Diffusiophoresis in drying colloidal blends: A powerful tool to control film architecture

Gradients in particle concentration promote size segregation in drying colloidal blends. As the solvent evaporates, colloids accumulate near the top interface as it moves down. This results in a larger particle concentration close to the air/solvent interface and smaller near the substrate. Such gradient pushes down larger particles at a faster speed than small particles, yielding a stratified colloidal film with the majority of small particles at the top and the majority of large particles at the bottom.¹
In this talk, I will present our recent efforts to exploit this phenomenon to control the architecture of colloidal films. First, I will discuss our work on understanding not only the size segregation, but also the formation of honeycomb superstructures in zinc oxide and polymer colloidal films.² Then, I will describe our recent study on how to extend size segregation to ternary blends in order to increase the colloidal film surface stability.³
References
1 A. Fortini, I. Martín-Fabiani, et al. Phys. Rev. Lett., 2016, 116, 1–5.
2 Y. Dong, I. Martín-Fabiani, et al. ACS Appl. Polym. Mater., 2020, 2, 626–635.
3 J. D. Tinkler, I. Martín-Fabiani, et al. J. Colloid Interface Sci., 2021, 581, 729–740.