Phase Separation Micromolding: A New Generic Approach for Microstructuring Various Materials

Phase separation micromolding (PSμM) is a versatile microfabrication technique that can be used to structure a very broad range of polymers, including block copolymers and biodegradable and conductive polymers without the need for clean‐room facilities. By incorporating a subsequent process step, carbon, ceramic, and metallic microstructures can also be fabricated from a polymeric or hybrid precursor. The replication process is straightforward and cost‐effective. It relies on phase separation of a polymer solution while in contact with a structured mold. Intrinsic shrinkage during the phase separation facilitates the release of the replica from the mold, which increases the reliability of the process even at small feature sizes, thin polymer films, or high aspect ratios. Under suitable circumstances perforation of the polymer film can be obtained, resulting in completely open “through” microstructures. Furthermore, porosity can be introduced in a microstructure, which may result in unknown functionalities. Phase separation micromolding (PSμM) is a reliable technique for microstructuring a broad range of materials. The picture shows a silicon mold and two transparent PMMA replicas floating in the nonsolvent used for phase separation (water). A periodic pattern is replicated, causing the diffraction of white light by the mold and the replicas.