Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose
The dynamics of water and agarose molecules in an agarose aqueous solution has been studied by means of quasielastic neutron scattering (QENS). The dynamic structure factor <i>S</i> (<i>Q</i>,<i>E</i>) of the agarose aqueous solution was fitted well to the sum of...
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MDPI AG
2023-11-01
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| Online Access: | https://www.mdpi.com/2310-2861/9/11/879 |
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| author | Noriko Onoda-Yamamuro Yasuhiro Inamura Osamu Yamamuro |
| author_facet | Noriko Onoda-Yamamuro Yasuhiro Inamura Osamu Yamamuro |
| author_sort | Noriko Onoda-Yamamuro |
| collection | DOAJ |
| description | The dynamics of water and agarose molecules in an agarose aqueous solution has been studied by means of quasielastic neutron scattering (QENS). The dynamic structure factor <i>S</i> (<i>Q</i>,<i>E</i>) of the agarose aqueous solution was fitted well to the sum of the Lorentz and delta function. The former is attributed to the diffusive motion of water molecules and the latter to the local vibrational motion of agarose molecules. The self-diffusion coefficient <i>D</i> of water molecules was obtained from the <i>Q</i>-dependence of the width of the Lorentz function, while the mean square displacement <<i>u</i><sup>2</sup>> of agarose molecules was obtained from the <i>Q</i>-dependence of the intensity of the delta term. In the cooling direction, both <i>D</i> and <<i>u</i><sup>2</sup>> decreased with decreasing temperature and showed discontinuous changes around the thermal gelation temperature (around 314 K). In the heating direction, however, <i>D</i> and <<i>u</i><sup>2</sup>> did not show the obvious change below 343 K, indicating a large hysteresis effect. The present results of <<i>u</i><sup>2</sup>> and <i>D</i> revealed that the thermal gelation suppresses the motion of the polymer and accelerates the diffusion of water molecules. The activation energy <i>E</i><sub>a</sub> of the diffusion of water in the sol state is the same as that of bulk water, but the <i>E</i><sub>a</sub> in the gel state is clearly smaller than that of bulk water. |
| first_indexed | 2024-03-09T16:49:19Z |
| format | Article |
| id | doaj.art-d9226fce6d304ea5be7a11288be5fd30 |
| institution | Directory Open Access Journal |
| issn | 2310-2861 |
| language | English |
| last_indexed | 2024-03-09T16:49:19Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Gels |
| spelling | doaj.art-d9226fce6d304ea5be7a11288be5fd302023-11-24T14:43:22ZengMDPI AGGels2310-28612023-11-0191187910.3390/gels9110879Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of AgaroseNoriko Onoda-Yamamuro0Yasuhiro Inamura1Osamu Yamamuro2Department of Natural Sciences, School of Science and Engineering, Tokyo Denki University, Hiki-gun, Saitama 350-0394, JapanNeutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, JapanNeutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, JapanThe dynamics of water and agarose molecules in an agarose aqueous solution has been studied by means of quasielastic neutron scattering (QENS). The dynamic structure factor <i>S</i> (<i>Q</i>,<i>E</i>) of the agarose aqueous solution was fitted well to the sum of the Lorentz and delta function. The former is attributed to the diffusive motion of water molecules and the latter to the local vibrational motion of agarose molecules. The self-diffusion coefficient <i>D</i> of water molecules was obtained from the <i>Q</i>-dependence of the width of the Lorentz function, while the mean square displacement <<i>u</i><sup>2</sup>> of agarose molecules was obtained from the <i>Q</i>-dependence of the intensity of the delta term. In the cooling direction, both <i>D</i> and <<i>u</i><sup>2</sup>> decreased with decreasing temperature and showed discontinuous changes around the thermal gelation temperature (around 314 K). In the heating direction, however, <i>D</i> and <<i>u</i><sup>2</sup>> did not show the obvious change below 343 K, indicating a large hysteresis effect. The present results of <<i>u</i><sup>2</sup>> and <i>D</i> revealed that the thermal gelation suppresses the motion of the polymer and accelerates the diffusion of water molecules. The activation energy <i>E</i><sub>a</sub> of the diffusion of water in the sol state is the same as that of bulk water, but the <i>E</i><sub>a</sub> in the gel state is clearly smaller than that of bulk water.https://www.mdpi.com/2310-2861/9/11/879agarosedynamicsquasielastic neutron scatteringQENSthermal gelation |
| spellingShingle | Noriko Onoda-Yamamuro Yasuhiro Inamura Osamu Yamamuro Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose Gels agarose dynamics quasielastic neutron scattering QENS thermal gelation |
| title | Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose |
| title_full | Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose |
| title_fullStr | Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose |
| title_full_unstemmed | Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose |
| title_short | Quasielastic Neutron Scattering Study on Thermal Gelation in Aqueous Solution of Agarose |
| title_sort | quasielastic neutron scattering study on thermal gelation in aqueous solution of agarose |
| topic | agarose dynamics quasielastic neutron scattering QENS thermal gelation |
| url | https://www.mdpi.com/2310-2861/9/11/879 |
| work_keys_str_mv | AT norikoonodayamamuro quasielasticneutronscatteringstudyonthermalgelationinaqueoussolutionofagarose AT yasuhiroinamura quasielasticneutronscatteringstudyonthermalgelationinaqueoussolutionofagarose AT osamuyamamuro quasielasticneutronscatteringstudyonthermalgelationinaqueoussolutionofagarose |