Transparent Materials Top-Down Constructed by Using Animal Skins for Light Management Application

With the continuous consumption of nonrenewable resources, the increasing shortage of energy, and the gradual aggravation of environmental pollution, the research and development of biomass-based transparent materials (TM) with the potential to replace traditional glass and plastics has already been a hot and difficult point in the field of biomass materials. Herein, a novel TM, called transparent leather (TL), was constructed by using goatskin, following a top-down strategy. Specifically, goatskin was first impregnated in a mixed solution containing monomer (2-hydroxyethyl acrylate (HEA)) and cross-linking agent (N,N′-methylene diacrylamide (MBA)), and then the hot-pressure in situ free-radical polymerization of HEA and MBA was conducted in the gaps of goatskin collagen fibers, which leads to the network interpenetrating structure containing the three-dimensional woven network of collagen fibers and the network of polymer chains of poly­(2-hydroxyethyl acrylate), and thus the formation of TL. Due to the dense filling of the polymer network and the reinforcement of goatskin’s collagen fibers framework, the resulting TL exhibited excellent tensile strength (31.78 MPa) and transmittance (85%), excellent flexibility, impact resistance, and degradability. The excellent mechanical and optical properties of TL were derived from the dense interpenetrating network structure formed by the collagen fiber network and the refractive index-matched polymer network, as well as the abundant hydrogen-bonding interactions present in the system. Further, fluorescent TL was prepared by doping carbon quantum dots with blue and yellow fluorescence in the impregnation solution, which can be used as the light conversion layer and assembled with LED chips to realize effective light conversion. This work skillfully utilizes the natural multilevel biological structure of animal skin to provide a novel strategy for the preparation of green, renewable, and degradable TM, which can effectively broaden the application fields of novel TM and alleviate the energy crisis and environmental hazards brought by the traditional TM.