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Blovský T, Šindelka K, Limpouchová Z, Procházka K. Self-Assembly of Symmetric Copolymers in Slits with Inert and Attractive Walls. Polymers (Basel) 2023; 15:4458. [PMID: 38006182 PMCID: PMC10675682 DOI: 10.3390/polym15224458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/01/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
Although the behavior of the confined semi-dilute solutions of self-assembling copolymers represents an important topic of basic and applied research, it has eluded the interest of scientists. Extensive series of dissipative particle dynamics simulations have been performed on semi-dilute solutions of A5B5 chains in a selective solvent for A in slits using a DL-MESO simulation package. Simulations of corresponding bulk systems were performed for comparison. This study shows that the associates in the semi-dilute bulk solutions are partly structurally organized. Mild steric constraints in slits with non-attractive walls hardly affect the size of the associates, but they promote their structural arrangement in layers parallel to the slit walls. Attractive walls noticeably affect the association process. In slits with mildly attractive walls, the adsorption competes with the association process. At elevated concentrations, the associates start to form in wide slits when the walls are sparsely covered by separated associates, and the association process prevents the full coverage of the surface. In slits with strongly attractive walls, adsorption is the dominant behavior. The associates form in wide slits at elevated concentrations only after the walls are completely and continuously covered by the adsorbed chains.
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Affiliation(s)
- Tomáš Blovský
- The Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 128 40 Prague, Czech Republic;
| | - Karel Šindelka
- Department of Molecular and Mesoscopic Modelling, Institute of Chemical Process Fundamentals, Czech Academy of Sciences, Rozvojová 135, 165 02 Prague, Czech Republic;
| | - Zuzana Limpouchová
- The Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 128 40 Prague, Czech Republic;
| | - Karel Procházka
- The Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 128 40 Prague, Czech Republic;
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Modeling the Phase Equilibria of Associating Polymers in Porous Media with Respect to Chromatographic Applications. Polymers (Basel) 2022; 14:polym14153182. [PMID: 35956697 PMCID: PMC9370872 DOI: 10.3390/polym14153182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/31/2022] [Accepted: 07/31/2022] [Indexed: 11/28/2022] Open
Abstract
Associating copolymers self-assemble during their passage through a liquid chromatography (LC) column, and the elution differs from that of common non-associating polymers. This computational study aims at elucidating the mechanism of their unique and intricate chromatographic behavior. We focused on amphiphilic diblock copolymers in selective solvents, performed the Monte Carlo (MC) simulations of their partitioning between a bulk solvent (mobile phase) and a cylindrical pore (stationary phase), and investigated the concentration dependences of the partition coefficient and of other functions describing the phase behavior. The observed abruptly changing concentration dependences of the effective partition coefficient demonstrate the significant impact of the association of copolymers with their partitioning between the two phases. The performed simulations reveal the intricate interplay of the entropy-driven and the enthalpy-driven processes, elucidate at the molecular level how the self-assembly affects the chromatographic behavior, and provide useful hints for the analysis of experimental elution curves of associating polymers.
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Simulation of gas chromatographic separation based on random diffusion. Se Pu 2022; 40:281-288. [PMID: 35243838 PMCID: PMC9421567 DOI: 10.3724/sp.j.1123.2021.10011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
色谱分离过程中的粒子扩散问题是色谱动力学研究的基础,深入理解粒子的扩散行为对优化分离操作条件、提升色谱性能和开发新型色谱柱尤为关键。现有的模拟方法多集中于局部过程的热力学研究,而整体的扩散分离过程报道并不多见。为此,该文基于微尺度受限空间内随机扩散的方法,通过动态追踪粒子的运动轨迹,实现粒子在气相色谱开管柱内的扩散全过程模拟。基于前期烷烃同系物的分离模拟研究,结合Kovats保留指数,分别建立了吸附步数与温度、吸附步数与碳数的函数关系,由此获得不同类型的同系物在不同温度条件下的分离参数系统。以醇类同系物的分离验证模拟的可靠性,结果表明保留时间的相对误差基本控制在5%以内,而峰宽相对误差在0.75%~60%之间。峰宽误差较大的原因在于:(1)参数化计算过程中未能充分迭代以及使用外推法;(2)模型中忽略了醇分子之间的氢键作用。该文提出的模拟方法虽然可以准确地预测色谱保留时间以及合理描述色谱峰的基本形貌特征,但尚有进一步发展空间,特别是增加对分子间相互作用的细节处理,例如可参考分子力学的方法建立分子间势函数和吸附步数的关系,利用分子力学计算的能量来取代参数化的吸附步数,从而实现更为精确的分离过程模拟。总体而言,该文所提出的模拟方法为优化色谱分离操作条件和开发新型色谱分离技术提供了有价值的参考。
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Reaction-diffusion model to quantify and visualize mass transfer and deactivation within core-shell polymeric microreactors. J Colloid Interface Sci 2021; 608:1999-2008. [PMID: 34749148 DOI: 10.1016/j.jcis.2021.10.092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 12/13/2022]
Abstract
HYPOTHESIS The performance of a polymeric core-shell microreactor depends critically on (i) mass transfer, (ii) catalyzed chemical reaction, and (iii) deactivation within the nonuniform core-shell microstructure environment. As such, these three basic working principles control the active catalytic phase density in the reactor. THEORY We present a high-fidelity, image-based nonequilibrium computational model to quantify and visualize the mass transport as well as the deactivation process of a core-shell polymeric microreactor. In stark contrast with other published works, our microstructure-based computer simulation can provide a single-particle visualization with a micrometer spatial accuracy. FINDINGS We show how the interplay of kinetics and thermodynamics controls the product-induced deactivation process. The model predicts and visualizes the non-trivial, spatially resolved active catalyst phase patterns within a core-shell system. Moreover, we also show how the microstructure influences the formation of foulant within a core-shell structure; that is, begins from the core and grows radially onto the shell section. Our results suggest that the deactivation process is highly governed by the porosity/microstructure of the microreactor as well as the affinity of the products towards the solid phase of the reactor.
