Polymer chain binding with a flat adsorbent in the case of selective adsorption of segments: Monte Carlo simulation

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Abstract
Adsorption of a single regular AB copolymer chain on a flat impenetrable surface is studied by Monte Carlo simulation. Type A segments, which are regularly distributed over the chain length, are attracted to the surface with the energy ε, whereas for type B segments the surface serves only as an impenetrable obstacle. The critical adsorption energy is found as a function of fraction of type A segments φ. The dependencies of the average numbers of adsorbed sections (i.e., trains), loops, and tails and the average numbers of segments in these sections on ε are obtained. These dependencies are qualitatively different for homogeneous (φ=1) and heterogeneous (φ<1) chains. At φ⩽0.25, the lengths of train and loop sections become independent of the parameters φ and ε and determined solely by geometric peculiarities of the chain model under consideration. The average number and length of tails are always independent of the chain length. In the strong adsorption regime, the average numbers of loops and trains are proportional to the chain length for both heterogeneous and homogeneous chains. The segment density distribution for the adsorbed chain near the surface is different for homogeneous and heterogeneous chains in both weak and strong adsorption regimes.