High pressure studies on structural and secondary relaxation dynamics in silyl derivative of D-glucose
PBN-AR
Instytucja
Wydział Matematyki, Fizyki i Chemii (Uniwersytet Śląski w Katowicach)
Informacje podstawowe
Główny język publikacji
EN
Czasopismo
JOURNAL OF CHEMICAL PHYSICS (35pkt w roku publikacji)
ISSN
0021-9606
EISSN
1089-7690
Wydawca
AMER INST PHYSICS
DOI
URL
Rok publikacji
2017
Numer zeszytu
6
Strony od-do
064502-1-8
Numer tomu
147
Identyfikator DOI
Liczba arkuszy
0,50
Autorzy
Pozostali autorzy
+ 4
Słowa kluczowe
EN
Chemical compounds
Spectroscopy
Carbohydrates
Amorphous solids
Polymers
Streszczenia
Język
EN
Treść
In this paper, broadband dielectric spectroscopy was applied to investigate molecular dynamics of 1,2,3,4,6-penta-O-(trimethylsilyl)-D-glucopyranose (S-GLU) at ambient and elevated pressures. Our studies showed that apart from the structural relaxation, one well resolved asymmetric secondary process (initially labeled as β) is observed in the spectra measured at p = 0.1 MPa. Analysis with the use of the coupling model and criterion proposed by Ngai and Capaccioli indicated that the β-process in S-GLU is probably a Johari-Goldstein relaxation of intermolecular origin. Further high pressure experiments demonstrated that there are in fact two secondary processes contributing to the β-relaxation. Therefore, one can postulate that the coupling model is a necessary, but not sufficient criterion to identify the true nature of the given secondary relaxation process. The role of pressure experiments in better understanding of the molecular origin of local mobility seems to be much more important. Interestingly, our research also revealed that the structural relaxation in S-GLU is very sensitive to compression. It was reflected in an extremely high pressure coefficient of the glass transition temperature (dTg/dp = 412 K/GPa). According to the literature data, such a high value of dTg/dp has not been obtained so far for any H-bonded, van der Waals, or polymeric glass-formers.
Cechy publikacji
original-article
Inne
System-identifier
3342800136966
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