Partitioning of polymers into pores near the critical adsorption point
We have examined the critical adsorption transition for a nonreversible random walk chain (NRRW) and a self-avoiding walk chain (SAW) at the surface and have identified the critical adsorption point. We then examine the partition coefficient of a NRRW chain and a SAW chain confined in a slit with two adsorbing walls near the critical adsorption point. For a NRRW chain, the partition coefficient at the critical adsorption point is equal to one and is independent of the chain length. This property has been utilized in the liquid chromatography operated at the critical adsorption point (LCCAP). For a SAW chain, however, the partition coefficient at the critical adsorption point Kcr is greater than one and is dependent on the chain length and slit width. This confirms the experimental observation of a weak chain length dependence of the partition coefficient at the critical point. Moreover, the study found that Kcr for a SAW scales with (Rg0/D2) to a first-order approximation where Rg0 is the radius of the gyration of the unconfined chain in the dilute solution and D is the slit width.
Gong, Y., & Wang, Y. (2002). Partitioning of polymers into pores near the critical adsorption point. Macromolecules, 35 (19), 7492-7498. https://doi.org/10.1021/ma0205461