1
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Yagasaki T, Matubayasi N. High Antifouling Performance of Weakly Hydrophilic Polymer Brushes: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:15046-15058. [PMID: 39004900 DOI: 10.1021/acs.langmuir.4c01365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
The antifouling performance of polymer brushes usually improves with increasing hydrophilicity of the grafted polymer. However, in some cases, less hydrophilic polymers show comparable or better antifouling performance than do more hydrophilic polymers. We investigate the mechanism of this anomalous behavior using molecular dynamics (MD) simulations of coarse-grained (CG) models of weakly and strongly hydrophilic polymers. The antifouling performance is evaluated from the potential of mean force of a model protein. The strongly hydrophilic polymer exhibits a better antifouling performance than the weakly hydrophilic polymer when the substrate of the polymer brush is repulsive. However, when the substrate is sufficiently attractive, the weakly hydrophilic polymer brush becomes more effective than the strongly hydrophilic brush in a certain range of grafting density. This is because the weakly hydrophilic polymer chains form a tightly packed layer that prevents the adsorbate molecule from contacting the substrate. We also perform all-atom (AA) MD simulations for several standard polymers to examine the correspondence with the CG polymer models. The weakly hydrophilic CG polymer is found to be similar to poly[N-(2-hydroxypropyl)methacrylamide] and poly(2-hydroxyethyl methacrylate), both of which have a hydroxyl group in a monomer unit. The strongly hydrophilic CG polymer resembles zwitterionic poly(carboxybetaine methacrylate). A discussion referring to the adsorption free energies of proteins on surfaces calculated in previous AA MD studies suggests that the higher antifouling performance of less hydrophilic polymer brushes can be realized for various combinations of protein and surface.
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Affiliation(s)
- Takuma Yagasaki
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
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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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Mims JT, Tsuna L, Spangler EJ, Laradji M. Nanoparticles insertion and dimerization in polymer brushes. J Chem Phys 2024; 160:084906. [PMID: 38415837 DOI: 10.1063/5.0188915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/28/2024] [Indexed: 02/29/2024] Open
Abstract
Molecular dynamics simulations are conducted to systematically investigate the insertion of spherical nanoparticles (NPs) in polymer brushes as a function of their size, strength of their interaction with the polymers, polymer grafting density, and polymer chain length. For attractive interactions between the NPs and the polymers, the depth of NPs' penetration in the brush results from a competition between the enthalpic gain due to the favorable polymer-NP interaction and the effect of osmotic pressure resulting from displaced polymers by the NP's volume. A large number of simulations show that the average depth of the NPs increases by increasing the strength of the interaction strength. However, it decreases by increasing the NPs' diameter or increasing the polymer grafting density. While the NPs' effect on the polymer density is local, their effect on their conformations is long-ranged and extends laterally over length scales larger than the NP's size. This effect is manifested by the emergence of laterally damped oscillations in the normal component of the chains' radius of gyration. Interestingly, we found that for high enough interaction strength, two NPs dimerize in the polymer brush. The dimer is parallel to the substrate if the NPs' depth in the brush is shallow. However, the dimer is perpendicular to the substrate if the NPs' are deep in the brush. These results imply that polymer brushes can be used as a tool to localize and self-assemble NPs in polymer brushes.
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Affiliation(s)
- Jacob T Mims
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Lavi Tsuna
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Eric J Spangler
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Mohamed Laradji
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
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4
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Astier S, Johnson EC, Norvilaite O, Varlas S, Brotherton EE, Sanderson G, Leggett GJ, Armes SP. Controlling Adsorption of Diblock Copolymer Nanoparticles onto an Aldehyde-Functionalized Hydrophilic Polymer Brush via pH Modulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38320303 PMCID: PMC10883040 DOI: 10.1021/acs.langmuir.3c03392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Sterically stabilized diblock copolymer nanoparticles with a well-defined spherical morphology and tunable diameter were prepared by RAFT aqueous emulsion polymerization of benzyl methacrylate at 70 °C. The steric stabilizer precursor used for these syntheses contained pendent cis-diol groups, which means that such nanoparticles can react with a suitable aldehyde-functional surface via acetal bond formation. This principle is examined herein by growing an aldehyde-functionalized polymer brush from a planar silicon wafer and studying the extent of nanoparticle adsorption onto this model substrate from aqueous solution at 25 °C using a quartz crystal microbalance (QCM). The adsorbed amount, Γ, depends on both the nanoparticle diameter and the solution pH, with minimal adsorption observed at pH 7 or 10 and substantial adsorption achieved at pH 4. Variable-temperature QCM studies provide strong evidence for chemical adsorption, while scanning electron microscopy images recorded for the nanoparticle-coated brush surface after drying indicate mean surface coverages of up to 62%. This fundamental study extends our understanding of the chemical adsorption of nanoparticles on soft substrates.
