在前离子离子液体中自发热可逆形成的阴离子囊泡
Carlos R López-Barrón1, Dongcui Li, Leo DeRita
1Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA.
Journal of the American Chemical Society
|October 4, 2012
概括
研究人员发现,在一个纯的阴离子表面活性剂 (二氧化二甲基化物) 中,在一个质离子离子液体 (乙酸) 中,自发的囊泡形成. 这一发现提供了这种系统中平衡囊泡和海绵阶段的第一个证据.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 体科学 体科学 体科学
背景情况:
- 稳定的囊泡结构在各种应用中非常受欢迎.
- 很少有表面活性剂系统在真正的热力学平衡中自发形成囊泡.
- 了解像离子液体这样的新型溶剂中的自我组装是至关重要的.
研究的目的:
- 为了研究从一个纯的阴离子双尾表面活性剂在一个前离子离子液体中自发形成的囊泡.
- 使用先进的散射和显微镜技术来描述由此产生的囊泡结构和相位.
- 为这个系统中存在平衡囊泡提供实验证据.
主要方法:
- 小角和超小角中子散射 (SANS/USANS) 用于确定结构性质.
- 风病学评估溶液粘度和流动行为.
- 明亮场显微镜用于直接可视化囊泡形态和大小.
主要成果:
- 在乙烯酸 (EAN) 中,首次实验证实了二甲基二甲基化物 (DDAB) 的自发囊泡形成.
- 识别了两个同时存在的含有囊泡的阶段:一个低密度,高粘度的阶段与巨型囊泡和海绵阶段,以及一个稀释的,高密度的阶段与大囊泡.
- 囊泡通过不同的热力学路径自发形成,呈现一致的尺寸分布,支持真正的热力学平衡.
- 通过离子交换和在前离子离子液体内的溶效应促进平衡囊泡和L(3) 阶段的形成.
结论:
- 该研究表明,平衡囊泡的自发形成来自一个纯的阴离子表面活性剂在一个离子液体.
- 离子交换和离子液体内的溶恐惧相互作用是形成这些稳定结构的关键驱动因素.
- 这项工作为在离子液体环境中设计自组装软材料开辟了新的途径.
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