer, azobenzene works as an orientation control component. The trans form of azobenzene stabilizes the liquid crystal phase or itself functions as a mesogen. On the other hand, a cis body with a bent structure destabilizes the liquid crystal phase. Therefore, the phase transition can be induced by inducing isomerization from the trans isomer to the cis isomer even under isothermal conditions.

  Factors that propagate the mesogenic orientation change due to photochromic molecule isomerization to the polymer backbone with high efficiency include cross-linking structure, type of photochromic molecule, introduction rate of photochromic molecule, liquid crystal type, irradiation condition, etc. be able to. The type of liquid crystal is not particularly limited. From the viewpoint of propagating the mesogen orientation change to the polymer skeleton with high efficiency, it is preferable to use a mesogen having high orientation ability and packing property. Examples of such a liquid crystal include a smectic liquid crystal and a ferroelectric liquid crystal.

  The light-driven rotor according to the present invention may be composed only of a crosslinked liquid crystal polymer molded body, but preferably includes a support for the crosslinked liquid crystal polymer molded body from the viewpoint of improving mechanical strength and the like. The material of the support is not particularly limited as long as it can move integrally with the crosslinked liquid crystal polymer molded body. For example, known materials such as general-purpose polymers such as polyethylene, polypropylene, and polyethylene terephthalate, inorganic materials such as elastomer, or silicon rubber can be used. The support may be composed of a single material or a plurality of materials.

  As the support, from the viewpoint of moving integrally with the crosslinked liquid crystal polymer molded body, it is preferable to use a highly elastic body such as an elastomer or a polymer molded body having sufficient flexibility at the operating temperature. By using a polymer molded body having a glass transition temperature equal to or lower than the operating temperature, a polymer having excellent flexibility can be obtained. Examples of such a polymer material include polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, polytetrafluoroethylene, and polyvinylidene fluoride. Of course, the glass transition temperature of the polymer molded product may be made to be lower than the working temperature by adding a plasticizer. Here, the “operating temperature” refers to the temperature at which the optically driven rotor is actually driven. When the polymer component material has a melting point (Tm), it is preferably used in a range where the use temperature does not exceed the melting point from the viewpoint of stably using the light-driven rotor. The material of the support is appropriately selected according to the intended use and required durability. The thickness of the support is determined according to the degree of flexibility of the material used, the strength, the intended use, and the like. The thickness is not particularly limited, but can be, for example, about 5 μm to 100 μm.

  A method for integrally producing the crosslinked liquid crystal polymer molded body and the support is not particularly limited, and a known method can be used. For example, a crosslinked liquid crystal polymer molded body can be laminated with the support as a film or a sheet. When making a laminated structure, it is important that the support and the crosslinked liquid crystal polymer molded article are sufficiently bonded. This is to prevent peeling or cracking when rotating by light driving. A known method can be used as the bonding method. For example, a method of laminating with a cross-linked liquid crystal polymer molded body using a support having an adhesive function, and bonding using various coating methods such as bar coater coating between the support and the cross-linked liquid crystal polymer molded body. Examples thereof include a method of providing a layer, and a method of bonding a support and a crosslinked liquid crystal polymer molded body with a double-sided tape. When an intermediate layer such as an adhesive layer or a double-sided tape is provided, it is preferable to select a layer having excellent flexibility from the viewpoint of moving integrally with the crosslinked liquid crystal polymer molded body. The thickness of the adhesive layer can be set to, for example, 0.5 μm to 20 μm, but is not limited to this. In place of the laminated structure, the support and the crosslinked liquid crystal polymer may be arranged to face each other via a gap holding member such as a spacer. In addition, the mechanical strength can be improved by sufficiently increasing the thickness of the crosslinked liquid crystal polymer molded body without providing a support.

  FIG. 1 is a schematic perspective view showing an example of a power transmission device according to the present invention. The power transmission device 4 includes an endless belt 1 that is an optically driven rotor, two shafts 2 that are power transmission members, and two pulleys 3. The endless belt 1 is wound around two rotatable cylindrical pulleys 3 as shown in FIG. The shaft 2 is fitted to the inner peripheral portion of the cylindrical portion of the pulley 3, and the pulley 3 and the shaft 2 are configured to rotate integrally. By irradiating the endless belt 1 with the first actinic ray and the second actinic ray, the light energy is converted into rotational energy to rotate the endless belt 1, which is used to rotate the pulley 3 and the shaft 2. Power can be transmitted to a roller or the like (not shown) that converts and rotates integrally with the shaft 2. Alternatively, the shaft 2 may be fixed and only the pulley 3 may be configured to be rotatable, and the power may be transmitted from the pulley 3 to other members.

  The endless belt 1 is endless using an adhesive or the like at the end of a film, sheet or the like (hereinafter referred to as “crosslinked liquid crystal polymer film” or the like) composed of a crosslinked liquid crystal polymer molded body having a desired size. It can be produced by forming a ring-shaped ring. Alternatively, a crosslinked liquid crystal polymer film or the like and a support (for example, a polymer film or a polymer sheet) may be laminated to produce a ring by the above-described method or the like. By configuring the inner peripheral surface side of the endless belt 1 in contact with the pulley 3 with a layer made of a support, the mechanical strength of the endless belt 1 can be increased. Of course, the endless belt 1 may include elements other than the support and the crosslinked liquid crystal polymer film. For example, a tooth meshing portion may be provided at the end on the inner peripheral surface side in the width direction of the endless belt 1 and the end of the pulley 3 so that no slip occurs between the endless belt 1 and the pulley 3. . Moreover, you may provide a protective layer etc. on upper layers, such as a crosslinked liquid crystal polymer film.

