ABSTRACT
The most obvious technique that utilizes the dynamic capability of the A F M is the measurement of friction, which is also called friction force microscopy or lateral force microscopy. Since the original work of Mate et al. [7], the fields of friction force mapping (sometimes called chemical imaging) and of nanotribology have grown greatly (see, for example, papers in Refs [8] and [9]). Although some progress has been made, this research has been limited by approximations or restrictions on the lateral calibration method for the A F M . This deficiency has been rectified quite recently by two techniques that yield the torsional spring constant of the cantilever and the voltage response of the lateral photodiode to cantilever twist [10-12]. This review begins by summarizing the limitations of previous calibration techniques and by detailing the procedures involved in the newer quantitative methods (Section 2). The results that we have obtained in our laboratory [13] for the quantitative dependence of friction on adhesion in a system with electrical doublelayer interactions are then reviewed (Section 3).
