Investigating drop behaviour and antifouling properties of polymer brush-functionalized superhydrophobic polydimethylsiloxane surfaces

Understanding drop behaviours on superhydrophobic surfaces is crucial in many applications. There has been a shift in efforts to integrate micro/nano-textured superhydrophobic surfaces with liquid-like surface structure to achieve superior interfacial properties. We investigate the drop behaviour on polymer brush-functionalized, laser-ablated superhydrophobic polydimethylsiloxane (PDMS) surfaces and explore its antifouling effect in both static and flow conditions. The presence of the nanoscale PDMS polymer brush (PB) significantly reduces the drop sliding angle to 2°, while maintaining a high contact angle of 165°. Furthermore, PBs inhibited micro-nanoscale infiltration of low surface tension liquids (e.g., isopropanol) into the micro-nano structures, thereby enabling a much faster regeneration of the superhydrophobic surface after wetting. Additional dynamic drop experiments, including impingement and evaporation, will be performed. In terms of antifouling, static culturing of E. coli and P. aeruginosa on the surfaces reveals that the biofilm coverage for the polymer brush-functionalized surface is less than pristine PDMS and superhydrophobic surfaces. Further fouling experiments will be performed under flow conditions and compared to the static case.