Universal features of complex $n$-block copolymers

Abstract: We study the conformational properties of complex polymer macromolecules, consisting in general of $n$ subsequently connected chains (blocks) of different lengths and distinct chemical structure. Depending on the solvent conditions, the inter- or intrachain interactions of some blocks may vanish, causing the rich conformational behavior. Our main attention is focused on the universal conformational properties of such molecules. Applying the direct polymer renormalization group approach, we derive the analytical expressions for the scaling exponent $\gamma(n)$, governing the number of possible conformations of $n$-block copolymer, and analyze the effective linear size measures of individual blocks. In particular, it is quantitatively estimated the degree of extension of the block sizes as functions of $n$ and position of blocks in sequence. The numerical simulations of the simplest $n=2$-block copolymer chain are performed as well for better illustration of the conformational behavior of such molecules.