Poly(ethylene chlorotrifluoroethylene) (ECTFE) microporous membranes were prepared via a thermally induced phase separation (TIPS) process using a mixed diluent of bis(2-ethylhexyl) adipate (DEHA) and diethyl phthalate (DEP). The formation mechanism of ECTFE membranes was proposed with the assistance of a pseudo-binary temperature-DEHA ratio phase diagram of the ECTFE-diluent mixture system. The morphologies of the prepared membranes were observed by using a scanning electron microscope (SEM) and an atomic force microscope (AFM). The membranes' corresponding distillation performances were characterized in terms of porosity, contact angle, mechanical strength, permeability and rejection rate. The results showed that the evolution of the membrane microstructure ranged from honeycomb to bicontinuous and spherulitic with an increase of the DEHA ratio. It was found that the membranes prepared via L–L phase separation had excellent hydrophobicity, high permeate flux and salt rejection ratio, and excellent anti-fouling properties, especially for the membrane with a DEHA/DEP mass ratio of 25 wt%/75 wt%.

Poly(ethylene chlorotrifluoroethylene) (ECTFE) porous membranes have been fabricated via thermally induced phase separation (TIPS). Dioctyl adipate (DOA) as the diluent, micro-scale SiO₂ particles and a composite powder (composed of soluble and insoluble particles) as the additives were used in this study. The filtration performance of the prepared membranes was characterized in terms of pure water flux, porosity, mean pore size, water contact angle, mechanical strength, and ultrafiltration tests. The morphologies of the obtained membranes were observed by a scanning electron microscope (SEM). The results showed that ECTFE membranes were a kind of homogeneous membrane, the addition of SiO₂ particles and the composite powder brought about interfacial microvoids (IFMs) and a dissolved pore structure. The porosity, pure water and protein solution fluxes decreased, while the rejection ratio and mechanical properties increased with the increase of polymer content. With the addition of additives, the ultrafiltration performance improved obviously. Moreover, the membranes showed good resistance to the aggressive chemical corrosive solutions.