Hydrophobic Antifouling Electrospun Mats from Zwitterionic Amphiphilic Copolymers

A porous material that is both hydrophobic and fouling-resistant is needed in many applications, such as water purification by membrane distillation. In this work, we take a novel approach to fabricating such membranes. Using the zwitterionic amphiphilic copolymer poly(trifluoroethyl methacrylate- random-sulfobetaine methacrylate), we electrospin nonwoven, porous membranes that combine high hydrophobicity with resistance to protein adsorption. By changing the electrospinning parameters and the solution composition, membranes can be prepared with a wide range of fiber morphologies including beaded, bead-free, wrinkly, and ribbonlike fibers, with diameters ranging between ∼150 nm and 1.5 μm. The addition of LiCl to the spinning solution not only helps control the fiber morphology but also increases the segregation of zwitterionic groups on the membrane surface. The resultant electrospun membranes are highly porous and very hydrophobic, yet resist the adsorption of proteins and retain a high contact angle (∼140°) even after exposure to a protein solution. This makes these materials promising candidates for the membrane distillation of contaminated wastewater streams and as self-cleaning materials.