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Evidence of microphase separation in controlled pore glasses

Vyalikh, A. and Emmler, T. and Gedat, E. and Shenderovich, I. and Findenegg, G. H. and Limbach, H. H. and Buntkowsky, G. (2005):
Evidence of microphase separation in controlled pore glasses.
28, In: Solid State Nuclear Magnetic Resonance, (2-4), pp. 117-124, [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

The phase separation of a mixture of water and isobutyric acid (iBA) confined in the pore space of Controlled Pore Glass (CPG) 10-75 has been studied by H-1 NMR relaxometry and H-1-pulsed field gradient (PFG) diffusion measurements. For an acid-rich mixture (mass fraction 54wt iBA), evidence of a phase separation process in the pores was obtained, which occurs in a temperature window between 32 and 39 degrees C, as indicated in the PFG data by an anomalous temperature dependence of the diffusion coefficient and in the relaxation data by a bi-exponential magnetization decay. The phase separation temperature of the mixture in the pore is slightly lower than in the bulk mixture of the same composition (41 degrees C) and extends over a finite temperature range. A qualitative model of the phase separation process in the pores is developed, which assumes a temperature-dependent domain-like structure of the liquid below the phase transition temperature and a breakdown of these domains upon reaching the transition temperature. (c) 2005 Elsevier Inc. All rights reserved.

Item Type: Article
Erschienen: 2005
Creators: Vyalikh, A. and Emmler, T. and Gedat, E. and Shenderovich, I. and Findenegg, G. H. and Limbach, H. H. and Buntkowsky, G.
Title: Evidence of microphase separation in controlled pore glasses
Language: English
Abstract:

The phase separation of a mixture of water and isobutyric acid (iBA) confined in the pore space of Controlled Pore Glass (CPG) 10-75 has been studied by H-1 NMR relaxometry and H-1-pulsed field gradient (PFG) diffusion measurements. For an acid-rich mixture (mass fraction 54wt iBA), evidence of a phase separation process in the pores was obtained, which occurs in a temperature window between 32 and 39 degrees C, as indicated in the PFG data by an anomalous temperature dependence of the diffusion coefficient and in the relaxation data by a bi-exponential magnetization decay. The phase separation temperature of the mixture in the pore is slightly lower than in the bulk mixture of the same composition (41 degrees C) and extends over a finite temperature range. A qualitative model of the phase separation process in the pores is developed, which assumes a temperature-dependent domain-like structure of the liquid below the phase transition temperature and a breakdown of these domains upon reaching the transition temperature. (c) 2005 Elsevier Inc. All rights reserved.

Journal or Publication Title: Solid State Nuclear Magnetic Resonance
Volume: 28
Number: 2-4
Uncontrolled Keywords: phase separation nmr diffusometry mesoporous silica nuclear-magnetic-resonance anisotropic self-diffusion solid-state nmr mesoporous silica porous silica water mcm-41 relaxation benzene surface
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:51
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
Additional Information:

998NH Times Cited:12 Cited References Count:41

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