  The cross-linked liquid crystal polymer film or the like does not necessarily have to be formed on the entire main surface of the endless belt. For example, the cross-linked liquid crystal polymer film may be disposed endlessly in the longitudinal direction of the central portion in the width direction of the belt having the support as a base, Different types of cross-linked liquid crystal polymer films or the like may be arranged in stripes in the major axis direction. A plurality of cross-linked liquid crystal polymer films or the like into which photochromic molecules having different wavelengths of actinic rays are introduced may be arranged in stripes so as to have a plurality of rotational motion modes. Further, the cross-linked liquid crystal polymer film or the like does not necessarily need to be disposed endlessly in the major axis direction, and may be disposed at an arbitrary position depending on the application.

  When power is transmitted to the driven shaft at a position away from the drive shaft via an endless belt, a motor unit is generally provided. According to the power transmission device 4 of the present invention, power can be transmitted to the shaft 2 and the pulley 3 by inducing rotation of the endless belt 1 without providing a motor portion. This makes it possible to reduce the size and weight of the device. In addition, since the rotation of the endless belt 1 can be turned on and off by the non-contact light source, a power transmission system capable of arbitrarily setting the distance of the light source can be provided. For example, it is possible to provide a power transmission system that can be remotely operated by disposing a light source at a distance.

  Next, the light induced rotation method according to the present invention will be described. In the photoinduced rotation method according to the present invention, a photochromic molecule is isomerized into a cross-linked liquid crystal polymer molded product into which a photochromic molecule that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray is introduced. The cross-linked liquid crystal polymer molded body is rotated by irradiating the first actinic ray and the second actinic ray so as to cause local occurrence and inducing a shape change of the cross-linked liquid crystal polymer molded body. is there. Examples of a method for locally causing isomerization of a photochromic molecule include a method for adjusting the light intensity to be irradiated according to the extinction coefficient of the crosslinked liquid crystal polymer molded body, and a method for adjusting the irradiation region.

  In order to perform the rotational motion continuously, isomerization of photochromic molecules is continuously induced. In order to continuously induce isomerization of the photochromic molecule, both the first actinic ray and the second actinic ray may be irradiated simultaneously or sequentially. If the isomerization occurs continuously, the light irradiation may be intermittent. Note that “continuous” as used herein does not mean that a specific photochromic molecule is continuously isomerized, but isomerization of any photochromic molecule in the crosslinked liquid crystal polymer molded body occurs. It means a state.

  The irradiation positions of the first actinic ray and the second actinic ray on the crosslinked liquid crystal polymer molded body may be the same or different. However, when the positions are different, the positions are such that the isomerization of the photochromic molecule can be induced by the irradiation of the first actinic ray and the second actinic ray. This is because it is necessary to induce isomerization by irradiation of each light beam and to propagate the orientation change of the mesogen to the polymer skeleton. It is convenient that at least a part of the irradiation region of the second actinic ray is included in the portion isomerized by the irradiation of the first actinic ray.

As a result of extensive studies by the present inventors, it has been found that the rotation direction can be appropriately changed according to the irradiation position of the actinic ray. The rotation direction and the rotation behavior with respect to the irradiation position can vary depending on the crosslinked liquid crystal polymer molded product used and the irradiation conditions. It may be configured to rotate in a single direction according to the application to be used, or may be configured to switch the rotation in both directions by controlling the irradiation position. The irradiation light intensity is selected so as to be optimal according to the type of the introduced photochromic molecule, the introduction rate of the photochromic molecule, the thickness of the crosslinked liquid crystal polymer molded product, the desired rotational behavior, etc., but usually 1 to 1000 mJ. / Cm ² or so. Either non-polarized light or polarized light may be used depending on the desired rotational behavior and photochromic molecules. As the irradiation light source, various known light sources such as a high-pressure mercury lamp and a laser beam can be used.

  It is preferable that the irradiation site of the first actinic ray and the second actinic ray with respect to the crosslinked liquid crystal polymer molded body has a glass transition temperature or higher. This is because the micro-Brownian motion, which affects the motion of the polymer main chain, is activated at high temperatures, while it is frozen below the glass transition temperature. Note that when the crosslinked liquid crystal polymer molded body is irradiated with light, a part of the polymer can be converted into thermal energy, but some of the irradiation region is locally at or above the glass transition temperature due to this heat. However, when the melting point (Tm) is present in the crosslinked liquid crystal polymer molded product, it is used in a range where the temperature of the irradiated part is lower than the melting point.

  Next, the mechanism by which the light-driven rotor according to the present invention rotates will be described with reference to FIGS. In the following, a film composed of a crosslinked liquid crystal polymer in which azobenzene is introduced into a side chain polymer mesogen will be described as an example. In addition, the size and shape of each part in the drawing are for convenience of explanation, and the ratio, shape, etc. of each part are different from actual ones.

  FIG. 2A is an explanatory view schematically showing a change in the shape of the isomerization of the azobenzene molecule shown in the above formula (1). In the figure, reference numeral 10 schematically shows the shape of a rod-shaped transformer body, and reference numeral 20 schematically shows the shape of a bent cis body. As shown in the figure, when the azobenzene molecule is irradiated with ultraviolet light 7 as the first actinic light, it is isomerized from the rod-shaped trans isomer 10 to the cis-body 20 bent, and the visible light 8 is irradiated as the second actinic light. To return to the original transformer body 10. That is, the rod-like transformer body 10 and the bent cis body 20 can be reversibly changed by light.

