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Tohamy HAS, Elnasharty MMM, Abdel-Aziz MS, El-Sakhawy M, Turky G, Kamel S. Antibacterial activity and dielectric properties of the PVA/cellulose nanocrystal composite using the synergistic effect of rGO@CuNPs. Int J Biol Macromol 2024; 261:129801. [PMID: 38309410 DOI: 10.1016/j.ijbiomac.2024.129801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/05/2024]
Abstract
This work aims to enhance the performance of the polyvinyl alcohol (PVA) composite by using cellulose nanocrystal (CNC) as reinforcement and copper nanoparticles (CuNPs)/reduced graphene oxide (rGO) as conducting and antimicrobial reagents. Firstly, rGO was loaded onto CuNPs using an eco-friendly microwave method. Different techniques characterized the components and prepared composites, which indicated the incorporation of cellulose nanocrystals and rGO@CuNPs within the polyvinyl alcohol matrix. Utilizing the clear zone of inhibition, the antibacterial test was quantified. Compared to the neat composite, the rGO@CuNPs loaded polyvinyl alcohol/ cellulose nanocrystal composites exhibited no bacterial growth against S. aureus, E. coli, and C. albicans. However, all composites did not have antifungal activity against A. niger. The combination of conductivity and interfacial polarization is the reason for the abrupt increase of permittivity with decreasing frequency. Besides, adding rGO@CuNPs improved the electrical conductivity. DC-Conductivity increased about a decade after adding cellulose nanocrystal to polyvinyl alcohol, then another decade after adding CuONPs. The electric loss modulus representation shows a systematic shift in the peak position towards higher frequencies, decreasing the so-called conductivity relaxation time. This is the main reason for the enhancement of conductivity. The systematic attenuation of peaks' height with increasing conductivity is still unclear.
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Affiliation(s)
- Hebat-Allah S Tohamy
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
| | | | - Mohamed S Abdel-Aziz
- Microbial Chemistry Department, National Research Centre, 33 El Bohouth st. (former El tahrir st.), P.O. 12622, Dokki, Giza, Egypt
| | - Mohamed El-Sakhawy
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
| | - Gamal Turky
- Microwave Physics and Dielectrics Department, National Research Centre, 12622, Egypt.
| | - Samir Kamel
- Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str., PO 12622, Dokki, Giza, Egypt
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2
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Hoffmann L, Beerwerth J, Adjei-Körner M, Fuentes-Landete V, Tonauer CM, Loerting T, Böhmer R. Oxygen NMR of high-density and low-density amorphous ice. J Chem Phys 2022; 156:084503. [DOI: 10.1063/5.0080333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using oxygen-17 as a nuclear probe, spin relaxometry was applied to study the high-density and low-density states of amorphous ice, covering temperatures below and somewhat above their glass transitions. These findings are put in perspective with results from deuteron nuclear magnetic resonance and with calculations based on dielectrically detected correlation times. This comparison reveals the presence of a wide distribution of correlation times. Furthermore, oxygen-17 central-transition echo spectra were recorded for wide ranges of temperature and pulse spacing. The spectra cannot be described by a single set of quadrupolar parameters, suggesting a distribution of H–O–H opening angles that is broader for high-density than for low-density amorphous ice. Simulations of the pulse separation dependent spin-echo spectra for various scenarios demonstrate that a small-step frequency diffusion process, assigned to the presence of homonuclear oxygen–oxygen interactions, determines the shape evolution of the pulse-separation-dependent spectra.
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Affiliation(s)
- Lars Hoffmann
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Joachim Beerwerth
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | | | - Violeta Fuentes-Landete
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
| | - Christina M. Tonauer
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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3
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Becher M, Körber T, Döß A, Hinze G, Gainaru C, Böhmer R, Vogel M, Rössler EA. Nuclear Spin Relaxation in Viscous Liquids: Relaxation Stretching of Single-Particle Probes. J Phys Chem B 2021; 125:13519-13532. [PMID: 34860530 DOI: 10.1021/acs.jpcb.1c06722] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spin-lattice relaxation rates R1(ω,T), probed via high-field and field-cycling nuclear magnetic resonance (NMR), are used to test the validity of frequency-temperature superposition (FTS) for the reorientation dynamics in viscous liquids. For several liquids, FTS is found to apply so that master curves can be generated. The susceptibility spectra are highly similar to those obtained from depolarized light scattering (DLS) and reveal an excess wing. Where FTS works, two approaches are suggested to access the susceptibility: (i) a plot of deuteron R1(T) vs the spin-spin relaxation rate R2(T) and (ii) a plot of R1(T) vs an independently measured reference time τref(T). Using single-frequency scans, (i) allows one to extract the relaxation stretching as well as the NMR coupling constant. Surveying 26 data sets, we find Kohlrausch functions with exponents 0.39 < βK ≤ 0.67. Plots of the spin-spin relaxation rate R2─rescaled by the NMR coupling constant─as a function of temperature allow one to test how well site-specific NMR relaxations couple to a given reference process. Upon cooling of flexible molecule liquids, the site-specific dynamics is found to merge, suggesting that near Tg the molecules reorient essentially as a rigid entity. This presents a possible resolution for the much lower stretching parameters reported here at high temperatures that contrast with the ones that were reported to be universal in a recent DLS study close to Tg. Our analysis underlines that deuteron relaxation is a uniquely powerful tool to probe single-particle reorientation.
