Hydrophobic polymer surfaces by lotus leaf replication using an alternating current electric field with an interdigitated electrode

We fabricated a hydrophobic surface of polycaprolactone (PCL) and dynamic hydrophobic surface of poly(ethylene oxide) (PEO), which is an inherently hydrophilic material, by varying the surface pattern that is replicated with the lotus leaf. To improve the replication efficiency, we applied an electric field-aided technique, supplemented with an interdigitated electrode. Electrostriction occurred due to the electric field applied to the liquid silicone, and the interdigitated electrode showed high-flow movement for liquid silicone relative to the parallel plate electrode. The PCL and PEO surfaces replicated with an electric field showed fine surface roughness and microscale protrusions compared with PCL and PEO surface fabricated without an applied electric field (no-field method). The water contact angles of the PCL and PEO surfaces fabricated with an electric field were higher than those of the no-field casting method. Thus, we conclude that the field-induced casting technique is a good supplement for the general casting method.