Nanostructure-Enabled Apparent Slip through Dynamic Hydration Reorganization.

Abstract

Dynamic transport across solid-liquid nanointerfaces is commonly interpreted through equilibrium wettability, although increasing evidence suggests that interfacial hydration rather than contact angle governs nanoscale liquid motion. However, how hydration reorganizes under ionic and hydrodynamic perturbations at strongly hydrophilic nanostructured interfaces remains poorly understood. Here, we demonstrate that dendritic silica nanostructures create a hydration-rich interphase whose dynamic mechanical state can be programmed by electrolyte concentration, flow, and biomolecular adsorption. Contact-angle measurements, density functional theory calculations, and overtone-resolved quartz crystal microbalance with dissipation monitoring reveal that intermediate ionic strengths maximize near-surface acoustic loading without a proportional increase in dissipation, while increasing flow induces a flow-dependent enhancement in model-derived apparent mobility. The response is strongest at higher overtones and persists after bovine serum albumin adsorption, demonstrating that the adaptive hydration state survives the formation of a complex protein-water interphase. Rather than reflecting the classical hydrophobic slip, the observations identify a dynamically reconfigurable hydration layer that decouples equilibrium wettability from interfacial mechanics. These findings establish hydration-layer reconfigurability as a general mechanism governing liquid mobility at hydrophilic nanostructured interfaces and provide a design framework for nanofluidic transport, antifouling materials, separation membranes, and interfacial biosensing technologies.