Engineering amphiphilic membrane surfaces based on PEO and PDMS segments for improved antifouling performances

Antifouling membrane surfaces capable of reducing biofouling are highly desirable in a broad range of applications. In this study, amphiphilic membrane surfaces, derived from block copolymers bearing hydrophilic poly(ethylene oxide) (PEO) and low surface energy polydimethylsiloxane (PDMS) segments, have been constructed via surface segregation during the standard phase inversion process. The surface chemical features of the membranes are confirmed by contact angle measurement, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and surface energy analysis. The PEO segments are utilized to prevent biofoulant adsorption (fouling-resistance) whereas the PDMS segments are utilized to drive away the adsorbed biofoulants (fouling-release). The resultant surfaces exhibit better antifouling properties compared with the control polyethersulfone (PES) membrane when using bovine serum albumin (BSA), sodium alginate (SA) and yeast as three model biofoulants (proteins, polysaccharides and microorganisms). During the filtration of model biofoulant aqueous solutions, both irreversible and reversible flux declines are remarkably decreased and the flux recovery is retained completely after simple hydraulic washing. Static and dynamic biofoulants adsorption experiments reveal the synergistic effect of the PEO and PDMS segments on biofouling-resistance and biofouling-release. It is also found that the biofouling can be significantly reduced by the coexistence of optimized hydrophilic microdomains, low surface energy microdomains, and shear flow near membrane surfaces. Hopefully, the demonstrated attempt of membrane surface construction is favorable to prepare a wide spectrum of environmentally benign antifouling membranes.