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Ko CH, Wastian P, Schanzenbach D, Müller-Buschbaum P, Laschewsky A, Papadakis CM. Dynamic Behavior of Poly( N-isopropylmethacrylamide) in Neat Water and in Water/Methanol Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:15150-15160. [PMID: 38980191 PMCID: PMC11270994 DOI: 10.1021/acs.langmuir.4c01515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/05/2024] [Accepted: 07/02/2024] [Indexed: 07/10/2024]
Abstract
We investigate the collective dynamics of thermoresponsive polymer poly(N-isopropylmethacrylamide) (PNIPMAM) in aqueous solution and in water/methanol mixtures in the one-phase region. In neat water, the polymer concentration c is varied in a wide range around the overlap concentration c*, that is estimated at 23 g L-1. Using dynamic light scattering (DLS), two decays ("modes") are consistently observed in the intensity autocorrelation functions for c = 2-150 g L-1 with relaxation rates which are proportional to the square of the momentum transfer. Below c*, these are attributed to the diffusion of single chains and to clusters from PNIPMAM that are formed due to hydrophobic interactions. Above c*, they are assigned to the diffusion of the chain segments between overlap points and to long-range concentration fluctuations. From the temperature-dependent behavior of the overall scattering intensities and the dynamic correlation lengths of the fast mode, the critical temperatures and the scaling exponents are determined. The latter are significantly lower than the static values predicted by mean-field theory, which may be related to the presence of the large-scale inhomogeneities. The effect of the cosolvent methanol on the dynamics is investigated for polymer solutions having c = 30 g L-1 and methanol volume fractions in the solvent mixtures of up to 60 vol %. The phase diagram was established by differential scanning calorimetry. The slow mode detected by DLS becomes significantly weaker as methanol is added, i.e., the solutions become more homogeneous. Beyond the minimum of the coexistence line, which is located at 40-50 vol % of methanol, the dynamics is qualitatively different from the one at lower methanol contents. Thus, going from the water-rich to the methanol-rich side of the miscibility gap, the change of interaction of the PNIPMAM chains with the two solvents has a severe effect on the collective dynamics.
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Affiliation(s)
- Chia-Hsin Ko
- TUM
School of Natural Sciences, Physics Department, Soft Matter Physics
Group, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
| | - Patrick Wastian
- TUM
School of Natural Sciences, Physics Department, Soft Matter Physics
Group, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
| | - Dirk Schanzenbach
- Institut
für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
| | - Peter Müller-Buschbaum
- TUM
School of Natural Sciences, Physics Department, Chair for Functional
Materials, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
| | - André Laschewsky
- Institut
für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam-Golm, Germany
- Fraunhofer-Institut
für Angewandte Polymerforschung, Geiselbergstraße 69, 14476 Potsdam-Golm, Germany
| | - Christine M. Papadakis
- TUM
School of Natural Sciences, Physics Department, Soft Matter Physics
Group, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
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2
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Wang P, Geiger C, Kreuzer LP, Widmann T, Reitenbach J, Liang S, Cubitt R, Henschel C, Laschewsky A, Papadakis CM, Müller-Buschbaum P. Poly(sulfobetaine)-Based Diblock Copolymer Thin Films in Water/Acetone Atmosphere: Modulation of Water Hydration and Co-nonsolvency-Triggered Film Contraction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6934-6948. [PMID: 35609178 DOI: 10.1021/acs.langmuir.2c00451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The water swelling and subsequent solvent exchange including co-nonsolvency behavior of thin films of a doubly thermo-responsive diblock copolymer (DBC) are studied via spectral reflectance, time-of-flight neutron reflectometry, and Fourier transform infrared spectroscopy. The DBC consists of a thermo-responsive zwitterionic (poly(4-((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate)) (PSBP) block, featuring an upper critical solution temperature transition in aqueous media but being insoluble in acetone, and a nonionic poly(N-isopropylmethacrylamide) (PNIPMAM) block, featuring a lower critical solution temperature transition in water, while being soluble in acetone. Homogeneous DBC films of 50-100 nm thickness are first swollen in saturated water vapor (H2O or D2O), before they are subjected to a contraction process by exposure to mixed saturated water/acetone vapor (H2O or D2O/acetone-d6 = 9:1 v/v). The affinity of the DBC film toward H2O is stronger than for D2O, as inferred from the higher film thickness in the swollen state and the higher absorbed water content, thus revealing a pronounced isotope sensitivity. During the co-solvent-induced switching by mixed water/acetone vapor, a two-step film contraction is observed, which is attributed to the delayed expulsion of water molecules and uptake of acetone molecules. The swelling kinetics are compared for both mixed vapors (H2O/acetone-d6 and D2O/acetone-d6) and with those of the related homopolymer films. Moreover, the concomitant variations of the local environment around the hydrophilic groups located in the PSBP and PNIPMAM blocks are followed. The first contraction step turns out to be dominated by the behavior of the PSBP block, whereas the second one is dominated by the PNIPMAM block. The unusual swelling and contraction behavior of the latter block is attributed to its co-nonsolvency behavior. Furthermore, we observe cooperative hydration effects in the DBC films, that is, both polymer blocks influence each other's solvation behavior.
