Liquid crystal / polymer composite electrically controlled light control film and its manufacturing method

Abstract

To provide a liquid crystal / polymer composite electric control lighting control film.SOLUTION: A liquid crystal / polymer composite electric control lighting control film comprises a liquid crystal material, a polymer substrate, and a double layer conductive substrate. The polymer substrate is held between the double layer conductive substrate, the polymer substrate has a porous fine structure. The liquid crystal material is dispersed in the polymer substrate for forming liquid crystal fine droplets, and the liquid crystal fine droplets have a polymer network which is vertically oriented.EFFECT: The liquid crystal / polymer composite electric control lighting control film has a unique composite micro structure, in the composite micro structure, the polymer substrate of the porous fine structure applies preferable mechanical processing performance to the film, and the vertically oriented polymer network in the liquid crystal fine droplets further reduces difficulty of orientation of the liquid crystal molecules and is advantageous for reduction of a drive voltage of the liquid crystal / polymer composite electric control lighting control film, and is suitable for processing and production of a large area.SELECTED DRAWING: None

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This specification claims priority to Chinese patent application 202210696701.8 filed on June 20, 2022 and to international patent application PCT / CN2022 / 104274 filed on July 7, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present specification relates to the field of optical films, and in particular to a liquid crystal / polymer composite electrically controlled light control film and a method for manufacturing the same. [Background technology]

[0003] There are two main fields of practical application of liquid crystal, one is display screen, the other is optical film. Here, in order to realize large-scale roll-to-roll processing during the production of optical film, liquid crystal and polymer material are generally combined to produce a composite film, which can combine the excellent external field response of liquid crystal and the excellent mechanical performance of polymer. At present, there are mainly two kinds of electric control light control film that can be driven by electric field, one is polymer dispersed liquid crystal (abbreviated as PDLC) film, and the other is polymer stabilized liquid crystal (abbreviated as PSLC) film.

[0004] In PDLC film, the liquid crystal is dispersed in the polymer substrate in the form of microdroplets. Such films have been on the market for several years in the form of light control films, and there are companies in the United States, Japan and China that produce and sell them. After the film is produced, it generally exhibits a state of light scattering, which is due to the mismatch of the refractive index of the unoriented liquid crystal with the polymer substrate and the mismatch of the refractive index of the liquid crystal molecules themselves. When an electric field of a suitable magnitude is applied to the film, the film exhibits a state in which light is transmitted, that is, a transparent state. This is achieved by the fact that the liquid crystal molecules form a vertical orientation under the action of the electric field, the liquid crystal micro-domains are transparent, and at the same time, the refractive index of the liquid crystal molecules and the polymer substrate also match when observed from the direction along the long axis of the liquid crystal molecules. In the manufacturing method of such films, the non-liquid crystal polymerizable monomer and the liquid crystal are mixed to obtain a uniform mixture solution, and then the mixture solution is sandwiched between two layers of ITO conductive plastic film, and then the polymerization of the photo- or thermally polymerizable monomer is initiated by ultraviolet irradiation or heating. After the polymerization is completed, a phase separation structure of the polymer substrate and the liquid crystal micro is formed, specifically, the liquid crystal is dispersed in the polymer substrate in the form of microdroplets, and the polymer substrate has a porous microstructure (as shown in Figure 1). At present, PDLC films have broad application prospects in many fields, such as architectural and automotive doors and windows, architectural partitions, smart anti-peeping, projection screens and touch panels.

[0005] PDLC systems generally have a relatively high polymer substrate content, at least greater than 10%, and some even greater than 40%, and this ratio also allows the PDLC film to have high peel strength between the two substrates, allowing the film to be processed continuously in roll-to-roll. However, because the boundary of the polymer substrate has a relatively strong binding effect on the liquid crystal molecules, the driving voltage of PDLC is relatively high, and the driving voltage of commercially available PDLC films is generally above 60 volts, which limits the further application of PDLC films in fields such as display.

[0006] A polymer stabilized liquid crystal film material is a film material that stabilizes a certain alignment state of liquid crystal molecules or tends to make liquid crystal molecules into a certain alignment. It is generally made by mixing a liquid crystal polymerizable monomer with liquid crystal, initiating polymerization of the liquid crystal photopolymerizable monomer by ultraviolet irradiation or heating, etc., and forming a polymer network with an alignment mode that is the same as the alignment direction of the liquid crystal molecules before polymerization, thereby stabilizing a certain alignment state of the liquid crystal molecules before polymerization or tending to make the liquid crystal molecules into a certain alignment. For example, a liquid crystal polymerizable monomer is mixed with a cholesteric liquid crystal, and after a planar alignment treatment, the polymerized film can be obtained with a PSLC film with a planar aligned polymer network after polymerization. A liquid crystal polymerizable monomer is mixed with a nematic liquid crystal, and after a vertical alignment treatment, the polymerized film can be obtained with a vertical aligned polymer network (as shown in Figure 2) after polymerization.

[0007] The driving voltage of PSLC film is relatively low, and generally it can be driven by a voltage of several volts. Therefore, PSLC film is widely used in the field of some functional liquid crystal devices. However, the content of polymer network in PSLC film is relatively low, generally less than 10%, so that the peel strength of PSLC film between two substrates is relatively low, and such film is difficult to fabricate on a large-area flexible substrate, which limits the application range of PSLC film. Although some PSLC materials can have a high polymer network content, such materials with a very high polymer network content are unified in terms of function, and cannot be driven by methods such as electric field, which causes the application of PSLC film to be limited.

[0008] Therefore, it is necessary to provide a liquid crystal / polymer composite electrically controlled light control film that combines the mechanical processing performance of PDLC film and the low driving voltage of PSLC film, and a manufacturing method thereof. Summary of the Invention

