General behaviour of forces at liquid interfaces

The modelling of the AFM measurement provides a means to examine the general behaviour of the forces in these systems and the sensitivity to different model parameters [63,65-67], in the context of experimental observations [57,60,62,65]. First, the effects of wetting properties on the force behaviour are discussed below. Then the effects of different disjoining pressures are split into two sections, based in the best way to discuss 

FIGURE 4.8. The effect of changing contact angle c of the drop is plotted as F(AX)/o versus AX with y = 50 dynes/cm, tfro = 50 mV, k = 10 nm and a = 2pm (left). The effect of changing surface tension y is shown for a disjoining pressure with both attraction and repulsion (0c = 80°, = 50 mV, at = 10 nm 

Jump-In. Jump-in arises from attractive forces for both rigid and deformable systems alike, caused by a mechanical instability when the gradient of the force-distance curve is equal to the spring constant of the cantilever. The process occurs quickly. 

Wrapping. In [66] it was shown that the interface may wrap around the sphere when the surface tension of the interface is decreased sufficiently and/or the repulsive force is sufficiently strong that a separation distance D can be found satisfying 

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