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Affiliation(s)
- Samuel Astier
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Edwin C Johnson
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Oleta Norvilaite
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Spyridon Varlas
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Emma E Brotherton
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - George Sanderson
- GEO Specialty Chemicals, Hythe, Southampton, Hampshire SO45 3ZG, U.K
| | - Graham J Leggett
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Steven P Armes
- Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
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5
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Yagasaki T, Matubayasi N. Molecular Dynamics Study of the Antifouling Mechanism of Hydrophilic Polymer Brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13158-13168. [PMID: 37672759 DOI: 10.1021/acs.langmuir.3c01552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
We perform all-atom molecular dynamics simulations of the adsorption of amino acid side-chain analogues on polymer brushes. The analogues examined are nonpolar isobutane, polar propionamide, negatively charged propionate ion, and positively charged butylammonium ion. The polymer brushes consist of a sheet of graphene and strongly hydrophilic poly(carboxybetaine methacrylate) (PCBMA) or weakly hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA). The effective interactions between isobutane and polymer chains are repulsive for PCBMA and attractive for PHEMA. Gibbs energy decomposition analysis shows that this is due to the abundance of water in the PCBMA brush, which increases the steric repulsion and decreases the Lennard-Jones attraction. The affinity of the hydrophilic analogues is low for both PCBMA and PHEMA chains, but the balance between the components of the Gibbs energy is different for the two polymers. The simulations are performed at several θ, where θ is the degree of overlap of polymer chains. The antifouling performance against the neutral analogues is better for PCBMA than for PHEMA in the low and high θ regimes. However, in the middle θ regime, the antifouling performance of PHEMA is close to or better than that of PCBMA. This is attributed to the formation of a dense layer of PHEMA on the graphene surface that inhibits direct adsorption of analogue molecules on graphene. The charged analogues do not bind to either the PHEMA or PCBMA brush irrespective of θ.
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Affiliation(s)
- Takuma Yagasaki
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
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6
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Johnson EC, Varlas S, Norvilaite O, Neal TJ, Brotherton EE, Sanderson G, Leggett GJ, Armes SP. Adsorption of Aldehyde-Functional Diblock Copolymer Spheres onto Surface-Grafted Polymer Brushes via Dynamic Covalent Chemistry Enables Friction Modification. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:6109-6122. [PMID: 37576584 PMCID: PMC10413866 DOI: 10.1021/acs.chemmater.3c01227] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/05/2023] [Indexed: 08/15/2023]
Abstract
Dynamic covalent chemistry has been exploited to prepare numerous examples of adaptable polymeric materials that exhibit unique properties. Herein, the chemical adsorption of aldehyde-functional diblock copolymer spherical nanoparticles onto amine-functionalized surface-grafted polymer brushes via dynamic Schiff base chemistry is demonstrated. Initially, a series of cis-diol-functional sterically-stabilized spheres of 30-250 nm diameter were prepared via reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization. The pendent cis-diol groups within the steric stabilizer chains of these precursor nanoparticles were then oxidized using sodium periodate to produce the corresponding aldehyde-functional spheres. Similarly, hydrophilic cis-diol-functionalized methacrylic brushes grafted from a planar silicon surface using activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) were selectively oxidized to generate the corresponding aldehyde-functional brushes. Ellipsometry and X-ray photoelectron spectroscopy were used to confirm brush oxidation, while scanning electron microscopy studies demonstrated that the nanoparticles did not adsorb onto a cis-diol-functional precursor brush. Subsequently, the aldehyde-functional brushes were treated with excess small-molecule diamine, and the resulting imine linkages were converted into secondary amine bonds via reductive amination. The resulting primary amine-functionalized brushes formed multiple dynamic imine bonds with the aldehyde-functional diblock copolymer spheres, leading to a mean surface coverage of approximately 0.33 on the upper brush layer surface, regardless of the nanoparticle size. Friction force microscopy studies of the resulting nanoparticle-decorated brushes enabled calculation of friction coefficients, which were compared to that measured for the bare aldehyde-functional brush. Friction coefficients were reasonably consistent across all surfaces except when particle size was comparable to the size of the probe tip. In this case, differences were ascribed to an increase in contact area between the tip and the brush-nanoparticle layer. This new model system enhances our understanding of nanoparticle adsorption onto hydrophilic brush layers.
