Cross Interaction Drives Stratification in Drying Film of Binary Colloidal Mixtures.
When a liquid film of a colloidal solution consisting of particles of different sizes is dried on a substrate, the colloids often stratify, where smaller colloids are laid upon larger colloids. This phenomenon is counterintuitive because larger colloids which have a smaller diffusion constant, are expected to remain near the surface during the drying process, leaving a layer of larger colloids on top of smaller colloids. Here we show that the phenomenon is caused by the interaction between the colloids, and can be explained by a diffusion model accounting for the interaction between the colloids. By studying the evolution equations both numerically and analytically, we derive the condition at which the stratified structures are obtained.
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, China.|Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China.
Jiajia
J
Zhou
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, China.|Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China.
Ying
Y
Jiang
Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China.
Masao
M
Doi