Self-Assembly of Fine Particles using Patterned Wettability

Abstract

This paper proposes a technique to assemble fine particles combining the continuous-convective-method and patterned wettability. A substrate patterned with hydrophilic or hydrophobic region is drawn-up from suspension that contains particles at specific angle. At the boundary of air/suspension, the particles arrange themselves selectively on hydrophilic region as the evaporation of water. Firstly, we discuss the method of wettability patterning. Line-and-space patterns that consist of PTFE/SiO2 and OTS/SiO2 were prepared. Then, the relationship between the contact angle of each region and trapping force of suspension was discussed. Secondary, design guideline is discussed where the condition to full-up the particles only in hydrophilic region is focused. It was found that the width and spacing of hydrophilic region should be designed to keep sufficient supply of particles.