Comparison of solubility and vapor sensing properties of methyl- and thiophene-terminated alkanethiol-protected gold nanoparticle films

摘要

Gold nanoparticles, protected by monolayers of two different lengths of methyl- and omega-thienyl-terminated alkanethiols, have been synthesized, and their solubility properties in various solvents have been evaluated by measuring the energy of the plasmon band using UV-Vis absorbance spectroscopy and by transmission electron microscopy. Chemical sensors have been fabricated by spin-coating films of the monolayer-protected gold particles onto interdigitated microelectrode arrays. Exposure to chloroform, toluene, and hexane vapors causes the electrical resistance of the films to increase. A sensor based on 12-(3-thienyl) dodecanethiol is shown to be dramatically more sensitive to both chloroform and toluene than one based on tridecanethiol. However, in the case of hexane, these two alkanethiol-protected gold nanoparticle sensors perform similarly. These results suggest that for very nonpolar solvents such as hexane, the functional group at the periphery of the particle is much less significant than the effect of alkanethiol chain length.