PHOTON DIFFUSION STUDY IN FILMS FORMED FROM HIGH-T LATEX-PARTICLES

The steady-state fluorescence technique was used to study the evolutio n of transparency during film formation from high-T latex particles. T he latex films were prepared from pyrene-labelled poly(methyl methacry late) particles and annealed in 10 min time intervals above the glass transition temperature (T-g) Scanning electron microscopy was used to detect the variation in physical structure of annealed films. Monte Ca rlo simulations were performed for photons diffusing the latex films a nd the number of emitted and scattered photons was calculated. The cro ssing density of polymer chains at the particle-particle interface was found to depend linearly on (time)(1/2). The activation energy for ba ck-and-forth motion of a reptating polymer chain was measured and foun d to be 29 kcal mol(-1). The corresponding frequencies of a reptating chain were between 1.5 and 42 s(-1) above T-g.