Cation effects on phase transition of kappa-iota-carrageenan hybrids: a photon transmission study
Yükleniyor...
Dosyalar
Tarih
2007
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Taylor & Francis Group
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Phase transitions of kappa-iota-carrageenan hybrid in various types of salts were studied using photon transmission technique: NaCl, KCI, MgCl2, CaCl2 and KCl+CaCl2 were chosen as the salt solutions for the carrageenan hybrid. Coil-to-helix (c-h), helix-to-dimer (h-d) and back to helix-to-coil (h-c), dimer-to-helix (d-h) phase transitions of carrageenan hybrid in these mono- and bivalent cation solutions were studied upon cooling and heating, respectively. Photon transmission intensity, It, was monitored against temperature to determine the (c-h), (h-d) and (h-c), (d-h) transition temperatures (T-ch, T-hd and T-hc, T-dh) and activation energies (Delta E-ch, Delta E-hd and Delta E-hc, Delta E-dh) of carrageenan hybrids. Two distinct transition regions were observed both during heating and cooling of the carrageenan-bivalent salt systems. During the heating process, at first dimers decompose into helices by making a (d-h) transition. Then at the high temperature region, a (h-c) transition takes place. During cooling, back transitions repeat themselves. However, the carrageenan-monovalent salt system presented only (c-h) and (h-c) transitions during the cooling and heating processes, respectively. A hysteresis was observed between (h-c)-(c-h) and (d-h)-(h-d) transitions for the monovalent and bivalent cation systems respectively.
Açıklama
Anahtar Kelimeler
Carrageenan hybrid, Activation energy, Hysteresis, Transition temperature, Phase transition, Salt solution, Conformational transition, Sol-gel, Indicative evidence, Liquid-crystal, Real-time, Gelation, Systems, Dynamics, Release, Organic compounds, Positive ions, Superconducting transition temperature, Bivalent cation systems
Kaynak
Composite Interfaces
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
14
Sayı
1
Künye
Arda, E., Kara, S. & Pekcan, M. Ö. (2007). Cation effects on phase transition of kappa-iota-carrageenan hybrids: A photon transmission study. Composite Interfaces, 14(1), 1-19. doi:10.1163/156855407779230344
