Fourier transform infrared study on the phase transitions of an octadecyltrimethylammonium chloride-water system

Infrared Spectroscopy of Anionic, Cationic, and Zwitterionic Surfactants

“…The problem is that some surfactants show a broad band in the spectral region between 1300 and 900 cm −1 , which may be due to the water crystallization. The addition of several percentages of methanol as a cosolvent (20,40, and 60%) was tried to solve this matter, nevertheless 40% seemed to avoid perfectly this problem to each surfactant. Prosser and Franses [10] had pointed out that the contamination by residual ethanol may cause two problems in the preparation of the cast films.…”

“…Therefore, there is an increase of all-trans conformers on the methylene chain and a decrease of gauche ones. Figure 5(a) shows that the ν as (CH 2 ) feature for the CTAB molecule is lower than 2917 cm −1 and the ν sym (CH 2 ) frequency is lower than 2849 cm −1 , meaning that it is a crystalline phase, which distinguishes from a micelle conformation [46,47]. Figures 6(c) [45,[49][50][51][52].…”

Melt, Hydration, and Micellization of the PEO–PPO–PEO Block Copolymer Studied by FTIR Spectroscopy

“…Vibrational spectroscopy is a very powerful technique which has been extensively used to study the conformational states of the normal low molecular weight surfactant micelles in aqueous solution (25)(26)(27)(28)(29)(30)(31). Many spectral features of the low molecular weight surfactants are sensitive to the conformational changes, the inter-and intrachain interactions, and the chain mobility.…”

“…It is evident that a drastic change of the infrared spectrum occurs over a given temperature interval, with small changes before and after the temperature interval. The starting temperature of the interval can be taken as the phase transition temperature and the CMT (25,26).…”

Reflection–absorption FT-IR spectroscopy of pentadecanoic acid at the air/water interface

“…5. The width of the absorbance peak is dependent on the rotational motion and flexibility of the methylene chains [30,31,[39][40][41], with increased widths resulting from an increased mobility and flexibility [42]. Furthermore an increase in the hydrocarbon chain mobility reflects a reduction in the lateral interchain interactions and also indicates the presence of gauche rotamers.…”