A novel free-standing organic/inorganic hybrid mesoporous silica membrane (HMSM) composed of mesoporous silica rods inside the channels of porous polyethylene terephthalate (PET) membrane was synthesized by employing the aspiration-induced infiltration method combined with solvent extraction. As-synthesized HMSM, in short PET-templated HMSM, was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), N-2 adsorption-desorption, thermal gravimetric analysis (TG) and molecule permeation measurements. The results indicate that the PET-templated HMSM presents the structural integrity of membrane material, the mesoporosity of hybrid mesoporous material, and the size-selectivity of nanofilter between small molecule and biomacromolecule. Moreover, the ion transfer behaviors occurring at the liquid/liquid (water/1, 2-dichloroethane) interface supported by PET-templated HMSM were investigated. It is found that such a HMSM-support liquid/liquid interface presents the asymmetric diffusion field with meso-sized selectivity between small ion and biomacromolecule. Both of the molecule permeation and the ion transfer experiment results demonstrate that the PET-templated HMSM can be applied as the nanofiltration membrane not only in aqueous solution but also at the membrane-supported liquid/liquid interface due to the meso-sized selectivity of mesopores formed in the channels of PET. This work firstly extends the applications of HMSMs with unique structure of pores-in-pores to the membrane-supported liquid/liquid interface electrochemistry and the size-selective ion transfer at the liquid/liquid interface. (C) 2014 Elsevier B.V. All rights reserved.