Surface forces measurement brush layer interactions

In the force measurement (SFB) experiments that will be described atomically smooth mica surfaces are used as substrate onto which the polymers are attached. When polymers are attached to surfaces in a brush-like configuration, the detailed nature of the surfaces in these experiments does not play a major role in the frictional interactions (which are initially dominated by the polymer-polymer interface). Hie case of adsorbed polymers is somewhat different, in that bridging effects can dominate the friction - as well as the normal interactions when the adsorbance is low. The main role of the substrate is to determine the strength and the maimer of the polymer attachment (adsorbed or end-attachment), the density of the polymers on the surface (or absorbance), and to an extent the layer thickness and also the eventual likelihood of bridging. 

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