Electron hopping conductivity and vapor sensing properties of flexible network polymer films of metal nanoparticles.

摘要: Films of monolayer protected Au clusters (MPCs) with mixed alkanethiolate and omega-carboxylate monolayers, linked together in a network polymer by carboxylate-Cu2+-carboxylate bridges, exhibit electronic conductivities (sigma(EL)) that vary both the numbers methylene segments ligands bathing medium (N2, liquid or vapor). A chainlength-dependent swelling/contraction film's internal structure is shown to account for changes sigma(EL). The linker chains appear have sufficient flexibility collapse fold varied degrees film swelling dryness. Conductivity most influenced (exponentially dependent) chainlength nonlinker (alkanethiolate) ligands, result consistent electron tunneling through nonbonded contacts between those on individual, adjacent MPCs. sigma(EL) results concur behavior UV-vis surface plasmon adsorption bands, which are enhanced short when films dry. respond exposure organic vapors, decreasing conductivity increasing mass (quartz crystal microgravimetry, QCM). In presence vapor, flexible nanoparticles allows swelling-induced alteration either length chemical nature pathways both.