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(表面活性剂的缩写)在化学应用中的应用受到了广泛的关注。除了通常用作洗涤剂和乳化剂外，表面活性剂还被用作反应介质，用于合成纳米粒子、改进药物输送系统以及用于新型高性能涂料和涂料。传统上，表面活性剂由一个疏水的尾巴(通常是碳氢化合物)和一个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发现资助(DG)项目利用多种构造物(例如季戊四醇和氨基酸)合成了含有多个头基(所谓的双子和其他多头表面活性剂)的新型两亲性化合物。该项目的积极研究成果是表面活性剂结构的化学修饰与由此产生的表面活性剂溶液性能变化之间存在的联系。由于这项研究，该实验室目前正在合成具有优异的耐硬水性能(无皂浮渣和在硬水中具有良好的起泡能力)和优异的洗涤/乳化性能的表面活性剂。 本实验中开展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本质有一个基本的了解； 3.多核核磁共振波谱在胶束体系和聚合物-表面活性剂络合物分子结构研究中的应用 4.通过改变表面活性剂分子中的共沸-共沸平衡而形成的异常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础化学和商业重要方面。一个重点领域将是不对称双子表面活性剂(双头、双尾、尾长不等的表面活性剂)和相关化合物的合成，以及它们的溶液性质的测量。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导致其聚集成简单的球形胶束、蠕虫状胶束和巨大囊泡的力的微妙平衡，从而更好地了解表面活性剂的化学结构/性能。UG和硕士在这些项目中工作的学生将接受表面活性剂合成方面的培训，拥有400 MHz核磁共振、光散射仪、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类似ISO的研究环境中接受培训。

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.