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Mah E, Ghosh R. Synthesis and characterization of positive volume phase transition hydrogel membrane prepared using a cellulose substrate. SEP SCI TECHNOL 2023. [DOI: 10.1080/01496395.2023.2179493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Evan Mah
- Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada
| | - Raja Ghosh
- Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada
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2
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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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3
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A novel prewetting behavior of water adsorbed on solid surfaces modified with tethered chains resulting from a density functional theory. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Pastorino C, Urrutia I, Fiora M, Condado F. Heat flow through a liquid-vapor interface in a nano-channel: the effect of end-grafting polymers on a wall. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:344004. [PMID: 35688142 DOI: 10.1088/1361-648x/ac77ce] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Heat transfer through a liquid-vapor interface is a complex phenomenon and crucially relevant in heat-removal and cryogenic applications. The physical coupling among confining walls, liquid and vapor phases is very important for controlling or improving cooling rates or condensation efficiency. Surface modification is a promising route, which has been explored to taylor the heat transfer through confined two-phase systems. We use coarse-grained molecular-dynamics simulations to study the heat transfer through a nano-confined liquid-vapor interface as a function of fluid filling. We set up a stationary heat flow through a liquid-vapor interface, stabilized with the liquid in contact with a colder wall and a vapor in contact with a hotter wall. For these physical conditions, we perform extensive simulations by progressively increasing the number of fluid particles, i.e. the channel filling, and measure the fluid distribution in the channel, density, pressure and temperature profiles We also compare the heat flux behavior between a bare-surfaces nano-channel and others where the hot surface was coated with end-grafted polymers, with different wetting affinities and bending properties. We take extreme cases of polymer properties to obtain a general picture of the polymer effect on the heat transfer, as compared with the bare surfaces. We find that walls covered by end-grafted solvophylic polymers change the heat flux by a factor of 6, as compared with bare walls, if the liquid phase is in contact with the polymers. Once the liquid wets the coated wall, the improve on heat flux is smaller and dominated by the grafting density. We also find that for a wall coated with stiff polymers, the jump in heat flux takes place at a significantly lower channel filling, when the polymers' free ends interact with the liquid surface. Interestingly, the morphology of the polymers induces a 'liquid bridge' between the liquid phase and the hot wall, through which heat is transported with high (liquid-like) thermal conductivity.
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Affiliation(s)
- Claudio Pastorino
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
- Instituto de Nanociencia y Nanotecnología, CONICET-CNEA, CAC
| | - Ignacio Urrutia
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
- Instituto de Nanociencia y Nanotecnología, CONICET-CNEA, CAC
| | - María Fiora
- INTI-Micro y Nanotecnologías, Instituto Nacional de Tecnología Industrial, Av. Gral. Paz 5445, B1650WAB San Martín, Argentina
| | - Federico Condado
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av. Gral. Paz 1499, San Martín, Buenos Aires, 1650, Argentina
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Besford QA, Schubotz S, Chae S, Özdabak Sert AB, Weiss ACG, Auernhammer GK, Uhlmann P, Farinha JPS, Fery A. Molecular Transport within Polymer Brushes: A FRET View at Aqueous Interfaces. Molecules 2022; 27:molecules27093043. [PMID: 35566393 PMCID: PMC9102696 DOI: 10.3390/molecules27093043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022] Open
Abstract
Molecular permeability through polymer brush chains is implicated in surface lubrication, wettability, and solute capture and release. Probing molecular transport through polymer brushes can reveal information on the polymer nanostructure, with a permeability that is dependent on chain conformation and grafting density. Herein, we introduce a brush system to study the molecular transport of fluorophores from an aqueous droplet into the external “dry” polymer brush with the vapour phase above. The brushes consist of a random copolymer of N-isopropylacrylamide and a Förster resonance energy transfer (FRET) donor-labelled monomer, forming ultrathin brush architectures of about 35 nm in solvated height. Aqueous droplets containing a separate FRET acceptor are placed onto the surfaces, with FRET monitored spatially around the 3-phase contact line. FRET is used to monitor the transport from the droplet to the outside brush, and the changing internal distributions with time as the droplets prepare to recede. This reveals information on the dynamics and distances involved in the molecular transport of the FRET acceptor towards and away from the droplet contact line, which are strongly dependent on the relative humidity of the system. We anticipate our system to be extremely useful for studying lubrication dynamics and surface droplet wettability processes.