[0009] One aspect of the present specification provides a liquid crystal / polymer composite electrically controlled light control film (liquid crystal polymer composite electrically controlled light control film). The liquid crystal / polymer composite electrically controlled light control film includes a liquid crystal material, a polymer substrate, and two layers of conductive substrates. The polymer substrate is sandwiched between the two layers of conductive substrates, and the polymer substrate has a porous microstructure. The liquid crystal material is dispersed in the polymer substrate to form liquid crystal microdroplets, and the liquid crystal microdroplets have a vertically aligned polymer network. In some embodiments, the polymer substrate is prepared by photopolymerization from a first polymerizable monomer, the first polymerizable monomer being a radical photopolymerizable monomer or a cationic photopolymerizable monomer, and the polymer network is prepared by thermal polymerization from a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being a rod-shaped thermally polymerizable monomer, or the second polymerizable monomer being a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0010] In some embodiments, the polymer substrate is prepared by photopolymerization from a first polymerizable monomer, the first polymerizable monomer being a radical photopolymerizable monomer or a cationic photopolymerizable monomer, and the polymer network is prepared by thermal polymerization from a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0011] In some embodiments, the polymer substrate is prepared by thermal polymerization from a first polymerizable monomer, the first polymerizable monomer being a thermally polymerizable monomer, and the polymer network is prepared by photopolymerization from a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0012] In some embodiments, the polymer substrate is prepared by thermal polymerization from a first polymerizable monomer, the first polymerizable monomer being a thermally polymerizable monomer, the polymer network is prepared by thermal polymerization from a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being a rod-shaped thermally polymerizable monomer, or the second polymerizable monomer being a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0013] In some embodiments, the radical photopolymerizable monomer is one or more of acrylate monomers or olefin monomers capable of radical polymerization by irradiation with ultraviolet light, the cationic photopolymerizable monomer is one or more of olefin monomers, vinyl ether monomers, and epoxy monomers capable of cationic polymerization by irradiation with ultraviolet light, the rod-shaped radical photopolymerizable monomer is one or more of rod-shaped acrylate monomers or rod-shaped olefin monomers capable of radical polymerization by irradiation with ultraviolet light, and the rod-shaped cationic photopolymerizable monomer is a rod-shaped epoxy monomer capable of cationic polymerization by irradiation with ultraviolet light. The thermally polymerizable monomer is one or more of a rod-shaped vinyl ether monomer and a rod-shaped olefin monomer, the thermally polymerizable monomer is a mixture of an epoxy monomer that can be thermally polymerized under heating conditions and a mercaptan or amine monomer, or a mixture of a monomer containing an amino group, a hydroxyl group, a carboxyl group, a mercapto group, or the like, and an isocyanate monomer, and the rod-shaped thermally polymerizable monomer is a mixture of a rod-shaped epoxy monomer that can be thermally polymerized under heating conditions and a rod-shaped mercaptan or amine monomer, or a mixture of a rod-shaped monomer containing an amino group, a hydroxyl group, a carboxyl group, or a mercapto group, and a rod-shaped isocyanate monomer.

[0014] In some embodiments, the liquid crystal material is a cholesteric liquid crystal material with positive dielectric anisotropy, or a liquid crystal material with nematic, smectic and smectic-cholesteric phase transition properties.

[0015] In some embodiments, the liquid crystal material comprises one or more of the molecular structures (1): wherein M and N are an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a siloxane group having 1 to 20 carbon atoms, a cyano group, an ester group, a halogen, an isothiocyano group, or a nitro group; A and B are an aromatic ring or an alicyclic alkyl group and include at least one of a benzene ring, a six-membered ring, a six-membered heterocyclic ring, a five-membered ring, a five-membered heterocyclic ring, a biphenyl, a terphenyl, and a naphthalene ring; A and B are linked via a covalent bond or a linking group Z; A and B each contain a pendant group or do not contain a pendant group, the pendant group being a halogen, a cyano group, or a methyl group; x and y are each an integer of 0 to 4; and Z is an ester group, an alkynyl group, an alkane group, a nitrogen double bond, or an ether bond.

[0016] In some embodiments, the pore size of the pores in the polymeric substrate is between 0.1-100 microns.

[0017] In some embodiments, the conductive substrate includes a conductive film containing a metal compound such as ITO, silver, aluminum, or a glass substrate.

[0018] One aspect of the present specification provides a method for manufacturing a liquid crystal / polymer composite electrically controlled light control film, which includes the steps of: 1) mixing a liquid crystal material, a first polymerizable monomer, a second polymerizable monomer, a first initiator, a second initiator, and spacer particles to obtain a uniform mixture; 2) filling the mixture between two laminated conductive substrates to manufacture a film, forming a polymer substrate with a porous microstructure through a first reaction, and dispersing the liquid crystal material in the form of liquid crystal microdroplets in the polymer substrate; and 3) applying an electric field to the film to vertically align the liquid crystal material molecules and the second polymerizable monomer molecules, and forming a vertically oriented polymer network in the liquid crystal microdroplets through a second reaction, thereby manufacturing a liquid crystal / polymer composite electrically controlled light control film.

[0019] In some embodiments, the first reaction includes a first initiator initiating a photopolymerization reaction of a first polymerizable monomer, the first polymerizable monomer being a radical photopolymerizable monomer or a cationic photopolymerizable monomer, the second reaction includes a second initiator initiating a thermal polymerization reaction of a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being a rod-shaped thermally polymerizable monomer, or the second polymerizable monomer being a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0020] In some embodiments, the first reaction includes a first initiator initiating a photopolymerization reaction of a first polymerizable monomer, the first polymerizable monomer being a radical photopolymerizable monomer or a cationic photopolymerizable monomer; the second reaction includes a second initiator initiating a photopolymerization reaction of a second polymerizable monomer, the second polymerizable monomer being capable of being aligned and oriented along the electric field direction along with the liquid crystal material molecules; the second polymerizable monomer being one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0021] In some embodiments, the first reaction includes a first initiator initiating a thermal polymerization reaction of a first polymerizable monomer, the first polymerizable monomer being a thermally polymerizable monomer, and the second reaction includes a second initiator initiating a photopolymerization reaction of a second polymerizable monomer, the second polymerizable monomer being capable of being aligned and oriented along the electric field direction along with the liquid crystal material molecules, and the second polymerizable monomer being one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0022] In some embodiments, the first reaction includes a first initiator initiating a thermal polymerization reaction of a first polymerizable monomer, the first polymerizable monomer being a thermally polymerizable monomer, the second reaction includes a second initiator initiating a thermal polymerization reaction of a second polymerizable monomer, the second polymerizable monomer being capable of orienting and aligning along the electric field direction along with the liquid crystal material molecules, the second polymerizable monomer being a rod-shaped thermally polymerizable monomer, or the second polymerizable monomer being a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0023] In some embodiments, the radical photopolymerizable monomer is one or more of acrylate monomers or olefin monomers capable of radical polymerization by irradiation with ultraviolet light, the cationic photopolymerizable monomer is one or more of olefin monomers, vinyl ether monomers, and epoxy monomers capable of cationic polymerization by irradiation with ultraviolet light, the rod-shaped radical photopolymerizable monomer is one or more of rod-shaped acrylate monomers or rod-shaped olefin monomers capable of radical polymerization by irradiation with ultraviolet light, the rod-shaped cationic photopolymerizable monomer is a rod-shaped epoxy monomer capable of cationic polymerization by irradiation with ultraviolet light, The thermopolymerizable monomer is one or more of a rod-shaped vinyl ether monomer and a rod-shaped olefin monomer, the thermally polymerizable monomer is a mixture of an epoxy monomer that can be thermally polymerized under heating conditions and a mercaptan or amine monomer, or a mixture of a monomer containing an amino group, a hydroxyl group, a carboxyl group, a mercapto group, or the like, and an isocyanate monomer, and the rod-shaped thermopolymerizable monomer is a mixture of a rod-shaped epoxy monomer that can be thermally polymerized under heating conditions and a rod-shaped mercaptan or rod-shaped amine monomer, or a mixture of a rod-shaped monomer containing an amino group, a hydroxyl group, a carboxyl group, or a mercapto group, and a rod-shaped isocyanate monomer. In some embodiments, the liquid crystal material, the first polymerizable monomer, and the second polymerizable monomer may be mixed in a ratio of parts by weight as follows: Liquid crystal material: 10.0~95.0 parts by weight, First polymerizable monomer: 5.0 to 80.0 parts by weight, The second polymerizable monomer: 0.1 to 40.0 parts by weight. [Brief description of the drawings]

