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Li CW, Merlitz H, Sommer JU. Comparison of different thermostat settings in the implicit solvent approach for nanoparticles through brush-decorated nanopores. Phys Rev E 2024; 110:034503. [PMID: 39425399 DOI: 10.1103/physreve.110.034503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 08/26/2024] [Indexed: 10/21/2024]
Abstract
Nanoparticles (NPs) that are forcefully driven through a brush-decorated nanochannel form a nonequilibrium system with a rich physical behavior, including a dynamical phase transition between two modes of propagation that correspond to either separate clusters of NPs or a continuous flow channel. The peculiar properties of this system make it an ideal benchmark candidate for a comparison of three thermostat settings, the dissipative particle dynamics (DPD), the Langevin (LGV) dynamics, and a modified LGV setup, denoted as LGV^{-}, in which the thermostatting is disabled in the direction of the driving force. We demonstrate that the choice of the thermostat has little influence on the conformations of NPs, and that, due to differences in the dissipation modes, notable differences arise in their dynamical properties, such as effective friction constants and average velocities. This also includes differences in the coupling between NP clusters and the surrounding brush and affects the corresponding phase diagrams of the two propagation modes. We conclude that the conventional DPD and LGV thermostats yield results that display a reasonable degree of coincidence, but we cannot recommend the use of the LGV^{-} algorithm for the present system.
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2
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Akbarishandiz S, Khani S, Maia J. Adhesion dynamics of Janus nanocarriers to endothelial cells: A dissipative particle dynamics study. Phys Rev E 2024; 109:064408. [PMID: 39020963 DOI: 10.1103/physreve.109.064408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 03/28/2024] [Indexed: 07/20/2024]
Abstract
Janus nanocarriers (NCs) provide promising features in interfacial applications such as targeted drug delivery. Herein, we use dissipative particle dynamics simulations to study the adhesion dynamics of NCs with Janus ligand compositions to the endothelial cell as a function of a series of effects, such as the initial orientation, ligand density, shape, and size of Janus NCs. The Janus NCs, with its long axis parallel to the endothelial glycocalyx (EG) layer, has the best penetration depth due to its lower potential energy and the lowest shell entropy loss. Among different shapes of Janus NCs, both the potential energy and the EG entropy loss control the penetration. In fact, at the parallel orientations, Janus shapes with a robust mechanical strength and larger surface area at the EG/water interface can rotate and penetrate more efficiently. An increase in the ligand density of Janus NCs increases entropy losses of both the hydrophilic and the hydrophobic ligands and decreases the potential energy. Thus, for a specific Janus NCs, functionalizing with an appropriate ligand density would help driving forces prevail over barriers of penetration into the EG layer. For a particular ligand density, once the radius of the Janus NCs exceeds the appropriate size, barriers such as hydrophobic ligands and shell entropy losses are also reinforced significantly and surpass driving forces. Our observations reveal that entropy losses for hydrophobic ligands of Janus NCs and for the shell of NCs are decisive for the adhesion and penetration of Janus NCs to endothelial cells.
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3
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Akbarishandiz S, Khani S, Maia J. Adhesion dynamics of functionalized nanocarriers to endothelial cells: a dissipative particle dynamics study. SOFT MATTER 2023; 19:9254-9268. [PMID: 38009071 DOI: 10.1039/d3sm00865g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Targeted drug delivery to endothelial cells utilizing functionalized nanocarriers (NCs) is an essential procedure in therapeutic and diagnosis therapies. Using dissipative particle dynamics simulation, NCs have been designed and combined with an endothelial environment, such as the endothelial glycocalyx (EG) layer, receptors, water, and cell wall. Furthermore, the energy landscapes of the functionalized NC with the endothelial cell have been analyzed as a function of properties such as the shape, size, initial orientation, and ligand density of NCs. Our results show that an appropriate higher ligand density for each particular NC provides more driving forces than barriers for the penetration of the NCs. Herein we report the importance of shell entropy loss for the NC shape effect on the adhesion and penetration into the EG layer. Moreover, the rotation of the disc shape NC as a wheel during the penetration is an extra driving force for its further inclusion. By increasing the NCs' size larger than the appropriate size for each particular ligand density, due to an increase in the NCs' shell entropy loss, the barriers surpass the driving forces for NC penetration. Furthermore, the parallel orientation provides the NCs with the best penetration capabilities. However, the rotation of the disc shape NCs enhances their diffusion in the perpendicular orientation too. Overall, our findings highlight the crucial role of the shell entropy loss in governing the penetration of NCs. Besides, studying NCs with a homogeneous ligand composition enabled us to cross barriers and probe energetics after the complete inclusion of the NCs.
