Steady-state fluorescence technique was used for studying film formation from TiO_2 covered nano-sized polystyrene latex particles.The composite films were prepared from pyrene (P)-labeled PS particles by covering them with various layers of TiO_2 at room temperature.These films then annealed at elevated temperatures in 10 min time interval above glass transition (T_g) temperature of polystyrene.Five different composite films were studied in various TiO_2 layer contents.Fluorescence emission intensity,I_p from P was measured after each annealing step to monitor the stages of film formation.Films present significant increase in I_p above the certain onset temperature called minimum film forming temperature,T_o.However,at higher annealing temperatures,I_p showed a decrease.Increase and decrease in I_p were modeled by void closure and interdiffusion processes and related activation energies were determined,respectively.Dissolution of annealed PS film,with high TiO_2 content presented a nice,ordered nano-sized ceramic structure,which may predict the construction of nano-layer photonic crystals.
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