JP2009031667A - Electric optical function film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a film shape of an iron complex having spin crossover characteristics. <P>SOLUTION: A function film device 10 has a function film 20 containing an iron complex formed on a base film 12. The function film 20 containing an iron complex includes substantially hemispherical polymer microsphere parts 22 of several tens nm to several hundreds nm in diameter, and connecting polymer parts 28 for connecting the adjacent polymer microsphere parts 22 with each other. The polymer microsphere parts 22 include a polymer shell 24 at the outer shell part connected integrally with the connecting polymer parts 28, and a polymer core 26 as a central core part. The polymer core 26 contains an iron complex having spin crossover characteristics. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electro-optical functional film, and more particularly, to an electro-optical functional film including an iron complex having a spin crossover characteristic in which magnetic characteristics and light absorption characteristics change by light or heat.

  A complex or a complex salt is a general term for molecular compounds formed by coordination bonds or hydrogen bonds, but in many cases, a complex is synthesized from a ligand and a metal salt. Those in which iron is used as the central metal of the complex are called iron complexes. Iron complexes and the like are very widely used as catalysts in the fields of organic chemistry, polymer chemistry, and chemical industry, and can control chemical reaction, speed, and molecular weight of products.

  In addition, certain iron complexes have a characteristic that the spin state of iron ions transitions between a high spin state and a low spin state by external stimuli such as temperature, light, and pressure, so-called spin crossover characteristics. Has been issued. Here, a high spin state is a state in which a plurality of electrons of iron ions enter each electron orbit with the same spin direction, and a low spin state is a state in which each electron orbit is such that the spin directions are opposite to each other. It is in a state to enter.

  The spin crossover characteristic is a spin state transition characteristic, and the absorbance, magnetism, and volume change accordingly. As an example, certain iron complexes have a large magnetic moment at high temperatures, high absorbance and appear black, and expand in volume. On the other hand, at a low temperature, the magnetic moment is small, the absorbance is low and the color appears white, and the volume shrinks. Instead of temperature, the same behavior is caused by light irradiation and blocking, and exhibits switching characteristics. Such an iron complex is an iron complex having spin crossover characteristics.

  Thus, since the state of an iron complex having spin crossover characteristics changes due to an external stimulus, it is expected to be a functional device by using the external stimulus as an input and the changing state quantity as an output. For example, applications such as a storage element that stores and erases according to a temperature change, and an optical switch that changes absorbance by turning on and off irradiation light are expected. So far, iron complexes having various types of spin crossover properties have been synthesized and researched and developed.

  For example, in Patent Document 1, as a novel phase transition spin crossover triazole iron complex, a pink form obtained by reacting a triazole ligand having a long-chain alkoxyl group having 14 to 18 carbon atoms with an iron salt. A solid one is disclosed. This triazole iron complex is soluble in a solvent such as hexane and can be formed into a solid or film of any shape by evaporation or casting. It is described that the spin state of the central iron exhibits a spin crossover phenomenon in which the spin state of the central iron transitions between a high spin state and a low spin state due to the phase transition of the long-chain alkoxyl group.

  Patent Document 2 discloses a triazole iron complex obtained by reacting a triazole ligand having a linear alkoxyl group having 8 to 16 carbon atoms and an alkylsulfonic acid as a functional organic gel comprising a triazole iron complex. And mixed with a liquid straight-chain alkane having 8 to 16 carbon atoms. It is stated that this organic gel undergoes a sol-gel transition at the sol-gel transition temperature, causing not only a color change but also a spin transition at the transition temperature.

  As a related technique, Patent Document 3 describes that polymer microspheres are produced by a hanging drop polymerization method, an emulsion polymerization method, or the like. It has been pointed out that the microspheres synthesized by the emulsion polymerization method have a uniform particle size, and the particle size is about 0.1 μm.

JP 2005-187413 A JP 2006-241207 A JP 2000-186104 A

  As described above, an iron complex having a spin crossover characteristic is expected to be applied to a functional device, but the iron complex itself having a spin crossover characteristic is limited in use because it is a solid. Therefore, in addition to the gel state as shown in Patent Document 2, it is used as a powder obtained by pulverizing a crystal, a suspension obtained by suspending a powder in a solution, a mixture obtained by mixing a powder with molten plastic, and the like. ing.

