Nanowire Transfer Enabled by Incomplete Wetting and Mechanical Tearing for Low-Cost Flexible Bactericidal Surfaces withMulti-Scale Superhydrophobicity

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 multi-scale superhydrophobicity with 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 non-planar 3D surfaces. The surface shows blood repellence and antimicrobial activity against E. coli with more than 5 log reductions in bacterial colony. The surface also shows hemocompatible behaviour making it suitable for healthcare applications. The fabricated surface is found to be extremely robust against stretching, twisting, sand paper 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.