COLL 453 |
| T. Kyle Vanderlick and Joelle Frechette. Department of Chemical Engineering, Princeton University, Princeton, NJ 08544 |
| A major shortcoming of the classic DLVO theory is its inability to accurately predict the real charge on a surface. We have developed a new framework, similar to electrocapillarity as typically applied to a mercury electrode, to determine the charge density from adhesion at electrified interfaces. Using an electrochemical surface forces apparatus, we are able to measure potential-dependent repulsive surface forces between a gold electrode and a mica surface up to the predicted saturation regime. In the attractive regime, pull-off forces are a strong function of applied potential. Adhesion measurements increase six-fold in a 250 mV window around the potential of zero charge. Electrode charge density can be extracted from the potential dependence of pull-off forces, providing estimates of charge density far more reasonable than those obtained from DLVO theory. Using this approach we are able to study specific adsorption phenomena, such as that of pyridine at the gold surface. |
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ACS Award in Colloid and Surface Chemistry Symposium Honoring Clay Radke
Division of Colloid and Surface Chemistry |