P (VDF‐co‐CTFE)‐g‐P2VP amphiphilic graft copolymers: Synthesis, structure, and permeation properties

A series of amphiphilic graft copolymers of poly (vinylidene fluoride‐ co ‐chlorotrifluoroethylene)‐ g ‐poly(2‐vinyl pyridine), P (VDF‐ co ‐CTFE)‐ g ‐P2VP, with different degrees of P2VP grafting (from 26.3 to 45.6 wt%) was synthesized via one‐pot atom transfer radical polymerization (ATRP). The amphiphilic properties of P (VDF‐ co ‐CTFE)‐ g ‐P2VP graft copolymers allowed itself to self‐assemble into nanoscale structures. P (VDF‐ co ‐CTFE)‐ g ‐P2VP graft copolymers were introduced into neat P (VDF‐ co ‐CTFE) as additives to form blending membranes. When two different solvents, N‐methyl‐2‐pyrrolidone (NMP) and dimethylformamide (DMF), were used, specific organized crystalline structures were observed only in the NMP systems. P (VDF‐ co ‐CTFE)‐ g ‐P2VP played a pivotal role in controlling the morphology and pore structure of membranes. The water flux of the membranes increased from 57.2 to 310.1 L m −2 h −1 bar −1 with an increase in the PVDF‐ co ‐CTFE‐ g ‐P2VP loading (from 0 to 30 wt%) due to increased porosity and hydrophilicity. The flux recovery ratio (FRR) increased from 67.03% to 87.18%, and the irreversible fouling ( R ir ) decreased from 32.97% to 12.82%. Moreover, the pure gas permeance of the membranes with respect to N 2 was as high as 6.2 × 10 4 GPU (1 GPU = 10 –6 cm 3 [STP]/[s cm 2 cmHg]), indicating their possible use as a porous polymer support for gas separation applications.