Bradley University, Chemistry, Peoria, IL 61606
Mesoporous thin films have a variety of applications spanning from solid state sensors to photovoltaic cells. Metal oxide thin films can be deposited via self assembly of metal oxides nano-particles. Self assembly has been induced by evaporation and screening of the electrical double layer. The molecular mass transport within mesoporous thin films, consisting of fumed silica (SiO2), has been investigated by Fluorescence Correlation Spectroscopy (FCS) using Nile Red encapsulated micellar nano-probes. The Nile Red encapsulated micellar nano-probe’s diffusion coefficients were measured in a silica thin film over a 6 hour period. The diffusion coefficient was found to range from 160.0 ± 80.0 μm2/s, for t=0 hours to 64.0 ± 9.0 μm2/s, for t=6 hours. Future work is focused on investigating methods of depositing fumed silica thin films by controlling synthesis parameters such as pH, salinity, and rate of evaporation. By use of varying humidity levels, the rate of formation of thin films can be altered. Currently, the most rapid formation of a silica film has been 3.5 hours in a dry environment, whereas, the longest formation time has been 18 hours in a more humid environment.
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