Surface-tension driven self-assembly of microchips on hydrophobic receptor sites with water using forced wetting

This letter reports water droplet self-alignment methods for self-assembly of microchips on hydrophobic receptor sites in ambient air environment. It is an open question if lyophobic receptor site of the self-alignment medium can be used for self-assembly. We investigate this question using both numerical simulation and experimental studies on hydrophobic receptor sites (advancing contact angle of 118 degrees) with superhydrophobic substrate (contact angle of 180 degrees). We demonstrate that self-alignment is possible using two forced wetting methods: (a) introducing an excessive amount of water and (b) applying external pressure. The results suggest that surface-tension driven self-alignment can be applied in a wider combination of materials and mediums. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751980]