TEMPERATURE-CONTROLLED DIMMING FILM WITH A FUNCTION OF SHIELDING NEAR-INFRARED LIGHT AND PREPARATION METHOD THEREOF

• US 20190310499A1
• Filed: 06/29/2017
• Published: 10/10/2019
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: Beijing Zhijing Times Technology Company Limited
• Original Assignee: Peking University
• Inventors: YANG, Huai, LIANG, Xiao, CHEN, Mei, GUO, Shumeng, ZHANG, Lanying, ZHANG, Cuihong, WANG, Qian, LI, Chenyue, ZOU, Cheng
• Granted Patent: US 10,725,328 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 19/02 characterised by optical, electrical or physical properties of the components, in general
• CPC Class Codes: C09K 19/544 as dispersing or encapsulating medium around the liquid crystal
• CPC Class Codes: C09K 2019/521 Inorganic solid particles
• CPC Class Codes: C09K 2019/548 stabilizing the alignment; Polymer stabilized alignment
• CPC Class Codes: G02F 1/1313 specially adapted for a particular application
• CPC Class Codes: G02F 1/132 Thermal activation of liquid crystals exhibiting a thermo-optic effect
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/13345 Network or three-dimensional gels
• CPC Class Codes: G02F 1/13775 Polymer-stabilized liquid crystal layers
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials

Abstract

The present invention relates to a temperature-controlled dimming film with a function of shielding near-infrared light, which comprises a polymer network skeleton and liquid crystal molecules, wherein the polymer network skeleton consists of a polymer-dispersed liquid crystal network structure and a polymer-stabilized liquid crystal network structure and comprises a polymer matrix with pores inside which polymer networks are vertically aligned; and the liquid crystal molecules are dispersed in the polymer network skeleton and have smectic (SmA)-cholesteric (N*) phase transition. Between the skeleton and the liquid crystal molecules, nanoparticles, having absorption at 800-3000 nm, are dispersed. In the invention, a stepwise polymerization method is utilized to construct a PD&SLC network structure between two substrates, which greatly improve the bonding strength between the two substrates and the heat insulation performance of the temperature-controlled liquid crystal dimming film.

Claims

1. A temperature-controlled dimming film with a function of shielding near-infrared light, characterized in that

said dimming film comprises a polymer network skeleton and liquid crystal molecules, wherein the polymer network skeleton consists of a polymer-dispersed liquid crystal network structure and a polymer-stabilized liquid crystal network structure and comprises a polymer matrix with pores inside which polymer networks are vertically aligned;

and the liquid crystal molecules are dispersed in the polymer network skeleton and have smectic-cholesteric phase transition;

between the skeleton and the liquid crystal molecules, nanoparticles, having absorption at 800-3000 nm, are dispersed.

2. The temperature-controlled dimming film according to claim 1, wherein the polymer network skeleton is prepared from polymerizable monomers by stepwise polymerization.

3. The temperature-controlled dimming film according to claim 1, wherein the liquid crystal material, the polymerizable monomers, and the nanoparticles are at a ratio by weight of:

liquid crystal material;

10.0˜

90.0 parts by weight;

polymerizable monomers;

10.0˜

80.0 parts by weight;

nanoparticles;

1.0 to 30.0 parts by weight;

in the raw materials to prepare the dimming temperature-controlled dimming film.

4. The temperature-controlled dimming film according to claim 1, wherein the nanoparticles comprise one or more selected from indium tin oxide, antimony tin oxide, tungsten trioxide, molybdenum trioxide, tungsten bronze or copper sulfide with oxygen defects.

5. The temperature-controlled dimming film according to claim 1, wherein the liquid crystal material is a liquid crystal material having SmA˜

N* phase transition and its phase transition temperature is −

10°

C. or higher.

6. The temperature-controlled dimming film according to claim 3, wherein the polymerizable monomers are ultraviolet-polymerizable monomers, comprising non-liquid crystal ultraviolet-polymerizable monomers and liquid crystal ultraviolet-polymerizable monomers.

7. The temperature-controlled dimming film according to claim 1, wherein the nanoparticles are grafted with surfactant on their surfaces.

8. The temperature-controlled dimming film according to claim 1, wherein the temperature-controlled dimming film shields 80% or more of near-infrared light and has a transmittance higher than 75% in visible light waveband while existing at a temperature lower than the phase transition temperature of the liquid crystal, and has a transmittance lower than 10% in both the visible and near-infrared light wavebands while existing at a temperature higher than the phase transition temperature of the liquid crystal.

9. A method for preparing the temperature-controlled dimming film according to claim 1, comprising:

mixing liquid crystal material, polymerizable monomers, an initiator, and spacer particles to obtain a uniform mixture;

adding the mixture into a solution containing nanoparticles and mixing it evenly;

then removing the solvent and placing the obtained liquid between conductive films;

allowing an incomplete polymerization reaction between the non-liquid crystal polymerizable monomers and the liquid crystal polymerizable monomers in the system; and

then polymerizing the remaining polymerizable monomers by applying an electric field to the conductive films, so as to generate the temperature-controlled dimming film.

10. The temperature-controlled dimming film prepared according to claim 9, wherein the surfactant is grafted on the surfaces of the nanoparticles by a microemulsion method, a reversed-phase microemulsion method or a surfactant method.