Fabrication of Low-Cost Flexible Superhydrophobic Antibacterial Surface with Dual-Scale Roughness.

In this work, we report a large-area fabrication of a flexible superhydrophobic bactericidal surface decorated with copper hydroxide nanowires. This involves a simple two-step method which involves growth followed by transfer of the nanowires onto the polydimethylsiloxane (PDMS) surface by mechanical peeling. Additional roughness in PDMS is obtained through incomplete wetting of the nanoscale gaps which leads to dual-scale roughness and superhydrophobicity with a contact angle of 169° and hysteresis of less than 2°. The simplicity of the process makes it low-cost and easily scalable. The process allows fabrication of nonplanar 3D surfaces. The surface shows blood repellence and antibacterial activity against Escherichia coli with more than 5 log reductions in bacterial colony. The surface also shows hemocompatible behavior, making it suitable for healthcare applications. The fabricated surface is found to be extremely robust against stretching, twisting, sandpaper abrasion, solid weight impact, and tape peel test. The surface is found to withstand human weight multiple times without losing its hydrophobicity, making it suitable for several practical scenarios in healthcare and household applications.