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Affiliation(s)
- Saeed Akbarishandiz
- Department of Macromolecular Science and Engineering, Case Western Reserve University, USA.
| | - Shaghayegh Khani
- Department of Macromolecular Science and Engineering, Case Western Reserve University, USA.
| | - Joao Maia
- Department of Macromolecular Science and Engineering, Case Western Reserve University, USA.
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4
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Morphology of Polymer Brushes in the Presence of Attractive Nanoparticles: Effects of Temperature. Int J Mol Sci 2023; 24:ijms24010832. [PMID: 36614298 PMCID: PMC9821464 DOI: 10.3390/ijms24010832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023] Open
Abstract
We study the role of temperature on the structure of pure polymer brushes and their mixture with attractive nanoparticles in flat and cylindrical geometries. It has previously been established that the addition of such nanoparticles causes the polymer brush to collapse and the intensity of the collapse depends on the attraction strength, the nanoparticle diameter, and the grafting density. In this work, we carry out molecular dynamics simulation under good solvent conditions to show how the collapse transition is affected by the temperature, for both plane grafted and inside-cylinder grafted brushes. We first examine the pure brush morphology and verify that the brush height is insensitive to temperature changes in both planar and cylindrical geometries, as expected for a polymer brush in a good solvent. On the other hand, for both system geometries, the brush structure in the presence of attractive nanoparticles is quite responsive to temperature changes. Generally speaking, for a given nanoparticle concentration, increasing the temperature causes the brush height to increase. A brush which contracts when nanoparticles are added eventually swells beyond its pure brush height as the system temperature is increased. The combination of two easily controlled external parameters, namely, concentration of nanoparticles in solution and temperature, allows for sensitive and reversible adjustment of the polymer brush height, a feature which could be exploited in designing smart polymer devices.
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Li CW, Romeis D, Koch M, Merlitz H, Sommer JU. Theoretical analysis of the elastic free energy contributions to polymer brushes in poor solvent: A refined mean-field theory. J Chem Phys 2022; 157:104902. [DOI: 10.1063/5.0103351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We consider polymer brushes in poor solvent that are grafted onto planar substrates and onto the internal and external surfaces of a cylinder using molecular dynamics simulation, self-consistent field (SCF), and mean-field theory. We derive a unified expression for the mean field free energy for the three geometrical classes. While for low grafting densities, the effect of chain elasticity can be neglected in poor solvent conditions, it becomes relevant at higher grafting densities and, in particular, for concave geometries. Based on the analysis of the end monomer distribution, we introduce an analytical term that describes the elasticity as a function of grafting density. The accuracy of the model is validated with molecular dynamics simulations as well as SCF computations and shown to yield precise values for the layer thickness over a wide range of system parameters. We further apply this model to analyze the gating behavior of switchable brushes inside nanochannels.
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Affiliation(s)
- Cheng-Wu Li
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Dirk Romeis
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Markus Koch
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Holger Merlitz
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
- Institute for Theoretical Physics, TU Dresden, Zellescher Weg 13, Dresden, Germany
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6
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Li CW, Merlitz H, Sommer JU. A nanofluidic system based on cylindrical polymer brushes: how to control the size of nanodroplets. SOFT MATTER 2022; 18:5598-5604. [PMID: 35857069 DOI: 10.1039/d2sm00527a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In molecular dynamics simulations we investigate the self-organized formation of droplets from a continuous flow of incoming nanoparticles. This transformation is facilitated by a cylindrical channel that is decorated with a polymer brush in a marginally poor solvent. We analyze droplet formation and propagation by means of simple scaling arguments which are tested in the simulations. Polymer brushes in marginally poor solvents serve as a pressure feedback system, exhibit a collapse transition under the moderate pressure of the incident flow, without the need for additional external stimuli, and finally close spontaneously after droplet passage. Our results qualitatively demonstrate the control of polymer brushes over continuous fluids and droplet formation, and its effectiveness as a means of fluid control can be used to design nanofluidic rectification devices that operate reliably under moderate pressure.
