The viscoelastic properties of latex-based paper coatings affect the performance of the coated sheet. Particle/particle or interfacial contacts and molecular interdiffusion of polymer chains between adjacent latex particles during the coalescence phase of film formation has been shown to be of critical importance in the development of the final mechanical strength of a latex polymer film. In addition to the development of the final mechanical strength of film, interfacial x-linking play a important role in changing of water-sorption amounts of polymer film.