The role of primitive relaxation in the dynamics of aqueous mixtures, nano-confined water and hydrated proteins

Capaccioli, S.; Ngai, K. L.; Ancherbak, S.; Rolla, Pierangelo; Shinyashiki, Naoki

doi:10.1016/j.jnoncrysol.2010.07.054

Cited by 45 publications

(62 citation statements)

References 121 publications

(252 reference statements)

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“…Details of the apparatus and the procedures used in TDR were reported previously. 33,34 A coaxial cylindrical cell with a geometrical capacitance of 0.20 pF was used for the measurements with the impedance analyzer.…”

Section: ' Experimental Sectionmentioning

confidence: 99%

Molecular Dynamics of Poly(N-isopropylacrylamide) in Protic and Aprotic Solvents Studied by Dielectric Relaxation Spectroscopy

et al. 2012

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We report the experimental results of dielectric relaxation spectroscopy for the systems of poly(N-isopropylacrylamide) [PNiPAM] in various solvents in the frequency range of 40 kHz to 20 GHz at the solution temperature of 25.0 °C. The solvents used in this study were protic solvents (water, methanol, ethanol, and 1-propanol) and aprotic solvents (acetone, methyl ethyl ketone, and dimethyl sulfoxide). Two relaxation processes were observed at frequencies of approximately 1 MHz and 10 GHz in all the solutions. The origins of the two relaxation processes are considered to be the reorientation of dipoles of the PNiPAM chains at middle frequencies (m-process) and that of solvent molecules at higher frequencies (h-process). For the PNiPAM solutions composed of protic solvents except for 1-propanol, the relaxation time of the h-process increased with increasing PNiPAM concentration, whereas that of the h-process for the 1-propanol decreased with increasing PNiPAM concentration. In contrast, the relaxation times of the h-process for the aprotic solvents were independent of the density of hydrogen-bonding sites. For the m-process, which is attributed to the local chain motion of PNiPAM, the extrapolated relaxation time to zero polymer concentration τ(m0) was scaled by the solvent viscosity for all the protic solvents, whereas for the aprotic solvents τ(m0) showed no correlation with the solvent viscosity. The dynamics of polymer chains and solvent molecules in their solution state are clarified in terms of cooperative motion, which is associated with the interactions through hydrogen bonding at the molecular level.

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Section: ' Experimental Sectionmentioning

confidence: 99%

Molecular Dynamics of Poly(N-isopropylacrylamide) in Protic and Aprotic Solvents Studied by Dielectric Relaxation Spectroscopy

et al. 2012

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“…The sharp change in temperature behavior has been observed for water in a variety of confining systems such as MCM-41, 4 carbon nanotubes, 5 white cement 6 as well as in aqueous solution of DNA, 7 RNA, 8 and lysozyme. 9 Some of these, or similar confining systems, have also been studied by using other different experimental techniques, such as broadband dielectric spectroscopy (BDS), [10][11][12][13][14][15] nuclear magnetic resonance (NMR), 16 or a combination of different techniques. [17][18][19][20][21][22] In such studies, most likely due to the broadband frequency range analyzed such crossover for water was either not observed, or attributed to other causes different to that of the fragile-to-strong transition scenario.…”

Section: Introductionmentioning

confidence: 99%

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

Monasterio

Jansson

Gaitero

et al. 2013

The Journal of Chemical Physics

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Articles you may be interested inCause of the fragile-to-strong transition observed in water confined in C-S-H gel In this study, the rotational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel with a water content of 22 wt.% was studied by broadband dielectric spectroscopy in broad temperature (110-300 K) and frequency (10 −1 -10 8 Hz) ranges. The C-S-H gel was used as a 3D confining system for investigating the possible existence of a fragile-to-strong transition for water around 220 K. Such transition was observed at 220 K in a previous study

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“…The hydration of our lysozyme sample was limited roughly to the first water layer at the protein surface: this observation suggests that the observed relaxation dynamics is due to single water molecule reorientational dynamics and not to the viscosity, in agreement with ref. [49]. Since the fast relaxation time measured for water confined within the pores of xerogel or MCM41-S15 has almost the same behavior as that of lysozyme hydration water, with no clear dependence on the pore size (~40 Å for xerogel and~20 Å for MCM), it is reasonable to ascribe it to the dynamics of the dense water layer wetting the pore surfaces, contrarily to what traditionally thought.…”

Section: Second Trick: Confinementmentioning

confidence: 85%

“…These interpretation has been criticized by several authors, who instead ascribe the claimed transition to the onset of finite size effects [46,47], or to an artifact of the data analysis [48]. More recently Capaccioli and co-workers [49] have cast some doubt about the relation between the NS data and the viscosity, based on the absence of such transition in their dielectric spectroscopy experiments.…”

Section: Second Trick: Confinementmentioning

confidence: 99%

How safe is to safely enter in the water no-man's land?

Bruni

Mancinelli

Ricci

2012

Journal of Molecular Liquids

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The role of primitive relaxation in the dynamics of aqueous mixtures, nano-confined water and hydrated proteins

Cited by 45 publications

References 121 publications

Molecular Dynamics of Poly(N-isopropylacrylamide) in Protic and Aprotic Solvents Studied by Dielectric Relaxation Spectroscopy

Molecular Dynamics of Poly(N-isopropylacrylamide) in Protic and Aprotic Solvents Studied by Dielectric Relaxation Spectroscopy

Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

How safe is to safely enter in the water no-man's land?

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