Temperature Dependence of Crack Spacing in Drying Latex Films

Latex dispersions with different glass-transition temperatures have been dried in Petri dishes over a range of temperatures. The crack spacing is reported and is observed to increase as the temperature approaches the glass-transition temperature of the latex. The data for crack spacing over a range of temperatures is collapsed to a single curve by adapting a scaling for the crack spacing of hard particles. The increase in temperature requires an account to be made for particle deformation and, hence, an increase in particle volume fraction, as well as the temperature dependence of the evaporation rate. The importance of measuring the stress at which films crack is highlighted.