SPP 2171 Spring Conference: Dynamic Wetting of Flexible, Adaptive, and Switchable Substrates

Polymer brushes with infused lubricants show significant potential in reducing drop adhesion, yet the depletion of lubricant hinders its durability and the underlying mechanisms remain poorly understood. Our study focuses on observing and analyzing drop-induced lubricant depletion process on Poly Lauryl Methacrylate (PLMA) brushes with dimple and wetting ridge forming. We achieved controllable lubricant saturation in brushes by hexadecane vapor infusing, e.g., from 0% to ~400% within ten minutes, to explore the saturation-dependent oil transport dynamics. We developed a thin-film interference-based colorimetric reflectometry method to measure the real-time brush thickness, which helps to record the oil depletion process from brush layer, resulting in a local brush collapsing for tens of nanometers and the region of collapsing extend to around two hundreds of micrometers. The wetting ridge growth was recorded by confocal scanning laser microscope with fluorescence dyed hexadecane. Now, we are trying to establish a quantitative oil transfer model to interpret the dynamics of oil depletion and phase separation. This approach may help us unravel the competition between capillary force-driving lubricant extraction and osmotic pressure-induced lubricant retention.