Fouling resistant amphiphilic poly(dimethylsiloxane)-linked-poly(ethylene glycol) network on ultrafiltration poly(vinylidene fluoride) membrane and effect of spatial chain arrangement on separation of oil-water emulsions

In continuation of previous work (J. Membr. Sci. 566, 2018, 415) on construction of superhydrophilic membrane with hierarchical surface morphology, herein a facile route for the fabrication of membrane surface containing dangling amphiphilic chains for the separation of oil-in-water emulsions and protein has been reported. A reactive blend membrane prepared with poly(vinyl fluoride), poly(vinyl pyrrolidone) (360 kDa) and a poly(methyl methacrylate)-co-poly(chloromethyl styrene) upon sequential treatment with amine terminated poly(di-methylsiloxane) (H2N-PDMS-NH2) and single-end isocyanate terminated poly(ethylene glycol) (H3CO-PEG-NCO) gave modified membrane containing dangling PDMS-linked-PEG chains. Membrane surface constructed under optimized reaction conditions showed superior fouling resistant ability during separation of oil-in-water emulsions and bovine serum albumin to that of corresponding hydrophilic or hydrophobic membranes. The membrane was able to separate oil-in-water emulsions with oil rejection as high as > 99.5%, flux reduction of about 20%, and flux recovery ratio of > 98%. The underlying mechanism of good antifouling property of the membrane is attributed to the easy release of fouling agents from the surface by PDMS segments and cleaning by hydrated PEG segments of dangling PDMS-linked-PEG chains. This membrane is stable owing to formation of partially crosslinked network on membrane surface. Evidently, membrane containing both-end tethered PDMS-linked-PEG chains showed comparatively lower antifouling property than that of membrane containing dangling PDMS-linked-PEG chains due to low water response by the PEG chains.