Hydrophobic stretchable polydimethylsiloxane films with wrinkle patterns prepared via a metal-assisted chemical etching process using a Si master mold

摘要

We fabricated hydrophobic, stretchable, wrinkle-patterned polydimethylsiloxane (PDMS) films via a metal-assisted chemical etching (MACE) process using a Si master mold, which is a mask-free technique for fabricating large-area films. The wrinkle-patterned PDMS surface prepared via MACE exhibited high hydrophobicity and stretchability, which are difficult to achieve with wrinkle-patterned PDMS prepared via a conventional process, such as, plasma treatment, e-beam, or laser patterning. The contact angle of the wrinkled PDMS surface was dependent on the size of the micro/nanostructures, and the largest contact angle was 135.8 +/- 0.1 degrees for the film prepared under the optimum conditions. To confirm the applicability of the wrinkled PDMS films to flexible electronics, we tuned the mechanical properties by controlling the crosslinker ratio in the films. The Young's modulus ranged from 0.193 to 1.364 MPa depending on the crosslinker ratio, and the stress of the optimum film was 1.5 MPa under 250% strain.