Study of Healing and Interdiffusion Processes at Particle-Particle Junction during Latex Film Formation by Fluorecence Technique

Abstract

When amorphous polymers of same type are brought into contact at temperatures above the glass transition, the interface gradually heals and junction boundaries eventually disappear. Here we used steady state fluorescence technique to examine the healing and the interdiffusion of polymer molecules during annealing of latex film above glass transition. The film was prepared from a mixture of naphthalene (donor) and pyrene (acceptor) labeled poly (methylmethacrylate) latex particles. We report that during the annealing processes transparency of film changed considerably. Healing temperature and time were measured when latex film became completely transparent. Above healing temperature interdiffusion of polymer chains were observed by detecting the energy transfer from excited naphthalene to pyrene molecules. Healing and diffusion activation energies were calculated and found to be 9.84 kcal/molecule and 30 kcal/molecule respectively for the annealed latex film samples.