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Affiliation(s)
- Edwin C. Johnson
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Spyridon Varlas
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Oleta Norvilaite
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Thomas J. Neal
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Emma E. Brotherton
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | | | - Graham J. Leggett
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Steven P. Armes
- Department
of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
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7
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Hanssen KØ, Malthe-Sørenssen A. Perineuronal nets restrict transport near the neuron surface: A coarse-grained molecular dynamics study. Front Comput Neurosci 2022; 16:967735. [DOI: 10.3389/fncom.2022.967735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/02/2022] [Indexed: 11/18/2022] Open
Abstract
Perineuronal nets (PNNs) are mesh-like extracellular matrix structures that wrap around certain neurons in the central nervous system. They are hypothesized to stabilize memories in the brain and act as a barrier between cell and extracellular space. As a means to study the impact of PNNs on diffusion, the nets were approximated by negatively charged polymer brushes and simulated by coarse-grained molecular dynamics. Diffusion constants of single neutral and single charged particles were obtained in directions parallel and perpendicular to the brush substrate. The results for the neutral particle were compared to different theories of diffusion in a heuristic manner. Diffusion was found to be considerably reduced for brush spacings smaller than 10 nm, with a pronounced anisotropy for dense brushes. The exact dynamics of the chains was found to have a negligible impact on particle diffusion. The resistance of the brush proved small compared to typical values of the membrane resistance of a neuron, indicating that PNNs likely contribute little to the total resistance of an enwrapped neuron.
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8
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Yagasaki T, Matubayasi N. Molecular dynamics study of the interactions between a hydrophilic polymer brush on graphene and amino acid side chain analogues in water. Phys Chem Chem Phys 2022; 24:22877-22888. [PMID: 36124732 DOI: 10.1039/d2cp03112d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We perform all-atom molecular dynamics simulations of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in aqueous solutions of isobutane, propionamide, and sodium propionate. These solutes are side chain analogues to leucine, glutamine, and glutamic acid, respectively. We compute the Gibbs energy profile of the solute's adsorption to the polymer brush and decompose it into the contributions from the steric repulsion, van der Waals interaction, and Coulomb interaction to reveal the energetic origin of repulsion or attraction of the solute by the polymer brush. The Henry adsorption constant is the amount of adsorption normalized by the concentration in aqueous solution. We examine the dependence of this quantity on the grafting density and chain length. Our results suggest that the concurrent primary and ternary adsorption mechanism may be more important than previously expected when the solute is hydrophobic.
