Characteristic configurations of chains considered in this work: (1) completely confined chain, (2) tethered chain inside the pore, (3) tethered chain outside the pore, (4) chain adsorbed at the external surface, and (5) unconfined chain in the mobile phase. Tethered chains inside and outside the pore constitute the “root” and the “stem” of a chain that is partially translocated into the pore; these configurations are called below “flower” configurations.
Henry constant for surface adsorption as a function of the adsorption potential for chains of lengths N = 50, 100, and 200. Both ideal chains (a) and real chains (b) display the existence of CPA, at which the Henry constant is independent of the chain length.
The dependence of the excess free energy difference for complete adsorption of ideal (a)–(c) and real (d)–(f) chains on the adsorption potential for chains of different lengths, N = 50, 100, and 200 in pores of different radii R = 5, 10, and 15 (from left to right).
The excess free energy of a chain confined in a sphere (R = 10) as a function of chain length for ideal chains (a) and real chains (b) at different adsorption potentials. The critical adsorption potentials are also given in each figure.
The dependence of the excess free energy difference including partially translocated configurations of ideal (a)–(c) and real (d)–(f) chains on the adsorption potential. Different chains of lengths 50, 100, 200 and pore radii R = 5, 10, 15 are considered. Critical adsorption potential can be introduced in large pore cases. For the smallest pore of R = 5, CPA does not exist for both ideal (see zooming inset) and real chains.
The contribution of flower configurations calculated by Eq. (10) for ideal (a) and real [(b) and (c)] chains.
The overall partition coefficient as a function of adsorption strength U for ideal (a)–(c) and real (d)–(f) chains of lengths N = 50, 100, and 200. The ratio of the pore volume to the external surface area of the stationary phase ɛ a /S ext = 1.2R corresponds to the dense packing of spherical pores at the external surface.
Spherical coordinates employed for calculating the free energy F t (r 0, N) of the tethered chain in a spherical pore of radius R.
FPT model of isocratic elution of ideal (top series) and real (bottom series) chains (of length 50, 100, and 200) at different adsorption potentials (U increases left to right) on a stationary phase with spherical pores of R = 10. Transition of the elution sequence from SEC to AC regimes is clearly seen. For ideal chains, this transition qualitatively resembles experimental data in LCCC regime with a pronounced CPA. For real chains, CPA does not exist and the transition from SEC to AC is continuous.
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