Effect of Hydrogen Bonding on the Physicochemical Properties and Bilayer Self-Assembly Formation of N-(2-Hydroxydodecyl)-L-alanine in Aqueous Solution

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• 作者：Arjun Ghosh ; Joykrishna Dey
• 刊名：Langmuir
• 出版年：2008
• 出版时间：June 17, 2008
• 年：2008
• 卷：24
• 期：12
• 页码：6018 - 6026
• 全文大小：453K
• 年卷期：v.24,no.12(June 17, 2008)
• ISSN：1520-5827

文摘

The aggregation behavior of N-(2-hydroxydodecyl)-L-alanine (C₁₂HAla) and N-(n-dodecyl)-L-alanine (C₁₂Ala) was studied in aqueous buffer (pH 12) over a concentration range above their critical aggregation concentration (cac). The C₁₂HAla amphiphile has two cacs in contrast to only one cac value for C₁₂Ala. The micropolarity and microviscosity of the aggregates were studied by use of pyrene and 1,6-diphenyl-1,3,5-hexatriene, respectively, as fluorescent probes. Dynamic light scattering was used to measure the average hydrodynamic diameter and size distribution of the aggregates. Large size, high microviscosity, and low micropolarity values of the aggregates suggested the formation of bilayer structures in dilute solutions of C₁₂HAla. In contrast, C₁₂Ala was observed to form micelles. Transmission electron micrographs of dilute and moderately concentrated solutions of C₁₂HAla revealed the existence of spherical vesicles and branching tubular structures, respectively. Comparison of the aggregation behavior of these amphiphiles to that of C₁₂Ala and the FT-IR spectrum suggested that intermolecular hydrogen-bonding interactions between adjacent hydrocarbon chains through the -OH and -NH- groups of C₁₂HAla are responsible for bilayer formation. The mechanism of nanotube formation was discussed. The temperature dependence of aggregate formation of the amphiphile also was investigated.