The electrical and optical response of thin films of
surface functionalized nanoparticles upon exposure to various
chemical vapours has been studied. It was found that the
electrical response to chemical vapours adsorbed on the various
nanoparticle films varied markedly and was determined by the
surface functional groups. Ellipsometric studies revealed that
the film thickness increased during exposure to the
chemical vapours. These thickness changes of the films
correlate with the changes in electrical conductivity. Two
physical effects are believed to play a role in determining
these conductivity changes. Under high partial pressure, the
change in nanoparticle core-core separation is the main
contribution to the change in conductivity and generally leads
to a reduction in the conductivity. However, for relatively low
partial pressures the adsorption of vapour molecules leads to
permittivity changes that tend to increase the conductivity.
Terahertz (THz) time-domain transmission spectroscopy was used to obtain the absorption coefficients and refractive indices of silica, Pyrex, and seven different Schott glasses. The refractive indices were analyzed using the Clausius–Mossotti equation, and the absorption coefficients in terms of the power-law model of far-infrared absorption. Relationships were observed between THz absorption and refractive indices on the one hand, and glass properties on the other. THz transmission data have been shown to provide a useful insight into glass structure.
This paper presents a novel method for supporting planar lipid bilayers using microcontact printed lipophilic self-assembled monolayers, in such a way as to retain their capacity to support biological functionality. Impedance spectroscopy, surface plasmon resonance, and atomic force microscopy are used to monitor the formation and investigate the properties of the supported bilayers. In addition, we show that the antibiotic peptide gramicidin and the ionophore valinomycin exhibit the expected ion selectivity. Finally, scanning force microscopy measurements show surface friction changes following bilayer formation. Chemically modified tips were used to obtain information about both the energy of the surface (hydrophobic/hydrophilic nature) and the mechanical properties of the surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.