Fabrication and morphological characterization of superhydrophobic PDMS replicated with laser-processed template

Abstract

A method for fabricating superhydrophobic PDMS replica surfaces using laser-processed templates is proposed in this research. The disordered micro-nano structures on PDMS surfaces can be replicated using templates irradiated with varying laser fluences, allowing the contact angles to be adjusted within the range of 110° to 160°. Fractal dimensions of both the template and replica surfaces were analysed using the box-counting method to characterize the relationship between disordered microstructures and the wettability of PDMS replica surfaces. The results indicated a strong correlation between the PDMS surface and the gas/solid area fractions within the contact region between the droplet and the surface. Furthermore, the PDMS surface attains a superhydrophobic state when the solid fraction reaches 0.27. Given the tensile and deformation behaviour of PDMS in practical applications, we further examined the stability of surface wettability in replicas under tensile strain. The results demonstrate that the superhydrophobic surface with hierarchical micro-nanostructures retains excellent performance even under a 40 % strain, owing to the stable solid fraction in the tensile state. This study presents a rapid and highly efficient method for preparing superhydrophobic PDMS. The PDMS composite produced using this method exhibits excellent self-cleaning properties and resistance to droplet interference, making it suitable for applications in medical and sensor technologies. Additionally, it provides an effective method for analyzing and tracing the relationship between surface microstructure and the wettability of elastic materials under tensile stress.