Electrospun polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofibers have been modified with cellulose regenerated from ionic liquid solution. Three-dimensional impregnation of cellulose provides greater control over porosity, pore size, wettability as well as the mechanical and thermal properties of the electrospun membrane. Formation of smaller pores with narrower pore size distribution is achieved as the fibers are coated with cellulose matrix. At 15 wt.% cellulose, the mechanical properties of electrospun PVDF-HFP are enhanced as the elastic modulus increases from 17 MPa to 54 MPa and the tensile strength also improves from 5.5 MPa to 8.6 MPa. The resulting membrane exhibits superhydrophilicity and underwater supoeroleophobicity and is successfully applied for selective separation of water from oil with efficiencies up to 99.98%. (C) 2014 Elsevier B.V. All rights reserved.