  Multivalency is a common biological mechanism of formation of strong
reversible and selective bonds by grouping weak bonds. Polymers often act as a
scaffold to which multiple binding groups are attached. Here I present an
analytical theory allowing to calculate avidity and selectivity for multivalent
polymeric particles using tools from the theory of associating fluids. I
explicitly take into account conformational degrees of freedom of a polymeric
scaffold and discuss how they affect superselectivity. I also consider linear
polymeric particles with two types of ligands and show that superselectivity
does not depend on the sequence of ligands along the backbone for a Gaussian
chain with short linkers.
