Self-diffusion film formation of PS/P(S-EA) nanocomposite latices without coalescent by designing and tuning their nanostructure

•Nanosized PS/P(S-EA) core/shell-like particles were prepared at low surfactant amount.•Film formation proceeded smoothly at room temperature without any coalescents.•Films had nanosized sea-island structure after self-diffusion of macromolecules.•The VOC-free films had better mechanical properties and optical transparency.