NMR studies on the coupling of ion and water dynamics on various time and length scales in glass-forming LiCl aqueous solutions

2018 ◽  
Vol 149 (10) ◽  
pp. 104501 ◽  
Author(s):  
S. Schneider ◽  
M. Vogel
Keyword(s):  
Aqueous Solutions ◽  
Water Dynamics ◽  
Nmr Studies ◽  
Length Scales ◽  
Glass Forming

Length scales for fragile glass‐forming liquids

1995 ◽  
Vol 102 (13) ◽  
pp. 5408-5410 ◽  
Author(s):  
Raymond D. Mountain
Keyword(s):  
Length Scales ◽  
Glass Forming ◽  
Fragile Glass

scholarly journals 1H NMR Studies of Surfactants in Aqueous Solutions

2003 ◽  
Vol 19 (07) ◽  
pp. 675-680 ◽  
Author(s):  
Mao Shi-Zhen ◽  
◽  
Du You-Ru
Keyword(s):  
Aqueous Solutions ◽  
Nmr Studies ◽  
H Nmr

scholarly journals 2H NMR Studies on Water Dynamics in Functionalized Mesoporous Silica

2018 ◽  
Vol 232 (7-8) ◽  
pp. 1041-1058 ◽  
Author(s):  
Max Weigler ◽  
Martin Brodrecht ◽  
Hergen Breitzke ◽  
Felix Dietrich ◽  
Matthias Sattig ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Temperature Dependence ◽  
Liquid Water ◽  
Water Dynamics ◽  
Spin Lattice Relaxation ◽  
Nmr Studies ◽  
Solid Water ◽  
Water Species ◽  
Mcm 41 ◽  
Dynamic Crossover

AbstractMesoporous silica MCM-41 is prepared, for which the inner surfaces are modified by 3-(aminopropyl)triethoxysilane (APTES) in a controlled manner. Nitrogen gas adsorpition yields a pore diameter of 2.2 nm for the APTES functionalized MCM-41.2H nuclear magnetic resonance (NMR) and broadband dielectric spectroscopy (BDS) provide detailed and consistent insights into the temperature-dependent reorientation dynamics of water in this confinement. We find that a liquid water species becomes accompanied by a solid water species when cooling through ~210 K, as indicated by an onset of bimodal2H spin-lattice relaxation. The reorientation of the liquid water species is governed by pronounced dynamical heterogeneity in the whole temperature range. Its temperature dependence shows a mild dynamic crossover when the solid water species emerges and, hence, the volume accessible to the liquid water species further shrinks. Therefore, we attribute this variation in the temperature dependence to a change from bulk-like behavior towards interface-dominated dynamics. Below this dynamic crossover,2H line-shape and stimulted-echo studies show that water reorientation becomes anisotropic upon cooling, suggesting that these NMR approaches, but also BDS measurements do no longer probe the structural (α) relaxation, but rather a secondary (β) relaxation of water at sufficiently low temperatures. Then, another dynamic crossover at ~180 K can be rationalized in terms of a change of the temperature dependence of theβrelaxation in response to a glassy freezing of theαrelaxation of confined water. Comparing these results for APTES modied MCM-41 with previous findings for mesoporous silica with various pore diameters, we obtain valuable information about the dependence of water dynamics in restricted geometries on the size of the nanoscopic confinements and the properties of the inner surfaces.

Investigation on Correlation between the Modified Criterion and the Glass-Forming Ability for Metallic Glasses

2010 ◽  
Vol 97-101 ◽  
pp. 591-596
Author(s):  
Wen Bin Sheng ◽  
Chun Ming Zhang ◽  
Wan Li Gu
Keyword(s):  
Aqueous Solutions ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Statistical Correlation ◽  
Glass Forming Ability ◽  
Correlation Parameter ◽  
Glass Forming ◽  
A Value ◽  
The Relationship ◽  
Modified Equation

A modified criterion γ’ (=Tx/(1.5Tg+Tl) of glass-forming ability (GFA) for metallic glasses is suggested on the basis of present criterion γ (=Tx/(Tg+Tl) that correlates well with some systems including metallic glasses, some glassy oxides and some cryo-protective aqueous solutions. Results show that the modified criterion γ’ shows stronger correlation with the critical cooling rate Rc for metallic glasses than the criterion γ, which is demonstrated by a value increase in the statistical correlation parameter R2 from 0.9022 to 0.9037. Furthermore, a modified equation is given to reflect the relationship between γ’ and Rc.

scholarly journals The role of local-geometrical-orders on the growth of dynamic-length-scales in glass-forming liquids

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaikin Wong ◽  
Rithin P. Krishnan ◽  
Changjiu Chen ◽  
Qing Du ◽  
Dehong Yu ◽  
...  
Keyword(s):  
Length Scales ◽  
Glass Forming ◽  
Dynamic Length
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