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Affiliation(s)
- Peixi Wang
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Christina Geiger
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Lucas P Kreuzer
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Tobias Widmann
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Julija Reitenbach
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Suzhe Liang
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Robert Cubitt
- Institut-Laue-Langevin, 6 rue Jules Horowitz, Grenoble 38000, France
| | - Cristiane Henschel
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Street 24-25, Potsdam-Golm 14476, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Street 24-25, Potsdam-Golm 14476, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselberg Street 69, Potsdam-Golm 14476, Germany
| | - Christine M Papadakis
- Fachgebiet Physik weicher Materie, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Street 1, Garching 85748, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenberg Street 1, Garching 85748, Germany
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Kreuzer LP, Geiger C, Widmann T, Wang P, Cubitt R, Hildebrand V, Laschewsky A, Papadakis CM, Müller-Buschbaum P. Solvation Behavior of Poly(sulfobetaine)-Based Diblock Copolymer Thin Films in Mixed Water/Methanol Vapors. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Lucas P. Kreuzer
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Christina Geiger
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Tobias Widmann
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Peixi Wang
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Robert Cubitt
- Institut Laue-Langevin, 6 rue Jules Horowitz, 38000 Grenoble, France
| | - Viet Hildebrand
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselbergstr. 69, 14476 Potsdam-Golm, Germany
| | - Christine M. Papadakis
- Fachgebiet Physik weicher Materie, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
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Kreuzer LP, Lindenmeir C, Geiger C, Widmann T, Hildebrand V, Laschewsky A, Papadakis CM, Müller-Buschbaum P. Poly(sulfobetaine) versus Poly( N-isopropylmethacrylamide): Co-Nonsolvency-Type Behavior of Thin Films in a Water/Methanol Atmosphere. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02281] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Lucas P. Kreuzer
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Christoph Lindenmeir
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Christina Geiger
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Tobias Widmann
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Viet Hildebrand
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - André Laschewsky
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
- Fraunhofer Institut für Angewandte Polymerforschung, Geiselbergstr. 69, 14476 Potsdam-Golm, Germany
| | - Christine M. Papadakis
- Fachgebiet Physik weicher Materie, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Lehrstuhl für Funktionelle Materialien, Physik Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany
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Hibi Y, Hesse SA, Yu F, Thedford RP, Wiesner U. Structural Evolution of Ternary Amphiphilic Block Copolymer Solvent Systems for Phase Inversion Membrane Formation. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00595] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yusuke Hibi
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Sarah A. Hesse
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Fei Yu
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - R. Paxton Thedford
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Ulrich Wiesner
- Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
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Velychkivska N, Starovoytova L, Březina V, Hanyková L, Hill JP, Labuta J. Improving the Colloidal Stability of Temperature-Sensitive Poly( N-isopropylacrylamide) Solutions Using Low Molecular Weight Hydrophobic Additives. ACS OMEGA 2018; 3:11865-11873. [PMID: 31459272 PMCID: PMC6645090 DOI: 10.1021/acsomega.8b01811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/11/2018] [Indexed: 06/10/2023]
Abstract