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Affiliation(s)
- Cheng-Wu Li
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany.
| | - Holger Merlitz
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany.
| | - Jens-Uwe Sommer
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany.
- Institute for Theoretical Physics, TU Dresden, Zellescher Weg 13, Germany.
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7
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Bharadwaj S, Niebuur BJ, Nothdurft K, Richtering W, van der Vegt NFA, Papadakis CM. Cononsolvency of thermoresponsive polymers: where we are now and where we are going. SOFT MATTER 2022; 18:2884-2909. [PMID: 35311857 DOI: 10.1039/d2sm00146b] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cononsolvency is an intriguing phenomenon where a polymer collapses in a mixture of good solvents. This cosolvent-induced modulation of the polymer solubility has been observed in solutions of several polymers and biomacromolecules, and finds application in areas such as hydrogel actuators, drug delivery, compound detection and catalysis. In the past decade, there has been a renewed interest in understanding the molecular mechanisms which drive cononsolvency with a predominant emphasis on its connection to the preferential adsorption of the cosolvent. Significant efforts have also been made to understand cononsolvency in complex systems such as micelles, block copolymers and thin films. In this review, we will discuss some of the recent developments from the experimental, simulation and theoretical fronts, and provide an outlook on the problems and challenges which are yet to be addressed.
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Affiliation(s)
- Swaminath Bharadwaj
- Technical University of Darmstadt, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Computational Physical Chemistry Group, 64287 Darmstadt, Germany.
| | - Bart-Jan Niebuur
- Technical University of Munich, Physics Department, Soft Matter Physics Group, James-Franck-Str. 1, 85748 Garching, Germany
| | - Katja Nothdurft
- RWTH Aachen University, Institut für Physikalische Chemie, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Walter Richtering
- RWTH Aachen University, Institut für Physikalische Chemie, Landoltweg 2, 52056 Aachen, Germany, European Union
| | - Nico F A van der Vegt
- Technical University of Darmstadt, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Computational Physical Chemistry Group, 64287 Darmstadt, Germany.
| | - Christine M Papadakis
- Technical University of Munich, Physics Department, Soft Matter Physics Group, James-Franck-Str. 1, 85748 Garching, Germany
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8
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Pardehkhorram R, Andrieu-Brunsen A. Pushing the limits of nanopore transport performance by polymer functionalization. Chem Commun (Camb) 2022; 58:5188-5204. [PMID: 35394003 DOI: 10.1039/d2cc01164f] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Inspired by the design and performance of biological pores, polymer functionalization of nanopores has emerged as an evolving field to advance transport performance within the last few years. This feature article outlines developments in nanopore functionalization and the resulting transport performance including gating based on electrostatic interaction, wettability and ligand binding, gradual transport controlled by polymerization as well as functionalization-based asymmetric nanopore and nanoporous material design going towards the transport direction. Pushing the limits of nanopore transport performance and thus reducing the performance gap between biological and technological pores is strongly related to advances in polymerization chemistry and their translation into nanopore functionalization. Thereby, the effect of the spatial confinement has to be considered for polymer functionalization as well as for transport regulation, and mechanistic understanding is strongly increased by combining experiment and theory. A full mechanistic understanding together with highly precise nanopore structure design and polymer functionalization is not only expected to improve existing application of nanoporous materials but also opens the door to new technologies. The latter might include out of equilibrium devices, ionic circuits, or machine learning based sensors.
