Critical analysis of adhesion work measurements from AFM-based techniques for soft contact.

Hypothesis: The work of adhesion is a thermodynamic quantity that is frequently measured by atomic force microscopy (AFM). Determination of the work of adhesion requires quasi-equilibrium measurements, where we address the question of to what extent atomic force microscopy qualifies for quasi-equilibrium measurements.

Experiment: To measure the work of adhesion, we combined soft colloidal probe AFM (SCP AFM) with reflection interference contrast microscopy (RICM).

Influence of the Atmosphere on the Wettability of Polymer Brushes.

Polymer brushes, i.e., end-tethered polymer chains on substrates, are sensitive to adaptation, e.

Molecular Transport within Polymer Brushes: A FRET View at Aqueous Interfaces.

Molecular permeability through polymer brush chains is implicated in surface lubrication, wettability, and solute capture and release. Probing molecular transport through polymer brushes can reveal information on the polymer nanostructure, with a permeability that is dependent on chain conformation and grafting density. Herein, we introduce a brush system to study the molecular transport of fluorophores from an aqueous droplet into the external "dry" polymer brush with the vapour phase above.

Mechanofluorescent Polymer Brush Surfaces that Spatially Resolve Surface Solvation.

Polymer brushes, consisting of densely end-tethered polymers to a surface, can exhibit rapid and sharp conformational transitions due to specific stimuli, which offer intriguing possibilities for surface-based sensing of the stimuli. The key toward unlocking these possibilities is the development of methods to readily transduce signals from polymer conformational changes. Herein, we report on single-fluorophore integrated ultrathin (<40 nm) polymer brush surfaces that exhibit changing fluorescence properties based on polymer conformation.

Memory effects in polymer brushes showing co-nonsolvency effects.

Densely packed polymer chains grafted to a substrate, especially polymer brushes, have been studied intensively. Of special interest are systems that react to changes in external conditions or"remember" previous conditions. With this focus, we explore the properties of PNiPAAm brushes and relate published work to own results.