Polymers Derjaguin approximation

Recently,21,28 two kinds of self-consistent mean field models were developed to calculate the interaction potential between layers of flexible polymer chains grafted to spherical surfaces whose radii are comparable to the separation between the two surfaces. The calculations showed that for small particles the repulsion is less steep than that provided by the Derjaguin approximation, while with increasing radii, the interaction potential becomes close to that given by the... 

For particles stabilized with grafted polymer, generalization of the interaction potential in Eq. (136) to spheres via the Derjaguin approximation provides (Russel et al., 1989)... 

When dealing with polymer bmshes, in some cases the conditions required for the Derjaguin approximation are not fulfilled. Polymer bmshes can reach a thickness. 

With the given parameters lo = 15.8 nm. The force between a sphere and a planar surface is F = 2jtFp Va using Derjaguin s approximation. For the bare sphere and the polymer brush, we have... 

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