Time evolution of film formation from polystyrene particles: a percolation approach

Abstract

This work reports the film formation process from surfactant-free polystyrene (PS) latex particles. Steady state fluorescence and photon transmission techniques were used to study the evolution of film formation. The films were prepared from fluorescein (F)-labeled PS latex particles at room temperature and annealed in 2.5-min-time intervals above the glass transition temperature (T g) of PS. Fluorescence intensity (I F) from F was measured after each annealing step to monitor the stages of film formation. Evolution of transparency of latex films was monitored by using the photon transmission intensity, I tr. Drastic increase in I tr and I F above the critical annealing times, t r and t c, respectively, were attributed to the percolation behavior of the PS material. Critical exponents, β, of percolation clusters were measured and found to be around 0.31 and 0.37 for I tr and I F measurement, respectively, which were attributed to the site percolation model.