Replication of laser-textured alumina surfaces by polydimethylsiloxane: Improvement of surface hydrophobicity

Alumina tiles are textured by a laser beam to obtain improved hydrophobic characteristics at the surfaces. Since the textured surfaces are optically opaque, the resulting surfaces are copied and replicated by polydimethylsiloxane (PDMS). Some of the texture features such as whiskers-like structures with complex shapes could not be copied by PDMS and synthesized silica particles are deposited onto PDMS copied and replicated surfaces to create a lotus effect. Analytical tools are incorporated to characterize the PDMS copied and replicated surfaces as well as synthesized silica particles deposited surfaces. Dynamic water contact angle measurements are carried out to assess hydrophobic characteristics of the resulting surfaces. It is found that PDMS copied and replicated surfaces have almost identical surface texture morphology to that of laser treated surface. Introducing synthesized silica particles improved the lotus effect on the PDMS copied and replicated surfaces; in which case, the hysteresis of droplet contact angle remains significantly low.