Spectroscopic analysis of interactions between alkylated silanes and alumina nanoporous membranes.

Transport across alumina nanoporous membranes can be altered via surface attachment of alkylated trimethoxysilane compounds. The mechanism of attachment has been previously assumed to be monolayer silane coverage through full chemisorption regardless of reaction conditions. This chemisorption arises via covalent Si-O-Al bond formation resulting from condensation between the three putative silanols (due to hydrolysis of the three Si-OCH(3) bonds) and hydroxides present on the alumina surface.

Monitoring Transport Across Modified Nanoporous Alumina Membranes.

This paper describes the use of several characterization methods to examinealumina nanotubule membranes that have been modified with specific silanes. The functionof these silanes is to alter the transport properties through the membrane by changing thelocal environment inside the alumina nanotube. The presence of alkyl groups, either long(C18) or short and branched (isopropyl) hydrocarbon chains, on these silanes significantlydecreases the rate of transport of permeant molecules through membranes containingalumina nanotubes as monitored via absorbance spectroscopy.

Ion channel mimetic micropore and nanotube membrane sensors.

This paper describes synthetic micropore and nanotube membranes that mimic the function of a ligand-gated ion channel; that is, these membranes can be switched from an "off" state (no or low ion current through the membrane) to an "on" state (higher ion current) in response to the presence of a chemical stimulus. Ion channel mimics based on both microporous alumina and Au nanotube membranes were investigated. The off state was obtained by making the membranes hydrophobic by chemisorbing either a C18 silane (alumina membrane) or a C18 thiol (Au nanotube membrane).