Spin-Probe ESR Study on the Dynamics of Liquid Molecules in the MCM-41 Nanochannel:  Temperature Dependence on 2-Propanol and Water

2005 ◽  
Vol 109 (27) ◽  
pp. 13180-13185 ◽  
Author(s):  
Masaharu Okazaki ◽  
Kazumi Toriyama
Keyword(s):  
Temperature Dependence ◽  
Spin Probe ◽  
Mcm 41

Properties of the Silica Layer during the Formation of MCM-41 Studied by EPR of a Silica-Bound Spin Probe

2005 ◽  
Vol 109 (16) ◽  
pp. 7807-7816 ◽  
Author(s):  
Debbie Baute ◽  
Veronica Frydman ◽  
Herbert Zimmermann ◽  
Shifi Kababya ◽  
Daniella Goldfarb
Keyword(s):  
Spin Probe ◽  
Silica Layer ◽  
Mcm 41

The Condensation Process of Alcohol Molecules in the Nanochannel of MCM-41:  A Spin-Probe ESR Study

2008 ◽  
Vol 112 (3) ◽  
pp. 786-793 ◽  
Author(s):  
Masaharu Okazaki ◽  
Shinpei Iwamoto ◽  
Yoshimi Sueishi ◽  
Kazumi Toriyama
Keyword(s):  
Spin Probe ◽  
Condensation Process ◽  
Mcm 41

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.

Spin-Probe ESR Study on the Entrapment of Organic Solutes by the Nanochannel of MCM-41 in Benzene

Langmuir ◽  
2007 ◽  
Vol 23 (3) ◽  
pp. 1215-1222 ◽  
Author(s):  
Masaharu Okazaki ◽  
Sambandam Anandan ◽  
Sindhu Seelan ◽  
Masakazu Nishida ◽  
Kazumi Toriyama
Keyword(s):  
Spin Probe ◽  
Organic Solutes ◽  
Mcm 41

Temperature dependence of molecular motions in the polyurethane-based membranes studied with paramagnetic spin probe

Polymer ◽  
2005 ◽  
Vol 46 (8) ◽  
pp. 2461-2471 ◽  
Author(s):  
A. Wolińska-Grabczyk ◽  
W. Bednarski ◽  
A. Jankowski ◽  
S. Waplak
Keyword(s):  
Temperature Dependence ◽  
Spin Probe ◽  
Molecular Motions

Spin-Probe Study on the Dynamics and Distribution of Solution Molecules in the Nano-Channel of MCM-41

2004 ◽  
Vol 77 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Masaharu Okazaki ◽  
Kazumi Toriyama ◽  
Naoya Sawaguchi ◽  
Kiichi Oda
Keyword(s):  
Spin Probe ◽  
Nano Channel ◽  
Mcm 41

Temperature dependence of amplitudes of libration motion of guest spin-probe molecules in organic glasses

1999 ◽  
Vol 110 (16) ◽  
pp. 8150-8154 ◽  
Author(s):  
S. V. Paschenko ◽  
Yu. V. Toropov ◽  
S. A. Dzuba ◽  
Yu. D. Tsvetkov ◽  
A. Kh. Vorobiev
Keyword(s):  
Temperature Dependence ◽  
Spin Probe ◽  
Probe Molecules ◽  
Organic Glasses ◽  
Libration Motion
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