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Lee JH, Hyun JE, Kim J, Yang J, Zhang H, Ahn H, Lee S, Kim JH, Lim T. A highly conductive, robust, self-healable, and thermally responsive liquid metal-based hydrogel for reversible electrical switches. J Mater Chem B 2024; 12:5238-5247. [PMID: 38699788 DOI: 10.1039/d4tb00209a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
This study introduces a thermally responsive smart hydrogel with enhanced electrical properties achieved through volume switching. This advancement was realized by incorporating multiscale liquid metal particles (LMPs) into the PNIPAM hydrogel during polymerization, using their inherent elasticity and conductivity when deswelled. Unlike traditional conductive additives, LMPs endow the PNIPAM hydrogel with a remarkably consistent volume switching ratio, significantly enhancing electrical switching. This is attributed to the minimal nucleation effect of LMPs during polymerization and their liquid-like behavior, like vacancies in the polymeric hydrogel under compression. The PNIPAM/LMP hydrogel exhibits the highest electrical switching, with an unprecedented switch of 6.1 orders of magnitude. Even after repeated swelling/deswelling cycles that merge some LMPs and increase the conductivity when swelled, the hydrogel consistently maintains an electrical switch exceeding 4.5 orders of magnitude, which is still the highest record to date. Comprehensive measurements reveal that the hydrogel possesses robust mechanical properties, a tissue-like compression modulus, biocompatibility, and self-healing capabilities. These features make the PNIPAM/LMP hydrogel an ideal candidate for long-term implantable bioelectronics, offering a solution to the mechanical mismatch with dynamic human tissues.
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Affiliation(s)
- Joo Hyung Lee
- The Research Institute of Industrial Science, Hanyang University, Seoul 04763, South Korea
| | - Ji Eun Hyun
- Department of Organic and Nano Engineering, Hanyang University, Seoul 04763, South Korea
| | - Jongbeom Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, South Korea
| | - Jungin Yang
- Division of Chemical Engineering and Bioengineering, Kangwon National University, Chuncheon, Gangwon-do 24341, South Korea.
| | - Huanan Zhang
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | - Hyunchul Ahn
- Department of Fiber System Engineering, Yeungnam University, Gyeongsan, Gyeongsangbuk-do 38541, South Korea.
| | - Sohee Lee
- Department of Clothing and Textiles, Gyeongsang National University, Jinju, Gyeongsangnam-do 52828, South Korea.
| | - Jung Han Kim
- Department of Materials Science and Engineering, Dong-A University, Busan 49315, South Korea.
| | - Taehwan Lim
- Division of Chemical Engineering and Bioengineering, Kangwon National University, Chuncheon, Gangwon-do 24341, South Korea.
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2
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Vijayakumar B, Takatsuka M, Sasaki K, Kita R, Shinyashiki N, Yagihara S, Rathnasabapathy S. Dielectric relaxation of ice in a partially crystallized poly( N-isopropylacrylamide)microgel suspension compared to other partially crystalized polymer-water mixtures. Phys Chem Chem Phys 2023; 25:22223-22231. [PMID: 37566434 DOI: 10.1039/d3cp02116e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
A broadband dielectric spectroscopy study was conducted on a partially crystallized 10 wt% poly(N-isopropylacrylamide) [PNIPAM] microgel aqueous suspension to investigate the dielectric relaxation of ice in microgel suspensions. The measurements covered a frequency range of 10 mHz to 10 MHz and at temperatures ranging from 123 K to 273 K. Two distinct relaxation processes were observed at specific frequencies below the melting temperature. One is associated with the combination of the local chain motion of PNIPAM and interfacial polarization in the uncrystallized phase, while another is associated with ice. To understand the temperature-dependent behaviour of the ice relaxation process, the relaxation time of ice was compared with those observed in other frozen polymer water mixtures, including gelatin, poly-vinylpyrrolidone (PVP), and bovine serum albumin (BSA). For concentrations ≥ 10 wt%, the temperature dependence of the relaxation time of ice was found to be independent. Therefore, the study primarily focused on the 10 wt% data for easier comprehension of the ice relaxation process. It was found that the microgel and globular protein BSA had no significant effect on ice crystallization, while gelatin slowed down the crystallization process, and PVP accelerated it. To discuss the mechanism of the dielectric relaxation of ice, the trap-controlled proton transport model developed by Khamzin et al. [Chem. Phys., 2021, 541, 111040.] was employed. The model was used to discuss the dynamic heterogeneity of ice observed in this investigation, distinguishing it from the spatial heterogeneity of ice commonly discussed.
