Microcantilever-Based Sensors: Effect of Morphology, Adhesion, and Cleanliness of the Sensing Surface on Surface Stress

详细信息    查看全文

• 作者：Vincent Tabard-Cossa ; Michel Godin ; Ian J. Burgess ; Tanya Monga ; R. Bruce Lennox ; Peter Grü ; tter
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：November 1, 2007
• 年：2007
• 卷：79
• 期：21
• 页码：8136 - 8143
• 全文大小：321K
• 年卷期：v.79,no.21(November 1, 2007)
• ISSN：1520-6882

文摘

The surface stress response of micromechanical cantilever-based sensors was studied as a function of the morphology, adhesion, and cleanliness of the gold sensing surface.Two model systems were investigated: the adsorption ofalkanethiol self-assembled monolayers at the gas-solidinterface and the potential-controlled adsorption of anionsat the liquid-solid interface. The potential-induced surface stress, on a smooth and continuous polycrystallineAu(111)-textured microcantilever in 0.1 M HClO₄, is inexcellent agreement with macroscopic Au(111) single-crystal electrode results. It is shown that ambient contaminants on the sensing surface dramatically alter thesurface stress-potential response. This observation can bemisinterpreted as evidence that for polycrystalline Au(111) microcantilever electrodes, surface stress is dominated by surface energy change. Results for anionsadsorption on gold are in contrast to the gas-phase modelsystem. We demonstrate that the average grain size of thegold sensing surface strongly influences the magnitudeof the surface stress change induced by the adsorption ofoctanethiol. A 25-fold amplification of the change insurface stress is observed on increasing the average goldgrain size of the sensing surface from 90 to 500 nm.