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Affiliation(s)
- Takuma Yagasaki
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
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9
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Etha SA, Pial TH, Das S. Extensive Stable Physical Contacts between a Nanoparticle and a Highly Repulsive Polymeric Layer. J Phys Chem B 2022; 126:5715-5725. [PMID: 35867556 DOI: 10.1021/acs.jpcb.2c04010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interaction between nanoparticles (NPs) and a layer of grafted and solvated polymer molecules has been widely explored for a variety of applications ranging from fabrication of nanocomposites and sensors to developing nanocoating for virus deactivation. In all of these applications, the solvated polymer molecules are necessarily philic to the NPs, and consequently, driven by the favorable NP-polymer interactions, there is the formation of numerous stable direct (i.e., without any intervening solvent molecule) NP-monomer (monomer of the polymer) contact pairs. In this paper, we propose a paradigm shift in this problem: we employ molecular dynamics (MD) simulations and establish that under appropriate conditions, it is possible to develop numerous stable direct contacts between a NP and a solvated polymer layer even when the polymer molecules are extremely phobic to the NP. Here, by "stable" contacts, we refer to the NP-Polymer contacts that remain intact for a finite duration of time; of course, such contacts, after being intact for a finite time duration, might get broken and reformed. In terms of the mechanism of the process, the NP is driven inside a grafted layer of collapsed (in the absence of solvent) and phobic (to the NP) polymer molecules by a liquid drop (polymer is philic to the liquid). Subsequently, the liquid molecules imbibe and diffuse inside the polymer layer, but the NPs, due to the large steric effect imposed by the polymer molecules, remain localized within the polymer layer. This ensures the establishment of several stable direct contacts between the NP and the highly phobic polymer molecules. We quantify these contacts by their numbers, stability, and frequency of occurrences as well as their dependences on the NP-polymer interaction energies and NP sizes. We also quantify the associated NP dynamics inside the polymeric layer. Finally, we argue that our finding will open up avenues for leveraging NP-polymer interactions for a myriad of applications even for cases where the polymer molecules are phobic to the NPs.
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Affiliation(s)
- Sai Ankit Etha
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Turash Haque Pial
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
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10
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Ritsema van Eck G, Chiappisi L, de Beer S. Fundamentals and Applications of Polymer Brushes in Air. ACS APPLIED POLYMER MATERIALS 2022; 4:3062-3087. [PMID: 35601464 PMCID: PMC9112284 DOI: 10.1021/acsapm.1c01615] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/03/2022] [Indexed: 05/22/2023]
Abstract
For several decades, high-density, end-tethered polymers, forming so-called polymer brushes, have inspired scientists to understand their properties and to translate them to applications. While earlier research focused on polymer brushes in liquids, it was recently recognized that these brushes can find application in air as well. In this review, we report on recent progress in unraveling fundamental concepts of brushes in air, such as their vapor-swelling and solvent partitioning. Moreover, we provide an overview of the plethora of applications in air (e.g., in sensing, separations or smart adhesives) where brushes can be key components. To conclude, we provide an outlook by identifying open questions and issues that, when solved, will pave the way for the large scale application of brushes in air.
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Affiliation(s)
- Guido
C. Ritsema van Eck
- Sustainable
Polymer Chemistry Group, Department of Molecules & Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Leonardo Chiappisi
- Institut
Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Sissi de Beer
- Sustainable
Polymer Chemistry Group, Department of Molecules & Materials,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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11
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Durmaz EN, Sahin S, Virga E, de Beer S, de Smet LCPM, de Vos WM. Polyelectrolytes as Building Blocks for Next-Generation Membranes with Advanced Functionalities. ACS APPLIED POLYMER MATERIALS 2021; 3:4347-4374. [PMID: 34541543 PMCID: PMC8438666 DOI: 10.1021/acsapm.1c00654] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/10/2021] [Indexed: 05/06/2023]
Abstract
The global society is in a transition, where dealing with climate change and water scarcity are important challenges. More efficient separations of chemical species are essential to reduce energy consumption and to provide more reliable access to clean water. Here, membranes with advanced functionalities that go beyond standard separation properties can play a key role. This includes relevant functionalities, such as stimuli-responsiveness, fouling control, stability, specific selectivity, sustainability, and antimicrobial activity. Polyelectrolytes and their complexes are an especially promising system to provide advanced membrane functionalities. Here, we have reviewed recent work where advanced membrane properties stem directly from the material properties provided by polyelectrolytes. This work highlights the versatility of polyelectrolyte-based membrane modifications, where polyelectrolytes are not only applied as single layers, including brushes, but also as more complex polyelectrolyte multilayers on both porous membrane supports and dense membranes. Moreover, free-standing membranes can also be produced completely from aqueous polyelectrolyte solutions allowing much more sustainable approaches to membrane fabrication. The Review demonstrates the promise that polyelectrolytes and their complexes hold for next-generation membranes with advanced properties, while it also provides a clear outlook on the future of this promising field.
