胶束
粘弹性
层状结构
烷基
化学工程
液晶
离子液体
材料科学
化学
结晶学
高分子化学
有机化学
水溶液
复合材料
光电子学
工程类
催化作用
作者
Yimin Hu,Yu Chen,Zixian Cai,Shaoan Lei,Rong Guo
出处
期刊:Langmuir
[American Chemical Society]
日期:2023-05-10
卷期号:39 (20): 7143-7153
被引量:1
标识
DOI:10.1021/acs.langmuir.3c00574
摘要
The viscoelasticity of wormlike micelles composed of ionic surfactants typically shows an exponential decrease with increasing temperature, which limits their application in relatively high-temperature (>90.0 °C) oilfields and the synthesis of functional materials as supramolecular templates at high temperatures. In this work, a series of imidazolium gemini surfactants, 1,9-(ethane-1,2-diyl)bis(3-alkyl-1H-imidazol-3-ium) bromide ([Cn-2-Cnim]Br2, n = 12, 14, 16, 18, 20), were synthesized. Their surface activities and aggregation behaviors in water were studied by electrical conductivity, rheology, polarization optical microscopy, small-angle X-ray scattering, ζ potential, and hydrogen nuclear magnetic resonance measurements. [C12-2-C12im]Br2 and [C14-2-C14im]Br2 mainly precipitate in water. [Cn-2-Cnim]Br2 (n = 16, 18, 20) forms lamellar liquid crystals over a large range of concentrations at low temperatures. With the increase of temperature, the lamellar liquid crystals transit to wormlike micelles. Interestingly, the viscoelasticity of the three wormlike micelles first increases to the maximum and then decreases with increasing temperature. These wormlike micelles without additives retain high viscoelasticity up to 90.0 °C or above. With the increase of the alkyl chain length of the surfactants, the transition temperature of lamellar liquid crystal to wormlike micelles and the disintegration temperature of wormlike micelles increase. The unusual increase of the viscoelasticity of wormlike micelles was due to the desorption of weakly bound counterions and the extension of the long hydrophobic chains of surfactants at high temperatures.
科研通智能强力驱动
Strongly Powered by AbleSci AI