Poly(N-isopropylacrylamide) (PNIPAM) is an important polymer with stimuli-responsive properties, making it suitable for various uses. Phase behavior of the temperature-sensitive PNIPAM polymer in the presence of four low-molecular weight additives tert-butylamine (t-BuAM), tert-butyl alcohol (t-BuOH), tert-butyl methyl ether (t-BuME), and tert-butyl methyl ketone (t-BuMK) was studied in water (D2O) using high-resolution nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering. Phase separation was thermodynamically modeled as a two-state process which resulted in a simple curve which can be used for fitting of NMR data and obtaining all important thermodynamic parameters using simple formulas presented in this paper. The model is based on a modified van't Hoff equation. Phase separation temperatures T p and thermodynamic parameters (enthalpy and entropy change) connected with the phase separation of PNIPAM were obtained using this method. It was determined that T p is dependent on additives in the following order: T p(t-BuAM) > T p(t-BuOH) > T p(t-BuME) > T p(t-BuMK). Also, either increasing the additive concentration or increasing pK a of the additive leads to depression of T p. Time-resolved 1H NMR spin-spin relaxation experiments (T 2) performed above the phase separation temperature of PNIPAM revealed high colloidal stability of the phase-separated polymer induced by the additives (relative to the neat PNIPAM/D2O system). Small quantities of selected suitable additives can be used to optimize the properties of PNIPAM preparations including their phase separation temperatures, colloidal stabilities, and morphologies, thus improving the prospects for the application.
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Affiliation(s)
- Nadiia Velychkivska
- Department
of NMR Spectroscopy, Institute of Macromolecular
Chemistry AS CR, v.v.i., Heyrovsky Sq. 2, Prague 6 162 06, Czech Republic
| | - Larisa Starovoytova
- Department
of NMR Spectroscopy, Institute of Macromolecular
Chemistry AS CR, v.v.i., Heyrovsky Sq. 2, Prague 6 162 06, Czech Republic
| | - Václav Březina
- Faculty
of Mathematics and Physics, Department of Macromolecular Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Lenka Hanyková
- Faculty
of Mathematics and Physics, Department of Macromolecular Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Jonathan P. Hill
- National
Institute for Materials Science (NIMS), International Center for Materials
Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Jan Labuta
- National
Institute for Materials Science (NIMS), International Center for Materials
Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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7
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Dong Q, Qian M, Luo C. Phase separation behavior and fluorescence properties of poly(N-isopropylacrylamide) with chalcone side groups in mixed solvents. JOURNAL OF POLYMER RESEARCH 2016. [DOI: 10.1007/s10965-016-0923-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Characterization of free, restricted, and entrapped water environments in poly(N
-isopropyl acrylamide) hydrogels via 1
H HRMAS PFG NMR spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/polb.23591] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Spěváček J, Dybal J. Temperature-Induced Phase Separation and Hydration in Aqueous Polymer Solutions Studied by NMR and IR Spectroscopy: Comparison of Poly(N-vinylcaprolactam) and Acrylamide-Based Polymers. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/masy.201300002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jiří Spěváček
- Institute of Macromolecular Chemistry; Academy of Sciences of the Czech Republic; Heyrovsky Sq. 2 162 06 Prague 6 Czech Republic
| | - Jiří Dybal
- Institute of Macromolecular Chemistry; Academy of Sciences of the Czech Republic; Heyrovsky Sq. 2 162 06 Prague 6 Czech Republic
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Temperature-induced phase transition in hydrogels of interpenetrating networks poly(N-isopropylmethacrylamide)/poly(N-isopropylacrylamide). Colloid Polym Sci 2013. [DOI: 10.1007/s00396-013-2992-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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1H NMR study of temperature-induced phase transitions in aqueous solutions of poly(N-isopropylmethacrylamide)/poly(N-vinylcaprolactam) mixtures. Polym Bull (Berl) 2012. [DOI: 10.1007/s00289-012-0831-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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NMR and DSC study of temperature-induced phase transition in aqueous solutions of poly(N-isopropylmethacrylamide-co-acrylamide) copolymers. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2701-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Spěváček J. NMR Investigations of Temperature-Induced Phase Transition in Aqueous Polymer Solutions. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.201000107] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Spěváček J, Hanyková L, Labuta J. Behavior of Water during Temperature-Induced Phase Separation in Poly(vinyl methyl ether) Aqueous Solutions. NMR and Optical Microscopy Study. Macromolecules 2011. [DOI: 10.1021/ma200010h] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiří Spěváček
