Composition for electronic device housing, polymer dispersed liquid crystal film and preparation method thereof

文档序号：1856430 发布日期：2021-11-19 浏览：29次中文

阅读说明：本技术 用于电子设备壳体的组合物、聚合物分散液晶、聚合物分散液晶薄膜及其制备方法 (Composition for electronic device housing, polymer dispersed liquid crystal film and preparation method thereof ) 是由吴中正王雷李辉于 2021-08-13 设计创作，主要内容包括：本发明公开了用于电子设备壳体的组合物、聚合物分散液晶、聚合物分散液晶薄膜及其制备方法。所述组合物包括聚合物单体、液晶和光引发剂,所述聚合物单体包括丙烯酸酯类化合物,所述液晶包括主体液晶和高液晶介电各向异性化合物,所述高液晶介电各向异性化合物的介电各向异性参数不小于10。该组合物可以用于制备聚合物分散液晶材料,本发明通过在组合物中添加高液晶介电各向异性化合物,来降低聚合物分散液晶的驱动饱和电压,降低功耗。本发明的组合物、由组合物形成的聚合物分散液晶可以用于有低功耗要求的电子设备壳体中,改善了现有聚合物分散液晶材料的高功耗缺陷。(The invention discloses a composition for an electronic device shell, a polymer dispersed liquid crystal film and a preparation method thereof. The composition comprises a polymer monomer, liquid crystal and a photoinitiator, wherein the polymer monomer comprises an acrylate compound, the liquid crystal comprises main liquid crystal and a high liquid crystal dielectric anisotropy compound, and the dielectric anisotropy parameter of the high liquid crystal dielectric anisotropy compound is not less than 10. The composition can be used for preparing polymer dispersed liquid crystal materials, and the driving saturation voltage of polymer dispersed liquid crystal is reduced and the power consumption is reduced by adding the high liquid crystal dielectric anisotropy compound into the composition. The composition and the polymer dispersed liquid crystal formed by the composition can be used in electronic equipment shells with low power consumption requirements, and the defect of high power consumption of the conventional polymer dispersed liquid crystal material is overcome.)

1. The composition for the electronic equipment shell is characterized by comprising a polymer monomer, liquid crystal and a photoinitiator, wherein the polymer monomer comprises an acrylate compound, the liquid crystal comprises a main liquid crystal and a high liquid crystal dielectric anisotropy compound, and the dielectric anisotropy parameter of the high liquid crystal dielectric anisotropy compound is not less than 10.

2. The composition of claim 1, wherein the high liquid crystal dielectric anisotropy compound has a dielectric anisotropy parameter of not less than 15.

3. The composition of claim 1, wherein the acrylate compound comprises at least one of bisphenol a polyoxyethylene ether methacrylate, polyethylene glycol diacrylate, lauryl methacrylate, and hydroxypropyl methacrylate.

4. The composition of claim 1, wherein the high liquid crystal dielectric anisotropy compound comprises a fluorobiphenyl-based compound.

5. The composition of claim 4, wherein the fluorobiphenyl compounds comprise 4- ((3, 5-difluoro-4-isothiocyanatophenyl) ethynyl) -4 '-ethyl-1, 1' -biphenyl.

6. The composition of claim 1, wherein the host liquid crystal comprises 4- (2- (4-isothiocyanatobenzene) ethyl) -4- (4-cyclopentylhexyl) -1, 1-biphenyl.

7. The composition of claim 6, wherein the host liquid crystal further comprises at least one of 4-cyanobiphenyl, 4 "-n-pentyl-4-cyanobiphenyl.

8. The composition of claim 1, wherein the photoinitiator comprises benzoin diethyl ether.

9. The composition of claim 1, wherein the mass ratio of the high liquid crystal dielectric anisotropy compound to the liquid crystal is (5-23): 100.

10. the composition of claim 1, wherein the polymer monomer is present in an amount of 40 to 60 parts by weight, the liquid crystal is present in an amount of 40 to 60 parts by weight, and the photoinitiator is present in an amount of 1 to 3 parts by weight, based on the total mass of the composition.

