Concept of quasimonomers and its application to some problems of polymer statistics

Abstract The concept of quasimonomers is introduced, i.e. the concept of disconnected quasiparticles, which can be effectively substituted for a chain of connected monomers in the analysis of volume interactions in polymeric coils. Such a substitution becomes possible because each monomer of an infinite homogeneous chain is ‘standardly surrounded’ by the other monomers (primarily by near neighbours along the chain) and solvent molecules. This ‘standard surrounding’ renormalizes the monomer characteristics in such a way that each monomer can be considered as a disconnected quasiparticle, the properties of which do not coincide with the properties of the initial monomer. The application of the concept of quasimonomers to the analysis of volume interactions in inhomogeneous macromolecules (finite linear macromolecules, macromolecules with defects and branched macromolecules) leads to results which differ from the results of classical Flory-type theories. This is connected with the fact that the interaction characteristics for these macromolecules turn out to be dependent on the positions of corresponding monomers in the chain. The following topics are considered with the help of the method of quasimonomers: the θ behaviour of finite chains, of chains with defects and of branched chains; the partial specific volume of polymeric macromolecules; and the relation between the polymer chain models. In Appendix 2 the good solvent behaviour of branched macromolecules is also discussed.