High stable self-cleaning surface developed by monolithic hierarchical roughness

Abstract

ABSTRACTMany hierarchical structures are used to create self-cleaning capability. The stability and durability of superhydrophobic surfaces are still questionable in various applications. In this article, the effect of annealing process and wax-coating approach was considered to create nanostructures on micro-rice-like patterns. The morphology of resultant structures was analysed by FE-SEM and AFM instruments. The presence of nanostructures significantly increased contact angles on the hydrophobic surfaces (from 138° to 158° in the annealed process and to 161° in the wax-coating method). The decreased sliding angle from 60° in smooth surface to 10° and 6° in both superhydrophobic surfaces demonstrated a clear correlation between hierarchical structures and self-cleaning capability. From comparison, the monolithic pattern showed higher stable contact angle during 6 months period at room temperature, higher durable self-cleaning capability, good brushing and tapping resistance. Hence this approach would offer additional insights for developing self-cleaning characteristics.