Photonic Crystal-Engineered PVDF Membranes: Rapid Scalable Fabrication of Inverse Opal Architectures for...

Photonic crystal (PC) inverse opal (IO) structure is an ordered interconnected pore structure that is extremely advantageous for realizing high-precision separations. However, this structure is difficult to prepare quickly over a large area. Here, we designed a preparation strategy for PCs and a shear-induced assembly method based on the shear force. Porous membranes were prepared within 10 s in a fast and large area (900 cm²). We then explored the effects of factors such as casting liquid parameters and the preparation process on the structure and properties of PC membranes. The process and mechanism of membrane formation by shear-induced assembly were analyzed. The membranes with IO structures having different pore sizes fabricated after removing microspheres were also analyzed and tested. The IO-PVDF membrane had a microsphere rejection rate of up to 99.71%, a mechanical strength of up to 9.87 MPa, a porosity and pure water flux of up to 71.75% and 1364.51 L m^-2 h^-1, respectively, and a water-flux recovery of up to 94.35% after five test cycles. Porous membranes with high porosity are expected to be used in high-precision separations. This study provides an effective method of constructing large-area porous membranes and lays the foundation for applying IO-type porous membranes in the field of separation.