Abstract
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. The presence of an ionicsurfactant can alter the polarity of these modified nanotubes, which correlates to anincreased transport of ions. Fluorescent spectroscopy is also utilized to enhance thesensitivity of detecting these permeant molecules. Confirmation of the alkylsilaneattachment to the alumina membrane is achieved with traditional infrared spectroscopy,which can also examine the lifetime of the modified membrane. The physical parameters ofthese silane-modified porous alumina membranes are studied via scanning electronmicroscopy. The alumina nanotubes are not physically closed off or capped by the silanesthat are attached to the alumina surfaces.
Highlights
Thin alumina membranes containing cylindrical pores with diameters in the nanometer region have been utilized as sensor components in a wide variety of applications [1,2]
As molecules traveled through the porous membrane and arrived in the permeant half-cell, the concentration of these molecules was measured via simple ultraviolet-visible absorbance spectroscopy at the proper wavelength of light
This work examines a variety of spectroscopic methods to detect transport through modified porous alumina membranes
Summary
Thin alumina membranes containing cylindrical pores with diameters in the nanometer region have been utilized as sensor components in a wide variety of applications [1,2]. Ku and co-workers examined the nature of electrical conductivity across the C18-modified membranes [21] They concluded that even though these nanopores were filled with air (due to the presence of the hydrophobic alkylsilane), electrical conduction was still possible through a small amount of “hydrophilically defective” pores, which they confirmed using AC impedance spectroscopy and 29Si NMR [21]. In this preliminary work, we examine methods of detecting molecular transport through modified porous alumina membranes, along with characterization studies. The presence of alkylsilanes to the surfaces was confirmed via infrared spectroscopy experiments, while scanning electron microscopy images visualize the surface and cross-section of the porous membranes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