[0024] [Figure 1] 1 is a scanning electron micrograph of a porous polymer substrate of a prior art PDLC. [Diagram 2] 1 is a scanning electron micrograph of a vertically aligned polymer network of a prior art PSLC. [Diagram 3] FIG. 1 is a schematic diagram of producing a polymer substrate by photopolymerization and a polymer network by thermal polymerization according to some embodiments herein. [Figure 4] 1 shows structural formulas of acrylate monomers according to some embodiments herein, namely, hydroxypropyl methacrylate (HPMA), lauryl methacrylate (LMA), polyethylene glycol diacrylate (PEGDA600), and bisphenol A ethoxylate dimethacrylate (Bis-EMA15), respectively. [Diagram 5] 1 shows the structural formulas of epoxy monomers and mercaptan monomers according to some embodiments of the present specification, which are N,N'-di(2,3-epoxypropoxy)aniline (NDGA), polypropylene glycol diglycidyl ether (PGDE), bisphenol A epoxy resin (E44), and mercaptan monomer (Capure3800), respectively. [Figure 6] A rod-shaped epoxy monomer according to some embodiments of the present specification has the structural formula: 2-methyl-1,4-phenylenebis(4-(4-(epoxy-2-yl)butoxy)benzoate), abbreviated as E4M. [Figure 7] A rod-shaped mercaptan monomer according to some embodiments herein has the structural formula: 2-methyl-1,4-phenylenebis(4-(4-mercaptobutoxy)benzoic acid), abbreviated as S4M. [Figure 8] 1 is a molecular structure of photoinitiator 651, thermal initiator DMP-30, and cationic initiator UV6976 according to some embodiments of the present specification. [Figure 9] FIG. 2 is an electrical-optical curve diagram of a liquid crystal / polymer composite electrically controlled dimming film according to some embodiments of the present specification. [Figure 10] 1 is an electron microscope photograph of a microstructure of a liquid crystal / polymer composite electrically controlled light control film according to some embodiments of the present specification, which combines a porous polymer substrate and a vertically oriented polymer network. [Figure 11] 1 is an electron microscope photograph of a microstructure of a liquid crystal / polymer composite electrically controlled light control film according to some embodiments of the present specification, which combines a porous polymer substrate and a vertically oriented polymer network. [Figure 12]1 is an electron microscope photograph of a microstructure of a liquid crystal / polymer composite electrically controlled light control film according to some embodiments of the present specification, which combines a porous polymer substrate and a vertically oriented polymer network. [Figure 13] FIG. 2 is an electrical-optical curve diagram of a liquid crystal / polymer composite electrically controlled dimming film according to some embodiments of the present specification. [Figure 14] 1 is an electron microscope photograph of a microstructure of a liquid crystal / polymer composite electrically controlled light control film according to some comparative examples of the present specification, which combines a porous polymer substrate and a vertically oriented polymer network. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present specification will be further described in the manner of exemplary embodiments, which are illustrated in detail in the drawings, in which like numbers represent like structures, and in which the exemplary embodiments are not limited to the embodiments.

[0026] In order to more clearly describe the technical solutions of the embodiments of the present specification, the following briefly introduces the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are only some examples or embodiments of the present specification, and those skilled in the art can also apply the present specification to other similar scenarios based on these drawings without creative efforts. It should be understood that these exemplary embodiments are only intended to enable those skilled in the art to better understand and realize the technical solutions described in the present specification, and do not limit the scope of the present specification in any manner. Unless obvious from the language environment or otherwise described, the same symbols in the drawings represent the same structures or operations.

[0027] Some embodiments of the present specification provide a liquid crystal / polymer composite electric control light control film, which includes two layers of laminated conductive substrates, the conductive substrate includes a conductive film containing metal compounds such as ITO, silver, aluminum, etc., or a glass substrate, a porous microstructured polymer substrate is sandwiched between the two layers of the conductive substrates, the pore size of the porous microstructure is 0.1-100 microns, the liquid crystal material is dispersed in the micropore gaps of the polymer substrate in the form of liquid crystal microdroplets, and a vertically aligned polymer network is formed in the liquid crystal microdroplets in which the liquid crystal material is dispersed. The vertical alignment refers to the alignment perpendicular to the conductive substrate.

[0028] In some embodiments herein, step 1 may be used to represent a first reaction, the first reaction including a first initiator initiating a photopolymerization or thermal polymerization reaction of a first polymerizable monomer, and step 2 may be used to represent a second reaction, the second reaction including a second initiator initiating a photopolymerization or thermal polymerization reaction of a second polymerizable monomer. The above-mentioned representation does not limit the priority relationship between the two processes.

[0029] The polymer substrate is prepared from a first polymerizable monomer by photopolymerization or thermal polymerization in step 1, and the polymer network is prepared from a second polymerizable monomer by photopolymerization or thermal polymerization in step 2, and the second polymerizable monomer can be oriented and aligned along the electric field direction along with the liquid crystal material molecules.

[0030] In some embodiments, when photopolymerization is used to prepare the polymeric substrate in step 1, the first polymerizable monomer is a radically photopolymerizable monomer or a cationic photopolymerizable monomer.

[0031] In some embodiments, when the polymeric substrate is prepared in step 1 using thermal polymerization, the first polymerizable monomer is a thermally polymerizable monomer.

[0032] In some embodiments, the second polymerizable monomer may include a rod-shaped monomer. In some embodiments, the geometric shape of the rod-shaped monomer is rod-shaped, i.e., the length and width are different, and the aspect ratio of the rod-shaped monomer molecule is 1.1 to 10, and the rod-shaped monomer molecule has a certain rigidity, and generally has a rigid structure in the center of the monomer molecule, and contains a polarizable group or a flexible chain at the end of the monomer molecule. In some embodiments, the rigid structure may be a conjugated system consisting of a double bond, a triple bond, or a benzene ring. In some embodiments, the rigid structure may include a six-membered ring, a six-membered heterocyclic ring, a five-membered ring, a five-membered heterocyclic ring, a biphenyl, a terphenyl, a naphthalene ring, or an anthracene ring. In some embodiments, the rigid structure may include a large aspect ratio structure formed by connecting at least two of six-membered rings, six-membered heterocyclic rings, five-membered rings, five-membered heterocyclic rings, biphenyl, terphenyl, naphthalene rings, or anthracene rings by a covalent bond or a linking group, and the linking group may include a dimethyl group, an ester group, a vinyl group, an ethynyl group, an azo group, or a Schiff base, etc. In some embodiments, the rod-shaped monomer may further have a pendant group, which may include a cyano group, a methoxy group, fluorine, or chlorine. In some embodiments, the flexible chains (or called flexible tail chains) on both sides of the rod-shaped monomer molecule may be carbon chains with an odd or even number of carbon atoms. In some embodiments, the rod-shaped monomer may include a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, or a rod-shaped thermally polymerizable monomer.

