Synthesis and Solution Chemistry of Dimeric Surface Active Agents - Enhancement of Surface Activity, Solubilization, and Rheology.

在过去的几十年里，表面活性剂（surface-active-agents的缩写）在化学应用中的使用已经获得了显着和不同的兴趣。除了通常用作洗涤剂和乳化剂外，表面活性剂还被用作合成纳米颗粒、改进药物递送系统以及新型高性能油漆和涂料的反应介质。 通常，表面活性剂由单个疏水尾部（通常为烃）和强极性或离子头基组成。 在过去的6年里，我们在StFX大学的NSERC发现赠款（DG）计划已经合成了含有多个头基的新型两亲物（所谓的双子和其他多头表面活性剂），利用多功能的构建单元（例如，季戊四醇和氨基酸）。 该计划的积极研究成果是表面活性剂结构的化学改性与表面活性剂溶液性能变化之间存在的联系。 本实验室目前正在合成具有上级耐硬水性（在硬水中没有皂垢和良好的发泡能力）和优异的洗涤/乳化性能的表面活性剂。 本实验中进行的项目分为以下一个或多个主题： 1.新型表面活性剂的合成 2.对自组装过程的分子性质有基本的了解; 3.多核核磁共振波谱在探测胶束体系和聚合物-表面活性剂复合物分子结构中的应用; 4.通过改变表面活性剂分子中的向液-离液平衡形成的不寻常的和大的表面活性剂组装体的显微镜检查。 这项由NSERC DG资助的研究将继续研究表面活性剂聚集的基本化学和商业重要方面。重点领域将是合成不对称双子表面活性剂（双头，双尾表面活性剂与不等的尾巴长度）和相关化合物，并测量其溶液性质。 我们还将确定两性离子表面活性剂和双子表面活性剂与其他表面活性剂和聚合物的混合物的基本溶液性质。 该计划的目标是通过了解表面活性剂结构的变化如何改变负责其聚集成简单的球形胶束，蠕虫状胶束和巨型囊泡的力的微妙平衡，更好地了解表面活性剂的化学结构/性能。 UG和硕士生在这些项目上的工作将在表面活性剂合成方面进行培训，拥有400 MHz核磁共振，光散射仪器，表面张力计，流变仪的实践经验，将建立自己的离子特定电极，并将在高度结构化的ISO样研究环境中进行培训。

The use of surfactants (short for surface-active-agents) in chemical applications has gained significant and varied interest over the last few decades. In addition to their common use as detergents and emulsifiers, surfactants have been employed as a reaction medium for the synthesis of nanoparticles, improved drug delivery systems, and in new high-performance paints and coatings. Conventionally, surfactants consist of a single hydrophobic tail (generally a hydrocarbon) and a strongly polar or ionic headgroup. Over the past 6 years, our NSERC Discovery Grants (DG) program at StFX University has synthesized novel amphiphiles containing multiple headgroups (so-called gemini and other multi-headed surfactants), utilizing versatile building blocks (e.g., pentaerythritol and amino acids). Positive research outcomes from this program are the link that exists between the chemical modification of the surfactant structure and the change in the solution performance of the surfactant that results. This lab is currently synthesizing surfactants that have superior hard water tolerance (no soap scum and good foaming ability in hard water) and excellent detergency/emulsification properties as a result of this research. Projects undertaken in this lab fall into one or more of the following themes: 1. The synthesis of new surfactants; 2. A fundamental understanding of the molecular nature of the self-assembly process; 3. Applications of multi-nuclear nmr spectroscopy in probing the molecular structure of micellar systems and polymer- surfactant complexes; and 4. Microscopic examination of unusual and large surfactant assemblies formed through altering the kosmotropic-chaotropic balance in the surfactant molecules. This NSERC DG funded research will continue to investigate fundamental chemical and commercially important aspects of surfactant aggregation. An area of focus will be the synthesis of asymmetric gemini surfactants (twin-headed, twin-tailed surfactants with an unequal tail length) and related compounds, and the measurement of their solution properties. We will also determine the fundamental solution properties of mixtures of zwitterionic surfactants and gemini surfactants with other surfactants and polymers. The objectives of the program are a better understanding of surfactant chemical structure/performance by understanding the how the variation in the surfactant structure changes the subtle balance of forces responsible for their aggregation into simple, spherical micelles, worm-like micelles, and giant vesicles. UG and Masters's students working on these projects will be trained in surfactant syntheses, have hands-on experience with a 400 MHz nmr, a light scattering instrument, surface tensiometers, rheometers, will build their own ion-specific electrodes, and will be trained in a highly structured, ISO-like research environment.