Segmental Relaxation of Hydrophilic Poly(vinylpyrrolidone) in Chloroform Studied by Broadband Dielectric Spectroscopy

Shinyashiki, Naoki; Spanoudaki, Anna; Yamamoto, Wataru; Nambu, Eri; Yoneda, Kazunari; Kyritsis, Apostolos; Pissis, P.; Kita, R.; Yagihara, Shin

doi:10.1021/ma102394s

Cited by 26 publications

(40 citation statements)

References 40 publications

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“…For PVP solutions with polar solvents, two relaxation processes have been observed at frequencies above 100 MHz and below 10 MHz at 298 K. 38,38,39,45,46 The origin of these relaxation processes has been determined to be the segmental motion of PVP for the process at frequencies below 10…”

Section: Molecular Origin Of the Relaxation Processesmentioning

confidence: 99%

Glass Transition and Dynamics of the Polymer and Water in the Poly(vinylpyrrolidone)–Water Mixtures Studied by Dielectric Relaxation Spectroscopy

et al. 2016

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In this study, broadband dielectric spectroscopy and differential scanning calorimetry (DSC) measurements are performed to study the dynamics of water and polymers in an aqueous solution of poly(vinylpyrrolidone) (PVP) with concentrations of 60, 65, and 70 wt % PVP in a temperature range of 123-298 K. Two distinct relaxation processes, l- and h-processes, which originate from the segmental chain motion of PVP and the primary relaxation process of water, respectively, are observed simultaneously. The relationship between l- and h-processes and their temperature dependences mimic those of the α-process and Johari-Goldstein β-process, which are observed in ordinal glass formers. The relaxation time of the l-process, τl, obeys the Vogel-Fulcher (VF)-type temperature dependence, and the glass-transition temperature of the l-process, Tg,l, which is defined by the temperature that is reached in a τl of 100-1000 s, shows good agreement with the calorimetric Tg obtained by DSC. The temperature dependence of the relaxation time of the h-process, τh, exhibits a crossover from VF to Arrhenius behavior at the so-called fragile-to-strong transition (FST) of water at Tg,l. The temperature dependence of the relaxation strength of the h-process, Δεh, increases with a decrease in temperature from 298 K to Tg,l. Below Tg,l, Δεh is nearly constant or slightly decreases with decreasing temperature. According to previous studies on aqueous solutions of sugars and alcohols, the Δε of the ν-process, which originates from local motion of water, decreases with decreasing temperature above the Tg of the α-process, which originates from the cooperative motion of the solute and water. Therefore, the l-process in the PVP-water mixture is not a result of the cooperative motion of PVP and water but rather a result of the polymer-polymer cooperative motion of PVP. In addition, agreement among Tg,l, the temperature of the FST of water, and calorimetric Tg suggests that the FST of water occurs at Tg.

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Section: Molecular Origin Of the Relaxation Processesmentioning

confidence: 99%

Glass Transition and Dynamics of the Polymer and Water in the Poly(vinylpyrrolidone)–Water Mixtures Studied by Dielectric Relaxation Spectroscopy

et al. 2016

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“…The loss peak at 100 Hz is partly concealed by ionic contributions, namely, EP and dc conductivity. We also studied the two dielectric relaxation processes at 298 K in PVP solutions with water, alcohol, and chloroform and examined the origins in detail [3,[46][47][48][49]. The relaxation process observed above 100 MHz is the primary relaxation of the solvents.…”

Section: Figurementioning

confidence: 99%

“…In addition to the studies at 298 K, we studied the dielectric constant of PVP solutions with chloroform and PG from the liquid state to the glassy state over a wide range of temperatures and frequencies [48,50]. In these studies, the PVP-process observed at 298 K was the α-relaxation of PVP in solution, which is related to the glass transition of the solutions.…”

