Smart windows can dynamically and adaptively adjust the light transmittance in non-energy or low-energy ways to maintain a comfortable ambient temperature, which are conducive to efficient use of energy. This work proposes a liquid crystal (LC) smart window with highly efficient near-infrared (NIR) response using carbon nanotubes grafted by biphenyl LC polymer brush (CNT-PDB) as the orientation layer. The resultant CNT-PDB polymer brush can provide the vertical orientation of LC molecules to maintain the initial transparency. At the same time, the smart window shows a rapid response to NIR light, which can quickly adjust the light transmittance to prevent sunlight from entering the room. Different from common doping systems, this method avoids the problem of poor compatibility between the LC host and photothermal conversion materials, which is beneficial for improving the durability of the device.
Polyimide (PI), an important engineering polymer with a rigid chemical structure, readily has excellent chemical stability, heat resistance, and electrical insulation but lacks broadband photothermal properties. Herein, we design and synthesize PI copolymers that embrace intrinsic photothermal properties by using two diamine monomers of (Z)‐2,3‐bis(4‐aminophenyl) acrylonitrile (CNDA) and 4,4‐diphenyldiamine (NDA) with strong ultraviolet (UV), and near‐infrared (NIR) absorption capabilities, respectively. Tuning the molar ratio of the two diamines can modulate UV and NIR light absorption and regulate the intrinsic photothermal properties of PIs. After condensation with pyromellitic dianhydride, the resulting PI‐0.5 with a unit molar ratio of CNDA:NDA = 1 shows the best photothermal efficiency. PI‐0.5 is used to construct 3D steam generators with vertically dried channels by a freeze‐drying method. The 3D steam generators show a good water evaporation rate and continuously operate with excellent stability under varying salinity and pH conditions. The synthetic design herein suggests that PI can be molecularly engineered to be intrinsic photothermal materials, expanding the properties and applications of existing PIs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.