A dual-layer hollow fiber membrane with highly ordered isoporous surface and excellent mechanical strength was fabricated via block copolymer self-assembly and non-solvent induced phase separation. The isoporous outer layer formed by the self-assembly of poly(styrene-b-4-vinylpyridine) (PS4VP) was based on a poly(vinylidene fluoride) (PVDF) microfiltration membrane as the robust support layer. The prepared membranes showed high tensile strength between 6.21 and 6.95 MPa. The good adhesion between the layers was ascribed to the infiltration of PS4VP into the porous PVDF support, which in turn increased transport resistance as well. Therefore, intermediate-treatment agents were introduced to reduce the infiltration depth of PS4VP, and the resultant membranes showed improved water permeability and remained interfacial adhesion. The highest water flux of the membranes reached 90.8 L/m(2) h bar and the molecular weight cut-off was 74 kDa. Such a novel PS4VP/PVDF dual-layer hollow fiber ultrafiltration membrane is a promising candidate for highly selective separation. (C) 2016 Elsevier B.V. All rights reserved.