Xiu Wang1, Zuzana Limpouchová2, Karel Procházka3, Yidong Liu4, Yonggang Min5. 1. School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China. Electronic address: xiu.wang@natur.cuni.cz. 2. Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2 128 43, Czech Republic. Electronic address: zuzana.limpouchova@natur.cuni.cz. 3. Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2 128 43, Czech Republic. Electronic address: karel.prochazka@natur.cuni.cz. 4. School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China. Electronic address: ydliu@gdut.edu.cn. 5. School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China. Electronic address: ygmin@gdut.edu.cn.
Abstract
HYPOTHESIS: The intricate entropy-enthalpy interplay of dendrimers confined in pores affects their conformation and retention in the porous stationary phase. This work aims at providing important insights into its impacts on partitioning and chromatographic separation in both size-exclusion chromatography (SEC) and interaction chromatography (IC) regimes. SIMULATIONS: Using Monte Carlo (MC) simulations, we investigated the bulk-pore phase equilibria and the conformational behavior of flexible dendrimers differing in generation, in spacer length and in fraction of modified terminal groups interacting differently with pore walls than the majority building units. FINDINGS: With increasing interaction strength, a distinct transition from a roughly spherical shape caused by simultaneous interactions with two walls to an ellipsoidal (or even disklike) conformation tenaciously adhering to only one wall was observed for moderately confined dendrimers. The strongly deformed dendrimers subjected to severe confinement gain high energy and the samples differing in the degree of modification become chromatographically discernable thanks to large energy differences. Consequently, our results suggest that the column fillings with fairly narrow pores which are ineffective in SEC, are highly efficient separation media for dendrimer studies by IC above the critical adsorption point (CAP). Overall, our simulations reveal useful information for advancing and optimizing experimental liquid chromatography studies of dendrimers.
HYPOTHESIS: The intricate entropy-enthalpy interplay of dendrimers confined in pores affects their conformation and retention in the porous stationary phase. This work aims at providing important insights into its impacts on partitioning and chromatographic separation in both size-exclusion chromatography (SEC) and interaction chromatography (IC) regimes. SIMULATIONS: Using Monte Carlo (MC) simulations, we investigated the bulk-pore phase equilibria and the conformational behavior of flexible dendrimers differing in generation, in spacer length and in fraction of modified terminal groups interacting differently with pore walls than the majority building units. FINDINGS: With increasing interaction strength, a distinct transition from a roughly spherical shape caused by simultaneous interactions with two walls to an ellipsoidal (or even disklike) conformation tenaciously adhering to only one wall was observed for moderately confined dendrimers. The strongly deformed dendrimers subjected to severe confinement gain high energy and the samples differing in the degree of modification become chromatographically discernable thanks to large energy differences. Consequently, our results suggest that the column fillings with fairly narrow pores which are ineffective in SEC, are highly efficient separation media for dendrimer studies by IC above the critical adsorption point (CAP). Overall, our simulations reveal useful information for advancing and optimizing experimental liquid chromatography studies of dendrimers.
Authors: Karel Procházka; Zuzana Limpouchová; Miroslav Štěpánek; Karel Šindelka; Martin Lísal Journal: Polymers (Basel) Date: 2022-01-20 Impact factor: 4.329