The SelfConsistent Field Study of the Adsorption of Flexible Polyelectrolytes onto Two Charged Objects
Professor Chauhui Tong
Department of Physics, Ningbo University, China
ABSTRACT
The continuum selfconsistent field theory is applied to the study of the adsorption of flexible polyelectrolyte (PE) onto the surfaces of two twodimensional charged square objects with a constant electric field strength immersed in a weakly charged polyelectrolyte solution. The dependences of the different chain conformations, i.e., bridging, loop, tail and train, and in particular, the bridging chain conformation, on various system parameters (the charge fraction of the PE chains, the surface charge density, the object size, the salt concentration, etc.) are investigated. The efficient Multigrid method is adopted to numerically solve the modified diffusion equation and the Poisson equation. It is found that, the thickness
L_{B} of the boundary layer of the adsorbed PE chains is independent of the chain length, and scales with the surface charge density \sigma and the fraction of charges on PE chains
\alpha_{p} as
L_{B}~\sigma^{0.36} and L_{B}~\alpha_{p}^{0.36},
respectively. Simulation results reveal that, the total amount of bridging chain conformation in the system scales linearly with respect the size of the charge objects, and scales linearly with the chain length in the long polymer chain regime. Simulation results reveal that, the total amount of the bridging chain conformation in the system scales with the charge fraction of PE chains as a power law, and the scaling exponent is dependent on all the other system parameters. Simulation results show that, the total amount of charges on the adsorbed chains in the system can overcompensate the surface charges for relatively long chains with high charge fractions.
