RIPENING OF CELLULAR LATEX FILMS

Cellular films have been produced through evaporation of aqueous dispersions containing latex particles. The membranes of the cells are made of hydrophilic species which originate from the surfaces of the particles; they form a periodic structure which separates the cell cores from each other. Thermal treatments have been applied to induce the fragmentation of membranes. The resulting structural changes have been observed through small-angle neutron scattering and electron microscopy. It has been found that the fragmentation of membranes is controlled by three parameters: the mobility of membrane polymers, the anchoring of these polymers on the core, and the mobility of the core. After fragmentation occurs, the hydrophilic membrane material is expelled to large lumps immersed in a continuous latex matrix.