  However, in view of convenience as a device, it is preferably a thin film or a film. As described above, in the prior art, no thin film or film that shows spin crossover characteristics has been reported.

  An object of the present invention is to provide an electro-optical functional film containing an iron complex having a film shape and spin crossover characteristics. Another object is to provide an electro-optical functional film that enables an iron complex having spin crossover characteristics to be arranged in a minute unit.

  An electro-optical functional film containing an iron complex according to the present invention is a functional film having a spin crossover characteristic in which light or heat is input and a change in magnetic characteristics or a change in light absorption characteristics is output, and the outer shell portion It consists of a polymer microsphere part having a polymer shell and a core polymer core and synthesized by an emulsion polymerization method and an emulsifier used in the emulsion polymerization method, and the adjacent polymer microsphere part is formed into a film. A connecting polymer part to be connected, and the polymer microsphere part contains an iron complex having a spin crossover characteristic in which light or heat is input and a change in magnetic characteristics or a change in light absorption characteristic is output. Features.

  In the electro-optic functional film according to the present invention, the amount of the iron complex having spin crossover characteristics is preferably 0.1% or more and 5% or less as a mass ratio with respect to the whole film.

  In the electro-optical functional film according to the present invention, the polymer microsphere part preferably has a diameter of 10 nm to 1000 nm.

  In the electro-optical functional film according to the present invention, the polymer core component is preferably polytrifluoroethyl methacrylate.

  In the electro-optical functional film according to the present invention, the polymer shell and the connecting polymer component are preferably polyvinyl alcohol.

  In the electro-optical functional film according to the present invention, the iron complex having spin crossover characteristics has 1,2,4-1H-triazole or 4-amino-1,2,4-triazole as a ligand, It is preferable that iron (II) tetrafluoroborate hexahydrate is produced as an iron salt by these reactions.

  With the above configuration, the electro-optical functional film includes a polymer microsphere portion having a polymer shell as an outer shell portion and a polymer core as a core portion, and a connecting polymer portion that connects adjacent microsphere portions in a film shape. The polymer microsphere part contains an iron complex having spin crossover characteristics. That is, the polymer microsphere part is a fine spherical body as the name suggests, and the form of the core part that is the polymer core is ensured by the outer shell part that is the polymer shell. And this polymer microsphere part is connected one after another by the connection polymer part, and is reinforced, and becomes a film form. Such a structure can be obtained by synthesizing polymer microspheres by an emulsion polymerization method and coating or casting the obtained emulsion on, for example, a suitable substrate. In each polymer microsphere part, an iron complex having a spin crossover characteristic is arranged. Thereby, it can be set as the electro-optic optical functional film reinforced with the connection polymer comprised with the emulsifier used for an emulsion polymerization method. In addition, in the film, an iron complex having a spin crossover characteristic can be arranged in units of the polymer microsphere part which is a microsphere, and for example, when used for a storage element or the like, the storage density can be improved. it can.

  In the electro-optical functional film, the amount of the iron complex having spin crossover characteristics is 0.1% or more and 5% or less as a mass ratio with respect to the whole film. As described above, the iron complex is widely used as a catalytic application in the field of organic chemistry. In that case, the iron complex is very small in mass ratio. In order to take advantage of electro-optical properties, the mass ratio used in catalytic applications is not sensitive enough. Moreover, since the polymer microsphere part is synthesized by an emulsion polymerization method, it is necessary to control the particle size according to the application. The mass ratio, which is the content of the iron complex having spin crossover characteristics, may have a lower limit set by sensitivity of electro-optical characteristics, and an upper limit set by polymerization rate of emulsion polymerization and particle size control. preferable. According to experiments, the range is preferably 0.1% or more and 5% by mass ratio of the iron complex.

  In the electro-optical functional film, the polymer microsphere part has a diameter of 10 nm or more and 1000 nm or less, so that the spin crossover complex can be arranged in a so-called nm size, for example, when applied to a storage element or the like. It is possible to increase the density.

