Selective bonding method for self-assembly of heterogeneous components using patterned surfaces

Abstract This study demonstrates the selective bonding of millimeter-scale components using the complementary patterning of hydrophilic and hydrophobic surfaces. The hydrophobic surface of the millimeter-scale components fabricated from hydrophobic polydimethylsiloxane (PDMS) was partially made hydrophilic with a designed pattern by exposure to an excimer light of 172 nm through a stencil mask. We used liquid paraffin as the adhesive and deposited it only on the hydrophobic surface. We prepared twenty components with two different complementary patterns, which were agitated in water by the computer-controlled propeller stirrer. As a result, we succeeded in obtaining a significantly higher yield of correct bonds, in comparison to that of erroneous bonds under an appropriate stirring condition. The result can be explained by the contrast in bonding strength between the correct and erroneous bonds. This principle could be used as a versatile strategy to realize programmed self-assembly with selective bonding patterns.