Superhydrophobic surfaces like a lotus leaf that can repel water due to their surface morphology or chemical properties have a broad range of interest in science and practical applications. However, rapid and cost-effective fabrication of the lotus leafs hierarchical micro/nanoscale structures can be challenging. To this end, we have developed a facile soft lithography method of polydimethylsiloxane (PDMS) that has beneficial features such as flexibility, inertness, and hydrophobicity to improve its surface water repellency. Herein, we present the fabrication of PDMS microstructure surfaces via the double casting method. Steam annealing process was employed to produce PDMS master with microscale hole, and the replicas with micropillars were fabricated via replica molding using the masters. We investigated the base silicone elastomer and curing agent ratio for the master fabrication. The different ratio varies the pore diameter and surface roughness of the master surface. We characterized the morphology via scanning electron microscopy (SEM) and anti-wetting behavior via contact angle measurement. SEM images of replicas show that replica surfaces generated from steam annealed master mold with 20:1 ratio of base silicone elastomer and curing agent show similar structures as the lotus leaf, which is frequently mentioned with its superhydrophobic behavior. Furthermore, its static contact angle value larger than 170º and sliding angle value less than 2◦ show that micropillars had given the surface superhydrophobic feature, facilitating water rolling off from the surface.
Anahtar Kelimeler: Superhydrophobicity, Polydimethylsiloxane (PDMS), Soft lithography, Contact Angle Measurement