Bio-based and bio-degradable nanofiber materials: A sustainable platform for energy, environmental, and biomedical applications

In the context of carbon neutrality, bio-based and biodegradable materials have attracted extensive research efforts and have been recognized as promising alternatives to petroleum-based materials in various industrial fields. Biopolymer nanofiber materials, featuring biodegradability, biocompatibility, sustainability, flexibility, high porosity, and functionality, are promising candidates for constructing practical platforms for solving energy, environmental, and biomedical issues. In this comprehensive review, we focused on the recent pioneering developments in the synthesis, preparation, and functionalization of sustainable nanofiber materials based on natural biopolymers (starch, cellulose, chitosan, etc.) and synthetic biodegradable polymers (polylactic acid, polycaprolactone, etc.) for energy, environmental, and biomedical applications. First, we briefly introduce the intrinsic component, structure, properties, and life cycle of biopolymers. The fabrication protocols of nanofiber platforms based on these typical biopolymers are then summarized, followed by presenting the intriguing structures, morphologies, and properties of biopolymer 1D nanofibers, 2D membranes, and 3D sponges/aerogels. We further systematically summarize the structure–function correlations and proof-of-concept demonstrations of bio-nanofiber platforms for energy storage and conversion, gas filtration and separation, oil–water separation, water treatment, and biomedical applications. Finally, the review provides a future perspective on the development of biological fibers.