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Affiliation(s)
- Elif Nur Durmaz
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
| | - Sevil Sahin
- Laboratory
of Organic Chemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Ettore Virga
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
- Wetsus, European
Centre of Excellence for Sustainable Water
Technology, Oostergoweg
9, 8911 MA Leeuwarden, The Netherlands
| | - Sissi de Beer
- Sustainable
Polymer Chemistry Group, Department of Molecules and Materials MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Louis C. P. M. de Smet
- Laboratory
of Organic Chemistry, Wageningen University, 6708 WE Wageningen, The Netherlands
| | - Wiebe M. de Vos
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, Faculty
of Science and Technology, University of
Twente, Enschede 7500 AE, The Netherlands
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12
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Nourbakhsh S, Yu L, Ha BY. Modeling the Protective Role of Bacterial Lipopolysaccharides against Membrane-Rupturing Peptides. J Phys Chem B 2021; 125:8839-8854. [PMID: 34319722 DOI: 10.1021/acs.jpcb.1c02330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipopolysaccharide (LPS) is a key surface component of Gram-negative bacteria, populating the outer layer of their outer membrane. A number of experimental studies highlight its protective role against harmful molecules such as antibiotics and antimicrobial peptides (AMPs). In this work, we present a theoretical model for describing the interaction between LPS and cationic antimicrobial peptides, which combines the following two key features. The polysaccharide part is viewed as forming a polymer brush, exerting an osmotic pressure on inclusions such as antimicrobial peptides. The charged groups on LPS (those in lipid A and the two Kdo groups in the inner core) form electrostatic binding sites for cationic AMPs or cations. Using the resulting model, we offer a quantitative picture of how the brush component enhances the protective role of LPS against magainin-like peptides, in the presence of divalent cations such as Mg2+. The LPS brush tends to diminish the interfacial binding of the peptides, at the lipid headgroup region, by about 30%. In the presence of 5 mM of Mg2+, the interfacial binding does not reach a threshold value for wild-type LPS, beyond which the LPS layer is ruptured, even though it does for LPS Re (the simplest form of LPS, lacking the brush part), as long as [AMP] ≤ 20 μM, where [AMP] is the concentration of AMPs. At a low concentration of Mg2+ (≈1 mM), however, a smaller [AMP] value (≳2 μM) is needed to reach the threshold coverage for wild-type LPS. Our results also suggest that the interfacial binding of peptides is insensitive to their possible weak interaction with the surrounding brush chains.
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Affiliation(s)
- Shokoofeh Nourbakhsh
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Liu Yu
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Bae-Yeun Ha
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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13
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Andersson J, Ferrand-Drake del Castillo G, Bilotto P, Höök F, Valtiner M, Dahlin A. Control of Polymer Brush Morphology, Rheology, and Protein Repulsion by Hydrogen Bond Complexation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4943-4952. [PMID: 33851532 PMCID: PMC8154870 DOI: 10.1021/acs.langmuir.1c00271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/02/2021] [Indexed: 06/12/2023]
Abstract
Polymer brushes are widely used to alter the properties of interfaces. In particular, poly(ethylene glycol) (PEG) and similar polymers can make surfaces inert toward biomolecular adsorption. Neutral hydrophilic brushes are normally considered to have static properties at a given temperature. As an example, PEG is not responsive to pH or ionic strength. Here we show that, by simply introducing a polymeric acid such as poly(methacrylic acid) (PMAA), the highly hydrated brush barrier can change its properties entirely. This is caused by multivalent hydrogen bonds in an extremely pH-sensitive process. Remarkably, it is sufficient to reduce the pH to 5 for complexation to occur at the interface, which is two units higher than in the corresponding bulk systems. Below this critical pH, PMAA starts to bind to PEG in large amounts (comparable to the PEG amount), causing the brush to gradually compact and dehydrate. The brush also undergoes major rheology changes, from viscoelastic to rigid. Furthermore, the protein repelling ability of PEG is lost after reaching a threshold in the amount of PMAA bound. The changes in brush properties are tunable and become more pronounced when more PMAA is bound. The initial brush state is fully recovered when releasing PMAA by returning to physiological pH. Our findings are relevant for many applications involving functional interfaces, such as capture-release of biomolecules.