[0033] In some embodiments, when photopolymerization is used to produce the polymer network in step 2, the second polymerizable monomer is one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0034] In some embodiments, when the polymer network is produced using thermal polymerization in step 2, the second polymerizable monomer is a rod-shaped thermally polymerizable monomer, or the second polymerizable monomer is a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0035] In some embodiments, the radical photopolymerizable monomer is one or more of an acrylate monomer or an olefinic monomer, and is radically polymerizable upon irradiation with ultraviolet light.

[0036] In some embodiments, the cationically photopolymerizable monomer is one or more of a vinyl ether monomer, an epoxy monomer, and an olefinic monomer, and is cationically polymerizable upon irradiation with ultraviolet light.

[0037] The preferred irradiation intensity and irradiation time of ultraviolet light varies depending on the material system. In some embodiments, the ultraviolet light intensity for photopolymerization is 0.01 to 100 mw / cm 2 In some embodiments, the UV intensity for photopolymerization may be 0.1 to 90 mw / cm 2 In some embodiments, the UV intensity for photopolymerization may be 1 to 200 mw / cm 2 In some embodiments, the UV intensity for photopolymerization may be 5 to 70 mw / cm 2 In some embodiments, the UV intensity for photopolymerization is 10 to 60 mw / cm 2 In some embodiments, the UV intensity for photopolymerization is 20 to 50 mw / cm 2 In some embodiments, the UV intensity for photopolymerization is 30-40 mw / cm 2In some embodiments, the UV irradiation time for photopolymerization may include 0.1 to 60 min. In some embodiments, the UV irradiation time for photopolymerization may include 1 to 50 min. In some embodiments, the UV irradiation time for photopolymerization may include 10 to 40 min. In some embodiments, the UV irradiation time for photopolymerization may include 20 to 30 min. In some embodiments, the UV intensity for photopolymerization is 5.0 mw / cm. 2 and the irradiation time is 10 min.

[0038] In some embodiments, the thermally polymerizable monomer is a mixture of epoxy monomers and mercaptan or amine monomers that are thermally polymerizable under heating conditions, or a mixture of monomers containing amino groups, hydroxyl groups, carboxyl groups, or mercapto groups, etc., and isocyanate monomers.

[0039] In some embodiments, the rod-shaped radical photopolymerizable monomer is one or more of rod-shaped acrylate monomers, rod-shaped olefin-based monomers, and can be radically polymerized by irradiation with ultraviolet light.

[0040] In some embodiments, the rod-shaped cationic photopolymerizable monomer is one or more of rod-shaped epoxy monomers, rod-shaped vinyl ether monomers, and rod-shaped vinyl monomers, and can be cationic polymerized by irradiation with ultraviolet light.

[0041] In some embodiments, the rod-shaped thermally polymerizable monomer is a mixture of a rod-shaped epoxy monomer and a rod-shaped mercaptan monomer, or a mixture of a rod-shaped monomer containing an amino group, a hydroxyl group, a carboxyl group, or a mercapto group and a rod-shaped isocyanate monomer, and is thermally polymerizable under heating conditions.

[0042] In some embodiments of the present specification, the rod-shaped radical photopolymerizable monomer may be selected from one or more of the following structural formulas: JPEG0007681339000002.jpg3775However, m and n are from 1 to 20, x and y are from 1 to 2, and E and Q are acrylate or epoxy acrylate or olefin functional groups.

[0043] In some embodiments of this specification, one or more of the following structural formulas may be selected as the rod-shaped cationic photopolymerizable monomer. JPEG0007681339000003.jpg3675However, m and n are from 1 to 20, x and y are from 1 to 2, and E and Q are vinyl ether or epoxy functional groups.

[0044] In some embodiments of this specification, the rod-shaped epoxy and the rod-shaped mercaptan monomer as the rod-shaped thermopolymerizable monomer may select one or more of the following structural formulas. JPEG0007681339000004.jpg88103However, m and n are from 1 to 20, x and y are from 1 to 2.

[0045] In some embodiments, the liquid crystal material is a cholesteric liquid crystal material having a positive dielectric anisotropy, or a liquid crystal material having nematic, smectic, and smectic-cholesteric phase transition characteristics. The nematic liquid crystal material may include, but is not limited to, commercially available liquid crystal materials, such as SLC-1717, SLC-7011, TEB30A, etc. of Yongsheng Huaqing Liquid Crystal Materials Co., Ltd., and E7, E44, E48, ZLI-1275, etc. of Merck Liquid Crystal Materials GmbH in Germany. A cholesteric liquid crystal material can be obtained by mixing the aforementioned materials with a chiral compound. Here, the chiral compound includes, but is not limited to, one or more of cholesteryl nonanoate, CB15, C15, S811, R811, S1011, R1011, etc.

[0046] In some embodiments, the liquid crystal material may include one or more of the molecular structures (1). JPEG0007681339000005.jpg1460 wherein M and N are an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a siloxane group having 1 to 20 carbon atoms, a cyano group, an ester group, a halogen, an isothiocyano group, or a nitro group; A and B are aromatic rings or alicyclic alkyl groups, and contain at least one of a ring, a six-membered ring, a six-membered heterocyclic ring, a five-membered ring, a five-membered heterocyclic ring, a biphenyl, a terphenyl, and a naphthalene ring; A and B are linked via a covalent bond or a linking group Z; A and B contain or do not contain a pendant group, and the pendant group is a halogen, a cyano group, or a methyl group; x and y are each 0 to 4; and Z is an ester group, an alkynyl group, an alkane group, a nitrogen double bond, or an ether bond.

[0047] Some embodiments of the present specification further provide a method for manufacturing a liquid crystal / polymer composite electrically controlled light control film, the method including: 1) mixing a liquid crystal material, a first polymerizable monomer, a second polymerizable monomer, a first initiator, a second initiator, and spacer particles to obtain a uniform mixture; 2) filling the mixture between two layers of laminated conductive substrates to manufacture a film, forming a polymer substrate with a porous microstructure through a first reaction, and dispersing the liquid crystal material in the form of liquid crystal microdroplets in the polymer substrate; and 3) applying an electric field to the film to vertically align the liquid crystal material molecules and the second polymerizable monomer molecules, and forming a vertically oriented polymer network in the liquid crystal microdroplets through a second reaction, thereby manufacturing a liquid crystal / polymer composite electrically controlled light control film.

[0048] The first reaction is a reaction to produce a polymeric substrate, in some embodiments, the first reaction includes a first initiator initiating a photopolymerization or thermal polymerization reaction of a first polymerizable monomer.

[0049] The second reaction is a reaction to produce a polymer network, in some embodiments, the second reaction includes a second initiator initiating a photopolymerization or thermal polymerization reaction of a second polymerizable monomer.