  In the electro-optical functional film containing an iron complex, the component of the polymer core is polytrifluoroethyl methacrylate (PTFEMA). Since the polymer core contains an iron complex having spin crossover characteristics, it is preferably composed of a polymer having high translucency. As a result, the iron complex contained in the polymer core can be sufficiently irradiated with light, and the change in absorbance of the iron complex having the spin crossover property can be detected with sufficient sensitivity. As the polymer having high translucency, it is preferable to use polytrifluoroethyl methacrylate (PTFEMA) which is an acrylate polymer.

  In the electro-optical functional film containing an iron complex, the polymer shell and the connecting polymer are preferably polyvinyl alcohol (PVA). Since the connecting polymer is composed of an emulsifier used in the emulsion polymerization method, here, PVA is used as the emulsifier, and the polymer shell is also composed of the PVA. The polymer shell is an outer shell portion surrounding a polymer core containing an iron complex having a spin crossover characteristic, and ensures the stability of the form such as the particle size of the polymer microsphere portion and defines this. Therefore, the polymer shell is preferably a material having good affinity with iron and good controllability of the particle size of the polymer microsphere part in the emulsion polymerization method. PVA is water-soluble and has good affinity with iron. By using PVA, the particle size of the polymer microspheres is controlled moderately while appropriately incorporating an iron complex with spin crossover properties into the polymer core. can do. Moreover, since PVA is water-soluble as described above, a reinforcing effect can be induced when it is formed into a film shape.

In the electro-optical functional film, the iron complex having spin crossover characteristics has 1,2,4-1H-triazole or 4-amino-1,2,4-triazole as a ligand, and iron (II). It is synthesized by these reactions using tetrafluoroborate hexahydrate as an iron salt. The iron complex exhibits electro-optical properties by a phase transition between a high spin state and a low spin state. Therefore, a material with good controllability for setting the phase transition temperature is preferable. One control of the phase transition temperature is the control of the spacing between adjacent irons. In order to control the phase transition temperature, it is necessary to introduce a substituent into the ligand of the iron complex and select an appropriate counter ion. Note that Zn or Co having a size larger than that of iron may be introduced as the metal ion of the complex. As in the above configuration, it is preferable to select an amino group as the triazole ligand and BF ₄ (tetrafluoroborate) as the counter ion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the specific material demonstrated below is an example for description, and should just be a material which has the characteristic which falls in the range of selection criteria. Further, the generation conditions and the like are also examples for explanation, and can be appropriately changed depending on a combination of various conditions.

  FIG. 1 is a diagram showing a state of a functional film device 10 using a functional film 20 containing an iron complex. The functional film device 10 is an electro-optical device that receives light or heat as an input and outputs a change in magnetic characteristics or a change in light absorption characteristics, and the functional film 20 containing an iron complex is formed on the base film 12. It has a structure. The base film 12 is a base film for supporting the functional film 20 that is made of a non-magnetic material having optical transparency and containing an iron complex.

  The functional film 20 containing an iron complex is a thin film having electro-optical characteristics in which light or heat is input and a change in magnetic characteristics or a change in light absorption characteristics is output. Specifically, a plurality of minute spherical or substantially hemispherical polymer particles having a diameter of about 10 nm to several hundreds of nm are connected to each other to form a so-called sea-island structure in the form of a film. Here, the sea-island structure is a structure in which substances of two or more components are distributed in islands in one substance. As will be described later, since the thin film is obtained by synthesizing microspheres of PTFEMA using PVA as an emulsifier, here, a fine granular PTFEMA is distributed in islands in the PVA. ing. The minute polymer particles contain an iron complex having a spin crossover characteristic having an electro-optical characteristic in which light or heat is input and a change in magnetic characteristic or a change in light absorption characteristic is output. . The fine polymer particles are so-called polymer microspheres, and the size thereof is about 10 nm to several 100 nm as described above, but is 10 nm to 1000 nm, preferably 30 nm to 600 nm.

