Temperature‐Responsive Thermochromic Phase Change Materials with Tunable Photothermal Conversion Efficiency Toward Solar Energy Storage

Abstract

There are many reports in the literatures on the use of phase change materials (PCMs) with photothermal conversion to store and harness solar energy. However, few works have reported intelligent PCMs with thermochromic capabilities that can controllably adjust their photothermal conversion efficiency to change the heating rate through temperature response. In this work, thermochromic phase change materials (TC‐PCMs) are successfully prepared by integrating the reversible thermochromic microcapsules into dynamically cross‐linked PCMs. The designed TC‐PCMs have a high photothermal conversion efficiency by using different styles of reversible thermochromic microcapsules, which can intelligently adjust the surface color of TC‐PCMs according to the substrate temperature under illumination conditions. Based on the fast temperature‐responsive thermochromic function of TC‐PCMs, the intriguing function of the reversible information storage and encryption can be realized by designing the shape and space of TC‐PCMs under the only thermal‐triggered condition. Importantly, the process of information storage and encryption can be controllable and reversible when repeatedly increasing and decreasing the external temperature. Additionally, TC‐PCMs capable of reprocessing ability based on dynamic oxime bond, are beneficial to the preparation of complex shape devices and recycling, expanding the application field of TC‐PCMs.

The Synergistic Effects between Liquid Crystal and Crystalline Phase on Photo‐Responsive Elastomers toward Quick Photo‐Responsive Performance

“…At 25 °C, the stress–strain curve of AE showed a yield point and a subsequent plateau, which was typical of the “thin necking” of crystalline polymers during stretching. [ 41 ] The tensile strength of AE, AT, and AP were 30.8, 12.4, and 14.3 MPa, respectively. Surprisingly, elongation at break of AE, AT, and AP can reach 997.4%, 944.6%, and 914.8%, whose elongation at break of the samples were all greater than 900%, displaying the exceptional flexibility relative to conventional ALCEs.…”

A General Strategy for Developing Ultrasensitive “Transistor‐Like” Thermochromic Fluorescent Materials for Multilevel Information Encryption

“…Phase-change materials (PCMs) have been widely applied to various applications including biomedicine, [24,25] sensing, [26] and information encryption, [5,12] which are attributed to their stimuliresponsive properties, including viscosity, volume, and crystallinity, during the phase transition process between solid and liquid state. [27] Recently, by utilizing the thermoresponsive properties of PCMs as a matrix to load the fluorophores with different optical properties, varieties of colorimetric or "OFF-ON" switchable TFMs have been successfully developed.…”

“…[27] Recently, by utilizing the thermoresponsive properties of PCMs as a matrix to load the fluorophores with different optical properties, varieties of colorimetric or "OFF-ON" switchable TFMs have been successfully developed. [5,12,13] However, these previous studies were mostly aimed at extending the color range and amplifying the difference between the "ON" and "OFF" states of the TFMs, while little attention was paid to the improvement of thermosensitivity and fluorescence response performance.…”

“…[3][4][5][6][7][8][9][10][11] Compared with other stimuli, heat driving mode is low-cost, easy to operate, and in situ controllable both at the large-area and nanoscale levels. [12] As a result, thermochromic fluorescent materials (TFMs) have attracted tremendous attention in the information storage and anti-counterfeiting fields. [5] However, to achieve reliable and convenient temperature-modulated information encryption for practical applications, TFMs with low cost, highly sensitive thermalresponse luminescence, sharp temperature response, and color-tunable emission are required, which is still a challenge.…”

“…Up to now, numerous TFMs have been reported and applied for information encryption. [5,6,12,13] According to the difference in their thermal-response mechanism, these TFMs can be grouped into two categories. One type of TFMs is constructed by using an emitter (nano-luminophores like lanthanide nanoparticles [14] and carbon dots, [15] molecular luminophores like transition metal complexes, [16] and organic dyes [17][18][19] ) with the intrinsically thermally responsive property.…”