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Affiliation(s)
- John Andersson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, 41296 Gothenburg, Sweden
| | | | - Pierluigi Bilotto
- Institute
of Applied Physics, Group of Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Fredrik Höök
- Department
of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Markus Valtiner
- Institute
of Applied Physics, Group of Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria
| | - Andreas Dahlin
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, 41296 Gothenburg, Sweden
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14
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Yu Y, Brió Pérez M, Cao C, de Beer S. Switching (bio-) adhesion and friction in liquid by stimulus responsive polymer coatings. Eur Polym J 2021. [DOI: 10.1016/j.eurpolymj.2021.110298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Mensink LIS, de Beer S, Snoeijer JH. The role of entropy in wetting of polymer brushes. SOFT MATTER 2021; 17:1368-1375. [PMID: 33325963 DOI: 10.1039/d0sm00156b] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The wetting of polymer brushes exhibits a much richer phenomenology than wetting of normal solid substrates. These brushes allow for three wetting states, which are partial wetting, complete wetting and mixing. Here, we study the transitions between these wetting states for brushes in contact with polymer melts and compare them to predictions using enthalpic arguments based on brush and melt interactions. We show that the transitions are shifted compared to the enthalpic predictions and that the shifts can be positive or negative depending on the length of the melt polymer and the brush grafting density. The reason for this is that these brush and melt parameters can have a positive or negative effect on the entropic contribution to the free energy of the system. Our results highlight the relevance of entropy in predicting the exact wetting transitions, which is important for the design of brush-based coating applications.
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Affiliation(s)
- Liz I S Mensink
- Physics of Fluids and the MESA+ Institute, University of Twente, PO box 217, 7500 AE Enschede, The Netherlands
| | - Sissi de Beer
- Sustainable Polymer Chemistry and the MESA+ Institute, University of Twente, PO box 217, 7500 AE Enschede, The Netherlands.
| | - Jacco H Snoeijer
- Physics of Fluids and the MESA+ Institute, University of Twente, PO box 217, 7500 AE Enschede, The Netherlands
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16
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Nakamura S, Mitomo H, Ijiro K. Assembly and Active Control of Nanoparticles using Polymer Brushes as a Scaffold. CHEM LETT 2021. [DOI: 10.1246/cl.200767] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Satoshi Nakamura
- National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya, Aichi 463-8560, Japan
| | - Hideyuki Mitomo
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
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17
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Spencer RKW, Ha BY. How a Polymer Brush Interacts with Inclusions and Alters Their Interaction. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Russell K. W. Spencer
- Department of Physics & Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Bae-Yeun Ha
- Department of Physics & Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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18
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Hassanpour F, Jalili K, Behboodpour L, Afkhami A. Microstructural Capture of Living Ultrathin Polymer Brush Evolution via Kinetic Simulation Studies. J Phys Chem B 2020; 124:9438-9455. [PMID: 32935990 DOI: 10.1021/acs.jpcb.0c04890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Performing dynamic off-lattice multicanonical Monte Carlo simulations, we study the statics, dynamics, and scission-recombination kinetics of a self-assembled in situ-polymerized polydisperse living polymer brush (LPB), designed by surface-initiated living polymerization. The living brush is initially grown from a two-dimensional substrate by end-monomer polymerization-depolymerization reactions through seeding of initiator arrays on the grafting plane which come in contact with a solution of nonbonded monomers under good solvent conditions. The polydispersity is shown to significantly deviate from the Flory-Schulz type for low temperatures because of pronounced diffusion limitation effects on the rate of the equilibration reaction. The self-avoiding chains take up fairly compact structures of typical size Rg(N) ∼ Nν in rigorously two-dimensional (d = 2) melt, with ν being the inverse fractal dimension (ν = 1/d). The Kratky description of the intramolecular structure factor F(q), in keeping with the concept of generalized Porod scattering from compact particles with fractal contour, discloses a robust nonmonotonic fashion with qdF(q) ∼ (qRg)-3/4 in the intermediate-q regime. It is found that the kinetics of LPB growth, given by the variation of the mean chain length, follows a power law ⟨N(t)⟩ ∝ t1/3 with elapsed time after the onset of polymerization, whereby the instantaneous molecular weight distribution (MWD) of the chains c(N) retains its functional form. The variation of ⟨N(t)⟩ during quenches of the LPB to different temperatures T can be described by a single master curve in units of dimensionless time t/τ∞, where τ∞ is the typical (final temperature T∞-dependent) relaxation time which is found to scale as τ∞ ∝ ⟨N(t = ∞)⟩5 with the ultimate average length of the chains. The equilibrium monomer density profile ϕ(z) of the LPB varies as ϕ(z) ∝ ϕ-α with the concentration of segments ϕ in the system and the probability distribution c(N) of chain lengths N in the brush layer scales as c(N) ∝ N-τ. The computed exponents α ≈ 0.64 and τ ≈ 1.70 are in good agreement with those predicted within the context of the Diffusion-Limited Aggregation theory, α = 2/3 and τ = 7/4.
