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Funari R, Matsumoto A, de Bruyn JR, Shen AQ. Rheology of the Electric Double Layer in Electrolyte Solutions. Anal Chem 2020; 92:8244-8253. [DOI: 10.1021/acs.analchem.0c00475] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Riccardo Funari
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Atsushi Matsumoto
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - John R. de Bruyn
- Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Amy Q. Shen
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
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van Duinen D, Butt HJ, Berger R. Two-Stage Collapse of PNIPAM Brushes: Viscoelastic Changes Revealed by an Interferometric Laser Technique. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15776-15783. [PMID: 31633361 PMCID: PMC6943814 DOI: 10.1021/acs.langmuir.9b03205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 10/21/2019] [Indexed: 06/10/2023]
Abstract
Many temperature-responsive polymers exhibit a single-phase transition at the lower critical solution temperature (LCST). One exception is poly(N-isopropylacryamide) (PNIPAM). PNIPAM brush layers (51 ± 3 nm thick) that are end-grafted onto glass beads collapse in two stages. The viscoelastic changes of a PNIPAM brush layers were investigated with an interferometric laser method at different temperatures. This method is able to measure the two-stage collapse of beads coated with a polymer brush layer. When these beads are situated close to a hydrophilic glass surface, they exhibit Brownian motion. As this Brownian motion changes with temperature, the collapse of the polymer layer is revealed. The characteristic spectrum of the Brownian motion of beads is modeled by a damped harmonic oscillator, where the polymer layer acts as both spring and damping elements. The change of the Brownian motion spectrum with temperature indicates two transitions of the PNIPAM brush layer, one at 36 °C and one at 46 °C. We attribute the first transition to the LCST volume collapse of PNIPAM. Here, changes of the density and viscosity of the brush dominate. The second transition is dominated by a stiffening of the brush layer.
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Parveen N, Jana PK, Schönhoff M. Viscoelastic Properties of Polyelectrolyte Multilayers Swollen with Ionic Liquid Solutions. Polymers (Basel) 2019; 11:E1285. [PMID: 31374899 PMCID: PMC6722675 DOI: 10.3390/polym11081285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 11/16/2022] Open
Abstract
Polyelectrolyte multilayers (PEM) obtained by layer-by-layer assembly can be doped with ionic liquid (IL) via the swelling of the films with IL solutions. In order to examine the mechanical properties of IL-containing PEM, we implement a Kelvin-Voigt model to obtain thickness, viscosity and elastic modulus from the frequency and dissipation shifts determined by a dissipative quartz crystal microbalance (QCM-D). We analyze the changes in the modeled thickness and viscoelasticity of PEI(PSS/PADMAC)4PSS and PEI(PSS/PAH)4PSS multilayers upon swelling by increasing the concentration of either 1-Ethyl-3-methylimidazolium chloride or 1-Hexyl-3-methylimidazolium chloride, which are water soluble ILs. The results show that the thickness of the multilayers changes monotonically up to a certain IL concentration, whereas the viscosity and elasticity change in a non-monotonic fashion with an increasing IL concentration. The changes in the modeled parameters can be divided into three concentration regimes of IL, a behavior specific to ILs (organic salts), which does not occur with swelling by simple inorganic salts such as NaCl. The existence of the regimes is attributed to a competition of the hydrophobic interactions of large hydrophobic ions, which enhance the layer stability at a low salt content, with the electrostatic screening, which dominates at a higher salt content and causes a film softening.
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Affiliation(s)
- Nagma Parveen
- Institute of Physical Chemistry, University of Muenster, 48149 Münster, Germany.
- NRW Graduate School of Chemistry, University of Muenster, 48149 Münster, Germany.
| | - Pritam Kumar Jana
- Interdisciplinary Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Monika Schönhoff
- Institute of Physical Chemistry, University of Muenster, 48149 Münster, Germany.
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Backes S, Von Klitzing R. Nanomechanics and Nanorheology of Microgels at Interfaces. Polymers (Basel) 2018; 10:E978. [PMID: 30960903 PMCID: PMC6404016 DOI: 10.3390/polym10090978] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/19/2018] [Accepted: 08/20/2018] [Indexed: 11/16/2022] Open
Abstract
The review addresses nanomechanics and nanorheology of stimuli responsive microgels adsorbed at an interface. In order to measure the mechanical properties on a local scale, an atomic force microscope is used. The tip presents an indenter with a radius of curvature of a few 10 s of nm. Static indentation experiments and dynamic studies with an excited cantilever are presented. The effect of several internal and external parameters on the mechanical properties is reviewed. The focus is on the correlation between the swelling abilities of the gels and their mechanical properties. Several results are surprising and show that the relationship is not as simple as one might expect.
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Affiliation(s)
- Sebastian Backes
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, D⁻10623 Berlin, Germany.
| | - Regine Von Klitzing
- Soft Matter at Interfaces, Department of Physics, TU Darmstadt, Alarich-Weiss-Strasse 10, D⁻62487 Darmstadt, Germany.
