Composite electrochromic material, and preparation method therefor and application thereof
A composite electrochromic material, a preparation method therefor and an application thereof, the material comprising a core layer, a skin layer having an electrochromic function, and a light-transmitting protective layer formed by a flexible polymer material, that are arranged in sequence. The material of the core layer comprises a fluid conductive mixture, which comprises liquid metal and carboxylated carbon nanotubes. The preparation method comprises: carrying out spinning by co-extrusion using a three-channel nozzle to form hollow double-layer fibers each having a skin layer and a protective layer as well as a cavity, injecting the conductive mixture into the cavity of the hollow double-layer fiber. The material has excellent deformation ability, stable and sensitive color changing function, and a controllable deformation degree. The material has a stable color changing function even in the case of severe deformation, good fatigue resistance, and is suitable for the preparation of intelligent textiles.
1 . A composite electrochromic material, wherein, the composite electrochromic material comprises a core layer, a skin layer coating on the core layer and having an electrochromic function, and a light-transmitting protective layer formed by a flexible polymer material and coating on the skin layer, the core layer comprises a conductive mixture fluid, wherein the conductive mixture fluid comprises liquid metal and carboxylated carbon nanotubes.
2 . The composite electrochromic material according to claim 1 , wherein, a mass ratio of the carboxylated carbon nanotubes to the liquid metal is (2-5): 100.
3 . The composite electrochromic material according to claim 1 , wherein, the carboxylated carbon nanotubes have a length of 15-30 μm, an inner diameter of 6-10 nm, and an outer diameter of 12-20 nm.
4 . The composite electrochromic material according to claim 1 , wherein, a mass ratio of the carboxylated carbon nanotubes to the liquid metal is (2-5):100, and the carboxylated carbon nanotubes have a length of 15-30 μm, an inner diameter of 6-10 nm, and an outer diameter of 12-20 nm.
5 . The composite electrochromic material according to claim 1 , wherein, the carboxylated carbon nanotubes are carboxylated multi-walled carbon nanotubes.
6 . The composite electrochromic material according to claim 1 , wherein, the liquid metal is a fluid mixture comprising gallium, indium and tin, with a melting point of ≤16° C. and a viscosity of 0.0014-0.0023 Pa*s at 20° C.
7 . The composite electrochromic material according to claim 1 , wherein, the light-transmitting protective layer has an outer diameter of 0.8-1.1 mm and a thickness of 0.2-0.4 mm.
8 . The composite electrochromic material according to claim 1 , wherein, the skin layer has an outer diameter of 0.5-0.7 mm and a thickness of 0.2-0.3 mm.
9 . The composite electrochromic material according to claim 1 , wherein, the core layer has a diameter of 0.3-0.5 mm.
10 . The composite electrochromic material according to claim 1 , wherein, the skin layer has an optical contrast percentage of 40-60% and a color brightness during stretching of 0.80-0.95; the optical contrast percentage is measured by an optical contrast measurement method according to HG/T 4951-2016, and the color brightness during stretching is measured by a visual colorimetry according to GB/T6749-1997.
11 . The composite electrochromic material according to claim 1 , wherein, the skin layer is an organic electrochromic material or an inorganic electrochromic material.
12 . The composite electrochromic material according to claim 1 , wherein, the skin layer consists of polyvinyl alcohol and an organic electrochromic material and/or an inorganic electrochromic material, with a mass ratio of the polyvinyl alcohol to the organic electrochromic material and/or the inorganic electrochromic material of (0.5-1):1.
13 . The composite electrochromic material according to claim 12 , wherein, the polyvinyl alcohol has a weight-average molecular weight of 72,600-81,400, and the organic electrochromic material is polyaniline with a weight-average molecular weight of 55,000-60,000.
14 . The composite electrochromic material according to claim 1 , wherein, the light-transmitting protective layer is a polyolefin material with an elastic elongation of 300-500%, an elastic recovery rate of 97-99% and a softening temperature of greater than 200° C.
15 . A method for preparing the composite electrochromic material according to claim 1 , wherein, the preparation method comprises the following steps:
(1) drying a raw material of the skin layer, the and a raw material of the light-transmitting protective layer, respectively;
(2) melting the raw material of the skin layer and the raw material of the light-transmitting protective layer dried in step (1) in a screw extruder, and spinning by co-extrusion method using a three-channel nozzle to make a hollow double-layer fiber with a cavity;
(3) injecting the conductive mixture into the cavity of the hollow double-layer fiber to make the composite electrochromic material.
16 . The method for preparing the composite electrochromic material according to claim 15 , wherein, in step (2), the temperature of melting is 300-350° C.; in step (3), injecting is carried out using a syringe, a needle of the syringe is inserted into the cavity of the hollow double-layer fiber, and two ends of the fiber are heated to shrink and prevent leakage.
17 . An intelligent textile, wherein, the intelligent textile comprises the composite electrochromic material according to claim 1 .