Low Dimensional Particle Patterning

Abstract

We developed novel processes to fabricate micro‐patterns of particle assembly by the use of capillary force in the drying process of colloidal solution. Liquid mold method was developed to fabricate particle wires through self‐assembly on hydrophilic regions of self‐assembled monolayers (SAMs). Ethanol or water containing particles was dropped onto a patterned SAM which has hydrophobic regions and hydrophilic regions. The solution was separated into two droplets with a liquid bridge between the droplets along the hydrophilic regions of a patterned SAM. The droplets and the liquid bridge were used as a mold for fabrication of a two‐dimensional pattern of colloid crystals. Particle wire was formed between two droplets and colloid crystals such as an opal structure were formed at both ends of the particle wire after drying the solution. The particle wires constructed from a close‐packed structure or non‐close‐packed structure, i.e., square lattice, were fabricated through self‐assembly at room temperature by using this method. Furthermore, we developed a self‐assembly process to fabricate an orderly array of particle wires constructed from a close‐packed structure from colloidal solution without preparation of patterned templates. A substrate was immersed into the solution containing particles perpendicular to the liquid surface and the liquid surface was moved downward by evaporation of solution. Particles formed a mono/multi‐particle layer and the particle layer was cut by the periodic drop‐off of the solution. This process allowed us to fabricate the orderly array of particle wires and to show the high ability of the self‐assembly process for fabrication of nano/micro‐structures constructed from nano/micro‐particles or blocks.

Keywords:

• Particle assembly
• Nano/micro‐patterning
• Self‐assembly
• Capillary force
• Self‐assembled monolayer

Acknowledgment

This work was partly supported by a Grant‐in‐Aid for Scientific Research (Grant‐in‐Aid for Young Scientists No. 14703025, Exploratory Research No. 14655239) from the Ministry of Education, Culture, Sports, Science and Technology granted to Y. Masuda.