MONTE-CARLO SIMULATION OF THE ADSORPTION OF DIBLOCK COPOLYMERS FROM A NONSELECTIVE SOLVENT .1. ADSORPTION-KINETICS AND ADSORPTION-ISOTHERMS

The adsorption of diblock copolymers from a nonselective solvent onto a surface that attracts one of the two blocks has been simulated on a cubic lattice. The simulation uses periodic boundary conditions in two directions and places the surface at the edges of the box in the third direction. The diblock copolymers are A(NA)B(NB) with 6 < N(A) less-than-or-equal-to 20 and 10 less-than-or-equal-to N(B) less-than-or-equal-to 30, where A is the anchoring block and B does not adsorb. This report describes the adsorption isotherms and the kinetics of adsorption in the simulation. Good approximations to a Langmuir adsorption isotherm are observed only at small values of NA and the adsorption energy per segment. The kinetics observed in the isotherm has an initial stage that depends on square-root I, followed by a second stage that depends on [ 1 - exp ( - I/constant) ], where I is the number of iterations. These results are in agreement with expectations based on previous experimental and theoretical results in the situation. The internal structure of the adsorbed layer is addressed in the following paper.