11. The composition of claim 10, wherein the polymer monomers comprise 13 to 20 parts by weight of bisphenol a polyoxyethylene ether methacrylate, 3 to 7 parts by weight of polyethylene glycol diacrylate, 8 to 14 parts by weight of lauryl methacrylate, 12 to 19 parts by weight of hydroxypropyl methacrylate, based on the total mass of the composition;

the liquid crystal comprises 10-20 parts by weight of 4-cyanobiphenyl, 18-26 parts by weight of 4 ' -n-pentyl-4-cyanobiphenyl, 4-10 parts by weight of 4- (2- (4-isothiocyanatobenzene) ethyl) -4- (4-cyclopentylhexyl) -1, 1-biphenyl, and 3-9 parts by weight of 4- ((3, 5-difluoro-4-isothiocyanatobenzene) ethynyl) -4 ' -ethyl-1, 1 ' -biphenyl, based on the total mass of the composition.

12. A polymer dispersed liquid crystal comprising a polymer formed by reacting:

a polymer monomer comprising an acrylate compound;

a liquid crystal comprising a bulk liquid crystal and a high liquid crystal dielectric anisotropy compound, the high liquid crystal dielectric anisotropy compound having a dielectric anisotropy parameter of not less than 10;

a photoinitiator.

13. The polymer-dispersed liquid crystal according to claim 12, wherein the liquid crystal droplets in the polymer-dispersed liquid crystal have a major axis size of 2.3 to 9 μm.

14. A polymer dispersed liquid crystal film comprising two conductive films and a polymer dispersed liquid crystal layer between the two conductive films, the polymer dispersed liquid crystal layer having the polymer dispersed liquid crystal according to claim 12 or 13.

15. The polymer-dispersed liquid crystal film according to claim 14, wherein the polymer-dispersed liquid crystal layer has a thickness of 14 to 16 μm.

16. The polymer-dispersed liquid crystal film according to claim 14, wherein the polymer-dispersed liquid crystal film can achieve a haze of 1.2 to 89% in a voltage range from 0 to a driving saturation voltage of 18 to 30V.

17. A method of making a polymer dispersed liquid crystal film, comprising: applying the composition of any one of claims 1-11 between two conductive films and uv curing to obtain a polymer dispersed liquid crystal film.

18. The method as claimed in claim 17, wherein the energy of the uv curing is 600-1200 mj;

optionally, the time of the ultraviolet curing is 0.8-2 min.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a composition for an electronic equipment shell, a polymer dispersed liquid crystal film and a preparation method thereof.

Background

Polymer dispersed liquid crystals, also known as pdlc (polymer dispersed liquid crystal), are liquid crystals dispersed in small micron-sized droplets within an organic solid polymer matrix. In polymer dispersed liquid crystals, liquid crystal molecules form a microphase separation structure with a polymer matrix in which liquid crystal material is dispersed in the form of droplets. When no electric field is applied, the direction vectors of the liquid crystal molecules are randomly distributed under the action of the polymer matrix boundary, and a scattering state is presented. After the electric field is applied, the long axes of the liquid crystal molecules are arranged in parallel or perpendicular to the electric field, and the liquid crystal display device is in a transparent state. The polymer dispersed liquid crystal has the characteristic of electrically controlled optical switch under the action of an electric field, wherein the transparent state and the scattering state can be changed along with the magnitude of voltage, and when the transparency reaches the maximum, the corresponding voltage is called as driving saturation voltage. At present, due to this characteristic, polymer dispersed liquid crystal is widely used in large area projection screens, buildings and automobile doors and windows, glass curtain walls, and indoor partitions, but its driving saturation voltage is always above 36V.

Therefore, the current compositions, polymer dispersed liquid crystals, polymer dispersed liquid crystal films and the methods for preparing the same are still in need of improvement.

Disclosure of Invention

The inventor finds that the conventional polymer dispersed liquid crystal has the defects of high driving saturation voltage, high energy consumption, high power consumption and the like, and can only be used in the field without special requirements on the power consumption. The existing polymer dispersed liquid crystal can not be applied to electronic equipment with low power consumption requirement.

