A facile approach to enhance performance of PVDF-matrix nanocomposite membrane via manipulating migration behavior of graphene oxide

Abstract

Abstract Graphene oxide (GO) is an attracting nanomaterial to enhance membrane performance, but its migration behavior in polymer-matrix nanocomposite membrane is rarely discussed. In this study, three kinds of polyvinylpyrrolidone (PVP) with different molecular weights (K17, K30, K90) were used as the pore former and the dragging agent to investigate the migration behavior of GO in PVDF-matrix nanocomposite membrane. Compared with K17 (9\u202fkDa) and K30 (50\u202fkDa) with the relatively lower MW, K90 with the largest MW (1400\u202fkDa) promoted more GO to migrate toward the membrane top surface due to the strong hydrogen bonding interactions between K90 and GO. On the contrary, K17 and K30 favored more GO embedded within PVDF-matrix nanocomposite membranes due to the weak interactions between K17/K30 and GO. As a result, the PMGK90 membrane incorporating K90 and GO possessed the superior water permeability (694.3 LMH·bar−1) with the lowest water contact angle (66.85°) and the maximum surface free energy (51.16\u202fmJ/m2). Moreover, the PMGK90 membrane exhibited the excellent antifouling performance with the minimum BSA adsorption (21.47\u202fμg/cm2), the high flux recovery rate (89%) and the low irreversible fouling (11%) resulted from the synergetic effects of K90 and GO, especially the migration of GO to the top surface. Therefore, the migration behavior of GO could be easily manipulated using PVP with different MWs via nonsolvent-induced phase separation method, presenting a facile approach to enhance membrane performance.