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Affiliation(s)
- Fatemeh Hassanpour
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Kiyumars Jalili
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Leila Behboodpour
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
| | - Ali Afkhami
- Department of Polymer Engineering, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran.,Institute of Polymeric Materials, Sahand University of Technology, New Town of Sahand, 5331817634 Tabriz, Iran
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19
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Nakamura S, Mitomo H, Sekizawa Y, Higuchi T, Matsuo Y, Jinnai H, Ijiro K. Strategy for Finely Aligned Gold Nanorod Arrays Using Polymer Brushes as a Template. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3590-3599. [PMID: 32049537 DOI: 10.1021/acs.langmuir.9b03835] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The development of a strategy for the assembly of nanoscale building blocks, in particular, anisotropic nanoparticles, into desired structures is important for the construction of functional materials and devices. However, control over the orientation of rod-shaped nanoparticles on a substrate for integration into solid-state devices remains challenging. Here, we report a strategy for the fabrication of finely aligned gold nanorod (GNR) arrays using polymer (DNA) brushes as a nanoscale template. The gold nanorods modified with cationic surface ligands were electrostatically adsorbed onto the DNA brush substrates under various conditions. The orientational behavior of the GNRs was examined by spectral analyses and transmission electron microtomography (TEMT). As a result, we found several important factors, such as moderate interaction between GNRs and polymers and polymer densities on the substrate, related to the vertical alignment of GNRs on the substrates. We also developed a purification method to remove the undesired adsorption of GNRs onto the arrays. Finally, we have succeeded in the fabrication of extensive vertical GNR arrays of high quality via the easy bottom-up process.
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Affiliation(s)
- Satoshi Nakamura
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-Ku, Sapporo 060-8628, Japan
| | - Hideyuki Mitomo
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-Ku, Sapporo 001-0021, Japan
| | - Yu Sekizawa
- Graduate School of Life Sciences, Hokkaido University, Kita 10, Nishi 8, Kita-Ku, Sapporo 060-0810, Japan
| | - Takeshi Higuchi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Yasutaka Matsuo
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
| | - Hiroshi Jinnai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University, Kita 21, Nishi 10, Kita-Ku, Sapporo 001-0021, Japan
- Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Kita 21, Nishi 11, Kita-Ku, Sapporo 001-0021, Japan
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20
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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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21
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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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22
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Mensink LI, Snoeijer JH, de Beer S. Wetting of Polymer Brushes by Polymeric Nanodroplets. Macromolecules 2019; 52:2015-2020. [PMID: 30894780 PMCID: PMC6416710 DOI: 10.1021/acs.macromol.8b02409] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/13/2019] [Indexed: 01/30/2023]
Abstract
End-anchoring polymers to a solid surface to form so-called polymer brushes is a versatile method to prepare robust functional coatings. We show, using molecular dynamics simulations, that these coatings display rich wetting behavior. Depending on the interaction between the brushes and the polymeric droplets as well as on the self-affinity of the brush, we can distinguish between three wetting states: mixing, complete wetting, and partial wetting. We find that transitions between these states are largely captured by enthalpic arguments, while deviations to these can be attributed to the negative excess interfacial entropy for the brush droplet system. Interestingly, we observe that the contact angle strongly increases when the softness of the brush is increased, which is opposite to the case of drops on soft elastomers. Hence, the Young to Neumann transition owing to softness is not universal but depends on the nature of the substrate.
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Affiliation(s)
- Liz I.