[0050] Some examples herein propose to construct a liquid crystal / polymer composite electrically controlled light control film that combines the good mechanical processing performance of a PDLC film and the low driving voltage of a PSLC film by using a two-step polymerization method (i.e., a two-step polymerization method consisting of step 1 and step 2) by a first reaction and a second reaction, and its feature is that a micro-morphology of a vertically aligned polymer network is formed in a polymer substrate by using a two-step polymerization method. Here, the polymer substrate with a fine structure ensures the good mechanical processing performance of the liquid crystal / polymer composite electrically controlled light control film, and the vertically aligned polymer network present in the pores reduces the difficulty of aligning the liquid crystal molecules under the action of an electric field, thereby reducing the driving voltage of the liquid crystal / polymer composite electrically controlled light control film. As can be seen, the first reaction is used to prepare a polymer substrate, i.e., the polymer substrate is prepared by step 1, and the second reaction is used to prepare a polymer network, i.e., the polymer network is prepared by step 2.

[0051] The two-step polymerization method according to some embodiments of the present specification may include four preparation routes, including photo-photo two-step polymerization, photo-thermal two-step polymerization, thermal-photo two-step polymerization and thermal-thermal two-step polymerization, respectively.

[0052] The photo-photo two-step polymerization refers to using photopolymerization to prepare a polymer substrate in step 1, and using photopolymerization to prepare a polymer network in step 2. In some embodiments, when using the photo-photo two-step polymerization, the first polymerizable monomer is a radical photopolymerizable monomer or a cationic photopolymerizable monomer, and the second polymerizable monomer is one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0053] Photo-thermal two-step polymerization refers to producing a polymer substrate using photopolymerization in step 1 and producing a polymer network using thermal polymerization in step 2. In some embodiments, when using photo-thermal two-step polymerization, the first polymerizable monomer is a radical photopolymerizable monomer or a cationic photopolymerizable monomer, and the second polymerizable monomer is a rod-shaped thermally polymerizable monomer or a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0054] The thermal-photo two-step polymerization refers to preparing a polymer substrate using thermal polymerization in step 1, and preparing a polymer network using photopolymerization in step 2. In some embodiments, when using the thermal-photo two-step polymerization, the first polymerizable monomer is a thermally polymerizable monomer, and the second polymerizable monomer is one of a rod-shaped radical photopolymerizable monomer, a rod-shaped cationic photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, a combination of a radical photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer, a combination of a cationic photopolymerizable monomer and a rod-shaped radical photopolymerizable monomer, or a combination of a cationic photopolymerizable monomer and a rod-shaped cationic photopolymerizable monomer.

[0055] Thermal-thermal two-step polymerization refers to using thermal polymerization to produce a polymer substrate in step 1 and using thermal polymerization to produce a polymer network in step 2. In some embodiments, when using thermal-thermal two-step polymerization, the first polymerizable monomer is a thermally polymerizable monomer and the second polymerizable monomer is a rod-shaped thermally polymerizable monomer or a combination of a rod-shaped thermally polymerizable monomer and a thermally polymerizable monomer.

[0056] Among the above four manufacturing routes, the technical route of manufacturing a composite film by light-heat two-step polymerization is as shown in Figure 3. Note that the principles of the technical routes of manufacturing a composite film by light-light two-step polymerization, heat-light two-step polymerization and heat-heat two-step polymerization are similar to those in Figure 3, and thus no examples are given here one by one. In some embodiments, the liquid crystal material, the first polymerizable monomer, and the second polymerizable monomer raw materials used in preparing the mixture in step 1) are in a ratio of parts by weight: Liquid crystal material: 10.0 to 95.0 parts by weight, First polymerizable monomer: 5.0 to 80.0 parts by weight, Second polymerizable monomer: 0.1 to 40.0 parts by weight.

[0057] Since the vertically aligned polymer network is restricted by the pore size of the porous microstructure, by changing the type and blending ratio of each material among the liquid crystal material, the first polymerizable monomer, and the second polymerizable monomer, it is possible to realize the adjustment and control of the pore size of the micropores in the polymer matrix. Furthermore, the adjustment and control of the content and density of the vertically aligned polymer network can be realized. In this way, liquid crystal / polymer composite electro-optic dimming films with different driving voltages and electro-optical properties can be manufactured, thereby meeting various usage requirements.

[0058] In actual applications, as the pore size of the polymer matrix having a microstructure, various range values can be selected, for example, 0.1 - 1 micron, 1 - 10 microns, 10 - 20 microns, 20 - 40 microns, 40 - 60 microns, 60 - 80 microns, 80 - 100 microns, etc., and the corresponding vertically aligned polymer network is also limited within these pore sizes. In some embodiments, the pore size of the polymer matrix having a microstructure is preferably less than 10 microns.

[0059] Regarding the liquid crystal / polymer composite electro-optic dimming film according to some embodiments of this specification, the liquid crystal material is dispersed in the polymer matrix in the form of liquid crystal droplets, that is, the polymer matrix has a microstructure of a plurality of micropores. There is a polymer network in the micro-region where the liquid crystal droplets are located. According to such a microstructure, the liquid crystal / polymer composite electro-optic dimming film not only has the advantages of the PDLC film such as excellent peel strength and large-area flexible processing, but also has the advantages of the PSLC film such as excellent electro-optical performance.

[0060] In order to make those skilled in the art better understand some technical solutions of the present specification, the technical solutions of manufacturing the liquid crystal / polymer composite electrically controlled light control film of the present specification will be described in more detail below through specific examples.

[0061] In the following Examples 1-3 and Comparative Example 1, a mixture of commercially available liquid crystal SLC1717, which is a cholesteric liquid crystal material, and chiral compound S811 is selected, and the ratio is 94: 6. Note that the following Examples 1-3 and Comparative Example 1 are all performed in a room temperature environment, and the abbreviations and structural formulas of the polymerizable monomers (first polymerizable monomer and second polymerizable monomer) and initiators (first initiator and second initiator) used are shown in Figures 4 to 8.

[0062] Example 1 In Example 1, photo-thermal two-step polymerization is used. The names and compounding ratios of the liquid crystal material, the first polymerizable monomer, the second polymerizable monomer, the first initiator, the second initiator, and the spacer particles used are shown in Table 1. The total mass of the mixture is 15 g. The materials in Table 1 are stirred at room temperature to form an isotropic liquid, which is mixed uniformly and sandwiched between two sheets of ITO conductive plastic film plated with indium tin oxide. The size of the ITO conductive plastic film is 0.4*0.4 m. 2 The film was uniformly pressed with a roll to form a film, and the film was irradiated with ultraviolet light having a wavelength of 365 nm at room temperature. The ultraviolet light intensity was 5.0 mw / cm. 2 The irradiation time was 10 min, and the first polymerization (photopolymerization) was performed. Then, a voltage of 100 V was applied to the film, and the film was left in an oven at 70° C. for 5 h to perform the second polymerization (thermal polymerization), thereby obtaining a liquid crystal / polymer composite electrically controlled light control film of the embodiment of this specification.