The present invention aims to ameliorate at least one of the above technical problems to at least some extent.

In order to improve the technical problem, the invention provides a composition for an electronic device shell, which comprises a polymer monomer, a liquid crystal and a photoinitiator, wherein the polymer monomer comprises an acrylate compound, the liquid crystal comprises a main liquid crystal and a high liquid crystal dielectric anisotropy compound, and the dielectric anisotropy parameter of the high liquid crystal dielectric anisotropy compound is not less than 10. Therefore, the polymer dispersed liquid crystal formed by the composition has lower driving saturation voltage and low power consumption, improves the limitation problem of the application field of the existing polymer dispersed liquid crystal, can be used in the shell of electronic equipment, improves the problem that the existing polymer dispersed liquid crystal can only be used in the shell of the electronic equipment without special field of power consumption, can be used in the shell of the electronic equipment with low power consumption requirement, and can realize the appearance change of the shell of the electronic equipment by using the lower driving saturation voltage.

The present invention also provides a polymer dispersed liquid crystal comprising a polymer formed by reacting: a polymer monomer, a liquid crystal and a photoinitiator; wherein the polymer monomer comprises an acrylate compound; the liquid crystal includes a bulk liquid crystal and a high liquid crystal dielectric anisotropy compound, the high liquid crystal dielectric anisotropy compound having a dielectric anisotropy parameter of not less than 10. The polymer dispersed liquid crystal has lower driving saturation voltage and low power consumption, and can be used in electronic equipment shells with low power consumption requirements.

In some embodiments of the invention, the polymer dispersed liquid crystal is obtained by reacting the composition as described above. Thus, the polymer dispersed liquid crystal has all the features and advantages of the composition described above, and thus, the description thereof is omitted. In general, the polymer dispersed liquid crystal has lower driving saturation voltage and low power consumption.

The invention also provides a polymer dispersed liquid crystal film, which comprises two conductive films and a polymer dispersed liquid crystal layer positioned between the two conductive films, wherein the polymer dispersed liquid crystal layer is provided with the polymer dispersed liquid crystal. Thus, the polymer dispersed liquid crystal film has all the features and advantages of the polymer dispersed liquid crystal described above, and thus, the description thereof is omitted.

The present invention also provides a method for preparing a polymer dispersed liquid crystal film, comprising: the composition described above was coated between two conductive films and uv cured to obtain a polymer dispersed liquid crystal film. Thus, the polymer dispersed liquid crystal film has all the features and advantages of the composition described above, and thus, the description thereof is omitted.

Drawings

FIG. 1 is a scanning electron micrograph of a conventional polymer dispersed liquid crystal;

FIG. 2 is a graph of haze vs. voltage for a conventional polymer dispersed liquid crystal;

FIG. 3 is a scanning electron micrograph of a polymer dispersed liquid crystal according to an embodiment of the present invention;

FIG. 4 is a graph of haze vs. voltage for polymer dispersed liquid crystal, in accordance with an embodiment of the present invention.

Detailed Description

Embodiments of the present application are described in detail below. The following description of the embodiments is merely exemplary in nature and is in no way intended to limit the present disclosure. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents used are not indicated by manufacturers, and are all conventional products available on the market.

Referring to FIG. 1, the liquid crystal droplets in the conventional polymer dispersed liquid crystal have a major axis size of 1.4 to 1.8 μm. Referring to fig. 2, the driving saturation voltage of the conventional polymer dispersed liquid crystal is 40V. The haze of the polymer dispersed liquid crystal film can be controlled to change between 1.2 and 89% when the voltage is 0 to 40V, and the existing polymer dispersed liquid crystal needs higher driving voltage and has the defect of high power consumption.

In order to improve the technical problem, the invention provides a composition for an electronic device shell, which comprises a polymer monomer, a liquid crystal and a photoinitiator, wherein the polymer monomer comprises an acrylate compound, the liquid crystal comprises a main liquid crystal and a high liquid crystal dielectric anisotropy compound, and the dielectric anisotropy parameter of the high liquid crystal dielectric anisotropy compound is not less than 10. The composition can be used for preparing a polymer dispersed liquid crystal device, the driving saturation voltage of the polymer dispersed liquid crystal can be reduced by adding the high liquid crystal dielectric anisotropy compound into the composition, the haze change between 1.2 and 89 percent can be realized by using lower driving saturation voltage, and the power consumption of the product is reduced. Specifically, the composition can be used in an electronic device shell, the polymer dispersed liquid crystal formed by the composition has lower driving saturation voltage, and the appearance change of the electronic device shell can be realized by using the lower driving saturation voltage.

