Closed-Loop Chemically Recyclable Separation Membranes With Superior Pervaporation Performance.

With low carbon footprint and reduced secondary pollution, membrane technique offers an energy-saving separation process while end-of-life disposal practices of polymer membranes remain an issue. Herein, a light-triggered dynamic polydimethylsiloxane (PDMS) network design, that enabled a closed-loop recyclable separation membrane with superior pervaporation performance, is proposed. Such a dynamic network is constructed through [4 + 4] photodimerization of anthracene grafted PDMS under 365-nm UV light, while 254-nm UV light transforms the crosslinked membranes into linear polymers. The facile deconstruction process is completed within 35 min at ambient temperature, and recycling test demonstrates efficient reconstruction of PDMS networks with 92.6% conversion of anthracene groups within 10 min. The membrane exhibits a superior ethanol recovery performance with a pervaporation separation index of 13,285, surpassing the reported state-of-the-art PDMS-based membranes. The recycled membrane retains efficient ethanol recovery even after five solid-liquid conversion cycles with minor deviations in flux and separation factor compared to the original membrane. Such a dynamic network also demonstrates an efficient self-healing capability with retained pervaporation performance toward minor defects. The design principle of closed-loop chemically recyclable separation membranes with retained and superior functionality provides a scalable membrane technique adaptable to diverse separation applications.