Control of Bacterial Attachment on Macroporous PDMS/Paraffin SLIPS With Varying Lubricant Viscosity

ABSTRACT Slippery liquid‐infused porous surfaces (SLIPS) have gained great attention as antifouling materials due to their outstanding properties, such as self‐repairing, self‐cleaning, and broad liquid‐ and microbe repellency. This material class relies on a nano‐ or microporous scaffold infused with an interlocked lubricating liquid. We developed a fluorine‐free, eco‐friendly, and biocompatible SLIPS series using macroporous PDMS substrates infused with medical‐grade liquid paraffin lubricants of five different viscosities: 68, 46, 32, 22, and 15 cSt. We systematically investigated the effect of substrate porosity and lubricant viscosity on the stability and durability of the system and its low‐fouling performance against the freshwater bacteria B. subtilis , E. coli , and P. fluorescens . Our results demonstrate the dominant character of substrate porosity in lubricant stabilization and the antifouling activity. For coarser, more corrugated substrates, the porosity was identified as a performance‐dominating property. In systems with a finer porosity, lower‐viscosity lubricants outperformed those with higher viscosities. The comparative overall analysis of the fouling data revealed that viscosities in the range of 15–32 cSt are best suited for antifouling SLIPS.