Superhydrophilic and ultrafine polyvinylidene fluoride (PVDF) electrospun nanofibrous membranes (ENMs) were successfully fabricated by electrospinning based on an in situ free radical polymerization. The properties of electrospinning solution were investigated, as well as the morphologies and hydrophilicity of ENMs. The results showed that PVDF ENMs with in situ free radical polymerization had high porosities and rough surfaces endowing their surfaces superhydrophilicities. The water contact angle reduced from 135 degrees to 0 degrees within 0.2 s. (C) 2015 Elsevier B.V. All rights reserved.