The polymer monomer may further include an epoxy compound, and the polymer monomer may further include an acrylate compound and an epoxy compound, and the specific type of the epoxy compound is not limited in the present invention, and the skilled person may select the epoxy compound according to the use requirement.

According to an embodiment of the present invention, the driving saturation voltage refers to a driving voltage at which the transmittance of the polymer dispersed liquid crystal layer in the PDLC device reaches a maximum, and the driving saturation voltage is a critical value at which the transmittance corresponding to a driving voltage greater than or equal to the critical value is maintained. The reduction of the driving saturation voltage can greatly reduce the energy consumption and greatly improve the use safety. Driving saturation voltage V of device formed by polymer dispersed liquid crystal_thThe following factors are relevant:

wherein d is the thickness of the polymer dispersed liquid crystal layer in the PDLC device, a is the semilong axis of the liquid crystal microdroplet, Delta epsilon is the dielectric anisotropy parameter of the liquid crystal, l is the length-diameter ratio of the elongated liquid crystal microdroplet, K is the effective elastic constant of the liquid crystal,the resistivity of the polymer and the liquid crystal, respectively.

According to the above formula: in addition to the size of the liquid crystal droplets, the liquid crystal dielectric anisotropy also affects the drive saturation voltage. Since the composition forms liquid crystal droplets when forming a polymer dispersed liquid crystal layer in a PDLC device, the liquid crystal dielectric anisotropy is a factor that greatly affects the driving saturation voltage of the PDLC device or the polymer dispersed liquid crystal composition. The invention adjusts the material formula of the traditional polymer dispersed liquid crystal, and adds the compound with high liquid crystal dielectric anisotropy into the composition to achieve the technical effects of reducing the driving saturation voltage and reducing the power consumption.

According to the embodiment of the present invention, the dielectric anisotropy parameter (Δ ∈) of the high liquid crystal dielectric anisotropy compound is not particularly limited, and in general, as long as it is not less than 10, it may play a role in lowering the driving saturation voltage. According to some embodiments of the present invention, the dielectric anisotropy parameter (Δ ∈) of the high liquid crystal dielectric anisotropy compound may be not less than 15, and thus, the driving saturation voltage may be further reduced.

According to the embodiment of the invention, the light transmittance of the acrylate compound is good, and the refractive index of the acrylate compound is matched with the light refractive index of the liquid crystal.

According to an embodiment of the present invention, the acrylate compound includes at least one of bisphenol a polyoxyethylene ether methacrylate (Bis-EMA15), polyethylene glycol diacrylate (PEGDA700), Lauryl Methacrylate (LMA), hydroxypropyl methacrylate (HPMA). The acrylate compound can be matched with liquid crystal and a photoinitiator, and the polymer dispersed liquid crystal formed by the composition has lower driving saturation voltage and low power consumption. According to an embodiment of the present invention, the high liquid crystal dielectric anisotropy compound includes a fluorine-containing biphenyl-based compound. The fluorine-containing biphenyl compound has larger dipole moment, and can increase dielectric anisotropy, thereby reducing the driving saturation voltage of the polymer dispersed liquid crystal.

According to an embodiment of the present invention, the fluorine-containing biphenyl compound includes 4- ((3, 5-difluoro-4-isothiocyanatobenzene) ethynyl) -4 '-ethyl-1, 1' -biphenyl, which has a large dipole moment and increases dielectric anisotropy. In addition, the high liquid crystal dielectric anisotropy compound has good intersolubility with polymer monomers, and is easier to react.

