Force-Distance Curve Features

From the general shape of the E r) curve, one can easily sketch the shape of a typical force versus distance curve, as shown in Fig. 4.6. The following salient features are noteworthy ... 

Table 4 Main features of the tensile behaviour of minicomposites determined from the force-deformation curves (Fj is proportional limit) and from SEM fractography (fiber pull out length Ip, crack spacing distance at saturation d,).

Fig. 12 Force-versus-distance (f-d) curves using atomic force microscope on (A) dithio-carbamated PST surface and CMS-DMAEMA-graft-copolymerized surfaces (B-1 GI surface, C-1 GUI surface in Fig. 11) and their scanned topological features (B-2 and C-2)... 

The qualitative features of the surface excess as a function of the distance of separation of the plates are summarized schematically in Fig. 17.19a. Its derivative gives the qualitative shape of the force curve shown in Fig. 17.19b. It is clear that the shape of the force curve predicted by the thermodynamic approach coincides with that predicted by the alternative approaches to depletion stabilization considered previously. 

Typically the SFA features two curved, molecularly smooth surfaces of mica of radius of about 1 cm. The interaction forces are measured via forcemeasuring springs. Usually, the sheets of mica are placed in a crossed cylinder configuration, locally equivalent to a sphere near a flat surface or to two spheres close together. An optical technique involving interference fringes provides a measure of the distance between the two cylinders. The motion of the two cylindrical surfaces can be toward each other, resulting in the measure... 

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