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Affiliation(s)
- Raheleh Pardehkhorram
- Macromolecular Chemistry, Smart Membranes, Technical University of Darmstadt, 64287 Darmstadt, Germany.
| | - Annette Andrieu-Brunsen
- Macromolecular Chemistry, Smart Membranes, Technical University of Darmstadt, 64287 Darmstadt, Germany.
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9
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Corti HR, Appignanesi GA, Barbosa MC, Bordin JR, Calero C, Camisasca G, Elola MD, Franzese G, Gallo P, Hassanali A, Huang K, Laria D, Menéndez CA, de Oca JMM, Longinotti MP, Rodriguez J, Rovere M, Scherlis D, Szleifer I. Structure and dynamics of nanoconfined water and aqueous solutions. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:136. [PMID: 34779954 DOI: 10.1140/epje/s10189-021-00136-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
This review is devoted to discussing recent progress on the structure, thermodynamic, reactivity, and dynamics of water and aqueous systems confined within different types of nanopores, synthetic and biological. Currently, this is a branch of water science that has attracted enormous attention of researchers from different fields interested to extend the understanding of the anomalous properties of bulk water to the nanoscopic domain. From a fundamental perspective, the interactions of water and solutes with a confining surface dramatically modify the liquid's structure and, consequently, both its thermodynamical and dynamical behaviors, breaking the validity of the classical thermodynamic and phenomenological description of the transport properties of aqueous systems. Additionally, man-made nanopores and porous materials have emerged as promising solutions to challenging problems such as water purification, biosensing, nanofluidic logic and gating, and energy storage and conversion, while aquaporin, ion channels, and nuclear pore complex nanopores regulate many biological functions such as the conduction of water, the generation of action potentials, and the storage of genetic material. In this work, the more recent experimental and molecular simulations advances in this exciting and rapidly evolving field will be reported and critically discussed.
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Affiliation(s)
- Horacio R Corti
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina.
| | - Gustavo A Appignanesi
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Marcia C Barbosa
- Institute of Physics, Federal University of Rio Grande do Sul, 91501-970, Porto Alegre, Brazil
| | - J Rafael Bordin
- Department of Physics, Institute of Physics and Mathematics, 96050-500, Pelotas, RS, Brazil
| | - Carles Calero
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Gaia Camisasca
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - M Dolores Elola
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
| | - Giancarlo Franzese
- Secció de Física Estadística i Interdisciplinària - Departament de Física de la Matèria Condensada, Universitat de Barcelona & Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Paola Gallo
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Ali Hassanali
- Condensed Matter and Statistical Physics Section (CMSP), The International Center for Theoretical Physics (ICTP), Trieste, Italy
| | - Kai Huang
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong, China
| | - Daniel Laria
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cintia A Menéndez
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - Joan M Montes de Oca
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, 8000, Bahía Blanca, Argentina
| | - M Paula Longinotti
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Javier Rodriguez
- Departmento de Física de la Materia Condensada & Instituto de Nanociencia y Nanotecnología (CNEA-CONICET), Comisión Nacional de Energía Atómica, B1650LWP, Buenos Aires, Argentina
- Escuela de Ciencia y Tecnología, Universidad Nacional de General San Martín, San Martín, Buenos Aires, Argentina
| | - Mauro Rovere
- Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146, Roma, Italy
| | - Damián Scherlis
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Igal Szleifer
- Biomedical Engineering Department, Northwestern University, Evanston, USA
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10
