Fabrication of PBAT Membranes with High Separation Accuracy Based on Inverse-Opal-Structural Photonic Crystals

Membrane technology is one of the most effective ways to cope with the filtration and separation. However, most polymer membranes are not uniform in pore size and have wide pore size distributions and low porosities, which restrict their application. A high-porosity homogeneous membrane with high filtration accuracy is an effective solution. Photonic crystals (PCs) with an inverse-opal (IO) structure provide a new way for preparing high-porosity homogeneous porous membranes. In this study, a rapid shear-induced assembly method for preparing biodegradable poly(butylene adipate-co-terephthalate) (PBAT) membranes based on PCs with an IO structure was proposed, and the design principles of the IO-structured PBAT membrane were investigated. Moreover, the effects of polymer solution concentrations, solvent evaporation temperature, and SiO₂/PBAT mass ratio on the SiO₂/PBAT PC structure, formation mechanism of shear-induced assembly, and the filtering efficiency of resultant PBAT membranes for solid-liquid separation were investigated. The study underscored the point that when the polymer concentration is in the range of 15-20 wt % and the drying temperature is at 80 °C, as the SiO₂-to-PBAT mass ratio increases, the pore of the membrane increases, the porosity is as high as to 84.11%, and pure water flux is up to 756.19 L m^-2 h^-1. After five cycles, the rejection rate of PBAT membranes for the contaminant still reached more than 99%. This study proposes a simple and rapid method for constructing an IO-structured membrane that is expected to address challenges encountered in achieving efficient and high-precision separation.