Role of the adhesion between a nanotip and a soft material in tapping mode AFM

• Published in: Surface science 2000-11, Vol.466 (1), p.137-143
• Main Authors: Dubourg, F., Aimé, J.P.
• Format: Article
• Language: English
• Subjects: Adhesion; Atomic force microscopy; Condensed matter: structure, mechanical and thermal properties; Curved surfaces; Electron, ion, and scanning probe microscopy; Exact sciences and technology; Mechanical and acoustical properties; adhesion; Models of non-linear phenomena; Physics; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Solid surfaces and solid-solid interfaces; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(00)00749-4

The present work investigates the role of the adhesion in the oscillation behavior of a tip cantilever system when soft materials are studied. To do so, the attractive interaction between a sphere and a concave surface is calculated with the aim of predicting the change in adhesion with indentation depth. The net result is an increase in adhesion as a function of the indentation depth. Then, the adhesion expression is included in equations describing intermittent contact situations. The computed variation of the oscillation amplitude differs significantly from that obtained when uniquely a sphere–plane interaction is considered. The predicted behavior is in good agreement, particularly at the bifurcation spot, with experimental results obtained on soft materials.