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic,
| | - Lenka Hanyková
- Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Jan Labuta
- Supermolecules Group, WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Van Assche G, Van Mele B, Li T, Nies E. Adjacent UCST Phase Behavior in Aqueous Solutions of Poly(vinyl methyl ether): Detection of a Narrow Low Temperature UCST in the Lower Concentration Range. Macromolecules 2011. [DOI: 10.1021/ma102572s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guy Van Assche
- Department of Physical Chemistry and Polymer Science, Vrije Universiteit Brussel, Belgium
| | - Bruno Van Mele
- Department of Physical Chemistry and Polymer Science, Vrije Universiteit Brussel, Belgium
| | - Ting Li
- Polymer Research Division, Department of Chemistry, The Leuven Mathematical Modeling and Computational Science Centre (LMCC) and the Leuven Materials Research Centre (LMRC), Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
| | - Erik Nies
- Polymer Research Division, Department of Chemistry, The Leuven Mathematical Modeling and Computational Science Centre (LMCC) and the Leuven Materials Research Centre (LMRC), Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
- Laboratory of Polymer Technology, Eindhoven University of Technology, The Netherlands
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Popa AM, Angeloni S, Bürgi T, Hubbell JA, Heinzelmann H, Pugin R. Dynamic perspective on the function of thermoresponsive nanopores from in situ AFM and ATR-IR investigations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:15356-65. [PMID: 20822117 DOI: 10.1021/la102611k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article describes the morphological and chemical characterization of stimuli-responsive functionalized silicon surfaces provided in parallel by atomic force spectroscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) enhanced by the single-beam sample reference attenuated total reflection method (SBSR-ATR). The stimuli-responsive behavior of the surfaces was obtained by grafting-to in melt carboxyl-terminated poly-N-isopropylacryl amides (PNIPAAM) with different degree of polymerization (DP) on epoxide-functionalized silicon substrates. The unprecedented real time and in situ physicochemical insight into the temperature-triggered response of the densely packed superficial brushes allowed for the selection of a PNIPAAM with a specific DP as a suitable polymer for the fabrication of silicon membranes exhibiting switchable nanopores. The fabrication process combines the manufacture of nanoporous silicon surfaces and their subsequent chemical functionalization by the grafting-to in melt of the selected polymer. Then, relevant information was obtained in what concerns the chemical modifications behind the topographical changes that drive the functioning of PNIPAAM-based hybrid nanovalves as well as the timescale on which the opening and closing of the nanopores occur.
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Affiliation(s)
- Ana Maria Popa
- Centre Suisse d'Electronique et de Microtechnique SA, Rue Jaquet Droz 1, CH-2000 Neuchâtel, Switzerland.
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Kouřilová H, Šťastná J, Hanyková L, Sedláková Z, Spěváček J. 1H NMR study of temperature-induced phase separation in solutions of poly(N-isopropylmethacrylamide-co-acrylamide) copolymers. Eur Polym J 2010. [DOI: 10.1016/j.eurpolymj.2010.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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On-line preferential solvation studies of polymers by coupled chromatographic-Fourier transform infrared spectroscopic flow-cell technique. J Chromatogr A 2009; 1216:8939-46. [DOI: 10.1016/j.chroma.2009.10.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 10/06/2009] [Accepted: 10/23/2009] [Indexed: 11/19/2022]
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19
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Kouřilová H, Hanyková L, Spěváček J. NMR study of phase separation in D2O/ethanol solutions of poly(N-isopropylmethacrylamide) induced by solvent composition and temperature. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.06.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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