title: Polydimethysiloxane Modified Silica Nanochannel Membrane for Hydrophobicity-Based Molecular Filtration and Detection.
abstract: We report in this work the fabrication of ultrathin silica nanochannel membranes inhomogeneously modified by polydimethysiloxane (PDMS), designated as PDMS-SNM, for hydrophobicity-based molecular filtration and detection. The modification was accomplished by spatially selective evaporation of hydrophobic PDMS oligomers onto the top surface of the membrane and orifice of silica nanochannels. Thanks to this hydrophobic ultrathin layer and beneath ultrasmall channels (2-3 nm in diameter), only small hydrophobic molecules are able to transport through the PDMS-SNM, whereas hydrophilic and large ones are remarkably inhibited. We first employed this PDMS-SNM as the molecular sieving matrix for selective electrochemical detection of hydrophobic organophosphates (OPs) in milk samples without pretreatment. The PDMS-SNM modified electrode displayed an excellent analytical performance and antifouling/anti-interference ability. We also prepared the free-standing PDMS-SNM consisting of perforated channels, which could filtrate molecules based on their hydrophobicity with an excellent selectivity. As demonstrated, 2,4,6-trinitrotoluene and dopamine could be separated with a selectivity coefficient as high as 335. Moreover, because of the inhomogeneous nanochannel structure and ultrasmall thickness, a remarkably high flux of hydrophobic molecules across the PDMS-SNM was obtained, which was 3-4 orders of magnitude higher than that reported previously.
authors.affiliation: Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Lin
authors.affiliation: Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
authors.forename: Bowen
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yan
authors.affiliation: Key Laboratory for Advanced Materials & Institute of Fine Chemicals, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Hua
authors.affiliation: Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Su