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Hoogenboom BW, Hough LE, Lemke EA, Lim RYH, Onck PR, Zilman A. Physics of the Nuclear Pore Complex: Theory, Modeling and Experiment. PHYSICS REPORTS 2021; 921:1-53. [PMID: 35892075 PMCID: PMC9306291 DOI: 10.1016/j.physrep.2021.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hallmark of eukaryotic cells is the nucleus that contains the genome, enclosed by a physical barrier known as the nuclear envelope (NE). On the one hand, this compartmentalization endows the eukaryotic cells with high regulatory complexity and flexibility. On the other hand, it poses a tremendous logistic and energetic problem of transporting millions of molecules per second across the nuclear envelope, to facilitate their biological function in all compartments of the cell. Therefore, eukaryotes have evolved a molecular "nanomachine" known as the Nuclear Pore Complex (NPC). Embedded in the nuclear envelope, NPCs control and regulate all the bi-directional transport between the cell nucleus and the cytoplasm. NPCs combine high molecular specificity of transport with high throughput and speed, and are highly robust with respect to molecular noise and structural perturbations. Remarkably, the functional mechanisms of NPC transport are highly conserved among eukaryotes, from yeast to humans, despite significant differences in the molecular components among various species. The NPC is the largest macromolecular complex in the cell. Yet, despite its significant complexity, it has become clear that its principles of operation can be largely understood based on fundamental physical concepts, as have emerged from a combination of experimental methods of molecular cell biology, biophysics, nanoscience and theoretical and computational modeling. Indeed, many aspects of NPC function can be recapitulated in artificial mimics with a drastically reduced complexity compared to biological pores. We review the current physical understanding of the NPC architecture and function, with the focus on the critical analysis of experimental studies in cells and artificial NPC mimics through the lens of theoretical and computational models. We also discuss the connections between the emerging concepts of NPC operation and other areas of biophysics and bionanotechnology.
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Affiliation(s)
- Bart W. Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Loren E. Hough
- Department of Physics and BioFrontiers Institute, University of Colorado, Boulder CO 80309, United States of America
| | - Edward A. Lemke
- Biocenter Mainz, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, 55128 Mainz, Germany
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Anton Zilman
- Department of Physics and Institute for Biomedical Engineering (IBME), University of Toronto, Toronto, ON M5S 1A7, Canada
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11
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Yong H, Molcrette B, Sperling M, Montel F, Sommer JU. Regulating the Translocation of DNA through Poly( N-isopropylacrylamide)-Decorated Switchable Nanopores by Cononsolvency Effect. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00215] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Huaisong Yong
- Leibniz-Institut für Polymerforschung Dresden e.V., Dresden 01069, Germany
- Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden 01069, Germany
| | - Bastien Molcrette
- Université de Lyon, École Normale Supérieure de Lyon, Université Claude Bernard, CNRS, Laboratoire de Physique, Lyon F-69342, France
| | - Marcel Sperling
- Fraunhofer-Institut für Angewandte Polymerforschung, Potsdam-Golm 14476, Germany
| | - Fabien Montel
- Université de Lyon, École Normale Supérieure de Lyon, Université Claude Bernard, CNRS, Laboratoire de Physique, Lyon F-69342, France
| | - Jens-Uwe Sommer
- Leibniz-Institut für Polymerforschung Dresden e.V., Dresden 01069, Germany
- Institute for Theoretical Physics, Technische Universität Dresden, Dresden 01069, Germany
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12
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Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems. Polymers (Basel) 2020; 12:polym12102282. [PMID: 33027995 PMCID: PMC7601300 DOI: 10.3390/polym12102282] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
Surface functionalization with end-tethered weak polyelectrolytes (PE) is a versatile way to modify and control surface properties, given their ability to alter their degree of charge depending on external cues like pH and salt concentration. Weak PEs find usage in a wide range of applications, from colloidal stabilization, lubrication, adhesion, wetting to biomedical applications such as drug delivery and theranostics applications. They are also ubiquitous in many biological systems. Here, we present an overview of some of the main theoretical methods that we consider key in the field of weak PE at interfaces. Several applications involving engineered nanoparticles, synthetic and biological nanopores, as well as biological macromolecules are discussed to illustrate the salient features of systems involving weak PE near an interface or under (nano)confinement. The key feature is that by confining weak PEs near an interface the degree of charge is different from what would be expected in solution. This is the result of the strong coupling between structural organization of weak PE and its chemical state. The responsiveness of engineered and biological nanomaterials comprising weak PE combined with an adequate level of modeling can provide the keys to a rational design of smart nanosystems.