  In FIG. 2, the expanded sectional view of the functional film device 10 is shown. As described above, the functional film device 10 is formed by forming the functional film 20 containing an iron complex on the base film 12, and the functional film 20 containing an iron complex is a substantially hemispherical polymer microsphere. The portion 22 and the adjacent polymer microsphere portion 22 are configured to include a connecting polymer portion 28 that is connected while being reinforced. The polymer microsphere portion 22 includes an outer shell polymer shell 24 connected integrally with the connecting polymer portion 28 and a polymer core 26 that is a core portion. The polymer core 26 contains an iron complex having spin crossover characteristics. The polymer core 26 of the polymer microsphere part 22 is made of polytrifluoroethyl methacrylate (PTFEMA), and the polymer shell 24 and the connecting polymer part 28 of the polymer microsphere part 22 are made of polyvinyl alcohol (PVA). .

  FIG. 3 shows a state in which a part of the functional film 20 containing the iron complex having the spin crossover characteristics shown in FIG. 1 is observed with an atomic force microscope (AFM). FIG. 3A is a morphological image, and FIG. 3B is a phase difference image. In the morphological image of FIG. 3 (a), irregularities showing a substantially spherical shape with a diameter of several tens of nanometers are observed, and in the phase difference image of FIG. 3 (b), a substantially spherical portion that appears black is observed. It can be seen that substances different from others are concentrated and arranged in a substantially spherical portion.

  FIG. 3 shows the case where the emulsifier used in the emulsion polymerization method is PVA, but sodium lauryl sulfate (SLS) can also be used as the emulsifier as described later. FIG. 4 is a diagram showing a state in which a part of a functional film obtained using SLS as an emulsifier is observed with an atomic force microscope (AFM). 4A is a morphological image, and FIG. 4B is a phase difference image. Comparing FIG. 3 and FIG. 4, it can be seen that the monodisperse distribution is shown more in the case of using fine particles and the portion that looks blacker in the case of using PVA than in the case of using SLS as the emulsifier.

  FIG. 5 is a diagram showing a model of the polymer microsphere part 22. As described above, the polymer microsphere part 22 includes the polymer shell 24 as the outer shell part and the polymer core 26 as the core part. As will be described later, since the polymer microsphere part 22 is synthesized by an emulsion polymerization method of a polymer, if there is no restriction in three dimensions, the polymer microsphere part 22 has a substantially spherical shape. When formed on the base film 12 as described in FIG. 2, the polymer microsphere portion 22 is substantially hemispherical, being restricted by the flat surface of the base film 12.

  In the polymer microsphere part 22, the polymer core 26, which is a core part surrounded by the polymer shell 24, is composed of PTFEMA 32 polymerized by an emulsion polymerization method and an iron complex 30 having spin crossover characteristics. As described below, the black substance observed by the AFM phase difference image of FIG. 3 corresponds to the iron complex 30 having the spin crossover characteristics.

  As shown in FIG. 3, it can be seen that a black substance is contained inside the substantially spherical polymer microsphere part, but in order to confirm that this is an iron complex having spin crossover characteristics. It is necessary to investigate the magnetic properties. Accordingly, the spin crossover characteristic will be described with reference to FIGS.

FIG. 6 shows the electron arrangement in the 3d orbit of plus divalent iron ions. A 3d orbital has five types of electron orbitals, but a plus divalent iron ion has six d electrons. These six electrons are arranged in order from the low energy orbit. Under low temperature, as shown on the right side of FIG. 5, two electrons are arranged in pairs in three orbits of t _{2g having} low energy. At this time, electrons having different spin directions are paired and arranged in one electron orbit, so that the spin difference S does not occur and a low spin state (S = 0) is obtained.

From this low spin state, if there is an appropriate energy excitation, two electrons is transferred to the higher e _g orbitals energy. This state is shown on the left side of FIG. Here, since two electrons move, one electron is arranged in some of the five electron orbits, and spins are not canceled in the orbits, so that a spin difference S is generated as a whole. That is, a high spin state (S = 2) is obtained. As the energy excitation from the low spin state to the high spin state, for example, thermal energy, optical energy, mechanical energy such as pressure, or the like can be used. To return from the high spin state to the low spin state, the temperature may be lowered. Alternatively, light having a wavelength different from that used for excitation from the low spin state to the high spin state may be irradiated at a low temperature.

