Percolation approach to film formation from surfactant-free polystyrene particles

In this study, a film formation process from surfactant-free polystyrene (PS) latex particles is reported. Steady state fluorescence (SSF) and photon transmission (UVV) techniques were used to study the evolution of film formation. The latex films were prepared from pyrene (P)-labeled PS particles at room temperature and annealed at time intervals of 2.5 min above the glass transition temperature (T-g) of PS. During the annealing processes, the transparency of the film changed considerably. Fluorescence intensity (I-0P) from P was measured after each annealing step to monitor the stages of film formation. Evolution of transparency of latex films were monitored by using photon transmission intensity, I-tr. A drastic increase in I-tr and I-0P above the critical annealing times, t(r) and t(c) were attributed, respectively to percolation behavior of PS material from one side to the other side of the latex film. Critical exponents, beta of percolation clusters were measured and found to be around 0.35 and 0.25 for I-tr and I-0P measurements, respectively.