A Thermoreversible Gelation Pathway to Plant Cuticle-Inspired Biopolymer Aerogel Monoliths Based on Network-Spherulitic Crystal Assemblies.

Plant-based and compostable biopolymers are vital in global shifts toward green materials. However, their adoption in aerogel fabrication is limited by material and structure-performance deficiencies (e.g., hydrophilicity, low surface area, brittleness, limited tactile tailorability). Nevertheless, stereocomplexation, or co-crystallization between polymeric enantiomers, offers a pathway toward overcoming such limitations. Herein, stereocomplexation is used to fabricate poly(lactide) (PLA)-based aerogels, with stereocomplex crystals (SCs) assembling into a highly ordered morphology/topology within aerogel precursors. To tailor aerogel bulk properties, a blending approach is implemented during sol-gel processing, leading to sequential crystallization of sol-gel system constituents. This pathway yields hierarchically macro-/meso-porous aerogels (SBET up to ∼186 m2·g-1), offering a variety of superstructures that resemble cuticular plant tissue. These aerogels resist brittle failure under compression (70% strain) and withstand cyclic loading (100 cycles, 20% strain) without significant densification. Such aerogels also exhibit functional properties including superhydrophobicity/superoleophilicity and are well-suited for continuous oil-water separation. Additionally, fantastic geometric-thermal stability, insulation/heat dissipation ability (kCond ∼36 mW·m-1·K-1), and phase-change insulation characteristics are achieved. These functionalities arise from multi-scale structural features and demonstrate how coupling stereocomplexation and sequential crystallization offers pathways to construct intricate superstructure morphologies/topologies, and overcome material/structure-performance limitations in green aerogels.