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13
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Li CW, Merlitz H, Sommer JU. Mean-Field Model of the Collapse Transition of Brushes inside Cylindrical Nanopores. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00618] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Cheng-Wu Li
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Holger Merlitz
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institut of Polymer Research Dresden, 01069 Dresden, Germany
- Institute for Theoretical Physics, TU Dresden, Zellescher Weg 13, 01069 Dresden, Germany
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14
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Gao HM, Li B, Zhang R, Sun ZY, Lu ZY. Free energy for inclusion of nanoparticles in solvated polymer brushes from molecular dynamics simulations. J Chem Phys 2020; 152:094905. [DOI: 10.1063/5.0002257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Hui-Min Gao
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
- School of Mathematics, Jilin University, Changchun 130023, China
| | - Bing Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Ran Zhang
- School of Mathematics, Jilin University, Changchun 130023, China
| | - Zhao-Yan Sun
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- University of Chinese Academy of Sciences, Beijing 100039, China
- Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matters, College of Physical Science and Technology, Yili Normal University, Yining 835000, China
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
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15
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Abstract
Polymer brushes are outstanding lubricants that can strongly reduce wear and friction between surfaces in sliding motion. In recent decades, many researchers have put great effort in obtaining a clear understanding of the origin of the lubricating performance of these brushes. In particular, molecular dynamics simulations have been a key technique in this scientific journey. They have given us a microscopic interpretation of the tribo-mechanical response of brushes and have led to the prediction of their shear-thinning behavior, which has been shown to agree with experimental observations. However, most studies so far have focused on parallel plate geometries, while the brush-covered surfaces might be highly curved in many applications. Here, we present molecular dynamics simulations that are set up to study the friction for brushes grafted on the exterior of cylinders that are moving inside larger cylinders that bear brushes on their interior. Our simulations show that the density distributions for brushes on the interior or exterior of these cylinders are qualitatively different from the density profiles of brushes on flat surfaces. In agreement with theoretical predictions, we find that brushes on the exterior of cylinders display a more gradual decay, while brushes on the interior of cylinders becomes denser compared to flat substrates. When motion is imposed, the density profiles for cylinder-grafted brushes adapt qualitatively differently to the shear motion than observed for the parallel plate geometry: the zone where brushes overlap moves away from its equilibrium position. Surprisingly, and despite all these differences, we observe that the effective viscosity is independent of the radius of the brush-grafted cylinders. The reason for this is that the viscosity is determined by the overlap between the brushes, which turns out to be insensitive to the exact density profiles. Our results provide a microscopic interpretation of the friction mechanism for polymer brushes in cylindrical geometries and will aid the design of effective lubricants for these systems.
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Yong H, Bittrich E, Uhlmann P, Fery A, Sommer JU. Co-Nonsolvency Transition of Poly(N-isopropylacrylamide) Brushes in a Series of Binary Mixtures. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01286] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Huaisong Yong
- Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Eva Bittrich
- Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Petra Uhlmann
- Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
- Department of Chemistry, University of Nebraska-Lincoln, Hamilton Hall, Lincoln, Nebraska 68588, United States
| | - Andreas Fery
- Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
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17
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Nothdurft K, Müller DH, Brands T, Bardow A, Richtering W. Enrichment of methanol inside pNIPAM gels in the cononsolvency-induced collapse. Phys Chem Chem Phys 2019; 21:22811-22818. [DOI: 10.1039/c9cp04383g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
From Raman, we determined an enrichment of methanol inside the polymer in the cononsolvency-induced collapse and donor-type hydrogen-bonding of methanol with pNIPAM.
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Affiliation(s)
- Katja Nothdurft
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
| | - David H. Müller
- Institute of Technical Thermodynamics
- RWTH Aachen University
- 52062 Aachen
- Germany
| | - Thorsten Brands
- Institute of Technical Thermodynamics
- RWTH Aachen University
- 52062 Aachen
- Germany
| | - André Bardow
- Institute of Technical Thermodynamics
- RWTH Aachen University
- 52062 Aachen
- Germany
| | - Walter Richtering
- Institute of Physical Chemistry
- RWTH Aachen University
- 52056 Aachen
- Germany
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