According to an embodiment of the present invention, the host liquid crystal comprises 4- (2- (4-isothiocyanatobenzene) ethyl) -4- (4-cyclopentylhexyl) -1, 1-biphenyl. The compound has good intersolubility with the high liquid crystal dielectric anisotropy compound, and is easy to react.

According to an embodiment of the invention, the host liquid crystal further comprises at least one of 4-cyanobiphenyl, 4 "-n-pentyl-4-cyanobiphenyl. The liquid crystal and the polymer monomer have good intersolubility and are easy to react. In addition, the refractive index of the liquid crystal of the present invention is matched to that of the polymer monomer, and the polymer dispersed liquid crystal layer shows a clear transparent state when an electric field is applied.

According to an embodiment of the present invention, the photoinitiator comprises benzoin diethyl ether (photoinitiator 651). Under the condition of ultraviolet irradiation, the photoinitiator can initiate polymerization reaction of polymer monomers to form a polymer network and liquid crystal droplets dispersed in the polymer network, namely polymer dispersed liquid crystal.

According to an embodiment of the present invention, the mass ratio of the high liquid crystal dielectric anisotropy compound to the liquid crystal is (5-23): 100, e.g., 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100, 20:100, 21:100, 22:100, 23: 100. At this time, the content of the high liquid crystal dielectric anisotropy compound is moderate, and the driving saturation voltage of the polymer dispersed liquid crystal formed by the composition can be effectively reduced. According to the embodiment of the present invention, the content of the polymer monomer is 40 to 60 parts by weight, the content of the liquid crystal is 40 to 60 parts by weight, and the content of the photoinitiator is 1 to 3 parts by weight, based on the total mass of the composition. When the content of the polymer monomer is too small, the polymer cannot form an interconnected network, but precipitates from the liquid crystal in the form of particles. As the content of the polymer monomer increases, a polymer network is gradually formed, and as the content of the polymer monomer increases, the gaps of the polymer network structure become smaller. However, the contact area between the polymer and the liquid crystal droplets is increased due to the excessively dense polymer network structure, and thus a larger voltage needs to be applied to change the state of the liquid crystal, and a larger driving saturation voltage is needed. When the content of the polymer monomer, the liquid crystal and the photoinitiator is within the range, a polymer network can be formed, the gaps of the network structure are proper, the liquid crystal dispersed in the polymer network structure has proper particle size, and the polymer dispersed liquid crystal formed by the composition has better electro-optical performance and lower driving voltage.

Furthermore, the inventors have surprisingly found that a composition having the above components can also control the size of the formed liquid crystal droplets by adjusting the photopolymerization energy when forming a polymer dispersed liquid crystal. Specifically, the composition with the components can obtain liquid crystal droplets with larger long axis size by reducing photopolymerization energy, so that polymer dispersed liquid crystal formed by the composition can be deflected in an electric field more easily, and the effect of reducing the saturation driving voltage of a device formed by the composition is achieved.

According to the embodiment of the invention, the polymer monomer comprises 13-20 parts by weight of bisphenol A polyoxyethylene ether methacrylate, 3-7 parts by weight of polyethylene glycol diacrylate, 8-14 parts by weight of lauryl methacrylate and 12-19 parts by weight of hydroxypropyl methacrylate based on the total mass of the composition.

The liquid crystal comprises 10-20 parts by weight of 4-cyanobiphenyl, 18-26 parts by weight of 4 ' -n-pentyl-4-cyanobiphenyl, 4-10 parts by weight of 4- (2- (4-isothiocyanatobenzene) ethyl) -4- (4-cyclopentylhexyl) -1, 1-biphenyl and 3-9 parts by weight of 4- ((3, 5-difluoro-4-isothiocyanatobenzene) ethynyl) -4 ' -ethyl-1, 1 ' -biphenyl based on the total mass of the composition.

According to some embodiments of the invention, the polymer dispersed liquid crystal is prepared from the composition as described hereinbefore. Thus, the polymer dispersed liquid crystal has all the features and advantages of the composition described above, and thus, the description thereof is omitted. In general, the polymer dispersed liquid crystal has the advantages of low driving saturation voltage and low power consumption.

