Evaporation-driven self-assembly of binary and ternary colloidal polymer nanocomposites for abrasion resistant applications

We harness the self-assembly of aqueous binary latex/silica particle blends during drying to fabricate films segregated by size in the vertical direction. We report for the first time the experimental drying of ternary colloidal dispersions and demonstrate how a ternary film containing additional small latex particles results in improved surface stability and abrasion resistance compared with a binary film. Through atomic force microscopy (AFM) and energy-dispersive X-ray spectroscopy (EDX), we show that the vertical distribution of filler particles and the surface morphologies of the films can be controlled by altering the evaporation rate and silica volume fraction. We report the formation of various silica superstructures at the film surface, which we attribute to a combination of diffusio-phoresis and electrostatic interactions between particles. Brownian dynamics simulations of the final stages of solvent evaporation provide further evidence for this formation mechanism. We show how an additional small latex particle population results in an increased abrasion resistance of the film without altering its morphology or hardness. Our work provides a method to produce water-based coatings with enhanced abrasion resistance as well as valuable insights into the mechanisms behind the formation of colloidal superstructures. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

In this study, films segregated by size in the vertical direction were fabricated through the self-assembly of aqueous binary latex/silica particle blends during drying. Ternary films containing additional small latex particles showed improved surface stability and abrasion resistance compared with binary films. The formation of various silica superstructures at the film surface was attributed to a combination of diffusio-phoresis and electrostatic interactions between particles, as supported by Brownian dynamics simulations.