Conformation of Adsorbed Polymeric Chain. III

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Abstract
Average properties of a copolymeric chain in which a segments of the kind A and b segments of the kind B occur alternatively are calculated for an infinite chain length. For the simplest case of a=b=1, i.e. an alternating copolymeric chain (–A–B–)N, the average number of adsorbed segments of A, \barνA, that of B, \barνB and the mean square end-to-end distance \barr2 are computed numerically as functions of the adsorption energies εA and εB. The values of \barνA, \barνB, and \barr2 are proportional to N for larger values of ηA (=exp(εA⁄kT)) than the critical value (ηA)c at fixed ηB, as found for the case of a homogeneous polymeric chain. It is seen that the behavior of the copolymeric chain near an interface is affected distinctively by the adsorption energies of the segments A and B, and the copolymeric chain is forced to adsorb even for a fairly low adsorption energy of the segment of one kind if the adsorption energy of the segment of the other kind is sufficiently large.