Enhanced Adhesion of Polydimethylsiloxane Using an Interlocked Finger Structure

Silicone-based polymers have been widely used for many applications, but their extremely low surface energies and the resulting poor adhesion have been the cause for continuous problems. Herein, a novel adhesion improvement technique using an interlocked finger structure is demonstrated, which enables up to 24.8 and 7.3-fold increases in adhesion compared to the untreated and conventional plasma-treated cases, respectively. The interlocked finger structure is fabricated by surface-confined dissolution and subsequent directional melt crystallization of a solvent. After removing the solvent crystals, porous surfaces are prepared from polyurethane, polyvinyl alcohol, and polystyrene, and these are used to fabricate interfaces of interlocked finger structures with polydimethylsiloxane. The improvement in adhesion strength linearly depends on the pore depth of the prepared surfaces. This novel technique of surface adhesion could improve the performance of polymers with intrinsically poor adhesion in future applications.