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Effects of Water Contamination on the Supercooled Dynamics of a Hydrogen-Bonded Model Glass Former

Johan Sjöström (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; Rikard Bergman (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; Carl Wadell (Institutionen för teknisk fysik, Kemisk fysik) ; Tobias Moberg (Institutionen för material- och tillverkningsteknik, Polymera material och kompositer) ; Jan Swenson (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; J Mattsson
Journal of Physical Chemistry B (1520-6106). Vol. 115 (2011), 8, p. 1842-1847.
[Artikel, refereegranskad vetenskaplig]

Broad-band dielectric spectroscopy is a commonly used tool in the study of glass-forming liquids. The high sensitivity of the technique together with the wide range of probed time scales makes it a powerful method for investigating the relaxation spectra of liquids. One particularly important class of glass-forming liquids that is often studied using this technique consists of liquids dominated by hydrogen (H) bond interactions. When investigating such liquids, particular caution has to be taken during sample preparation due to their often highly hygroscopic nature. Water can easily be absorbed from the atmosphere, and dielectric spectroscopy is a very sensitive probe of such contamination due to the large dipole moment of water. Our knowledge concerning the effects of small quantities of water on the dielectric properties of these commonly investigated liquids is limited. We here demonstrate the effects due to the presence of small amounts of water on the dielectric response of a typical H-bonded model glass former, tripropylene glycol. We show how the relaxation processes present in the pure liquid are affected by addition of water, and we find that a characteristic water induced relaxation response is observed for water contents as low as 0.15 wt %. We stress the importance of careful purification of hygroscopic liquids before experiments and quantify what the effects are if such procedures are not undertaken.

Nyckelord: dielectric-relaxation processes, goldstein beta-relaxation, secondary, relaxations, transition, cellulose, spectroscopy, polymers, liquids, glycol

Denna post skapades 2011-03-17. Senast ändrad 2017-10-03.
CPL Pubid: 138090


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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kondenserade materiens fysik (1900-2015)
Institutionen för teknisk fysik, Kemisk fysik (1900-2015)
Institutionen för material- och tillverkningsteknik, Polymera material och kompositer (2005-2017)


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Relaxation dynamics of perturbed water and other H-bonded liquids