Industrial & Engineering Chemistry Research, Vol.57, No.41, 13759-13768, 2018
Roll-to-Roll Fabrication of Residual-Layer-Free Micro/Nanoscale Membranes with Precise Pore Architectures and Tunable Surface Textures
Many technologies are increasingly dependent on the development of membranes with highly precise pore size and spatial order. While mold-based lithographic techniques are adopted for the fabrication of such ordered porous membranes, their transition toward large-scale fabrication remains challenging because of manual and laborious process requirements. To facilitate the transition from batch to continuous membrane production, a novel roll-to-roll (R2R) process was designed based on an established capillary-driven molding technique. Establishing conformal contact between patterned mold and web support and the capillary filling of the UV-curable resin forms the basis of the molding process, which is automated by the R2R platform with precise positioning and reproducible contact force. This results in the in situ formation of residual-layer-free membranes without additional complex, expensive etching steps and, more importantly, with high throughput up to 3000 mm(2)/min. The versatile process allows the combination of mold and web pattern geometry and length scale, yielding multilevel and multiscale membranes that are difficult to achieve with existing methods. Membranes with double-side surface textures and hierarchical pore architectures spanning a length scale from microscale to nanoscale (down to similar to 200 nm) can be fabricated by overcoming the intrinsically slow resin capillary filling at submicrometer length scale. The R2R platform's scalability and customizability open avenues toward manufacturing porous membranes with complex yet precise architectures for a broad range of applications.