  FIG. 2B is a partially enlarged explanatory view schematically showing a state before and after ultraviolet irradiation of a crosslinked liquid crystal polymer film (hereinafter also simply referred to as “film”) 30 in which azobenzene is introduced into a mesogen site. In the figure, reference numeral 31 denotes a polymer main chain, reference numeral 11 denotes a trans-type azobenzene side chain in which azobenzene is a trans isomer, reference numeral 12 denotes a non-azobenzene side chain in which azobenzene does not contain azobenzene, and reference numeral 21 denotes a cis-benzene cis isomer. The cis-type azobenzene side chain is shown. When the trans-type azobenzene side chain 11 is irradiated with ultraviolet light 7, the structure changes to a cis-type azobenzene side chain 21 in which the azobenzene portion is bent, and thereby the orientation change of the non-azobenzene side chain 12 is also induced. Then, this change propagates to the polymer skeleton and the crosslinked liquid crystal polymer film 30 contracts.

  By the way, the azobenzene molecule has a high molar extinction coefficient at a wavelength (near 360 nm) that induces isomerization from the trans form to the cis form. For this reason, when the azobenzene concentration in the film increases, the light that induces isomerization cannot be transmitted through the film 30, and the azobenzene molecules present on the irradiated surface side are selectively photoisomerized. As a result, anisotropy occurs in the shrinkage rate in the thickness direction of the film 30.

  FIG. 3 is a partially enlarged explanatory view schematically showing how anisotropy occurs in the shrinkage rate of the film 30 with respect to the thickness direction of the film. When the film 30 (see FIG. 3A) is irradiated with ultraviolet light, the structure changes from a trans isomer to a cis isomer in the irradiation region, thereby inducing a change in domain orientation. And as shown in FIG.3 (b), the anisotropy of a contraction rate generate | occur | produces in the thickness direction. As a result, the film 30 exhibits a mechanical response as shown in FIG. When visible light 8 is irradiated to this, the structure changes from a cis isomer to a trans isomer in the irradiated region, and a new orientation change of the domain is induced to generate a new anisotropy of the shrinkage rate.

  FIG. 4 is a schematic diagram for explaining an example of the rotational behavior of an endless belt film (hereinafter, also simply referred to as “endless belt”) 32. When the endless belt 32 is irradiated with ultraviolet light 7 from the left side in the drawing as shown in FIG. 4A, isomerization of azobenzene occurs in the irradiation area of the circumferential surface on the light source side of the endless belt 32. An orientation change accompanying the anisotropy of the shrinkage rate is induced. As shown in FIG. 4B, the endless belt 32 is once depressed in the central direction and then bent in the irradiation direction. At this time, when one side of the both ends of the depressed portion is irradiated with visible light 8 as shown in FIG. 4 (b), the irradiated portion tries to return to the original transformer body. 32 is pulled toward the light source irradiating visible light 8. As a result, the center of gravity of the endless belt 32 moves. Then, the irradiation position of the visible light 8 on the endless belt 32 is changed, and another surface is irradiated with the visible light 8. That is, by continuously irradiating the ultraviolet light 7 and the visible light 8, it is possible to move the irradiation spot and move the position of the center of gravity of the endless belt 32. The light irradiation side can be rotated.

  The thickness of the endless belt 32 is not particularly limited, but should be a thickness that can induce deformation as shown in FIG. 3, and is appropriately selected depending on the properties of the crosslinked liquid crystal polymer used and the support. It is not always necessary to induce the anisotropy of the shrinkage rate in the thickness direction, and it may be configured to rotate by inducing anisotropic deformation of the shrinkage rate in the circumferential direction.

  As described above, the trans form of azobenzene stabilizes the liquid crystal phase or itself functions as a mesogen. On the other hand, the cis form of azobenzene destabilizes the liquid crystal phase due to the bent structure. Therefore, when azobenzene is used, a phase transition from the liquid crystal phase to the isotropic phase can be induced isothermally by irradiation with ultraviolet light. For this reason, it is possible to change the orientation change of the domain drastically, propagate the orientation change to the polymer skeleton with high efficiency, and induce an anisotropic and mechanical response of the crosslinked liquid crystal polymer molded body to cause the rotational motion. Easy to convert. Needless to say, it is only necessary to induce an anisotropic and mechanical response of the crosslinked liquid crystal polymer molded body so as to be able to rotate, and it is needless to say that an isothermal phase transition from the liquid crystal phase to the isotropic phase is not essential.

  Since the present invention uses a liquid crystal having both orientation and fluidity, it is easy to induce an orientation change and to induce anisotropic deformation of the polymer skeleton. The mechanical properties can be changed by changing the orientation, material, crosslinking density, etc. of the liquid crystal in the crosslinked liquid crystal polymer molded body.

