title: Fabrication of self-supporting porous silicon membranes and tuning transport properties by surface functionalization.
abstract: This study presents a simple approach to perform selective mass transport through freestanding porous silicon (pSi) membranes. pSi membranes were fabricated by the electrochemical etching of silicon to produce membranes with controlled structure and pore sizes close to molecular dimensions (approximately 12 nm in diameter). While these membranes are capable of size-exclusion based separations, chemically specific filtration remains a great challenge especially in the biomedical field. Herein, we investigate the transport properties of chemically functionalized pSi membranes. The membranes were functionalized using silanes (heptadecafluoro-1,1,2,2-tetrahydrodecyl)dimethylchlorosilane (PFDS) and N-(triethoxysilylpropyl)-o-polyethylene oxide urethane (PEGS) to give membranes hydrophobic (PFDS) and hydrophilic (PEGS) properties. The transport of probe dyes tris(2,2'-bipyridyl)dichlororuthenium(ii) hexahydrate (Rubpy) and Rose Bengal (RB) through these functionalized membranes was examined to determine the effect surface functionalization has on the selectivity and separation ability of pSi membranes. This study provides the basis for further investigation into more sophisticated surface functionalization and coupled with the biocompatibility of pSi will lead to new advances in membrane based bio-separations.
authors.affiliation: Centre for NanoScale Science and Technology, Flinders University, School of Chemical and Physical Sciences, Australia.
authors.forename: Leonora
authors.initials: L
authors.lastname: Velleman
authors.forename: Cameron James
authors.initials: CJ
authors.lastname: Shearer
authors.forename: Amanda Vera
authors.initials: AV
authors.lastname: Ellis
authors.forename: Dusan
authors.initials: D
authors.lastname: Losic
authors.forename: Nicolas Hans
authors.initials: NH
authors.lastname: Voelcker
authors.forename: Joseph George
authors.initials: JG
authors.lastname: Shapter
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D049329:Nanostructures / Q000737:chemistry; D016062:Porosity; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D014520:Urethane / Q000737:chemistry
chemical_list: D012821:Silanes; D014520:Urethane; D012825:Silicon