  In this way, by applying or removing energy such as heat, light, and pressure, an iron complex containing iron ions can transition between a low spin state and a high spin state. An iron complex having such characteristics is an iron complex having spin crossover characteristics. This can simply be called a spin crossover iron complex. FIG. 7 is an example reported in the literature (O. Kahn and C. Jay Martinez, Science, vol. 279, 1988, p44), and a typical phase transition of spin crossover characteristics in relation to absorbance and temperature. Characteristics are shown.

  The difference in the spin state can be detected by using a superconducting quantum interferometer (SQUID), changing the temperature, and observing the change in magnetization at that time. Or it can detect by measuring the temperature dependence using an electron spin resonance method (Electron Spin Resonance: ESR). Further, when the spin state changes, a phase change as a material of the iron complex occurs, so that the color change accompanying the phase transition can be observed with a temperature variable phase contrast microscope. Moreover, since the color of an iron complex changes from white to black with a phase change, it can be observed also from a change in absorbance.

  FIG. 8 is an example showing the result of observing the change in heat flow (heat flow) when the temperature of the black substance in the polymer microsphere part 22 described in FIG. 3 is changed using the DSC method. Here, α-phase and β-phase transitions were observed at −19.1 ° C. and + 68.3 ° C.

  FIG. 9 is a diagram showing the results of observing changes in the spin state with temperature using an ESR method for powdery iron cross-over iron complexes formed by a general method. Each of the three diagrams in FIG. 9 takes the magnitude of the magnetic field on the horizontal axis and the differential value of the magnetization on the vertical axis. The top diagram is 295 ° K at room temperature, the middle diagram is 200 ° K, and the bottom diagram. These figures show the state at 5 ° K. From these figures, a value close to g = 2 is observed at room temperature, and g = 4 and g = 8 indicating the forbidden transition of the triplet state (S = 1) appear as the temperature decreases, and the high spin state It was found that this is an equilibrium state between a low spin state and a low spin state.

  FIG. 10 shows a state in which the spin state of the black substance in the polymer microsphere part 22 described with reference to FIG. In these drawings, the horizontal axis, the vertical axis, and the meanings of the three drawings are the same as those in FIG. From these figures, a value close to g = 2 is observed at room temperature, and g = 4 indicating a forbidden transition of a triplet state and g = 8 indicating a quintet appear at a low temperature of 5 ° K. It was found that this is an equilibrium state between a high spin state and a low spin state. This confirms that the iron complex 30 exhibiting spin crossover characteristics is concentratedly arranged in the polymer core 26 that is the core of the polymer microsphere portion 22 in FIG.

  FIG. 11 is a flowchart for explaining the procedure of the method for manufacturing the functional film device having the above-described configuration. Below, it demonstrates using the code | symbol of FIGS. 1-10. The functional film 20 containing an iron complex preferably has translucency as a whole. In consideration of applications such as memory elements, the iron complex 30 having spin crossover characteristics is preferably arranged in a concentrated manner in a minute region, and the minute region has a uniform size and is arranged at regular intervals. It is good to be done. Moreover, about the iron complex 30, it is preferable that the transition temperature range of a spin crossover characteristic can be controlled. From such a request, selection of the raw material of the iron complex 30, the method of forming the polymer microsphere part 22, the material constituting the polymer microsphere part 22 and the like becomes important. Below, each preparation sample preparation process is demonstrated about these selection criteria.

  In FIG. 11, the first step is the preparation of iron salt (S10). An iron salt is a raw material containing iron ions for reacting with triazole prepared in the next step to form an iron complex. The selection criterion for the iron salt is first the setting of the phase transition temperature. Since the phase transition temperature is a temperature that determines the transition between the material phase in the high spin state and the material phase in the low spin state, from the viewpoint of the functional device, the temperature is preferably as close to room temperature as possible, It is desirable to have an appropriate temperature difference in the hysteresis characteristics. On the other hand, in consideration of solubility, it is preferable to substitute an amino group for the triazole ligand of the iron complex and to select an appropriate counter ion as described later.

  The second selection criterion is the use of metal ions other than iron in terms of spin crossover characteristics. For example, by using cobalt ions together with iron ions, an antiferromagnetic interaction occurs, which makes it possible to suppress spin crossover characteristics.

The third selection criterion has optical characteristics based on counter counter ions, that is, ions that bind to iron ions, using an ion-binding iron salt. For example, when comparing ClO ₄ ions and BF ₄ ions, the former has a fading property. Therefore, it is preferable to select the latter as the counter ion.