  According to the present invention, it is possible to provide a light-induced rotation method, a light-driven rotor, and a power transmission device that can convert light energy into rotational energy. Further, it is possible to provide a power transmission system including the light-driven rotor and the light source. Since light is used as a control medium, there is an advantage that no inductive noise is generated, high-speed transmission such as multiplex transmission is possible, and non-contact connection is easy. In addition, by using a polymer material, the moldability is excellent, and weight reduction and cost reduction can be expected. In addition, by using the structure itself as a drive element, simplification and miniaturization can be easily realized. Furthermore, since rotation can be induced by a slight stimulus, it can be expected to be used in a wide variety of applications including drive devices such as plastic motors. In addition, according to the optically driven rotor according to the present invention, a power transmission system is provided that can eliminate the need for wiring for energy transmission and can induce rotational behavior only by irradiating laser light or the like from a distance. Can do. Furthermore, it can be expected to create an unprecedented high-performance micromachine or the like by combining with a micro modeling technique (Non-patent Document 2). The shape of the optically driven rotor according to the present invention is not limited to the endless belt, and the shape can be appropriately selected according to the application.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, the scope of the present invention is not limited to the following Example. The reagents and the like described below are generally commercially available unless otherwise specified. For nuclear magnetic resonance absorption spectrum measurement ( ¹ HNMR), Lamda-300 (300 MHz) was used, and tetramethylsilane (TMS) was used as an internal standard. The liquid crystallinity of the compound is measured using a differential scanning calorimeter (DSC; Seiko I & E, SSC-5200, DSC220C), a hot stage (Mettler, FP-90, FP-82HT), and a polarizing microscope (POM; OLYMPUS, BH-2). evaluated. The differential scanning calorimeter was measured under a nitrogen atmosphere with a polymer evaluation rate of 10 ° C./min and a monomer evaluation of temperature increase and temperature decrease rate of 2 ° C./min.

The light rotation behavior was observed with a CCD camera (OMRON VC-HRM20Z). For ultraviolet light, 365 nm monochromatic light was extracted using a UV-LED light source (LC-L1 manufactured by Hamamatsu Photonics or UV-400 manufactured by Keyence). The intensity of the output light was 200 mW / cm ^{2 for} LC-L1 and 240 mW / cm ^{2 for} UV-400. For the visible light, white light from a halogen lamp light source (FLH-50, Shimadzu Rika) was used. The intensity of the output light was 200 mW / cm ^{2 at} 540 nm. The irradiation distance between the measurement sample and the light source was about 15 to 5 mm.

In this example, a film-like one was used as the form of the crosslinked liquid crystal polymer molded body. The crosslinked liquid crystal polymer is composed of an acrylic ester polymer having a cyano group represented by the following formula (2) having an azobenzene structure introduced as a photochromic molecule (hereinafter abbreviated as “CALP-CN”), and a portion of the cyano group. An acrylate polymer (hereinafter abbreviated as “CALP-Alk”) represented by the following formula (3) changed to an alkyl group was used.
The CALP-CN represented by the above formula (2) is a monofunctional polymerizable monomer represented by the following formula (4) 6- [4- (4-cyanophenylazo) phenoxy] nonanyl acrylate (hereinafter referred to as “A9ABC”). ) And 4,4′-bis [6- (acryloyloxy) nonanyloxy] azobenzene (hereinafter abbreviated as “DA9AB”) represented by the following formula (5), which is a crosslinking polymerizable monomer. , And obtained by copolymerization under the condition of developing a liquid crystal phase.

The CALP-Alk represented by the above formula (3) is a monofunctional polymerizable monomer 6- [4- (4-nonanyloxyphenylazo) phenoxy] nonanyl acrylate (hereinafter, referred to as the following formula (6)). (Abbreviated as “A9AB9”) and the crosslinkable monomer DA9AB shown in the above formula (5) were mixed and copolymerized under the condition of developing a liquid crystal phase.

<Synthesis of monofunctional polymerizable monomer>
To a 500 ml eggplant flask, 3.5 g (27 mmol) of 4-aminobenzonitrile was added, 100 ml of 1N hydrochloric acid was added, and the mixture was stirred under ice-cooling conditions. An aqueous solution in which 2.2 g (32 mmol) of sodium nitrite was dissolved in 30 ml of water was slowly added thereto. Next, 12 ml of an aqueous solution in which 1.0 g (25 mmol) of sodium hydroxide and 3.0 g (32 mmol) of phenol are dissolved is slowly added to the reaction solution, and powdered potassium carbonate is added until the pH reaches about 9, and the mixture is kept under ice-cooling conditions for about 4 hours. Stir. Thereafter, 1N hydrochloric acid is added to adjust the pH to 4, and the deposited precipitate is recovered and recrystallized with a mixed solvent (ethyl acetate: hexane = 1: 1) to give 4-hydroxy 4′-cyanoazobenzene 5 as a red solid. 0.7 g (26 mmol) was obtained.

  5.7 g (26 mmol) of 4-hydroxy 4′-cyanoazobenzene was dissolved in 10 ml of N, N-dimethylformamide (DMF), and 3.5 g (30 mmol) of potassium carbonate and 10 g (30 mmol) of 9-bromononanol were added. The mixture was heated to reflux at 130 ° C. for 3 hours, and the completion of the reaction was confirmed by TLC. Thereafter, 50 ml of ethyl acetate and 30 ml of water were added to the solution, and then the organic layer was washed with dilute hydrochloric acid and distilled water, and the solvent was distilled off under reduced pressure and dried. The dried solid was recrystallized with a mixed solvent (ethyl acetate: hexane = 1: 1) to obtain 8.8 g (24 mmol) of 4- (6-hydroxynonanyloxy) 4′-cyanoazobenzene as a red solid.

