A Reversibly Switching Surface

TLDR

The study reports the design of surfaces that dynamically alter wettability in response to an electrical potential. The surface achieves this by surface‑confined single‑layer molecules that switch between hydrophilic and moderately hydrophobic conformations, amplifying molecular transitions to macroscopic property changes without altering the surface chemistry. Reversible conformational transitions were confirmed both molecularly via sum‑frequency generation spectroscopy and macroscopically via contact angle measurements, indicating that these surfaces could enable new interfacial engineering applications.

Abstract

We report the design of surfaces that exhibit dynamic changes in interfacial properties, such as wettability, in response to an electrical potential. The change in wetting behavior was caused by surface-confined, single-layered molecules undergoing conformational transitions between a hydrophilic and a moderately hydrophobic state. Reversible conformational transitions were confirmed at a molecular level with the use of sum-frequency generation spectroscopy and at a macroscopic level with the use of contact angle measurements. This type of surface design enables amplification of molecular-level conformational transitions to macroscopic changes in surface properties without altering the chemical identity of the surface. Such reversibly switching surfaces may open previously unknown opportunities in interfacial engineering.