Based on these selection criteria, for example, a II valent iron ion, BF ₄ to Fe (BF _{4) 2} formed of an ion, suitable molecular number of water molecule (H ₂ O) was bonded Fe (BF ₄ ) ₂ nH ₂ O can be selected and prepared as the iron salt. This iron salt is called iron (II) tetrafluoroborate hexahydrate.

  Next, a triazole serving as a ligand is prepared (S12). As described above, triazole is a raw material for synthesizing an iron complex together with an iron salt. As the triazole, a triazole having a hydrogen group or a triazole having an amino group can be used. As such a triazole, 1,2,4-1H-triazole or 4-amino-1,2,4-triazole can be used.

  Next, an iron complex is synthesized using an iron salt and triazole (S14). The iron complex can be synthesized by a method such as stirring in a mixed solvent containing methanol. And the powder of an iron complex is obtained by removing a solvent under reduced pressure with an evaporator.

FIG. 12 shows an iron complex using methanol with 1,2,4-1H-triazole or 4-amino-1,2,4-triazole as triazole, iron (II) tetrafluoroborate hexahydrate as iron salt. It is a figure which shows the reaction formula which obtains. The obtained iron complex is represented by a chemical formula of [Fe (Htrz) _3-3X (4-NH ₂ trz) _3X ] (BF ₄ ) ₂ .nH ₂ O (n = 6).

  Returning to FIG. 11 again, in parallel with the synthesis of the iron complex, preparation for polymer particle preparation is performed. As a polymerization method for producing polymer particles, a bulk polymerization method, a polymerization method in solution, an emulsion polymerization method, or the like can be used. The selection criterion at this time is ease of control of the particle size of the microsphere. From this viewpoint, an emulsion polymerization method in which polymerization and particle diameter can be controlled by an emulsifier is preferable. An emulsion polymerization method capable of controlling the formation of uniform fine particles is used, and a monomer, an emulsifier, and an initiator are prepared.

  In the monomer preparation (S16), the selection criterion is the optical properties of the material. That is, the iron complex having spin crossover characteristics can take light as an input, and the absorbance changes with the phase transition, and this is preferably used as an output. As a monomer having excellent optical properties, particularly transparency, for example, a fluorine-based monomer, a methyl methacrylate (MMA) monomer, a styrene monomer, or the like can be used. The light-transmitting property is best with a fluorine-based monomer, and then with a MMA monomer. It is known that a fluorinated monomer capable of emulsion polymerization has a low refractive index and a quenching effect occurs. Further, it is known that charge transfer occurs in the styrene monomer. From these points, 2,2,2 trifluoroethyl methacrylate (TFEMA) monomer is used as the monomer as the fluorinated monomer.

  In the preparation of the emulsifier (S18), the selection criteria are the adjustment of the polymerization rate accompanying the control of the particle diameter, the melting point of the polymer and the strength of the film. The emulsifier is preferably a kind of reinforcing agent. When the polymer is produced, the film preferably has a high melting point and high strength. Sodium lauryl sulfate (SLS), commonly known as an emulsifier, can be used to reduce the particle size and adjust the polymerization rate. However, it is better to use polyvinyl alcohol (PVA), which is known to help form a polymer film having a higher melting point and higher strength than SLS. SLS is an anionic surfactant, but PVA is known to be nonionic and have good affinity with Fe. From these points, it is preferable to use PVA as an emulsifier as compared with SLS.

  In the preparation of the initiator (S20), the selection criteria are water solubility and catalyst selectivity. Azo-based initiators known as emulsion polymerization initiators do not require a catalyst, but are generally poorly soluble, thereby reducing the range of use. On the other hand, APS known as a water-soluble initiator is easily soluble in water and has high versatility. In this case, a catalyst may be used. For example, Fe, Cr, Co can be used as a catalyst, and iron complexes are generally used in the industry. Furthermore, an iron complex substituted with an amino group is easily dissolved under acidity. From these viewpoints, it is preferable to use APS as an initiator as compared with Azo.

