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X‐ray Diffraction Studies on Mesophases of Cetyl‐ and Dodecyltrimethylammoniumbromide in Liquid Ammonia
Author(s) -
Bzik Stefan,
Jansen Martin
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390065
Subject(s) - monoclinic crystal system , lyotropic , lyotropic liquid crystal , dissolution , ammonia , mesoporous material , materials science , pulmonary surfactant , crystallography , aqueous solution , phase diagram , chemical engineering , phase (matter) , chemistry , liquid crystalline , organic chemistry , crystal structure , engineering , catalysis
We have studied solutions of the surfactants cetyltrimethylammoniumbromide (CTAB) and dodecyltrimethylammoniumbromide (DTAB) in liquid ammonia with respect to the formation of lyotropic phases. For this purpose, a set‐up for performing X‐ray scattering experiments at temperatures up to 120 °C on samples containing liquid ammonia has been developed. Both systems form hexagonal and monoclinic lyotropic phases above the dissolving temperature of the surfactant, thus representing the first examples for lyotropic phases in liquid ammonia, and for monoclinic phases in nonaqueous solvents. The phase diagrams of CTAB/liquid NH 3 and DTAB/liquid NH 3 show similarities to their respective aqueous systems. However, the regions of existence of monoclinic phases are much larger in the ammonia system, while the cubic phases, as observed in the water based systems, do not seem to exist. The liquid‐crystalline phases found provide potentiality for preparing mesoporous, nitride‐based solids.