[0063] The liquid crystal / polymer composite electrically controlled light control film produced in Example 1 was tested using a liquid crystal tester, and the obtained electro-optical curve was shown as a solid equilateral triangle curve in Figure 9. The liquid crystal / polymer composite electrically controlled light control film was immersed in cyclohexane to remove the liquid crystal material, and then dried. The obtained scanning electron microscope photograph is shown in Figure 10.

[0064] In Fig. 9, the abscissa is the voltage value, and the ordinate is the transmittance of the liquid crystal / polymer composite electrically controlled light control film. The solid equilateral triangular curve in Fig. 9 shows the electro-optical curve of the liquid crystal / polymer composite electrically controlled light control film obtained in Example 1, the driving voltage of the electro-optical curve corresponding to Example 1 is about 25V, and when the voltage is 100V, the transmittance of the liquid crystal / polymer composite electrically controlled light control film is 94%. The liquid crystal / polymer composite electrically controlled light control film obtained in Example 1 has a relatively low driving voltage.

[0065] As can be seen from FIG. 10, the liquid crystal / polymer composite electrically controlled light control film obtained by using the photo-thermal two-step polymerization in Example 1 can construct a vertically oriented polymer network in the pores of the porous microstructure, and the vertical orientation effect of the polymer network is high and exists in large quantities in the polymer mesh.

[0066] JPEG0007681339000006.jpg91158 Example 2 In Example 2, photo-photo two-step polymerization is used. The names and compounding ratios of the liquid crystal material, first polymerizable monomer, second polymerizable monomer, first initiator, second initiator, and spacer particles used are shown in Table 2, and the total mass of the mixture is 15 g. The raw materials in Table 2 are stirred at room temperature (25°C) to form an isotropic liquid, mixed uniformly, and sandwiched between two sheets of indium tin oxide-plated ITO conductive plastic film, and the size of the ITO conductive plastic film is 0.4*0.4 m. 2 The film was uniformly pressed with a roll to form a film, and the film was irradiated with ultraviolet light having a wavelength of 365 nm at room temperature (25°C). The ultraviolet light intensity was 5.0 mw / cm. 2and the irradiation time is 3 - 5 min. The first polymerization (photo - polymerization) is carried out. Subsequently, a voltage of 100 V is applied to the film, and it is irradiated with ultraviolet light of wavelength 254 nm under the condition of 25°C. The ultraviolet intensity is 5.0 mw / cm 2 and the irradiation time is 30 min. By carrying out the second polymerization (photo - polymerization), the liquid - crystal / polymer composite electro - optically controlled dimming film of the examples in this specification is obtained.

[0067] For the liquid - crystal / polymer composite electro - optically controlled dimming film manufactured in Example 2, its electro - optical curve is tested using a liquid - crystal tester, as shown by the solid circular curve in Fig. 9. After the liquid - crystal material in the liquid - crystal / polymer composite electro - optically controlled dimming film is removed by immersion and dried, the obtained scanning electron micrograph is as shown in Fig. 11.

[0068] What is shown by the solid circular curve in Fig. 9 is the electro - optical curve of the liquid - crystal / polymer composite electro - optically controlled dimming film obtained in Example 2. The driving voltage of the electro - optical curve corresponding to Example 2 is about 25 V. When the voltage is 100 V, the transmittance of the liquid - crystal / polymer composite electro - optically controlled dimming film is 90%. The liquid - crystal / polymer composite electro - optically controlled dimming film obtained in Example 2 has a relatively low driving voltage, but at the same voltage, its transmittance is lower than that of the liquid - crystal / polymer composite electro - optically controlled dimming film obtained in Example 1. This indicates that the liquid - crystal / polymer composite electro - optically controlled dimming film obtained by using photo - thermal polymerization in Example 1 has better optoelectronic performance than the liquid - crystal / polymer composite electro - optically controlled dimming film obtained by using photo - photo polymerization in Example 2.

[0069] As can be seen from Fig. 11, the liquid - crystal / polymer composite electro - optically controlled dimming film obtained by using photo - photo two - stage polymerization in Example 2 can construct a polymer network vertically oriented in the pores of the porous microstructure.

[0070] JPEG0007681339000007.jpg84163 Example 3 In Example 3, thermal-thermal two-step polymerization is used. The names and compounding ratios of the liquid crystal material, the first polymerizable monomer, the second polymerizable monomer, the initiator, and the spacer particles used are shown in Table 3, and the total mass of the mixture is 15 g. The raw materials in Table 3 are stirred at room temperature (25°C) to form an isotropic liquid, which is mixed uniformly and sandwiched between two sheets of ITO conductive plastic film plated with indium tin oxide. The size of the ITO conductive plastic film is 0.4*0.4 m. 2 The resulting film was uniformly pressed with a roll to form a film, which was then left in an open container at 50°C for 1 hour to carry out a first polymerization (thermal polymerization), and then a voltage of 100 V was applied to the film, which was then left in an open container at 80°C for 3 hours to carry out a second polymerization (thermal polymerization), thereby obtaining a liquid crystal / polymer composite electrically controlled light control film according to the examples of this specification. The electro-optical curve of the liquid crystal / polymer composite electrically controlled light control film prepared in Example 3 is tested using a liquid crystal tester, and is shown as a solid inverted triangle curve in Figure 9. The liquid crystal material in the liquid crystal / polymer composite electrically controlled light control film is immersed and removed, and then dried. The scanning electron microscope photograph obtained is as shown in Figure 12. As shown in the solid inverted triangular curve in FIG. 9, the driving voltage of the electro-optical curve corresponding to the liquid crystal / polymer composite electrically controlled light control film obtained in Example 3 is about 21V, and when the voltage is 100V, the transmittance of the liquid crystal / polymer composite electrically controlled light control film is 97%. The liquid crystal / polymer composite electrically controlled light control film obtained in Example 3 has a relatively low driving voltage, which is lower than the driving voltage of the liquid crystal / polymer composite electrically controlled light control film obtained in Example 1 and Example 2, which shows that the liquid crystal / polymer composite electrically controlled light control film obtained in Example 3 by using thermal-thermal polymerization has good photoelectric performance. However, during actual production, the photopolymerization step is more convenient and simpler than the operation of the thermal polymerization step, and overall, Example 1 using photo-thermal polymerization is more suitable for actual industrial production than Example 3 using thermal-thermal polymerization. As can be seen from FIG. 12, the liquid crystal / polymer composite electrically controlled light control film obtained by using the thermal-thermal two-step polymerization in Example 3 can construct a vertically oriented polymer network in the pores of the porous microstructure. JPEG0007681339000008.jpg83150 It should be noted here that the preparation route of this Example 3 is a thermal-thermal two-step polymerization, and the first initiator and the second initiator used to thermally initiate the polymerization in two steps are the same initiator.