According to an embodiment of the invention, the liquid crystal droplets in the polymer dispersed liquid crystal have a major axis size of 2.3 to 9 μm, such as 4 to 7.2. mu.m, 6.7 to 9. mu.m, 3.2 to 6. mu.m, 4.2 to 8. mu.m, 4.4 to 7. mu.m, 4.2 to 7. mu.m, 4.4 to 6. mu.m, 2.3 to 4. mu.m, 4.8 to 8. mu.m, 4.1 to 6. mu.m, 5.1 to 7.8. mu.m, 3.7 to 6.3. mu.m. According to some embodiments of the invention, the liquid crystal droplets in the polymer dispersed liquid crystal preferably have a major axis dimension of 3.2 to 9 μm. The size of the liquid crystal droplet is larger than that of the traditional liquid crystal droplet, so that the driving saturation voltage can be further reduced, and the power consumption is reduced.

According to an embodiment of the invention, the polymer dispersed liquid crystal layer has a thickness of 14-16 μm. The thickness of the polymer dispersed liquid crystal layer can be adjusted according to the use requirement and the manufacturing process, and the thickness of the polymer dispersed liquid crystal layer can be adjusted to include, but is not limited to 14 μm, 14.5 μm, 15 μm, 15.5 μm and 16 μm. According to some embodiments of the present invention, the polymer dispersed liquid crystal layer may have a thickness of 15 μm.

According to the embodiment of the invention, the polymer dispersed liquid crystal film can realize the change of the haze of 1.2-89% in the interval of the voltage of 0 to the driving saturation voltage of 18-30V, for example, the driving saturation voltage of 18V, 19V, 20V, 21V, 22V, 23V, 24V, 25V, 26V, 27V, 28V, 29V, 30V. The invention effectively reduces the driving saturation voltage and the power consumption of the product.

The present invention also provides a method for preparing a polymer dispersed liquid crystal film, comprising: the composition described above was coated between two conductive films and uv cured to obtain a polymer dispersed liquid crystal film. Thus, the method has all the features and advantages of the compositions described hereinbefore, which are not described in detail herein.

The coating method is not limited in the present invention, as long as the composition can be uniformly coated on the surface of the conductive film and dried to form a film layer. For example, coating means include, but are not limited to, roll coating, spin coating, spray coating, brush coating.

According to an embodiment of the present invention, the conductive film may be formed on a substrate, the substrate may provide a supporting function to the conductive film, the material forming the substrate may be PET (polyethylene terephthalate resin), and the material forming the conductive film may be ITO (indium tin oxide). When a driving voltage is applied to the two conductive films, liquid crystal droplets are deflected.

According to the embodiment of the invention, the energy of the ultraviolet curing is 600-1200mj, for example, 600mj, 650mj, 700mj, 750mj, 800mj, 850mj, 900mj, 950mj, 1000mj, 1050mj, 1100mj, 1150mj, 1200mj may be used. The inventor finds that when the energy of ultraviolet curing is 600-1200mj, the liquid crystal droplets in the polymer dispersed liquid crystal can have larger semimajor axis, and further reduces the saturation driving voltage of the polymer dispersed liquid crystal and reduces the power consumption.

According to the embodiment of the present invention, the time of the ultraviolet curing is 0.8-2min, for example, 0.8min, 0.9min, 1min, 1.1min, 1.2min, 1.3min, 1.4min, 1.5min, 1.6min, 1.7min, 1.8min, 1.9min, 2 min. The inventor finds that when the ultraviolet curing time is 0.8-2min, the liquid crystal droplets in the polymer dispersed liquid crystal can have larger semimajor axis, the driving saturation voltage of the polymer dispersed liquid crystal is further reduced, and the power consumption is reduced.

The inventor finds that the ultraviolet curing energy influences the appearance of the polymer network, and as the ultraviolet curing energy is reduced, the gaps of the polymer network become larger, and the network is sparse. As the energy of the uv cure increases, the size of the polymer network decreases. The possible reasons are: when the energy of ultraviolet curing is lower, few radicals are generated instantaneously, the polymerization rate is slow, the polymerization time is long, the system viscosity is small, the liquid crystal microdroplets have enough time to further grow, and the formed polymer network structure is sparse. When the energy of ultraviolet curing is increased, the instantaneously generated free radicals are more, the polymerization rate is high, the system viscosity is quickly increased, the free diffusion of liquid crystal molecules is prevented, the number of formed liquid crystal droplets is more, and the polymer network is denser.

