| The large surface-to-volume ratio and the fine-tunable interfacial chemistry of organic monolayer capped metal nanocrystals and their network assemblies are of increasing interest because of the ability to tailor surface properties. The study of such nanomaterials could lead to potential applications where predictable and controllable interfacial reactivity, sensitivity and selectivity are needed. We have developed a new class of nanostructured network assemblies which have open ligand frameworks in which void space forms channels with the nanometer-sized cores defining its size and the monolayer shell structure defining its chemical specificity. A main goal of this work is to explore nanostructured thin films built from functionalized monometallic and bimetallic nanoparticles as chemically/electrochemically responsive materials for the detection of chemical species. New and improved synthetic and assembly strategies have been developed for the construction of the nanostructures, including bimetallic nanoparticles with controllable composition and molecularly-mediated assembly of nanoparticles with selective interparticle linkage. We have employed an array of analytical techniques to characterize the structures and properties of the nanoparticles and their assemblies, including size, composition, surface structures, interfacial redox properties and mass fluxes across the nanostructured interfaces. The nanostructured materials are exploited as array sensing elements for developing detectors in microfluidic devices and tested for detecting neurotransmitters (e.g., dopamine), which are useful for development of chip-scale analytical miniaturization. Both chemiresistive and piezoelectric transducers were utilized as sensor platforms for testing bimetallic nanoparticle film assemblies with controllable interparticle spatial properties, and are demonstrated as sensing array materials for the detection of volatile organic compounds. Implications of the findings to the design of nanostructures for applications in water filtration, electrochemical monitoring of contaminants in water, controlled delivery of drugs, and chemical and biological micosensor technologies are also discussed. |