  Emulsion polymerization is performed using the monomer, emulsifier, and initiator for emulsion polymerization prepared as described above, and the particle size is controlled (S22). Specifically, the iron complex powder generated in S14, the monomer prepared in S16, the emulsifier prepared in S18, and the initiator prepared in S20 are mixed with water at an appropriate temperature, for example, 70 ° C. Ethanol is mixed into a 94/5 mixed solution to perform emulsion polymerization. The remaining 1 in the volume ratio is a monomer. By controlling the amount of emulsifier, the amount of initiator, temperature, etc., particle formation and polymerization rate are controlled.

  Here, how much an iron complex is contained affects device characteristics when a functional film is formed. If the mass ratio is very small, it is not possible to obtain sensitivity sufficient to sufficiently detect changes in spin crossover characteristics. On the other hand, since the polymer core 26 of the polymer microsphere part 22 is synthesized by an emulsion polymerization method, the particle size cannot be made too large, and the mass ratio of the iron complex cannot be increased too much. Therefore, the mass ratio, which is the content of the iron complex with respect to the entire film as a finished product, has a lower limit set by the sensitivity of electro-optical characteristics and an upper limit set by the particle size controllability of the emulsion polymerization method. It is preferable. According to experiments, the range is preferably 0.1% or more and 5% by mass ratio of the iron complex. Thus, the mass ratio of the iron complex in emulsion polymerization control can be set.

  Polymer microspheres having a particle size adjusted by emulsion polymerization control are cast on the base film 12 (S24). Casting can use a coating method.

  Then, the base film coated with the emulsion polymerization liquid is dried (S26), thereby forming a film (S28). Drying may be performed by standing at room temperature or by a so-called freeze-dried method in a refrigerator or the like.

  The functional film device 10 thus obtained has a configuration as shown in FIG. That is, a functional film 20 including an iron complex is formed on the base film 12, and the functional film 20 including the iron complex includes a substantially hemispherical polymer microsphere part 22 and an adjacent polymer microsphere part 22. The connecting polymer portion 28 is connected to each other. The polymer microsphere part 22 includes an outer shell polymer shell 24 connected integrally with a connecting polymer part 28 that is PVA, and a polymer core 26 that is a core part. The polymer core 26 contains an iron complex having spin crossover characteristics.

  Here, the polymer shell 24 and the connecting polymer portion 28 of the outer shell portion of the polymer microsphere portion 22 are mainly composed of polyvinyl alcohol (PVA) which is a component of an emulsifier. The polymer core 26 at the core part of the polymer microsphere part 22 is composed of polytrifluoroethyl methacrylate (PTFEMA) 32 obtained by polymerizing TFEMA, and an iron complex 30 having a spin crossover characteristic is formed inside the PTFEEMA 32. Contained.

  As described above, since the iron complex 30 having spin crossover characteristics is concentrated on polymer particles made of PTFEMA having good translucency, the change in the spin crossover characteristics can be detected with high sensitivity as a device. It can be carried out. In addition, the mass ratio of the iron complex 30 having spin crossover characteristics to the whole film is 0.1% or more and 5% or less, so that the diameter of the polymer microsphere part 22 is kept from several tens nm to several hundreds nm. However, it is possible to sufficiently detect changes in the spin crossover characteristics. Further, since the polymer shell 24 and the connecting polymer are PVA, the strength of the film can be made sufficient.

A functional film device containing an iron complex was produced using an emulsion polymerization method according to the procedure described in FIG. The iron complex has 1,2,4-1H-triazole or 4-amino-1,2,4-triazole as a ligand and iron (II) tetrafluoroborate hexahydrate as an iron salt. The produced [Fe (Htrz) _3-3X (4-NH ₂ trz) _3X ] (BF ₄ ) ₂ .nH ₂ O (n = 6) was used. Here, X = 0.1, 0.3, 1.0 and three types of iron complexes were used.

  In the emulsion polymerization, 0.01 g of iron complex, 1.18 g (1 ml) of TFEMA as a monomer, 1.0 g of PVA217 (DH as saponification degree is 88%, DP as polymerization degree is 1750) as an emulsifier, 0.05 g of APS was prepared as an initiator and mixed with water / ethanol. The water / ethanol volume ratio is 94/5. Polymerization was carried out at 50 ° C. for 3 hours in an argon atmosphere. The obtained emulsion was formed on a transparent base film and dried to produce a functional film device.