2.8 g (9.3 mmol) of 4- (6-hydroxynonanyloxy) 4′-cyanoazobenzene was dissolved in 150 ml of tetrohydrofuran (THF), pre-dried with magnesium sulfate, and then 2.6 ml (19 mmol) of triethylamine. , Hydroquinone was added in a small amount and stirred under ice-cooling conditions. A solution obtained by diluting 1.5 g (19 mmol) of acrylic acid chloride with 30 ml of THF was slowly added thereto using a dropping funnel, and the mixture was stirred for 2 hours under ice-cooling and then stirred at room temperature for 36 hours. A potassium carbonate aqueous solution was added until the pH reached 10, and THF was distilled off under reduced pressure, and then the reaction solution was filtered under reduced pressure. The residue was dissolved in chloroform, the organic layer was washed with dilute hydrochloric acid and brine, and the solvent was distilled off under reduced pressure. The dried solid was purified by column chromatography (chloroform), recrystallized with a mixed solvent (ethyl acetate: methanol = 1: 1), and 4- [6- (acryloyloxy) nonanyloxy] 4′-cyano, which was the target product. 1.4 g (3.4 mmol) of azobenzene (A9ABC) was obtained.
・ Yield 37%
¹ HNMR (δ, CDCl ₃ ); 1.2-1.4 (m, 12H), 1.8 (m, 4H), 4.0 (t, 2H), 4.1 (t, 2H), 5.7 (dd, 2H), 6.0 (dd , 2H), 6.3 (dd, 2H) 7.0 (m, 2H), 7.8 (m, 2H), 7.9 (d, 4H)

A9AB9 represented by the above formula (6) was synthesized by the same procedure as that for the later-described crosslinkable monomer DA9AB, and it was confirmed by NMR measurement that the target compound was obtained.
・¹ HNMR
(Δ, CDCl ₃ ); 0.86 (t, 4H), 1.2-1.4 (m, 20H), 4.0 (t, 4H), 4.1 (t, 2H), 5.8 (dd, 1H), 6.1 (dd, 1H) , 6.4 (dd, 1H), 6.9 (m, 4H), 7.8 (m, 4H)

<Synthesis of crosslinkable monomer>
4-Nitrophenol 3.5 g (25 mmol), potassium carbonate 3.5 mg (25 mmol), 9-bromononanol 7.0 g (30 mmol) were dispersed in DMF 5 ml, and the suspension was heated to reflux at 130 ° C. for 3 hours. . After confirming the completion of the reaction by TLC, 50 ml of ethyl acetate and 30 ml of water were added to the solution, and then the organic layer was washed with dilute hydrochloric acid and distilled water, and the solution was distilled off under reduced pressure and dried. The dried solid was dissolved in 50 ml of THF and stirred under ice cooling. To this was added 1.5 g of 5? Pd-C, and 2.0 g (50 mmol) of sodium borohydride was added in three portions, followed by stirring at room temperature for 2 hours. Thereafter, 100 ml of 1N hydrochloric acid was added dropwise to the solution with stirring under ice cooling. Solid potassium carbonate was added until pH 10 and the solution was filtered under reduced pressure. The reaction product was extracted from the precipitate and the solution with ethyl acetate, and the solution was distilled off under reduced pressure, followed by drying to obtain 4.0 g (16 mmol) of 4- (6-hydroxynonanyloxy) aniline as a reddish brown solid.

  To a 500 ml eggplant flask, 4.0 g (16 mmol) of 4- (6-hydroxynonanyloxy) aniline and 100 ml of 1N hydrochloric acid were added and stirred under ice cooling. 30 ml of an aqueous solution in which 1.2 g (17 mmol) of sodium nitrite was dissolved was slowly added dropwise thereto. Next, while maintaining this aqueous solution at 0 ° C., an aqueous solution in which 2.0 g (50 mmol) of sodium hydroxide and 1.6 g (17 mmol) of phenol were dissolved in 50 ml of water was dropped, and further, powdered potassium carbonate was adjusted to a pH of about 9. The mixture was added to the mixture and stirred for 4 hours under ice-cooling. Thereafter, 1N hydrochloric acid was added to adjust the pH to 4, followed by filtration under reduced pressure. The residue was dissolved in ethyl acetate with heating, washed with water, dried over anhydrous magnesium sulfate, and the desiccant was filtered. Further, ethyl acetate was distilled off under reduced pressure. The residue was recrystallized with a mixed solvent (ethyl acetate: hexane = 1: 1) to obtain 3.6 g (10 mmol) of 4-hydroxy-4 ′-(6-hydroxynonanyloxy) azobenzene as a brown solid.

  3.6 g (10 mmol) of 4-hydroxy-4 ′-(6-hydroxynonanyloxy) azobenzene was dissolved in 10 ml of DMF, and 3.5 g (30 mmol) of potassium carbonate and 3.5 g (16 mmol) of 9-bromononanol were added to the solution. ) And heated to reflux at 130 ° C. for 3 hours. After confirming the completion of the reaction by TLC, 50 ml of ethyl acetate and 30 ml of water were added to the solution, the organic layer was washed with dilute hydrochloric acid and distilled water, and the solution was evaporated under reduced pressure and dried. The dried solid was recrystallized from ethyl acetate and hexane to obtain 4.6 g (9.3 mmol) of 4,4′-bis (6-hydroxynonanyloxy) azobenzene as a bright yellow solid.

