New lyotropic mixtures with non-chiral n-acylamino acid surfactants presenting the biaxial nematic phase investigated by laser conoscopy, polarized optical microscopy and X-ray diffraction
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Dosyalar
Tarih
2014
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Mdpi Ag
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Amino acid-based surfactants were used as the main surfactants to prepare new lyotropic mixtures presenting three nematic phases. One of them is biaxial (N-B), and the two others are uniaxial, discotic (N-D) and calamitic (N-C). These surfactants were the non-chiral molecules, potassium N-dodecanoyl-DL-alaninate (DL-KDDA), potassium N-dodecanoyl-DL-serinate (DL-KDDS), disodium N-dodecanoyl-DL-aspartate (DL-NaDDAs) and potassium N-dodecanoyl-glycinate (KDDGly). Measurements of the optical birefringences and X-ray diffraction analysis were used to characterize the nematic phases and phase transitions. Mixtures with DL-KDDS exhibited the largest biaxial phase domain (similar to 9 degrees C) with respect to the other mixtures in this study. The results obtained with the KDDGly mixture showed that the existence of hydrogen bonding between the head groups of the surfactant molecules seems to hinder the orientation of the micelles under the action of an external magnetic field.
Açıklama
Anahtar Kelimeler
Biaxial Nematic, Phase Transitions, Birefringence, Laser Conoscopy, Structure, hydrogen bonding, X-ray Diffraction
Kaynak
Materials
WoS Q Değeri
Q1
Scopus Q Değeri
Q2
Cilt
7
Sayı
6
