Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (06): 1629-1636.doi: 10.3866/PKU.WHXB20100601


Self Consistent Field Analysis on the Adsorption of Equilibrium Polymers between Two Parallel Plates

SUN Zhe, YUE Xin-Rong, LIU Chuan, ZHANG Ai   

  1. School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384, P. R. China
  • Received:2009-12-09 Revised:2010-03-13 Published:2010-05-28
  • Contact: SUN Zhe


Self-consistent field theory is proposed to investigate equilibrium polymers adsorbed between two parallel plates. According to numerical results, the adsorption behavior of the equilibrium polymers can be classified into two regimes, viz. weak adsorption and strong adsorption. For strong adsorption, the apparent adsorption layers of the equilibrium polymers are observed from density profiles. Within this regime, the average chain length increases rapidly as the adsorption strength rising but the chain length distribution remains exponential. Compared with short chain equilibrium polymers, long chain equilibrium polymers are closer to the plates in the case of strong adsorption and are more concentrated in the middle of the gap in the case of weak adsorption. Given that the adsorption strength is weak, the forces applied to the plates are always repulsive for all separation distances. Widening the gap gives rise to a transition of the forces from repulsion to attraction if the adsorption is strong. Furthermore, the density profiles of the equilibrium polymers suggest competition among solubility, adsorption, and depletion. Higher solubility not only makes the density profiles more homogeneous but also decreases the pressures applied by the polymeric chains.

Key words: Adsorption, Equilibriumpolymer, Self-consistent field theory, Density profile, Association, Depletion effect


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