Correction of Random Surface Roughness on Colloidal Probes in Measuring Adhesion

详细信息    查看全文

• 作者：Seungho Yang ; Huan Zhang ; Stephen M. Hsu
• 刊名：Langmuir
• 出版年：2007
• 出版时间：January 30, 2007
• 年：2007
• 卷：23
• 期：3
• 页码：1195 - 1202
• 全文大小：414K
• 年卷期：v.23,no.3(January 30, 2007)
• ISSN：1520-5827

文摘

Atomic force microscopes (AFM) are commonly used to measure adhesion at nanoscale between two surfaces. Toavoid uncertainties in the contact areas between the tip and the surface, colloidal probes have been used for adhesionmeasurements. We measured adhesion between glass spheres and silicon (100) surface using colloidal probes ofdifferent radii under controlled conditions (relative humidity of <3%, temperature of 25 ± 1 C). Results showedthat the adhesion forces did not correlate with the radii of the spheres as suggested by elastic contact mechanics theories.Surface roughness and random surface features were found on the surfaces of the colloidal probes. We evaluatedvarious roughness parameters, Rumpf and Rabinovich models, and a load-bearing area correction model in an attemptto correct for the roughness effects on adhesion, but the results were unsatisfactory. We developed a new multiscalecontact model taking into account elastic as well as plastic deformation in a successive contacting mode. The newmodel was able to correct for most of the surface roughness features except for surface ridges with sharp angularfeatures, limited by the spherical asperity assumption made in the model.