The above 4,4′-bis (6-hydroxynonanyloxy) azobenzene (4.6 g, 9.3 mmol) was dissolved in 150 ml of THF, pre-dried with magnesium sulfate, and then added with 5.2 ml (37 mmol) of triethylamine. Next, a small amount of hydroquinone was added and stirred under ice cooling. 3 ml (37 mmol) of acrylic acid chloride diluted with 30 ml of THF was slowly added dropwise. The mixture was further stirred for 2 hours under ice cooling, and then stirred at room temperature for 12 hours. Thereafter, an aqueous potassium carbonate solution was added until the pH reached 10, THF was distilled off under reduced pressure, and the reaction solution was filtered under reduced pressure. The residue was dissolved in chloroform, the organic layer was washed with dilute hydrochloric acid and brine, and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography (chloroform), recrystallized from a mixed solvent (ethyl acetate: methanol = 1: 1), and 4,4′-bis [6- (acryloyloxy) nonanyloxy] azobenzene (the target product). DA9AB) 1.0 g (1.6 mmol) was obtained.
・ Yield 17%
_{^{· 1 HNMR (δ, CDCl 3}} ): 1.2-1.4 (m, 20H), 1.6 (m, 8H), 4.0 (t, 4H), 4.1 (t, 4H), 5.7 (dd, 2H), 6.0 (dd , 2H), 6.3 (dd, 2H), 6.9 (m, 4H), 7.8 (m, 4H)

Table 1 shows the phase transition temperatures of the obtained A9ABC, A9AB9, and DA9AB.

<Production of cross-linked liquid crystal polymer film>
The liquid crystal cell was produced as follows. First, a thin film of polyamic acid, which is a polyimide precursor, was prepared by spin coating on a glass substrate ultrasonically cleaned in a neutral detergent and isopropyl alcohol. And the glass substrate which has a polyimide orientation film was obtained by heat-processing. Next, the polyimide surface was rubbed using a rubbing apparatus (EHCRM-50), and then the substrate was bonded through a silica spacer so that the rubbing direction was anti-parallel, to obtain a homogeneous cell. The hybrid cell was obtained by subjecting one side of the substrate to homogeneous orientation treatment and the other to homeotropic orientation treatment.

Next, 80 mol% of A9ABC (monofunctional polymerizable monomer) of the chemical formula (4) and 20 mol% of DA9AB (crosslinked polymerizable monomer) of the chemical formula (6) were mixed, and the following chemical formula was used as a thermal polymerization initiator. A sample added with 2 mol% of V-7 (use of Wako recrystallized with ethanol) of (7) was heated to an isotropic phase temperature. And it enclosed with the said liquid crystal cell using the capillary phenomenon. This liquid crystal cell was kept in a drying oven heated to 98 ° C. for 24 hours and subjected to thermal polymerization to obtain a crosslinked liquid crystal polymer film.
In addition, 20 mol% of A9AB9 (monofunctional polymerizable monomer) of the above chemical formula (5) and 80 mol% of DA9AB (crosslinked polymerizable monomer) of the above chemical formula (6) were mixed, and the following chemical formula ( The sample to which 2 mol% of Irgacure 784 of 8) was added was heated to an isotropic phase temperature (97 ° C. or higher). And it enclosed with the said liquid crystal cell using the capillary phenomenon. The liquid crystal cell was cooled to 89 ° C. showing a smectic phase at 0.1 ° C./min, mesogens were uniaxially oriented, and then irradiated with visible light having a wavelength of 540 nm or more and a light intensity of 3 mW / cm ² for 2.5 hours. Then, a crosslinked liquid crystal polymer film was obtained by polymerization.

<Characteristics of cross-linked liquid crystal polymer film and endless belt film>
FIG. 5 (a) shows the CALP-CN and FIG. 5 (b) shows the profile of the CALP-Alk DSC measurement. As shown in the figure, a glass transition temperature was observed around 30 ° C. for both CALP-CN and CALP-Alk. When the anisotropy of the CALP-CN film was observed with a polarizing microscope, it was confirmed that the anisotropy was exhibited and that the anisotropy was stable up to 200 ° C. or higher.

(Experimental Example 1) An endless belt 32a having a diameter of 8 mm, a width of 3 mm, and a film thickness of 20 μm was produced by pressing both ends of a homogeneously oriented crosslinked liquid crystal polymer film made of CALP-CN. Then, it was placed on a plastic plate 33 made of polycarbonate as shown in FIG. The ultraviolet light 7 is irradiated on the endless belt 32a on the left side in FIG. 6 (a) and in the vicinity of the range from 7 o'clock to 8 o'clock from the direction where the angle with the mounting surface is about 30 °. As shown, the visible light 8 is on the right side in FIG. 6A with respect to the endless belt 32a, and the angle between the visible light 8 and the placement surface is about 45 °, and the time from 2 o'clock to 5 o'clock of the watch. It set so that the area vicinity might be irradiated. Both ultraviolet light 7 and visible light 8 were unpolarized and measured under the condition of 28 ° C. FIG. 6B shows a photograph of the light rotation behavior of the endless belt 32a. This figure shows photographs of the endless belt 32a before irradiation from the left side and at times of 5s, 8s and 10s from the start of irradiation, respectively. In about 10 seconds after the start of irradiation, it rotated about 50 mm toward the ultraviolet light source (left side in the figure).

(Experimental example 2) The endless belt produced in the same manner as in Experimental example 1 above was placed on black anodized, painted iron plate (black, white), and the floor instead of the plastic plate, and the rotational behavior of the endless belt was examined. did. As a result, it was confirmed that the same rotational behavior as in Experimental Example 1 was exhibited.

(Experimental example 3) About the endless belt produced similarly to the said experimental example 1, rotational behavior was examined on the measurement conditions similar to the said experimental example 1 except changing measurement temperature. Specifically, it was examined by placing an endless belt on a hot plate set at 30 ° C., 60 ° C., and 80 ° C. As a result, it was confirmed that the endless belt rotates at any temperature.

