Partitioning of bimodal polymer mixtures into a slit: Effect of slit width, composition and pore-to-bulk volume ratio


The partitioning of a bimodal polymer mixture with high and low molecular weight components (HMWCs and LMWCs) into a slit was studied by the lattice Monte Carlo simulations for a better understanding of the separation mechanism in high osmotic pressure chromatography (HOPC). The study examined a number of factors, slit width, composition of the mixture, and the pore-to-bulk volume ratio on the partitioning of the bimodal mixture. The study focused on the semidilute region where the partition coefficients of the LMWC KL and the HMWC KH differ most. The concentration φpeak at which KL and KH differ most was found to depend on the slit width D as φpeak∼D-1.5. A simple approximate scaling argument was given to account for the dependence. The partitioning of the mixture at different compositions and different pore-to-bulk volume ratios supported the hypothesis that the separation in HOPC was best achieved in the semidilute region where KL and KH differ most. Multistage equilibrations of a semidilute polydisperse polymer solution with the porous media account for the success of HOPC for large-scale fractionation. © 2002 Elsevier Science B.V. All rights reserved.

Publication Title

Colloids and Surfaces A: Physicochemical and Engineering Aspects