English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Polymer brushes have found extensive applications as responsive surfaces,particularly in achieving tunable friction in solvent environments. Despiterecent interest in extending this technology to air environments, little isknown about the impact of vapor absorption on friction. Consideringpolyelectrolyte brushes, we report findings that reveal, with increasingrelative humidity, a trend of frictional shear forces decaying over two ordersof magnitude only after achieving a critical humidity. However, waterabsorption, structure, and swelling of the brushes followed continuous trendswith increasing humidity. In contrast, a humidity-induced glass transitionoccurred which caused a shift from dry to fluid-like sliding with thewater-swollen brush acting as the lubricant. Below the glass transition,friction is large without regard to water concentration; thus, frictiontransitions sharply. This switching mechanism, shown to be a general propertyof the hygroscopic polymer, provides new opportunities for switchable frictionor other surface actuation from vapor stimuli.

Humidity-induced glass transition of a polyelectrolyte brush creates switchable friction in air