Monovalent and divalent cation effects on phase transitions of iota-carrageenan
Yükleniyor...
Dosyalar
Tarih
2007-01
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Sage Publications Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Phase transitions Of L-carrageenan in a variety of monovalent (Li, Na, K) and divalent (Mg, Ca, Sr) cation solutions were studied during heating and cooling by using photon transmission technique. Photon transmission intensity (I-tr) was monitored against temperature to determine the transition temperatures and activation energies during the heating and cooling processes in the monovalent and divalent systems. Three distinct transition regions were observed during the heating and cooling cycles for the carrageenan-divalent salt system. At the first step of the heating process, dimer groups were transformed into dimers that presented (g-d) transitions, then these dimers were directly converted into a double helix by undergoing a (d-h) transition. In the higher temperature region, a double helix-to-coil (h-c) transition took place. During the cooling process, these transitions are arranged in the order of (c-h), (h-d), and (d-g). The carrageenan-monovalent salt system presented only coil-to-rod-like helix (c-r) and rod-like helix-to-coil (r-c) transitions during the cooling and heating processes, respectively. A hysteresis was observed between (r-c)-(c-r) and (g-d)-(d-g) transitions for the monovalent and divalent cations, respectively.
Açıklama
Anahtar Kelimeler
Liquid-crystal, Perspectives, Dynamics, Gels, Drug-delivery systems, Photon transmission, Kappa-carrageenan, Carrageenan, Phase transition, Activation energy, Double helix, Hysteresis, Cooling, Dimers, High temperature effects, Magnesium printing plates, Phase transitions, Positive ions, Calcium, Divalent cation, Lithium, Magnesium, Monovalent cation, Potassium, Sodium, Strontium, Heating, Photon, Transition temperature, Cooling cycles, Transition temperatures, Salts
Kaynak
Journal of Bioactive and Compatible Polymers
WoS Q Değeri
Q3
Scopus Q Değeri
Q3
Cilt
22
Sayı
1
Künye
Kara, S., Arda, E. & Pekcan, M. Ö. (2007). Monovalent and divalent cation effects on phase transitions of iota-carrageenan. Journal of Bioactive and Compatible Polymers, 22(1), 42-61. doi:10.1177/0883911506073361
