Ultralight, superhydrophobic and biodegradable stereocomplex polylactide aerogel with superior oil-water separation and thermal insulation performances

Recently, renewable, biodegradable and eco-friendly polylactide (PLA) aerogels have attracted much attention due to the demand of sustainable development. However, how to accurately adjust the porous structures and achieve high-performance PLA aerogels remains a formidable challenge. Herein, we present a simple and promising strategy for preparing stereocomplex PLA (SC-PLA) aerogels with outstanding oil-water separation and thermal insulation performances by using polyethylene oxide (PEO) as porogen to regulate the porous structures of aerogels during the freeze-drying and porogen-leaching process. The results show that SC-PLA aerogels have hierarchical micro/nano porous structures and 100 % SC crystallites, and the micropore size, porosity and hydrophobicity increase while the density decreases with the increase of PEO content. The optimum SC-PLA aerogel has ultrahigh porosity (97.9 %), ultralow density (27.3 mg/cm(3)) and super hydrophobicity (160.7 degrees). SC-PLA aerogels exhibit outstanding adsorption capacities for oils and organic solvents (25.4-58.2 g/g), and high continuous oil-water separation efficiency (>95.0 %). Besides, SC-PLA aerogels show very low thermal conductivity and high solar reflectivity, which can achieve outstanding thermal insulation effect in the sunlight through reflective insulation and low thermal conduction. We believe that this high-performance SC-PLA aerogel can be applied in oil-water separation, thermal insulation and reflective insulation fields.