Section: Figurementioning

confidence: 99%

Heterogeneous Solvent Dielectric Relaxation in Polymer Solutions of Water and Alcohols

et al. 2020

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The dynamics of polymer solutions are heterogeneous. The different molecule sizes and structures cause different mobilities of polymers and solvents. Recently, regarding the heterogeneity of water, two dielectric relaxation processes of water were argued in several supercooled polymer-water mixtures. To investigate whether this is unique to water, we performed broadband dielectric spectroscopy measurements of poly(vinylpyrrolidone)-water (PVP-water), PVP-propylene glycol, PVP-ethylene glycol, and PVP-propanol mixtures with 65 wt% PVP in a temperature range of 123-298 K. For the PVP-water mixture, α-relaxation of PVP and two distinct relaxation processes appeared simultaneously: one was the primary relaxation process of water (fast water process) and the other was the relatively small relaxation process (slow process), at a frequency between that of the α-process of PVP and the fast water process. The strength ratio of the large fast water and small slow processes remained nearly constant in all the temperatures measured. For the PVP-alcohol mixtures, in addition to the α-process of PVP, two or three relaxation processes of alcohol appeared. The primary relaxation process of alcohol above 240 K changed to the small fast secondary process. The small slow processes, which can be recognized below 240 K (the glass transition temperature of the α-process of PVP, T g,PVP) appears at intermediate frequency between that of the PVP α-process and the primary process of alcohol. The small slow process changed to the primary larger process. The properties of the multiple relaxation processes of solvents below T g,PVP in PVP-alcohol mixtures are completely different from those in PVP-water mixture.

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“…This indicates that the relaxation time of alcohols is determined by ρ HB , the density of hydrogen-bonding sites in solution, which changes with increasing PVP concentration. Moreover, PVP solutions of chloroform, which has a lower permittivity than alcohol, are used to observe the PVP relaxation at different PVP concentrations and temperatures [17]. The results indicated that the apparent activation energy increases with decreasing temperature, which is known as the Vogel-FulcherTammann-Hesse (VFTH) [18][19][20] temperature dependence of relaxation time.…”

Section: Dielectric Relaxation Of Hydrophilic Polymer In Solutionsmentioning

confidence: 99%

Dynamics and Glass Transition of Aqueous Solutions of Molecular Liquid, Polymer, and Protein Studied by Broadband Dielectric Spectroscopy

Shinyashiki

2015

Nano/Micro Science and Technology in Biorheology

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Broadband dielectric spectroscopy (BDS) is the most powerful tool for observing the dynamics of molecules in an extremely wide frequency range between 1 μHz and 50 GHz or more, i.e., the time window between megaseconds and picoseconds that covers the dynamics of solids to liquids. The progress of the investigations using BDS on the dynamics of aqueous solutions of hydrophilic molecular liquids, polymers, and proteins from solid to liquid states in this decade is presented in terms of the glass transition. The relaxation process, ν-relaxation, originating from the local reorientational motion of water molecules and the α-relaxation originating from the cooperative motion of hydrated solute are strongly related. The universalities of the dynamical hierarchy from fast and local motion of water molecules to slow and global cooperative motion of hydrated guest molecules extending over a wide range of glass transition temperature are successfully explained by applying the theoretical interpretation of mixtures of van der Waals liquids using the coupling model. More complicated partially crystallized aqueous protein solutions are also included.

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Segmental Relaxation of Hydrophilic Poly(vinylpyrrolidone) in Chloroform Studied by Broadband Dielectric Spectroscopy

Cited by 26 publications

References 40 publications

Glass Transition and Dynamics of the Polymer and Water in the Poly(vinylpyrrolidone)–Water Mixtures Studied by Dielectric Relaxation Spectroscopy

Glass Transition and Dynamics of the Polymer and Water in the Poly(vinylpyrrolidone)–Water Mixtures Studied by Dielectric Relaxation Spectroscopy

Heterogeneous Solvent Dielectric Relaxation in Polymer Solutions of Water and Alcohols

Dynamics and Glass Transition of Aqueous Solutions of Molecular Liquid, Polymer, and Protein Studied by Broadband Dielectric Spectroscopy

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