Condensed Matter Physics, 2015, vol. 18, No. 2, 23802
DOI:10.5488/CMP.18.23802           arXiv:1506.03976

Title: Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case
  A.A. Polotsky (Institute of Macromolecular Compounds, Russian Academy of Sciences, 31 Bolshoy prospekt, 199004 Saint Petersburg, Russia; Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University), 49 Kronverkskiy prospekt, 197101 Saint Petersburg, Russia) ,

Adsorption of a symmetric (AB) random copolymer (RC) onto a symmetric (ab) random heterogeneous surface (RS) is studied in the annealed approximation by using a two-dimensional partially directed walk model of the polymer. We show that in the symmetric case, the expected a posteriori compositions of the RC and the RS have correct values (corresponding to their a priori probabilities) and do not change with the temperature, whereas second moments of monomers and sites distributions in the RC and RS change. This indicates that monomers and sites do not interconvert but only rearrange in order to provide better matching between them and, as a result, a stronger adsorption of the RC on the RS. However, any violation of the system symmetry shifts equilibrium towards the major component and/or more favorable contacts and lead to interconversion of monomers and sites.

Key words: random copolymer, random surface, polymer adsorption, annealed approximation, generating functions
PACS: 87.10.Hk, 82.35.Gh, 82.35.Jk

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