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Affiliation(s)
- Balachandar Vijayakumar
- Department of Physics, Sathyabama Institute of Science and Technology, Chennai-600119, India. drrskumar@
- Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai-600119, India
| | - Masanobu Takatsuka
- Graduate School of Science and Technology, Tokai University, Kanagawa 259-1292, Japan
| | - Kaito Sasaki
- Department of Physics, Tokai University, Kanagawa 259-1292, Japan.
- Micro/Nano Technology Centre, Tokai University, Kanagawa 259-1292, Japan
| | - Rio Kita
- Department of Physics, Tokai University, Kanagawa 259-1292, Japan.
- Micro/Nano Technology Centre, Tokai University, Kanagawa 259-1292, Japan
| | - Naoki Shinyashiki
- Department of Physics, Tokai University, Kanagawa 259-1292, Japan.
- Micro/Nano Technology Centre, Tokai University, Kanagawa 259-1292, Japan
| | - Shin Yagihara
- Department of Physics, Tokai University, Kanagawa 259-1292, Japan.
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Structure and Dynamics of Inhomogeneities in Aqueous Solutions of Graft Copolymers of N-Isopropylacrylamide with Lactide (P(NIPAM-graft-PLA)) by Spin Probe EPR Spectroscopy. Polymers (Basel) 2022; 14:polym14214746. [DOI: 10.3390/polym14214746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Coil-to-globule transition and dynamics of inhomogeneities in aqueous solutions of graft copolymers of NIPAM with different content of oligolactide groups were studied using spin probe continuous wave EPR spectroscopy. The technique of the suppressing of TEMPO as spin probe by spin exchange with Cu2+ ions was applied. This approach allowed us to detect individual EPR spectra of the probe in collapsed globules and estimate its magnetic and dynamic parameters reliably. The formation of inhomogeneities at temperatures lower than the volume phase transition temperature measured via transmission, and differential scanning calorimetry was fixed. An increase in oligolactide content in copolymers leads to the formation of looser globules, allowing for the exchange of the probe molecules between the globules and the external solution.
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Curry F, Lim T, Fontaine NS, Adkins MD, Zhang H. Highly conductive thermoresponsive silver nanowire PNIPAM nanocomposite for reversible electrical switch. SOFT MATTER 2022; 18:7171-7180. [PMID: 36098069 DOI: 10.1039/d2sm00700b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Highly conductive nanocomposite hydrogels have been challenging to produce due to their high water volumes inhibiting the incorporation of an essential amount of conductive nanofillers. Furthermore, the most common fillers used, typically for easy integration, display small aspect ratios. Thus, the formation of interparticle pathways for electronic travel is limited, resulting in low conductivities. Here, we introduce ultralong silver nanowires (ULAgNWs) into a thermoresponsive, volume changing PNIPAM gel to form a nanocomposite that shows switchable electronic performance. The produced nanocomposite surpasses other PNIPAM nanocomposites by expressing the largest electrical switch ratio and the highest peak conductivity. The PNIPAM matrix possesses an interconnected microporous structure that offers a spacious network for the dispersion of nanowires while still maintaining a high volume switch ratio and excellent elastic behavior under extreme compression cycles (98% compression). The ULAgNWs significantly enhance the probability of more numerous connections forming during shrinking cycles. The high swellability displayed by the PNIPAM gel provides the ability to separate the embedded nanowires by many lengths. Together, they form a nanocomposite that can thermo-modulate its electrical properties. Moreover, the conductive PNIPAM maintains the electrical switch of 4.3-4.4 orders of magnitude with thermo-responsive cycles. Because of their high electrical conductivity and outstanding elastic behavior, these stimuli-responsive nanocomposite hydrogels may expand the prospects for conductive hydrogel applications and provide greater performance in their applications.
