Abstract:
Naturally occurring surfaces such as in most aquatic plants display interesting surface wetting properties such as
superhydrophobicity, superoleophobicity and directional wettability. These phenomena arise from the micro/nano
structures present on these surfaces complimented by their surface chemistry. The replications of such surface
structures are highly pursued due to their potential in applications such as self-cleaning (Lotus effect), microfluidic
devices and antifouling surfaces. Soft lithography is a technique that has been used to replicate micro/nano structures
with varying degrees of success. Nevertheless, in the context of natural surfaces the technique has been mostly limited
to the replication of the lotus leaf structure. Therefore, a systematic investigation could be fruitful since it has the
potential to be scaled up to replicate different surface structures as well as large-area patterning. In this study, the
feasibility of soft lithography technique on natural leaf surfaces were investigated using five plant species with
different surface morphologies. The negatives of these primary molds were replicated using polydimethylsiloxane
(PDMS) and the final positive replica, was successfully replicated from PDMS while using hydroxypropyl
methylcellulose (HPMC) as an anti-stick layer. The structures were characterized based on SEM images and contact
angle measurements. Additionally, the effect of HPMC and degassing were also investigated. The technique can
easily be extended to broader applications in other areas that require micro/nanostructured surfaces such as anti
reflection coatings, chemical sensors and anti-microbial surfaces.
