화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.114, No.11, 3741-3753, 2010
Dynamics of Competitive Polymer Adsorption onto Planar Surfaces in Good Solvent
Adsorption of mixed polymer Solutions in good solvent containing polymers of different chain length has been Studied by applying simulation techniques Oil it coarse-grained bead-spring polymer model. Fully flexible polymers at varying bead-surface interaction strength and different combinations of flexible, semiflexible, and stiff polymers, at a single bead-surface interaction strength have been examined. Monte Carlo simulation techniques have been employed to investigate static equilibrium properties and Brownian dynamic simulations to follow the dynamics of the adsorption process. the properties examined comprise the adsorbed number of polymers, adsorbed number of heads, head density profiles, components of the polymer radius Of gyration, tail, loop, and train Configurations, and nematic bond order of adsorbed beads. The adsorption involves in initially independent adsorption of the two polymer types followed by competitive adsorption. the competitive adsorption is characterized by a maximum of the adsorbed amount and a desorption of the polymer with the smallest Surface affinity and a Continued, but reduced, growth Of the adsorbed amount of the polymer with the largest surface: affinity. The Surface affinity difference between the two polymer types of different length increased with increasing bead-surface interaction. Furthermore, lie Surface affinity of a polymer initially decreased but then largely increased at increasing stiffness. As a consequence, a stiff short polymer was found to displace a 4-fold longer flexible polymer. the spatial extension of adsorbed polymers as characterized by the radius of gyration parallel and perpendicular to the surface of a polymer of a given flexibility was independent of the flexibility of the other polymer type. The fraction of beads in tails was increased and ill trains reduced as the Surface affinity of the dissimilar polymer type was raised. Finally, the adsorption layer of a stiff polymer possesses a nematic bond order it mixed polymer systems, the nematic bond order of a given polymer type manifests a dependence oil the flexibility of the other type.