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Affiliation(s)
- Franky Curry
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
| | - Taehwan Lim
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
- Advanced Textile R&D Department, Korea Institute of Industrial Technology, Ansan-si, Gyeonggi-do 15588, South Korea
| | - Nicholas S Fontaine
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
| | - Michael D Adkins
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
| | - Huanan Zhang
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
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5
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Yang XD, Chen W, Ren Y, Chu LY. Exploring dielectric spectra of polymer through molecular dynamics simulations. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2083122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Xue-Dan Yang
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Wei Chen
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
- Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian, Liaoning, People's Republic of China
| | - Ying Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Liang-Yin Chu
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
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Vijayakumar B, Takatsuka M, Kita R, Shinyashiki N, Yagihara S, Rathinasabapathy S. Dynamics of the Poly(N-Isopropylacrylamide) Microgel Aqueous Suspension Investigated by Dielectric Relaxation Spectroscopy. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Balachandar Vijayakumar
- Department of Physics, Sathyabama Institute of Science and Technology, Chennai 600119, India
| | - Masanobu Takatsuka
- Graduate School of Science and Technology, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - Rio Kita
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
- Micro/Nano Technology Center, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - Naoki Shinyashiki
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
- Micro/Nano Technology Center, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - Shin Yagihara
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
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Savage DT, Hilt JZ, Dziubla TD. Assessing the perfluoroalkyl acid-induced swelling of Förster resonance energy transfer-capable poly( N-isopropylacrylamide) microgels. SOFT MATTER 2021; 17:9799-9808. [PMID: 34661226 PMCID: PMC8889493 DOI: 10.1039/d1sm00985k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
As a method to combat the extensive contamination of poly- and perfluoroalkyl substances (PFAS) in water supplies, poly(N-isopropylacrylamide) (PNIPAM) microgels copolymerized with 2,2,2-trifluoroethylacrylate (TFEA) represent a potential sensing tool for recognizing PFAS at dilute aqueous concentrations. The microgels exhibit exceptional temperature responsiveness, transitioning from a swollen z-average diameter of 890.8 ± 19.8 nm to a collapsed diameter of 246.4 ± 10.3 nm below and above their lower critical solution temperature, respectively, for non-fluorinated gels, offering broad size fluctuations that are susceptible to coadded contaminants. Monitoring size perturbations as a function of analyte concentration, the polymers were observed to deswell in the presence of perfluorooctanoic acid, octanoic acid, phenol, and sodium 1-octane sulfonate while tetraethylammonium perfluorooctane sulfonate (TPFOS) augmented swelling. Adding up to 40 mol% TFEA to the networks lowered the concentration at which the microgels' normalized z-average diameter demonstrated a significant deviation from 0.25 mM to 0.1 mM for TPFOS, indicating fluorophilicity as a key contributor to the copolymers' associative capacity. Implanting Förster resonance energy transfer-compatible dyes, cyanine 3 and cyanine 5, into non-fluorinated microgels largely reiterated results from light scattering, as expected for the size-dependent energy transfer mechanism. Including dyes did, however, reinforce the customizability of this system, leaving windows open for functionalization with other signal transduction motifs to lower the detection limits of the polymer further. The swelling changes for PNIPAM microgels stimulated by the acidic constituents of PFAS highlight the polymer as a candidate for detecting the substances following additional development.
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Affiliation(s)
- Dustin T Savage
- University of Kentucky, Department of Chemical and Materials Engineering, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046, USA.
| | - J Zach Hilt
- University of Kentucky, Department of Chemical and Materials Engineering, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046, USA.
| | - Thomas D Dziubla
- University of Kentucky, Department of Chemical and Materials Engineering, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046, USA.
