Adhesion force spectroscopy of model surfaces with wettability gradient

Model surfaces with controllable wettability gradient are made by adjusting the feed mole ratio of 11-mercapto-1-undecanol and 1-octadecanethiol to form mixed self-assembled monolayers on gold. The surface adhesion spectra were obtained by force volume analysis at nanometer scale with atomic force microscopy and direct force measurement of droplets on surfaces with a microbalance. The results from direct measurement of liquid droplet-substrate adhesion are in good agreement with the measurements of force volume statistics and contact angle. It can thus be a useful supplement approach to understand surface wetting and adhesion property.

The adhesive force spectroscopy between droplet and surface can be obtained with droplet displacement measurement and is in good agreement with wettability and force volume measurement.Figure optionsDownload as PowerPoint slideHighlights
► Modal wettability gradient surfaces were prepared.
► Surface wetting/adhesion was directly measured at microscale.
► Wettability measurements were well correlated with force volume statistics, friction force at nanoscale and contact angle measurement.
► Wetting/adhesion measurement is very important for enhanced oil recovery.