Enhancement of Bacterial Anti−Adhesion Properties on Robust PDMS Micro−Structure Using a Simple Flame Treatment Method

Abstract

Biofilm−associated infections caused by an accumulation of micro−organisms and pathogens significantly impact the environment, health risks, and the global economy. Currently, a non−biocide−releasing superhydrophobic surface is a potential solution for antibacterial purposes. This research demonstrated a well−designed robust polydimethylsiloxane (PDMS) micro−structure and a flame treatment process with improved hydrophobicity and bacterial anti−adhesion proper-ties. After the flame treatment at 700 ± 20 °C for 15 s, unique flower−petal re−entrant nano−structures were formed on pillars (PIL−F, width: 1.87 ± 0.30 μm, height: 7.76 ± 0.13 μm, aspect ratio (A.R.): 4.14) and circular rings with eight stripe supporters (C−RESS−F, width: 0.50 ± 0.04 μm, height: 3.55 ± 0.11 μm, A.R.: 7.10) PDMS micro−patterns. The water contact angle (WCA) and ethylene glycol contact angle (EGCA) of flame−treated flat−PDMS (FLT−F), PIL–F, and C–RESS−F patterns were (133.9 ± 3.8°, 128.6 ± 5.3°), (156.1 ± 1.5°, 151.5 ± 2.1°), and (146.3 ± 3.5°, 150.7 ± 1.8°), respectively. The Escherichia coli adhesion on the C−RESS−F micro−pattern with hydrophobicity and superoleophobicity was 42.6%, 31.8%, and 2.9% less than FLT−F, PIL−F, and Teflon surfaces. Therefore, the flame−treated C−RESS−F pattern is one of the promising bacterial anti−adhesion micro−structures in practical utilization for various applications.