Core-shell nanostructured nanoparticle films as chemically sensitive interfaces

This paper reports the results of an investigation of vapor molecule sorpti on at different types of nanostructured nanoparticle films. Core-shell nano particles of two different core sizes, Au2-nm and Au5-nm, and molecular lin kers of two different binding properties, 1,9-nonanedithiol and 11-mercapto undecanoic acid, are utilized as building blocks for constructing chemicall y sensitive interfaces. The work couples measurements of two different tran sducers, interdigitated microelectrodes and quartz crystal microbalance, to determine the correlation of the electronic resistance change and the mass loading with vapor sorption. The responses to vapor sorption at these nano structured interfaces are demonstrated to be dependent on the core size of nanoparticles and the chemical nature of linking molecules. The difference of molecular interactions of vapor molecules at the nanostructured interfac e is shown to have a significant impact on the response profile and sensiti vity. For the tested vapor molecules, while there are small differences for the sorption of nonpolar and hydrophobic vapor molecules, there are striki ng differences for the sorption of polar and hydrophilic vapor molecules at these nanostructured interfacial materials. The implication of the finding s to the delineation of design parameters for constructing core-shell nanop article assemblies as chemically sensitive interfacial materials is also di scussed.