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Şarkaya K, Yildirim M, Alli A. One‐step preparation of poly(
NIPAM‐pyrrole
) electroconductive composite hydrogel and its dielectric properties. J Appl Polym Sci 2021. [DOI: 10.1002/app.50527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Koray Şarkaya
- Department of Chemistry, Faculty of Arts & Sciences Düzce University Düzce Turkey
| | - Mert Yildirim
- Department of Mechatronics Engineering, Faculty of Engineering Düzce University Düzce Turkey
| | - Abdulkadir Alli
- Department of Chemistry, Faculty of Arts & Sciences Düzce University Düzce Turkey
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9
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Molecular dynamics simulation study of curcumin interaction with nano-micelle of PNIPAAm-b-PEG co-polymer as a smart efficient drug delivery system. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115862] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Vialar P, Merzeau P, Barthel E, Giasson S, Drummond C. Interaction between Compliant Surfaces: How Soft Surfaces Can Reduce Friction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15723-15728. [PMID: 31566381 DOI: 10.1021/acs.langmuir.9b02384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We describe how a long-range repulsive interaction can surreptitiously modify the effective geometry of approaching compliant surfaces, with significant consequences on friction. We investigated the behavior under shear and compression of mica surfaces coated with poly(N-isopropylacrylamide) pNIPAM-based cationic microgels. We show that local surface deformations as small as a few nanometers must be considered to understand the response of such surfaces under compression and shear, in particular when the range of action of normal and friction forces are significantly different, as is often the case for macromolecular lubrication. Under these conditions, a subtle interplay between normal forces and surface compliance may significantly reduce friction increment by limiting the minimum approach of the surfaces under pressure. We found that stiffening of compressed microgels confined in the region of closest approach make it increasingly difficult to reduce the gap between the mica surfaces, limiting the deformation of microgels distant from the contact apex and their contribution to global friction while increasing the effective contact radius. These findings reveal a simple mechanism for a robust control of lubrication: by properly tuning the stiffness and geometry of the interacting bodies, for an ad hoc long-range interaction, the growth of friction with applied normal load can be significantly hindered. Thus, substrate compliance is as significant as surface interaction in the design of low friction, long life tribological systems.
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Affiliation(s)
- Pierre Vialar
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux 1, CRPP , F-33600 Pessac , France
| | - Pascal Merzeau
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux 1, CRPP , F-33600 Pessac , France
| | - Etienne Barthel
- Laboratoire Sciences et Ingénierie de la Matière Molle, ESPCI Paris, CNRS, PSL University , 75005 Paris , France
- Sorbonne Université, ESPCI Paris, Sciences et Ingénierie de la Matière Molle , 75005 Paris , France
| | - Suzanne Giasson
- Department of Chemistry and Faculty of Pharmacy , Université de Montréal , C.P. 6128, succursale Centre-Ville, Montréal , QC H3C 3J7 , Canada
| | - Carlos Drummond
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux 1, CRPP , F-33600 Pessac , France
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Vialar P, Merzeau P, Giasson S, Drummond C. Compliant Surfaces under Shear: Elastohydrodynamic Lift Force. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15605-15613. [PMID: 31408351 DOI: 10.1021/acs.langmuir.9b02019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, we have investigated the behavior under shear and compression of mica surfaces coated with poly(N-isopropylacrylamide) cationic microgels. We have observed the emergence of velocity dependent, shear-induced normal forces, which can be large enough to entrain a fluid film that separates the surfaces out of contact, driving the dynamic system from conditions of boundary to hydrodynamic lubrication. By implementing a feedback-loop control on the surface separation, we were able to quantify the magnitude of the lift force as a function of the surface separation and driving speed. Our results illustrate how elastohydrodynamic effects can play an important role in the lubrication of compliant surfaces, providing pathways for control of friction and wear.
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Affiliation(s)
- Pierre Vialar
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux, CRPP , F-33600 Pessac , France
| | - Pascal Merzeau
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux, CRPP , F-33600 Pessac , France
| | - Suzanne Giasson
- Department of Chemistry and Faculty of Pharmacy , Université de Montréal , C.P. 6128, succursale Centre-Ville , Montréal , QC Canada , H3C 3J7
| | - Carlos Drummond
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031 , F-33600 Pessac , France
- Université Bordeaux, CRPP , F-33600 Pessac , France
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12
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Responsive hydrogel colloids: Structure, interactions, phase behavior, and equilibrium and nonequilibrium transitions of microgel dispersions. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.02.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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13
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Saito H, Kato S, Matsumoto K, Umino Y, Kita R, Shinyashiki N, Yagihara S, Fukuzaki M, Tokita M. Dynamic Behaviors of Solvent Molecules Restricted in Poly (Acryl Amide) Gels Analyzed by Dielectric and Diffusion NMR Spectroscopy. Gels 2018; 4:E56. [PMID: 30674832 PMCID: PMC6209249 DOI: 10.3390/gels4030056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 06/01/2018] [Accepted: 06/14/2018] [Indexed: 12/05/2022] Open
Abstract
Dynamics of solvent molecules restricted in poly (acryl amide) gels immersed in solvent mixtures of acetone⁻, 1,4-dioxane⁻, and dimethyl sulfoxide⁻water were analyzed by the time domain reflectometry method of dielectric spectroscopy and the pulse field gradient method of nuclear magnetic resonance. Restrictions of dynamic behaviors of solvent molecules were evaluated from relaxation parameters such as the relaxation time, its distribution parameter, and the relaxation strength obtained by dielectric measurements, and similar behaviors with polymer concentration dependences for the solutions were obtained except for the high polymer concentration in collapsed gels. Scaling analyses for the relaxation time and diffusion coefficient respectively normalized by those for bulk solvent suggested that the scaling exponent determined from the scaling variable defined as a ratio of the size of solvent molecule to mesh size of polymer networks were three and unity, respectively, except for collapsed gels. The difference in these components reflects characteristic molecular interactions in the rotational and translational diffusions, and offered a physical picture of the restriction of solvent dynamics. A universal treatment of slow dynamics due to the restriction from polymer chains suggests a new methodology of characterization of water structures.
