HEALING AND INTERDIFFUSION PROCESSES AT PARTICLE-PARTICLE JUNCTION DURING FILM FORMATION FROM HIGH-T LATEX-PARTICLES

When amorphous polymers of same type are brought into contact at tempe ratures above the glass transition, the interface gradually heals and junction boundaries eventually disappear. Here we used a steady-state fluorescence technique to examine the healing and interdiffusion of po lymer molecules during annealing of latex film above the glass transit ion. The film was prepared from a mixture of naphthalene-(donor) and p yrene-(acceptor) labelled poly(methyl methacrylate) latex particles. W e report that during the annealing processes the transparency of the f ilm changed considerably. Healing temperature (T-H) and time (tau(H)) were measured when the latex film became almost transparent. Above T-H interdiffusion of polymer chains was observed by detecting the energy transfer from excited naphthalene to pyrene molecules. Healing and di ffusion activation energies were calculated and found to be 9.84 kcal mol(-1) and 30 kcal mol(-1), respectively, for the annealed latex film samples.