Properties ofABcopolymers with a special adsorption-tuned primary structure

Abstract

As one of the realizations of our recently proposed idea of conformation-dependent sequence design (engineering) of $\mathrm{AB}$ copolymers, here we introduce the notion of adsorption-tuned copolymers (ATC's). Such copolymers are prepared by adsorbing a homopolymer chain onto a flat surface, after which its adsorbed segments are called type A ones, and its unadsorbed segments type B ones. Next, for the primary structure generated in this way, we study the adsorption of ATC's on (some other) surface for the case when only the type A segments are attracted to this surface. The properties of the ATC copolymers are compared with those of random copolymers (RC's) with the same content of type A segments, and random-block copolymers (RBC's) with the same content of type A segments and the same number of blocks. It is shown that the specific features of the ATC primary structure promote adsorption of the ATC chains, leading to an increase of their (negative) critical adsorption energy and the number of adsorbed segments as compared to that of RC and RBC chains. Some characteristics of the adsorbed single chains (statistics of trains, loops, and tails) are studied. The difference between the ATC, RBC, and RC ensembles in these characteristics is explained by the difference in the primary structures of the copolymers. The results obtained support the general idea of conformation-dependent sequence design of $\mathrm{AB}$ copolymers, and are probably connected with the theory of the early stages of macromolecular prebiological evolution.