[0071] Comparative Example 1 The names and mixing ratios of the liquid crystal material, acrylate monomer, initiator, and glass beads used are shown in Table 4, and the total mass of the mixture is 35 g. The samples in the table are stirred at room temperature (25°C) to form an isotropic liquid, mixed uniformly, and sandwiched between two sheets of indium tin oxide (ITO)-plated conductive plastic film. The size of the ITO conductive plastic film is 1*1 m. 2 The film was uniformly pressed with a roll to form a film. The film was irradiated with ultraviolet light having a wavelength of 365 nm at room temperature (2525°C) with an ultraviolet intensity of 5.0 mW / cm. 2 and the irradiation time was 10 min to obtain a composite film.

[0072] JPEG0007681339000009.jpg66140 The electro-optical curve of the composite film prepared in Comparative Example 1 was tested using a liquid crystal tester and is shown in FIG. 9 as a solid square curve.

[0073] The square curve in FIG. 9 shows the electro-optical curve of the liquid crystal / polymer composite electrically controlled light control film obtained in Comparative Example 1, the driving voltage of the electro-optical curve corresponding to Comparative Example 1 is about 27V, and when the voltage is 100V, the transmittance of the liquid crystal / polymer composite electrically controlled light control film is 75%. As shown in FIG. 9, by comparing Examples 1, 2 and 3 with Comparative Example 1, it can be seen that the driving voltages of Examples 1, 2 and 3 are obviously smaller than that of Comparative Example 1, which shows that the materials of some Examples in this specification have a better reducing effect on the driving voltage of the composite electrically controlled light control film.

[0074] Comparative Example 2 In Comparative Example 2, photo-thermal two-step polymerization is used. The names and blending ratios of the liquid crystal material, the first polymerizable monomer, the second polymerizable monomer, the first initiator, the second initiator, and the spacer particles are shown in Table 1. The total mass of the mixture is 15 g. The materials in Table 1 are stirred at room temperature to form an isotropic liquid, uniformly mixed, and sandwiched between two indium tin oxide (ITO)-coated ITO conductive plastic films. The size of the ITO conductive plastic film is 0.4 * 0.4 m 2 and is uniformly pressed with a roll to form a film. This film is irradiated with ultraviolet light having a wavelength of 365 nm at room temperature, and the ultraviolet light intensity is 5.0 mw / cm 2 and the irradiation time is 10 min to perform the first polymerization (photo-polymerization). Subsequently, a voltage of 100 V is applied to the film, and the film is left in an oven at 70 °C for 5 h to perform the second polymerization (thermal polymerization), thereby obtaining the liquid crystal / polymer composite electro-optic dimming film of the example of this specification.

[0075] When the liquid crystal / polymer composite electro-optic dimming film manufactured in Comparative Example 2 was tested using a liquid crystal tester, the obtained electro-optical curve was as shown by the solid square curve in FIG. 13. After the liquid crystal material was removed by immersion using cyclohexane from the liquid crystal / polymer composite electro-optic dimming film, it was dried, and the obtained scanning electron micrograph was as shown in FIG. 14.

[0076] In JPEG0007681339000010.jpg96158, FIG. 13, the horizontal axis is the voltage value, and the vertical axis is the transmittance of the liquid crystal / polymer composite electro-optic dimming film. As shown by the solid square curve in FIG. 13, the driving voltage of the electro-optical curve corresponding to Example 1 is about 25 V, and when the voltage is 100 V, the transmittance of the liquid crystal / polymer composite electro-optic dimming film is 94%. As shown by the solid circular curve in FIG. 13, the driving voltage of the electro-optical curve obtained in Comparative Example 2 is about 43 V, and when the voltage is 100 V, the transmittance of the liquid crystal / polymer composite electro-optic dimming film is 80%.

[0077] By comparing and analyzing Example 1 and Comparative Example 2, as can be seen from Figure 13, the driving voltage of the composite electrically controlled light control film obtained in Example 1 is obviously smaller than the driving voltage of the composite electrically controlled light control film obtained in Comparative Example 2. Therefore, compared with the use of rod-shaped monomers as only a part of the second polymerizable monomer in Comparative Example 2 (i.e., using rod-shaped epoxy monomers and non-rod-shaped mercaptan monomers), the use of rod-shaped monomers (i.e., rod-shaped epoxy monomers and rod-shaped mercaptan monomers) as all of the second polymerizable monomers in Example 1 has a higher effect on reducing the driving voltage of the composite electrically controlled light control film.

[0078] As can be seen by comparing FIG. 14 corresponding to Example 2 with FIG. 10 corresponding to Example 1, the liquid crystal / polymer composite electrically controlled light control film obtained by using rod-shaped epoxy monomer and non-rod-shaped mercaptan monomer as the second polymerizable monomer in Comparative Example 2 cannot successfully construct a large amount of vertically aligned polymer network; when using photo-thermal polymerization reaction, by using rod-shaped epoxy monomer and rod-shaped mercaptan monomer as the second polymerizable monomer (i.e., all second polymerizable monomers use rod-shaped monomer), it is possible to form a large number of vertical polymer networks with good alignment, and this vertical polymer network can provide the composite electrically controlled light control film with a relatively low driving voltage and relatively good electro-optical performance.

[0079] As can be seen from the above, in Comparative Example 2, when rod-shaped epoxy monomer and non-rod-shaped mercaptan monomer are used in polymerization in step 2, the vertically aligned polymer network formed is relatively small, the supporting effect on the alignment of liquid crystal molecules is reduced, and the driving voltage cannot be reduced well, and the driving voltage is higher than that of Example 1. In Example 1, when a combination of rod-shaped epoxy monomer and rod-shaped mercaptan monomer is used in polymerization in step 2, these two monomers do not start to react during ultraviolet polymerization in step 1, but can fully react during heat polymerization in step 2, so that the alignment is relatively good and a large number of vertical polymer networks are formed. These vertical polymer networks are helpful in reducing the anchoring force of the polymer group that the liquid crystal molecules receive when the liquid crystal molecules are aligned and arranged in the direction of the electric field during the electric current passing through the light control film, so that the composite electrically controlled light control film obtained in Example 1 can have relatively good electric light performance at a low driving voltage.

[0080] In the conventional liquid crystal / polymer composite electric control light control film manufacturing technology, it can be manufactured by single-step polymerization, such as ultraviolet polymerization or thermal polymerization. The single-step method builds a PDLC porous polymer substrate, which on the one hand exerts a large anchoring force on the orientation of liquid crystal molecules, thereby increasing the driving voltage required when the optical state of the film is changed, which is not favorable for practical use. On the other hand, the single-step method has a relatively simple manufacturing process and adjustment control means, which is also unfavorable for adjusting and controlling the micro-morphology of the composite light control film.

[0081] In the manufacturing method of the liquid crystal / polymer composite electrically controlled dimming film according to some embodiments of this specification, a two-step polymerization method is used. First, through the polymerization reaction in Step 1, a polymer matrix with a porous microstructure similar to PDLC in the prior art is constructed. Further, by constructing a polymer network vertically oriented in the pores of the porous microstructure through the polymerization reaction in Step 2, a unique composite microstructure is realized. First of all, such a composite microstructure can effectively reduce the anchoring force on the orientation of liquid crystal molecules by the polymer matrix, thereby achieving the effect of reducing the driving voltage of the film. On the other hand, the manufacturing process and adjustment control means of the two-step polymerization method are more abundant, and the polymerization conditions and polymerization process can be changed more detailedly and effectively, thereby adjusting and controlling the composite microstructure of the film.

