Internal condensation of a polymer molecule induced by saturating bonds

This paper discusses the conformational phase change of a macromolecule caused by intramolecular bridging with saturated bonds. We provide a quantitative description of the variation of segment distribution and degree of bond formation among the reactive monomer units when the temperature and the bonding energy are varied. We show that sharp compactization is expected in a good solvent for a polymer chain along which reactive monomers are arranged with wide separation. In the asymptotic regime of high molecular weight M, the mean radius of gyration obeys a scaling law: ∼M0.5 (in good solvent), ∼M0.43 (in theta solvent), and ∼M1/3 (in poor solvent). The results can be intuitively understood by applying the c* theorem holding for a gel.