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Affiliation(s)
- M Becher
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Th Körber
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A Döß
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - G Hinze
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - C Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M Vogel
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - E A Rössler
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
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4
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Ahlmann S, Münzner P, Moch K, Sokolov AP, Böhmer R, Gainaru C. The relationship between charge and molecular dynamics in viscous acid hydrates. J Chem Phys 2021; 155:014505. [PMID: 34241375 DOI: 10.1063/5.0055179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Oscillatory shear rheology has been employed to access the structural rearrangements of deeply supercooled sulfuric acid tetrahydrate (SA4H) and phosphoric acid monohydrate, the latter in protonated (PA1H) and deuterated (PA1D) forms. Their viscoelastic responses are analyzed in relation to their previously investigated electric conductivity. The comparison of the also presently reported dielectric response of deuterated sulfuric acid tetrahydrate (SA4D) and that of its protonated analog SA4H reveals an absence of isotope effects for the charge transport in this hydrate. This finding clearly contrasts with the situation known for PA1H and PA1D. Our analyses also demonstrate that the conductivity relaxation profiles of acid hydrides closely resemble those exhibited by classical ionic electrolytes, even though the charge transport in phosphoric acid hydrates is dominated by proton transfer processes. At variance with this dielectric simplicity, the viscoelastic responses of these materials depend on their structural compositions. While SA4H displays a "simple liquid"-like viscoelastic behavior, the mechanical responses of PA1H and PA1D are more complex, revealing relaxation modes, which are faster than their ubiquitous structural rearrangements. Interestingly, the characteristic rates of these fast mechanical relaxations agree well with the characteristic frequencies of the charge rearrangements probed in the dielectric investigations, suggesting appearance of a proton transfer in mechanical relaxation of phosphoric acid hydrates. These findings open the exciting perspective of exploiting shear rheology to access not only the dynamics of the matrix but also that of the charge carriers in highly viscous decoupled conductors.
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Affiliation(s)
- S Ahlmann
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - P Münzner
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - K Moch
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - A P Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - C Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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Münzner P, Hoffmann L, Böhmer R, Gainaru C. Deeply supercooled aqueous LiCl solution studied by frequency-resolved shear rheology. J Chem Phys 2019; 150:234505. [DOI: 10.1063/1.5100600] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Philipp Münzner
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Lars Hoffmann
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
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Omara SS, Turky G, Ghoneim A, Thünemann AF, Abdel Rehim MH, Schönhals A. Hyperbranched poly(amidoamine)/kaolinite nanocomposites: Structure and charge carrier dynamics. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Moussa MA, Ghoneim AM, Abdel Rehim MH, Khairy SA, Soliman MA, Turky GM. Relaxation dynamic and electrical mobility for poly(methyl methacrylate)-polyaniline composites. J Appl Polym Sci 2017. [DOI: 10.1002/app.45415] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Mohammed A. Moussa
- Microwave Physics and Dielectrics Department; National Research Centre; 33 El Behooth Street Dokki Giza Egypt
| | - Ahmed M. Ghoneim
- Microwave Physics and Dielectrics Department; National Research Centre; 33 El Behooth Street Dokki Giza Egypt
| | - Mona H. Abdel Rehim
- Packing and Packaging Materials Department; National Research Centre; 33 El Behooth Street Dokki Giza Egypt
| | - Sherif A. Khairy
- Physics Division, Faculty of Science; Cairo University; Giza Egypt
| | | | - Gamal M. Turky
- Microwave Physics and Dielectrics Department; National Research Centre; 33 El Behooth Street Dokki Giza Egypt
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Gainaru C, Stacy EW, Bocharova V, Gobet M, Holt AP, Saito T, Greenbaum S, Sokolov AP. Mechanism of Conductivity Relaxation in Liquid and Polymeric Electrolytes: Direct Link between Conductivity and Diffusivity. J Phys Chem B 2016; 120:11074-11083. [PMID: 27681664 DOI: 10.1021/acs.jpcb.6b08567] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Combining broadband impedance spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance we analyzed charge and mass transport in two polymerized ionic liquids and one of their monomeric precursors. In order to establish a general procedure for extracting single-particle diffusivity from their conductivity spectra, we critically assessed several approaches previously employed to describe the onset of diffusive charge dynamics and of the electrode polarization in ion conducting materials. Based on the analysis of the permittivity spectra, we demonstrate that the conductivity relaxation process provides information on ion diffusion and the magnitude of cross-correlation effects between ionic motions. A new approach is introduced which is able to estimate ionic diffusivities from the characteristic times of conductivity relaxation and ion concentration without any adjustable parameters. This opens the venue for a deeper understanding of charge transport in concentrated and diluted electrolyte solutions.
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Affiliation(s)
- C Gainaru
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.,Fakultät Physik, Technische Universität Dortmund , D-44221 Dortmund, Germany
| | - E W Stacy
- Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - V Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - M Gobet
- Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States
| | - A P Holt
- Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - T Saito
- Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - S Greenbaum
- Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States
| | - A P Sokolov
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.,Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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9
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Didzoleit H, Storek M, Gainaru C, Geil B, Böhmer R. Dynamics of Glass Forming Ammonia Hydrates. J Phys Chem B 2013; 117:12157-63. [DOI: 10.1021/jp407581q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- H. Didzoleit
- Fakultät
für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M. Storek
- Fakultät
für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - C. Gainaru
- Fakultät
für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - B. Geil
- Institut
für Physikalische Chemie, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - R. Böhmer
- Fakultät
für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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