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Backes S, Krause P, Tabaka W, Witt MU, von Klitzing R. Combined Cononsolvency and Temperature Effects on Adsorbed PNIPAM Microgels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14269-14277. [PMID: 29166032 DOI: 10.1021/acs.langmuir.7b02903] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The present study addresses the multiresponsive behavior of poly(N-isopropylacrylamide) (PNIPAM) microgels adsorbed to interfaces. The microgels react to changes in temperature by shrinking in aqueous solution above their volume phase transition temperature (VPTT). Additionally, they shrink in mixtures of water and ethanol, although both individual liquids are good solvents for PNIPAM. The combination of this so-called cononsolvency effect and the temperature response of adsorbed microgels is studied by atomic force microscopy (AFM). Adsorbed microgels are of special interest because they are compressed considerably compared to those in bulk solution. It is shown that the impact of adsorption on swelling depends on the specific surface details, as well as the sample preparation. Thereby, the microgels are deposited on two different kinds of surfaces: on gold surface and on polycation (PAH) coating which show different interactions with the microgels in terms of electrostatic interaction and wettability. In addition, the microgels were deposited from different solvent mixtures. This influences the microgel structure and thereby the swelling properties. Nanorheology studies by dynamic AFM measurements lead to surprising results which are explained by the fact that not only polymer density but a subtle interaction between polymer and solvent might dominate the rheological properties. This work supports the view that preferential adsorption of ethanol at PNIPAM drives cononsolvency, while the shrinking at T > VPTT is caused by general breaking of hydrogen bonds between solvents and PNIPAM.
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Affiliation(s)
- Sebastian Backes
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut für Physik, Technische Universität Darmstadt , Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Patrick Krause
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17. Juni 124, 10623 Berlin, Germany
| | - Weronika Tabaka
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17. Juni 124, 10623 Berlin, Germany
| | - Marcus U Witt
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut für Physik, Technische Universität Darmstadt , Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Regine von Klitzing
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin , Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut für Physik, Technische Universität Darmstadt , Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
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Backes S, Krause P, Tabaka W, Witt MU, Mukherji D, Kremer K, von Klitzing R. Poly( N-isopropylacrylamide) Microgels under Alcoholic Intoxication: When a LCST Polymer Shows Swelling with Increasing Temperature. ACS Macro Lett 2017; 6:1042-1046. [PMID: 35650939 DOI: 10.1021/acsmacrolett.7b00557] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly(N-isopropylacrylamide) (PNIPAM) microgel is a smart polymer that shows a volume phase transition temperature (VPTT) at around 32 °C in aqueous solutions, above which it collapses. In this work, combining experiments and molecular simulations, it is shown that PNIPAM microgels do not always exhibit a collapsed structure above the VPTT. Instead, PNIPAM in aqueous alcohol mixtures shows a two-step conformational transition, i.e., a collapse at low temperatures (T < 32 °C) and a reswelling when T > 50 °C. The present analysis indicates that delicate microscopic interaction details, together with the bulk solution properties, play a key role in dictating the reswelling behavior. Even when PNIPAM microgels swell with increasing T, this is not a standard upper critical solution behavior.
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Affiliation(s)
- Sebastian Backes
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut
für Physik, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Patrick Krause
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany
| | - Weronika Tabaka
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany
| | - Marcus U. Witt
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut
für Physik, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
| | - Debashish Mukherji
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Kurt Kremer
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Regine von Klitzing
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany
- Institut
für Physik, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany
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Smith RJ, Moule MG, Sule P, Smith T, Cirillo JD, Grunlan JC. Polyelectrolyte Multilayer Nanocoating Dramatically Reduces Bacterial Adhesion to Polyester Fabric. ACS Biomater Sci Eng 2017; 3:1845-1852. [PMID: 29725614 PMCID: PMC5926799 DOI: 10.1021/acsbiomaterials.7b00250] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Bacterial adhesion to textiles is thought to contribute to odor and infection. Alternately exposing polyester fabric to aqueous solutions of poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA) is shown here to create a nanocoating that dramatically reduces bacterial adhesion. Ten PDDA/PAA bilayers (BL) are 180 nm thick and only increase the weight of the polyester by 2.5%. The increased surface roughness and high degree of PAA ionization leads to a surface with a negative charge that causes a reduction in adhesion of Staphylococcus aureus by 50% when compared to uncoated fabric, after rinsing with sterilized water, because of electrostatic repulsion. S. aureus bacterial adhesion was quantified using bioluminescent radiance measured before and after rinsing, revealing 99% of applied bacteria were removed with a ten bilayer PDDA/PAA nanocoating. The ease of processing, and benign nature of the polymers used, should make this technology useful for rendering textiles antifouling on an industrial scale.
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Affiliation(s)
- Ryan J. Smith
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Madeleine G. Moule
- Department of Microbial Pathogenesis and Immunology, Texas A&M College of Medicine, 8447 Riverside Parkway, Bryan, Texas 77807, United States
| | - Preeti Sule
- Department of Microbial Pathogenesis and Immunology, Texas A&M College of Medicine, 8447 Riverside Parkway, Bryan, Texas 77807, United States
| | - Travis Smith
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Jeffrey D. Cirillo
- Department of Microbial Pathogenesis and Immunology, Texas A&M College of Medicine, 8447 Riverside Parkway, Bryan, Texas 77807, United States
| | - Jaime C. Grunlan
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
- Department of Mechanical Engineering, Texas A&M University, 3123 TAMU, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, 3003 TAMU, College Station, Texas 77843, United States
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