Advances in polyethylene membranes for separation technologies: From fabrication methods to emerging applications

Polyethylene (PE) has emerged as a highly attractive material for separation membrane fabrication due to its outstanding chemical resistance, mechanical robustness, low-cost, and industrial scalability. In contrast to conventional membrane polymers, PE offers exceptional stability in harsh chemical and solvent environments, making it particularly suitable for advanced separation processes. This review provides a comprehensive overview of recent developments in PE-based separation membranes, focusing on polymer structure, membrane configurations, fabrication strategies, surface modification approaches, and application domains. The fundamental physicochemical properties of different PE types, including LDPE, LLDPE, HDPE, and UHMWPE, are discussed in relation to membrane performance. Various membrane architectures i.e. flat sheet, thin-film composite, nanofibrous, and hollow fiber are critically examined. Vital fabrication methods such as thermally induced phase separation (TIPS), stretching, melt-spinning, grafting on, and template-assisted techniques are systematically reviewed, highlighting their influence on pore structure and transport properties. Strategies to overcome the intrinsic hydrophobicity and poor interfacial adhesion of PE, including surface grafting, coating, copolymerization, and incorporation of functional additives, are also addressed. Furthermore, the review summarizes the application of PE-based membranes in micro- and ultrafiltration, nanofiltration, reverse and forward osmosis, membrane distillation, pervaporation, ion-exchange systems, and battery separators. Finally, current challenges and future research directions for advancing PE membrane technology toward high-performance and sustainable separation systems are outlined.