Comparative Example 1 An experiment was performed under the same conditions as in Experimental Example 1 except that no visible light was irradiated. As a result, the endless belt stopped rotating after about half a turn.

(Experimental example 4) With respect to the endless belt 32b produced in the same manner as in Experimental example 1, the irradiation region was changed as shown in FIG. That is, the ultraviolet light 7 is located on the left side in FIG. 7 (a) with respect to the endless belt 32b from the direction where the angle with the mounting surface is about 30 °, and around the range from 10:00 to 11:00 of the watch. As shown, the visible light 8 is on the right side in FIG. 7 (a) with respect to the endless belt 32b, and the angle with the mounting surface is about 45 °, from 2 o'clock to 5 o'clock of the watch. It was set so that the vicinity of the time range was irradiated. Other conditions such as the irradiation wavelength, irradiation intensity, and measurement temperature were the same as in Experimental Example 1. As a result, as shown in FIG. 7 (b), it rotated to the ultraviolet light source side (left side in the figure) about 20 mm in 12 seconds after the start of irradiation. It was confirmed that the rotation direction can be switched by changing the irradiation position of ultraviolet light.

(Experimental Example 5) The rotational behavior of an endless belt made of CALP-CN having a liquid crystal alignment property of hybrid alignment was examined. The size of the endless belt was the same as in Experimental Example 1. The visible light is endless so that the ultraviolet light is irradiated in the vicinity of the range from 10:00 to 11:00 on the left side of the endless belt at an angle of about 45 ° with the mounting surface. The watch was set to irradiate around 2 o'clock to 3 o'clock of the watch from the direction of about 60 ° on the right side of the belt. Other experimental conditions were the same as in Experimental Example 1 above. As a result, it rotated about 22 mm (about one rotation) in the direction away from the ultraviolet light source 12 seconds after the start of irradiation.

(Experimental example 6) Rotational behavior was examined in an endless belt made of CALP-CN in which the orientation of liquid crystal is twisted nematic alignment. Specifically, an endless belt having a diameter of 6 mm, a width of 3 mm, and a thickness of 20 μm was produced. The experimental conditions were the same as in Experimental Example 1 above. As a result, it rotated about 50 mm (about 3 rotations) to the ultraviolet light source side 30 seconds after the start of irradiation.

(Experimental Example 7) The rotational behavior was examined under the same conditions as in Experimental Example 1 except that CALP-Alk was used as the crosslinked liquid crystal polymer instead of CALP-CN. As a result, it was confirmed that the endless belt according to this experimental example rotated about one turn toward the ultraviolet light source 120 seconds after the start of irradiation.

(Experimental example 8) The cross-linked liquid crystal polymer film is a homogeneous liquid crystal polymer film made of CALP-Alk as the cross-linked liquid crystal polymer film, and the support is a polyethylene film (unstretched film, 50 μm, manufactured by Tosero Co., Ltd.). An endless belt comprising a support and a support was produced by the following method. First, using an automatic coating device type I (PI-1210 manufactured by Tester Sangyo Co., Ltd.) and a bar coater, a solution adhesive is supplied to one end of the polyethylene film, and the main surface of the polyethylene film is applied by bar coating. The adhesive was stretched so as to spread uniformly over the whole, and dried in an oven heated to 110 ° C. to obtain a film coated with an adhesive layer (12 μm). As the adhesive, a mixture of Arrow Base SB-1200 (manufactured by Unitika Ltd., acid-modified polyethylene resin aqueous dispersion) and Adeka Bontiter HUX380 (ADEKA Corporation, polyurethane resin aqueous dispersion) was used. Next, this film and a 20 μm cross-linked liquid crystal polymer film were laminated by thermocompression bonding at 110 ° C. Then, an endless belt (length: 45 mm) was attached to the end of the obtained laminate film with an epoxy adhesive (Hysol E-05CL, manufactured by Henkel) so that the cross-linked liquid crystal polymer film was on the outer peripheral surface side of the belt. , Width 8 mm, thickness 82 μm).

  FIG. 8A shows a schematic perspective view of a power transmission device according to Experimental Example 8. FIG. As shown in the figure, the power transmission device 34 includes an endless belt 32c, a housing 35, a large diameter shaft 36, a small diameter shaft 37, a large diameter pulley (ball bearing) 38, and a small diameter pulley (ball bearing) 39. Yes. The large-diameter pulley 38 has an outer diameter of 12 mm and an inner diameter of 8 mm, and the small-diameter pulley 39 has an outer diameter of 3 mm and an inner diameter of 1 mm. The large diameter shaft 36 and the small diameter shaft 37 are fixed to the housing 35. A large-diameter pulley 38 and a small-diameter pulley 39 are attached to the large-diameter shaft 36 and the small-diameter shaft 37, respectively, and an endless belt 32c is wound around these two pulleys. The ultraviolet light 7 travels in the vicinity where the endless belt 32c comes into contact with the small-diameter pulley 39, that is, the non-contact area between the small-diameter pulley 39 and the endless belt 32c and the vicinity of the contact area from a direction substantially perpendicular to the tangential direction of the endless belt 32c. Irradiated. Visible light 8 is in the vicinity of the endless belt 32c in contact with the large-diameter pulley 38, that is, the non-contact area between the large-diameter pulley 38 and the endless belt 32c and the vicinity of the contact area with respect to the tangential direction of the endless belt 32c. Irradiated from a substantially vertical direction. Both the ultraviolet light 7 and the visible light 8 were non-polarized, and the experiment was performed under the condition of 25 ° C. Other irradiation conditions were the same as in Experimental Example 1 above. FIG. 8B shows a photograph of the power transmission device 34 before light irradiation, FIG. 8C shows 30 seconds after irradiation, and FIG. 8D shows 60 seconds after irradiation. As shown in these figures, the endless belt 32c, the large-diameter pulley 38, and the small-diameter pulley 39 rotate counterclockwise in the figure.

