Interdiffusion of polymers in waterborne polymer colloids

Waterborne latex films, obtained from the dispersions of latex particles are of particular interest due to their applications in painting, coating, adhesive industries, etc. The film formation from latex particles (size range ~ 50-150 nm) involves three sequential overlapping steps: water evaporation followed by the increase of particle concentration and particle ordering, particle deformation, and particle coalescence with polymer chain interdiffusion across boundaries. However, abrupt water penetration inside the films restricting their lifespan and deteriorating the shining of the coating, limiting their uses. The inclusion of hydrophilic hairy layers to the latex particles leads to an interstitial phase in the latex film, which acts as a diffusion barrier for the interdiffusion of polymer chains between particles and also as a medium to transport water into the film and enhances the properties of the film. In this study, using SANS and TR-SANS, we will resolve the structure of individual segments of partially deuterated polymer latex particles (protonated core and deuterated shell) at different contrast conditions (in solution) and interdiffusion of polymers in polymer latex films, prepared from the mixing of D- and H-type latex particles. The kinetics of D/H mixing in the films will be initiated using elevated temperatures (40-70 oC). The rate of mixing between D/H type particles will be evaluated from the exponential/logarithmic decay in the scattering intensity.