Hexagonal deposits of colloidal particles.

Park, Hee Kyeong; Kim, Yeseul; Min, Hyeongho; Pang, Changhyun; Weon, Byung Mook · Phys Rev E · 2019

basic_science · Level V

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Abstract

Colloidal particles are essential materials for modern inkjet printing and coating. Here we demonstrate a versatile method to achieve hexagonal deposits of colloidal particles through droplet evaporation on hexagonal micropillar arrays. We identify how colloidal fluids turn into hexagonal deposits during evaporation with x-ray tomography. Interestingly, evaporation-driven hexagonal deposits are quite crack-free uniform. We attribute hexagonal deposit shape control to local contact line pinning by colloidal particles and geometric constraints by micropillar arrays. This deposition strategy offers a feasibility for high-quality evaporation-driven crack-free uniform polygonal deposits of colloidal particles for diverse applications.