[0082] In addition, the polymerization reaction in Step 1 and the polymerization reaction in Step 2 in the two-step polymerization method of the liquid crystal / polymer composite dimming film according to some embodiments of this specification may each use a different polymer monomer system. For example, during photo-thermal two-step polymerization, a radical photopolymerizable monomer or a cationic photopolymerizable monomer is used as the first polymerizable monomer in the former, and the second polymerizable monomer in the latter is a rod-shaped thermal polymerization monomer. Therefore, in the photopolymerization process of Step 1, since the second polymerizable monomer does not participate in the reaction, the separation of the polymerization reactions in Step 1 and Step 2 can be ensured. On this basis, by controlling the polymerization conditions (such as ultraviolet intensity, irradiation time, etc.) in Step 1, the first polymerizable monomer can be fully reacted without small molecule monomers remaining in the system and damaging the performance of all aspects of the film. At the same time, the second polymerizable monomer also does not participate in the polymerization reaction in Step 1, ensuring that the porous polymer matrix formed after the polymerization in Step 1 does not contain rod-shaped or liquid crystalline monomers, that is, it has a lower anchoring force on liquid crystal molecules and a higher effect on reducing the driving voltage.

[0083] Although the basic concept has been described above, it is clear to those skilled in the art that the above disclosure of the invention is merely illustrative and does not constitute a limitation of the present specification. Although not expressly stated herein, those skilled in the art may make various changes, improvements and modifications to the present specification. Since such changes, improvements and modifications are proposed in this specification, such changes, improvements and modifications still fall within the spirit and scope of the exemplary embodiments of the present specification.

Claims

1. A liquid crystal / polymer composite electrically controlled light control film, comprising a liquid crystal material, a polymer substrate and two layers of conductive substrates, wherein: the polymer substrate is sandwiched between the two conductive substrates, the polymer substrate having a porous microstructure; the liquid crystal material is dispersed in the polymer substrate to form liquid crystal droplets, the liquid crystal droplets having a vertically aligned polymer network; The polymer substrate is formed by photopolymerizing all of the radical photopolymerizable monomers, The polymer network is formed by thermally polymerizing all of the rod-shaped thermopolymerizable monomers. the rod-shaped thermopolymerizable monomer does not participate in the photopolymerization reaction of the radical photopolymerizable monomer, and can be aligned and arranged along the electric field direction along with the liquid crystal material molecules; The radical photopolymerizable monomer is one or more of acrylate monomers or olefin monomers that can be radically polymerized by irradiation with ultraviolet light, The rod-shaped thermally polymerizable monomer is a mixture of a rod-shaped epoxy monomer and a rod-shaped mercaptan or amine monomer that can be thermally polymerized under heating conditions, or a mixture of a rod-shaped monomer containing an amino group, a hydroxyl group, a carboxyl group, or a mercapto group and a rod-shaped isocyanate monomer. A liquid crystal / polymer composite electrically controlled light control film.

2. The liquid crystal material is a cholesteric liquid crystal material having positive dielectric anisotropy, or a liquid crystal material having nematic, smectic and smectic-cholesteric phase transition characteristics. The liquid crystal / polymer composite electrically controlled light control film according to claim 1.

3. The liquid crystal material comprises one or more types of molecular structure (1), wherein M and N are an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a siloxane group having 1 to 20 carbon atoms, a cyano group, an ester group, a halogen, an isothiocyano group, or a nitro group; A and B are aromatic rings or alicyclic alkyl groups and include at least one of a benzene ring, a six-membered ring, a six-membered heterocyclic ring, a five-membered ring, a five-membered heterocyclic ring, a biphenyl, a terphenyl, and a naphthalene ring; A and B are linked via a covalent bond or a linking group Z; A and B contain or do not contain a pendant group, the pendant group being a halogen, a cyano group, or a methyl group; x and y are each an integer of 0 to 4; and Z is an ester group, an alkynyl group, an alkane group, a nitrogen double bond, or an ether bond. The liquid crystal / polymer composite electrically controlled light control film according to claim 1.

4. The pore size of the micropores in the polymer substrate is characterized in that it is 0.1-100 microns. The liquid crystal / polymer composite electrically controlled light control film according to claim 1.

5. The conductive substrate is characterized in that it includes a conductive film containing a metal compound or a glass substrate. The liquid crystal / polymer composite electrically controlled light control film according to claim 1.

6. A method for producing a liquid crystal / polymer composite electrically controlled light control film, comprising the steps of: 1) mixing a liquid crystal material, a first polymerizable monomer, a second polymerizable monomer, a first initiator, a second initiator, and spacer particles to obtain a uniform mixture; 2) filling the mixture between two laminated conductive substrates to produce a film, in which the first polymerizable monomer is fully reacted in a first reaction to form a porous microstructured polymer substrate, and the liquid crystal material is dispersed in the polymer substrate in the form of liquid crystal microdroplets; 3) applying an electric field to the film to vertically align the liquid crystal material molecules and the second polymerizable monomer molecules, so that the second polymerizable monomer molecules are fully reacted through a second reaction to form a vertically oriented polymer network in the liquid crystal microdroplets, thereby producing the liquid crystal / polymer composite electrically controlled light control film; the first polymerizable monomer is a radical photopolymerizable monomer; The second polymerizable monomer is a rod-shaped thermally polymerizable monomer that can be aligned along the electric field direction along with the liquid crystal material molecules, and does not participate in the first reaction of the first polymerizable monomer; The radical photopolymerizable monomer is one or more of acrylate monomers or olefin monomers that can be radically polymerized by irradiation with ultraviolet light, The thermally polymerizable monomer is a mixture of an epoxy monomer and a mercaptan or amine monomer that can be thermally polymerized under heating conditions, or a mixture of a monomer containing an amino group, a hydroxyl group, a carboxyl group, or a mercapto group and an isocyanate monomer. A method for producing a liquid crystal / polymer composite electrically controlled light control film.

7. The first reaction includes the first initiator initiating a photopolymerization reaction of a radical photopolymerizable monomer, and the second reaction includes the second initiator initiating a thermal polymerization reaction of a rod-shaped thermally polymerizable monomer. A method for producing the liquid crystal / polymer composite electrically controlled light control film according to claim 6.

8. The raw materials of the liquid crystal material, the first polymerizable monomer, and the second polymerizable monomer are, in terms of a ratio of parts by weight, The liquid crystal material: 10.0 to 95.0 parts by weight, the first polymerizable monomer: 5.0 to 80.0 parts by weight, The second polymerizable monomer: 0.1 to 40.0 parts by weight A method for producing the liquid crystal / polymer composite electrically controlled light control film according to claim 6.

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