Analogy in the adsorption of random copolymers and homopolymers at solid-liquid interface: A Monte Carlo simulation study

The adsorption of random copolymers at solid-liquid interface from a nonselective solvent has been studied by Monte Carlo simulation in a cubic lattice. The polymeric molecules are modeled as self-avoiding linear chains composed of two types of segments A and B. The effects of copolymer composition (A/B ratio), segment-surface interaction, and bulk concentration are examined on the thermodynamic and structural adsorption properties including surface coverage, adsorption amount, adsorption layer thickness, and microscopic density distribution. At a given newly introduced effective adsorption energy, random copolymers are found to behave quantitatively as homopolymers regardless of the copolymer composition and surface affinity. This remarkable analogy provides an efficient way in predicting the adsorption of random copolymers from homopolymers.