(Experimental Example 9) Using the same power transmission device as in Experimental Example 8, the irradiation region was changed with the same sample, and the rotational behavior was examined. FIG. 9A shows a schematic perspective view of a power transmission device according to Experimental Example 9. FIG. The ultraviolet light 7 is substantially perpendicular to the tangential direction of the endless belt 32d in the vicinity where the endless belt 32d contacts the large diameter pulley 38, that is, in the non-contact area and the contact area between the large diameter pulley 38 and the endless belt 32d. Irradiated from the direction. Visible light 8 is substantially perpendicular to the endless belt 32d in the vicinity where the endless belt 32d is in contact with the small-diameter pulley 39, that is, in the non-contact area and the contact area between the small-diameter pulley 39 and the endless belt 32d. Irradiated from the direction. Other conditions such as irradiation wavelength, irradiation intensity, and measurement temperature were the same as in Experimental Example 8. FIG. 9B shows a photograph of the power transmission device 34 before light irradiation, FIG. 9C after 15 seconds of irradiation, and FIG. 9D after 30 seconds of irradiation. As shown in these drawings, the endless belt 32d was rotated in the direction opposite to that of the experimental example 8, that is, in the clockwise direction. It was confirmed that the rotation direction can be switched by changing the irradiation position.

  A light-induced rotation method, a light-driven rotator, and a power transmission system and power transmission device including the light-driven rotator according to the present invention, for example, a plastic motor, a switching element, It can be used for various applications such as toys and micromachines.

The typical perspective view which shows an example of the shape of an optically driven rotor. (A) is a schematic diagram for demonstrating the isomerization of an azobenzene molecule, (b) is a schematic diagram for demonstrating the structural change of a bridge | crosslinking liquid crystal polymer. The elements on larger scale for demonstrating the anisotropic deformation | transformation of a crosslinked liquid crystal polymer molded object. The schematic diagram for demonstrating the rotational behavior of the optically driven rotor which concerns on this invention. The figure which shows the DSC measurement profile of the crosslinked liquid crystal polymer which concerns on an Example. (A) is typical explanatory drawing of the optical system with respect to the endless belt which concerns on Experimental example 1, (b) is a photograph of the rotational behavior of the endless belt which concerns on Experimental example 1. FIG. (A) is typical explanatory drawing of the optical system with respect to the endless belt which concerns on Experimental example 4, (b) is a photograph of the rotational behavior of the endless belt which concerns on Experimental example 4. FIG. (A) is a typical perspective view of the power transmission device according to Experimental Example 8, and (b) to (d) are photographs of the endless belt according to Experimental Example 8 before and after light irradiation. (A) is a typical perspective view of the power transmission device according to Experimental Example 9, and (b) to (d) are photographs of the endless belt according to Experimental Example 9 before and after light irradiation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endless belt 2 Shaft 3 Pulley 4 Power transmission device 7 Ultraviolet light 8 Visible light 10 Transformer body 11 Transformer side chain 20 Cis body 21 Cis type side chain 30 Crosslinked liquid crystal polymer film 31 Polymer main chain 32 Endless belt film 33 Plastic plate 34 Power transmission device 35 Housing 36 Large diameter shaft 37 Small diameter shaft 38 Large diameter pulley 39 Small diameter pulley

Claims (10)

To a crosslinked liquid crystal polymer molded article into which a photochromic molecule that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray is introduced,
By irradiating the first actinic ray and the second actinic ray so as to cause the isomerization of the photochromic molecule locally, a shape change of the crosslinked liquid crystal polymer molded product is induced, so that A light-induced rotation method for rotating a molecular compact.   The irradiation part of the said 1st actinic ray and 2nd actinic ray in the said crosslinked liquid crystal polymer molded object is more than the glass transition temperature of the said crosslinked liquid crystal polymer molded object, The claim 1 characterized by the above-mentioned. Light-induced rotation method. Containing photochromic molecules that can be reversibly isomerized by irradiation with a first actinic ray and a second actinic ray;
A light-driven rotator comprising a crosslinked liquid crystal polymer molded body that exhibits a rotational behavior in response to irradiation with the first actinic ray and the second actinic ray.   The light-driven rotor according to claim 3, wherein the crosslinked liquid crystal polymer molded body is formed integrally with a support.   5. The light-driven rotor according to claim 3, wherein the support is made of at least a polymer molded body, and the glass transition temperature of the polymer molded body is equal to or lower than a use temperature.   The light-driven rotor according to claim 3, 4 or 5, wherein the support and the crosslinked liquid crystal polymer molded body have a laminated structure.   The light-driven rotor according to claim 3, wherein the photochromic molecule is azobenzene.   The optically driven rotor according to any one of claims 3 to 7, wherein the optically driven rotor is an endless belt.   A power transmission system comprising: the light-driven rotor according to claim 3; and a light source that irradiates the light-driven rotor with the first active light beam and the second active light beam.   A power transmission device comprising: the optically driven rotor according to any one of claims 3 to 8; and a power transmission member that moves in conjunction with the optically driven rotor.