The invention can make the liquid crystal microdroplet have proper size by adjusting the energy of ultraviolet curing and the time of ultraviolet curing, and in some embodiments of the invention, the long axis of the liquid crystal microdroplet is 2.3-9 μm. The major axis size of the liquid crystal droplets herein refers to the size of the liquid crystal droplets after the reaction, and does not refer to the size of the raw material liquid crystal before the reaction. Specifically, the major axis size of the liquid crystal droplet herein means: the liquid crystal droplet major axis size dispersed in the polymer network after uv curing is not meant to refer to the liquid crystal droplet size in the composition.

The term "electronic device housing" refers to a housing of an electronic device. The specific type of electronic device is not particularly limited by the present application and, for example, the electronic device may be a cell phone, a smart watch, a palm top computer, a notebook computer, a laptop computer, a desktop computer, a portable gaming device, a video recorder, a camera, a pager, or a printer, among others. In particular, the electronic device may be a mobile phone or smart phone (e.g., iPhone (TM) based, Android (TM) based phone), a Portable gaming device (e.g., Nintendo DS (TM), PlayStation Portable (TM), Gameboy Advance (TM), iPhone (TM)), a PDA, a Portable internet device, a music player, and a data storage device, other handheld devices, and a headset such as a watch, an in-ear headphone, a pendant, a headset, etc., and other wearable devices (e.g., a Head Mounted Device (HMD) such as electronic glasses, electronic clothing, an electronic bracelet, an electronic necklace, an electronic tattoo, or a smart watch).

The examples described below in this application, unless otherwise indicated, all reagents used are either commercially available or can be prepared by the methods described in this application.

Example 1

The polymer monomers include: 18 parts by weight of bisphenol A polyoxyethylene ether methacrylate, 5 parts by weight of polyethylene glycol diacrylate, 11 parts by weight of lauryl methacrylate and 17 parts by weight of hydroxypropyl methacrylate.

The liquid crystal includes 10 parts by weight of 4-cyanobiphenyl, 23 parts by weight of 4 ' -n-pentyl-4-cyanobiphenyl, 9 parts by weight of 4- (2- (4-isothiocyanatophenyl) ethyl) -4- (4-cyclopentylhexyl) -1, 1-biphenyl, and 5 parts by weight of 4- ((3, 5-difluoro-4-isothiocyanatophenyl) ethynyl) -4 ' -ethyl-1, 1 ' -biphenyl.

The photoinitiator included 2 parts by weight of benzoin diethyl ether.

And weighing the polymer monomer, the liquid crystal and the photoinitiator according to the proportion, wherein the content of the polymer monomer is 51 parts by weight, the content of the liquid crystal is 47 parts by weight, and the content of the photoinitiator is 2 parts by weight. Mixing to obtain the composition.

Preparation of polymer dispersed liquid crystal film: the composition is coated between two conductive films, wherein the conductive films are made of ITO (indium tin oxide), the coating mode is roll coating, ultraviolet curing is carried out after the films are coated by the roll coating, the energy of the ultraviolet curing is 1000mj, the time of the ultraviolet curing is 1min, a polymer dispersed liquid crystal layer is formed between the two conductive films, and the thickness of the polymer dispersed liquid crystal layer is 15 micrometers.

Referring to FIG. 3, the liquid crystal droplets have a major axis dimension of 4-7.2 microns.

Referring to fig. 4, the driving saturation voltage of the polymer dispersed liquid crystal is 20V. When the power is not supplied, the maximum haze is 89%, and when the minimum haze is 1.2%, the corresponding driving saturation voltage is 20V, that is, the control voltage is 0-20V, and the haze of the polymer dispersed liquid crystal layer can be controlled to be varied between 1.2-89%. The invention effectively reduces the driving saturation voltage of the polymer dispersed liquid crystal and reduces the power consumption.

Example 2