  About the functional film on a base film, the morphological image and the phase contrast image were observed with the atomic force microscope (AFM) by SEIKO. As a result, as described with reference to FIG. 3, the particle diameter of about 100 nm and the presence of the complex were confirmed. Using an ESR (EMX X-band 5K-290K) manufactured by Bruker, the spin state of the iron complex having spin crossover characteristics contained in the polymer microsphere part was observed. As a result, as described with reference to FIG. 3, a transition between a high spin state and a low spin state was observed depending on the temperature.

  Thus, an electro-optical functional film containing an iron complex having a spin crossover characteristic in a film form could be obtained. In addition, an iron complex having spin crossover characteristics can be arranged in the particles, and an electro-optical functional film containing an iron complex having spin crossover characteristics can be obtained.

  As described above, the electro-optical functional film including the iron complex having the electro-optical characteristics according to the present invention is used for a functional device having an external stimulus as an input and a changing state quantity as an output. For example, it is used for a storage element that performs storage and erasure by temperature change. It is also used for an optical switch that changes the absorbance by turning on and off the irradiation light.

In embodiment which concerns on this invention, it is a figure which shows the mode of the functional film device using the functional film containing an iron complex. In embodiment concerning this invention, it is an expanded sectional view of a functional film device. In embodiment which concerns on this invention, it is a figure which shows a mode that a part of functional film containing an iron complex was observed with the atomic force microscope. It is a figure which shows a result when another emulsifier is used by comparison with FIG. In embodiment which concerns on this invention, it is a figure which models and shows a polymer microsphere part. It is a figure which shows the mode of the electronic arrangement | positioning in 3d orbit of plus divalent iron ion. It is an example of the characteristic of the iron complex which has the spin crossover characteristic shown by literature. In embodiment which concerns on this invention, it is a figure which shows the result of having observed the mode of the phase transition by DSC method. It is a figure which shows the result of having observed the change of the spin state by temperature using the ESR method about the iron complex which has a powdery spin crossover characteristic. In embodiment which concerns on this invention, it is a figure which shows a mode that the spin state was investigated in the same measuring method as FIG. In embodiment concerning this invention, it is a flowchart explaining the procedure of the manufacturing method of a functional film device. In embodiment which concerns on this invention, it is a figure which shows the reaction formula which obtains an iron complex.

Explanation of symbols

  10 functional film device, 12 base film, 20 functional film, 22 polymer microsphere part, 24 polymer shell, 26 polymer core, 28 connecting polymer part, 30 iron complex, 32 PTFEMA.

Claims (6)

A functional film having a spin crossover characteristic in which light or heat is input and a change in magnetic characteristics or a change in light absorption characteristics is output,
A polymer microsphere portion having an outer shell polymer shell and a core polymer core and synthesized by an emulsion polymerization method;
Consists of an emulsifier used in the emulsion polymerization method, a connecting polymer part that connects adjacent polymer microsphere parts in a film,
With
The polymer microsphere part
An electro-optical functional film comprising an iron complex having a spin crossover characteristic in which light or heat is input and a change in magnetic characteristics or a change in light absorption characteristics is output. The electro-optical functional film according to claim 1,
The electro-optical functional film, wherein the content of the iron complex having spin crossover characteristics is 0.1% or more and 5% or less as a mass ratio to the whole film. The electro-optical functional film according to claim 1,
An electro-optical functional film, wherein the polymer microsphere part has a diameter of 10 nm to 1000 nm. The electro-optical functional film according to claim 1,
An electro-optical functional film, wherein the component of the polymer core is polytrifluoroethyl methacrylate. The electro-optical functional film according to claim 1,
An electro-optical functional film, wherein the polymer shell and the connecting polymer are made of polyvinyl alcohol. The electro-optical functional film according to claim 1,
An iron complex having a spin crossover characteristic has 1,2,4-1H-triazole or 4-amino-1,2,4-triazole as a ligand, and iron (II) tetrafluoroborate hexahydrate is an iron salt. As an electro-optical functional film containing an iron complex produced by these reactions.

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