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Affiliation(s)
- Quinn A. Besford
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
- Correspondence: (Q.A.B.); (A.F.)
| | - Simon Schubotz
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
| | - Soosang Chae
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
| | - Ayşe B. Özdabak Sert
- Molecular Biology and Genetics Department, Istanbul Technical University, 34469 Istanbul, Turkey;
| | - Alessia C. G. Weiss
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
| | - Günter K. Auernhammer
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
| | - Petra Uhlmann
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
| | - José Paulo S. Farinha
- Centro de Química Estrutural, Department of Chemical Engineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal;
| | - Andreas Fery
- Leibniz-Institut für Polymerforschung e.V., Hohe Str. 6, 01069 Dresden, Germany; (S.S.); (S.C.); (A.C.G.W.); (G.K.A.); (P.U.)
- Correspondence: (Q.A.B.); (A.F.)
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Perez Sirkin YA, Tagliazucchi M, Szleifer I. Nanopore gates via reversible crosslinking of polymer brushes: a theoretical study. SOFT MATTER 2021; 17:2791-2802. [PMID: 33544104 DOI: 10.1039/d0sm01760d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polymer-brush-modified nanopores are synthetic structures inspired by the gated transport exhibited by their biological counterparts. This work theoretically analyzes how the reversible crosslinking of a polymer network by soluble species can be used to control transport through nanochannels and pores. The study was performed with a molecular theory that allows inhomogeneities in the three spatial dimensions and explicitly takes into account the size, shape and conformations of all molecular species, considers the intermolecular interactions between the polymers and the soluble crosslinkers and includes the presence of a translocating particle inside the pore. It is shown than increasing the concentration of the soluble crosslinkers in bulk solution leads to a gradual increase of its number within the pore until a critical bulk concentration is reached. At the critical concentration, the number of crosslinkers inside the pore increases abruptly. For long chains, this sudden transition triggers the collapse of the polymer brush to the center of the nanopore. The resulting structure increases the free-energy barrier that a translocating particle has to surmount to go across the pore and modifies the route of translocation from the axis of the pore to its walls. On the other hand, for short polymer chains the crosslinkers trigger the collapse of the brush to the pore walls, which reduces the translocation barrier.
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Affiliation(s)
- Yamila A Perez Sirkin
- INQUIMAE-CONICET and DQIAQF, University of Buenos Aires, School of Sciences, Ciudad Universitaria, Pabellón 2, Ciudad Autónoma de Buenos Aires C1428EHA, Argentina.
| | - Mario Tagliazucchi
- INQUIMAE-CONICET and DQIAQF, University of Buenos Aires, School of Sciences, Ciudad Universitaria, Pabellón 2, Ciudad Autónoma de Buenos Aires C1428EHA, Argentina.
| | - Igal Szleifer
- Department of Biomedical Engineering, Department of Chemistry and Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA.
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Pastorino C, Müller M. Liquid and Droplet Transport in Brush-Coated Cylindrical Nanochannels: Brush-Assisted Droplet Formation. J Phys Chem B 2021; 125:442-449. [PMID: 33400523 DOI: 10.1021/acs.jpcb.0c09189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We study, by coarse-grained molecular dynamics simulations, equilibrium and flow properties of a liquid in cylindrical nanochannels, coated with polymer brushes. The parameters of the interaction potential model confer a chemical incompatibility between brush monomers and liquid particles. First, we study cylindrical channels whose radii are larger than the brush height and a continuous column of liquid forms at the center of the channel. These results are contrasted to the limiting case in which the radius of the cylinder is comparable to the brush height. In this second case, the grafted polymers interact across the channel and "close" it. We observe a train of droplets as the stable liquid morphology. The droplet size is comparable to the cylinder radius. By applying a constant body force onto the liquid, we induce a Poiseuille-like flow and investigate the morphology and flow rate as a function of driving force. Upon increasing the driving force, we encounter a nonequilibrium transition from a closed channel with slowly moving droplets to a flowing liquid thread at the center. The switching between these two states is reversible.
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Affiliation(s)
- C Pastorino
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA, Av.Gral. Paz 1499, B1650 San Martín, Pcia. de Buenos Aires, Argentina.,Instituto de Nanociencia y Nanotecnología CONICET-CNEA, B1650 Buenos Aires, Argentina
| | - M Müller
- Institut für Theoretische Physik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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Perez Sirkin YA, Szleifer I, Tagliazucchi M. Voltage-Triggered Structural Switching of Polyelectrolyte-Modified Nanochannels. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00082] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Yamila A. Perez Sirkin
- INQUIMAE-CONICET and DQIAQF, University of Buenos Aires, School of Sciences, Ciudad Universitaria, Pabellón 2, Ciudad Autónoma de Buenos Aires C1428EHA, Argentina
| | - Igal Szleifer
- Department of Biomedical Engineering, Department of Chemistry and Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States
| | - Mario Tagliazucchi
- INQUIMAE-CONICET and DQIAQF, University of Buenos Aires, School of Sciences, Ciudad Universitaria, Pabellón 2, Ciudad Autónoma de Buenos Aires C1428EHA, Argentina
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