Abstract: Omniphobic Liquid-Like Surfaces (OLSs) with fast removal of small droplets are highly desired for applications like heat exchangers and water collection. While OLSs have been widely reported, systematic optimization of fabrication parameters, guided by solid-liquid interfacial friction analysis, to achieve durable OLSs with superior performance remains limited. Here, we systematically investigated the dependence of Lateral Adhesion Force (FLA) on the type and length of flexible polymer chains, plasma Activation Time (tact), and Silanization Time (tsil). Based on these results, the optimal design parameters were identified, yielding an OLS with an ultra-low Sliding Angle (SA) of 3.6° and a FLA of 15.3 μN for a 20 μL water droplet. This enhanced performance is attributed to the optimal matching between the size of the tethered polymer brushes and the spacing between neighboring grafting sites, which enables droplet motion with negligible liquid penetration. Furthermore, Polydimethylsiloxane (PDMS) chains with different molecular lengths exhibit distinct interfacial sliding dynamics: short chains are insufficient to effectively support droplets, whereas excessively long chains tend to form terminal clusters that hinder chain mobility. The optimized OLS demonstrated excellent water repellency towards various water-based liquids and superior optical transparency. Durability tests further confirmed its robust stability under UV irradiation, high temperature, and corrosive environments. Overall, these findings provide fundamental insights into interfacial friction control and rational design of covalently grafted polymer brushes for industrial and biomedical applications.

Key words: Omniphobic liquid-like surfaces')">Omniphobic liquid-like surfaces, Solid-liquid interfacial friction, Slipperiness, Robustness