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Affiliation(s)
- Hironobu Saito
- Graduate School of Science and Technology, Tokai University, Kanagawa 259-1292, Japan.
| | - Shunpei Kato
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Keisuke Matsumoto
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Yuya Umino
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Rio Kita
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Naoki Shinyashiki
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Shin Yagihara
- Graduate School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan.
| | - Minoru Fukuzaki
- Liberal Arts Education Center in Kumamoto, Tokai University, Toroku 9-1-1, Higashi-ku, Kumamoto-shi, Kumamoto 862-0970, Japan.
| | - Masayuki Tokita
- Graduate School of Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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14
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Li W, Wang J, Yang M, Zhao K. Dielectric Behavior and Phase Behavior of Block Copolymer PEO 13-PPO 30-PEO 13 Aqueous Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5574-5580. [PMID: 29694785 DOI: 10.1021/acs.langmuir.8b00776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dielectric spectroscopy can be applied to study the structure and dynamics of block polymer. In this work, dielectric measurements of block copolymer Pluronic L64 solution are carried out in the frequency range between 40 Hz and 110 MHz with variable temperatures and concentrations. We analyze the phase behavior of the PEO13-PPO30-PEO13 (Pluronic L64) aqueous system according to the concentration/temperature-dependence of direct current conductivity. The result indicates the sensitivity of the phase behavior and conductivity of the Pluronic L64 solution to temperature. Besides, two relaxations were observed: relaxation 1 (0.5 MHz) is related to the gelation process, while relaxation 2 (5 MHz) is caused by the interface polarization. On the basis of relaxation 2, the volume fraction and permittivity of the particle were calculated. The formations of the block copolymer micelle and gel are monitored successfully by the temperature/concentration-dependence of the dielectric parameters and the volume fraction.
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Affiliation(s)
- Wantong Li
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Juan Wang
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Man Yang
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
| | - Kongshuang Zhao
- College of Chemistry , Beijing Normal University , Beijing 100875 , China
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15
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Zhang C, Yang M, Zhao K. Insight into the effect mechanism of urea-induced protein denaturation by dielectric spectroscopy. Phys Chem Chem Phys 2017; 19:32007-32015. [PMID: 29177311 DOI: 10.1039/c7cp05994a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dielectric relaxation spectroscopy was applied to study how urea affects the phase transition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), which has been widely used as a protein model. It was found that there is a pronounced relaxation near 10 GHz for the ternary system of PNIPAM in urea aqueous solution. The temperature dependence of dielectric parameters indicates that urea can reduce the lower critical solution temperature (LCST) of PNIPAM, i.e., stabilize the globule state of PNIPAM and collapse the PNIPAM chains. Based on our results, the interaction mechanism of urea on the conformational transition of PNIPAM was presented: urea replaces water molecules directly bonding with PNIPAM and acts as the bridging agent for the adjacent side chains of PNIPAM. Accordingly, the mechanism with which urea denatures protein was deduced. In addition, it is worth mentioning that, from the temperature dependence of the dielectric parameters obtained in the presence of urea, an interesting phenomenon was found in which the effect of urea on PNIPAM seems to take 2 M as a unit. This result may be the reason why urea and TMAO exit marine fishes at a specific ratio of 2 : 1.
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Affiliation(s)
- Cancan Zhang
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
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16
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Jiang P, Yang C, He X, Rodrigues AM, Zhang R. Viscoelastic changes in chlorinated butyl rubber modified with graphene oxide. IRANIAN POLYMER JOURNAL 2017. [DOI: 10.1007/s13726-017-0570-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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