Stewart, Andrew2015-12-132015-12-130957-0233http://hdl.handle.net/1885/89804An application of capacitance dilatometry to a surface-force apparatus is described. The distance between the surfaces is obtained from the capacitance of a cylindrical parallel-plate capacitor measured with a variable-ratio transformer bridge; the surface separation is made to vary with a magnetic force transducer. The method permits measurements of forces between opaque surfaces over periods of time ranging from tens of milliseconds to, in principle, an indefinite period. A new method of signal analysis that allows linear and accurate measurement of displacement over a large fraction of the separation between the plates of the capacitor is described.Keywords: Adhesion; Capacitance dilatometry; Electrical double layer; Surface potential; Surface-force apparatus; Transformer bridge200010.1088/0957-0233/11/3/3192015-12-12