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Wang X, Limpouchová Z, Procházka K, Liu Y, Min Y. Phase equilibria and conformational behavior of dendrimers in porous media: Towards chromatographic analysis of dendrimers. J Colloid Interface Sci 2021; 608:830-839. [PMID: 34689112 DOI: 10.1016/j.jcis.2021.09.177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/16/2021] [Accepted: 09/27/2021] [Indexed: 02/08/2023]
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.
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Affiliation(s)
- Xiu Wang
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
| | - Zuzana Limpouchová
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2 128 43, Czech Republic.
| | - Karel Procházka
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2 128 43, Czech Republic.
| | - Yidong Liu
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
| | - Yonggang Min
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
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Yang Y, Yu M, Ma G, Su Z, Zhang S. Performance of agarose and gigaporous chromatographic media as function of pore-to-adsorbate size ratio over wide span from ovalbumin to virus like particles. J Chromatogr A 2021; 1638:461879. [PMID: 33465583 DOI: 10.1016/j.chroma.2021.461879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 11/30/2022]
Abstract
Two commercially available agarose ion exchange media, DEAE-Capto and DEAE-Sepharose FF (DEAE-FF), and two gigaporous media DEAE -AP-120 nm and DEAE-AP-280 nm were evaluated for their applicability in adsorption of five proteins with large span of radius ranges from 2.9 nm to 14.1 nm, which include ovalbumin, bovine serum albumin (BSA), haptoglobin, thyroglobulin and hepatitis B surface antigen (HBsAg) virus like particle. The average pore radius of the four media was determined to be 6.9 nm, 18.5 nm, 59.4 nm and 139.3 nm, respectively, which was obtained by log normal distribution for DEAE-Capto and DEAE-FF and by bimodal Gaussian distribution for the two DEAE-AP media. The performance of these four media including phase ratio, static and dynamic binding capacity, and transport properties for the adsorption of these five model proteins as function of pore-to-adsorbate size ratio were investigated and compared. The best ratio of pore-to-adsorbate size was found dependent on the protein size. For protein with radius from 2.9 nm (ovalbumin) to 5.4 nm (BSA), the agarose media was superior to gigaporous media. Both the static and dynamic adsorption capacities reduced with the increase of pore size, and the highest values were obtained at the smallest pore-to-adsorbate size of about 2 times in this study, although the highest accessible surface area was obtained at pore-to-adsorbate size ratio about 16 to 20. For proteins with radius of 5.4 nm or larger than that, their adsorption capacities decreased firstly and then increased with the increase of ratio of pore-to-adsorbate size, and the highest values were obtained on the gigaporous media DEAE-AP-280 nm, which could provide faster diffusivity and larger accessible surface area. However, protein with radius of 14.1 nm (HBsAg) had much lower capacities compared to other proteins at the same pore-to-adsorbate size ratio, implying large protein needs greater pore-to-adsorbate size ratio to achieve a satisfactory capacity. For all the five tested proteins, the DEAE-Capto media having the smallest pore radius and branched dextran chains, was found superior to DEAE-FF in terms of both higher adsorption capacities and uptake kinetics, which suggested that the "chain delivery effect" took place on proteins over large size span from ovalbumin to HBsAg, though the effect on the larger proteins was much less significant than that on the smaller ones. Results from the present work provided more information on how do the relationships of pore size of chromatography media and adsorbate size interactively affect the chromatography behaviors, thus will provide general guidance for selection of suitable adsorbent for biologics of a given size.
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Affiliation(s)
- Yanli Yang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Mengran Yu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; Present address: Global Life Sciences Technologies (Shanghai) Co., Ltd, Shanghai 201203, PR China
| | - Guanghui Ma
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Zhiguo Su
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
| | - Songping Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
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Meunier DM, Wade JH, Janco M, Cong R, Gao W, Li Y, Mekap D, Wang G. Recent Advances in Separation-Based Techniques for Synthetic Polymer Characterization. Anal Chem 2020; 93:273-294. [DOI: 10.1021/acs.analchem.0c04352] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- David M. Meunier
- Core R&D, Analytical Science, The Dow Chemical Company, Midland, Michigan 48640, United States
| | - James H. Wade
- Core R&D, Analytical Science, The Dow Chemical Company, Midland, Michigan 48640, United States
| | - Miroslav Janco
- Core R&D, Analytical Science, The Dow Chemical Company, Collegeville, Pennsylvania 19426, United States
| | - Rongjuan Cong
- Packaging and Specialty Plastics, Characterization, The Dow Chemical Company, Lake Jackson, Texas 77566, United States
| | - Wei Gao
- Core R&D, Analytical Science, The Dow Chemical Company, Collegeville, Pennsylvania 19426, United States
| | - Yongfu Li
- Core R&D, Analytical Science, The Dow Chemical Company, Midland, Michigan 48640, United States
| | - Dibyaranjan Mekap
- Packaging and Specialty Plastics, Characterization, Dow Benelux, 4542 NM Terneuzen, The Netherlands
| | - Grace Wang
- School of Cinematic Arts, University of Southern California, Los Angeles, California 90089, United States
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