π-π Conjugated Bonds Stacking/Scattering for Switchable Lubrication in Supramolecular Hydrogel.

Existing polymer materials often lack the ability to dynamically adjust lubrication in response to external stimuli. This gap in adaptable lubrication technology limits their application in advanced systems such as intelligent motion devices and soft robotics. To address this challenge, a dual-responsive lubricating hydrogel is introduced designed with a thermal and shear-responsive supramolecular network integrated into a stable polymer framework. The hydrogel exhibits a partial gel-sol transition under thermal or shear stress, mimicking the mucus secretion behavior of hagfish. As a result, the hydrogel's surface secretes a liquid supramolecular layer that significantly alters its coefficient of friction (COF), achieving up to a 20-fold reduction in friction due to the reversible supramolecular transition. This hydrogel demonstrates significant potential as an intelligent lubrication material capable of dynamically responding to varying stimuli, paving the way for more adaptive and efficient lubrication technologies.