S. Mensink
- Physics
of Fluids, MESA+ Institute for Nanotechnology, and Materials Science
and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jacco H. Snoeijer
- Physics
of Fluids, MESA+ Institute for Nanotechnology, and Materials Science
and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Sissi de Beer
- Physics
of Fluids, MESA+ Institute for Nanotechnology, and Materials Science
and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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23
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Bos I, Merlitz H, Rosenthal A, Uhlmann P, Sommer JU. Design of binary polymer brushes with tuneable functionality. SOFT MATTER 2018; 14:7237-7245. [PMID: 30132780 DOI: 10.1039/c8sm01108g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Using coarse grained molecular dynamics simulations, we study how functionalized binary brushes may be used to create surfaces whose functionality can be tuned. Our model brushes consist of a mixture of nonresponsive polymers with functionalized responsive polymers. The functional groups switch from an exposed to a hidden state when the conformations of the responsive polymers change from extended to collapsed. We investigate quantitatively which sets of brush parameters result in optimal switching in functionality, by analyzing to which extent the brush conformation allows an external object to interact with the functional groups. It is demonstrated that brushes with species of comparable polymer lengths, or with longer responsive polymers than nonresponsive polymers, can show significant differences in their functionality. In the latter case, either the fraction of responsive polymers or the total grafting density has to be reduced. Among these possibilities, a reduction of the fraction of responsive polymers is shown to be most effective.
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Affiliation(s)
- Inge Bos
- Physical Chemistry and Soft Matter, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
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24
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Li CW, Merlitz H, Wu CX, Sommer JU. Nanopores as Switchable Gates for Nanoparticles: A Molecular Dynamics Study. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Cheng-Wu Li
- Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Department of Physics, Xiamen University, Xiamen 361005, China
| | - Holger Merlitz
- Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany
| | - Chen-Xu Wu
- Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Department of Physics, Xiamen University, Xiamen 361005, China
| | - Jens-Uwe Sommer
- Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany
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25
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Gu C, Coalson RD, Jasnow D, Zilman A. Free Energy of Nanoparticle Binding to Multivalent Polymeric Substrates. J Phys Chem B 2017. [DOI: 10.1021/acs.jpcb.7b00868] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chad Gu
- Department
of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
| | - Rob D. Coalson
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - David Jasnow
- Department
of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Anton Zilman
- Department
of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
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26
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Yu Y, Lopez de la Cruz RA, Kieviet BD, Gojzewski H, Pons A, Julius Vancso G, de Beer S. Pick up, move and release of nanoparticles utilizing co-non-solvency of PNIPAM brushes. NANOSCALE 2017; 9:1670-1675. [PMID: 28084477 DOI: 10.1039/c6nr09245d] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A critical complication in handling nanoparticles is the formation of large aggregates when particles are dried e.g. when they need to be transferred from one liquid to another. The particles in these aggregates need to disperse into the destined liquid medium, which has been proven difficult due to the relatively large interfacial interaction forces between nanoparticles. We present a simple method to capture, move and release nanoparticles without the formation of large aggregates. To do so, we employ the co-non-solvency effect of poly(N-isopropylacrylamide) (PNIPAM) brushes in water-ethanol mixtures. In pure water or ethanol, the densely end-anchored macromolecules in the PNIPAM brush stretch and absorb the solvent. We show that under these conditions, the adherence between the PNIPAM brush and a silicon oxide, gold, polystyrene or poly(methyl methacrylate) colloid attached to an atomic force microscopy cantilever is low. In contrast, when the PNIPAM brushes are in a collapsed state in a 30-70 vol% ethanol-water mixture, the adhesion between the brush and the different counter surfaces is high. For potential application, we demonstrate that this difference in adhesion can be utilized to pick up, move and release 900 silicon oxide nanoparticles of diameter 80 nm using only 10 × 10 μm2 PNIPAM brush.
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Affiliation(s)
- Yunlong Yu
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
| | - Ricardo A Lopez de la Cruz
- Physics of Fluids, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands
| | - Bernard D Kieviet
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
| | - Hubert Gojzewski
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
| | - Adeline Pons
- Physics of Fluids, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands
| | - G Julius Vancso
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
| | - Sissi de Beer
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.
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