Neutron scattering studies of CO2-based gels

该项目将提供基于稠密CO2的复杂流体，结合设计的自组装结构，以改变CO2的粘度和表面张力。从中期来看，这些系统有可能改进碳捕获技术，并加强二氧化碳作为溶剂的工业加工应用。小角中子散射（SANS）是用于确定这些复杂流体系统中的形状和尺寸的选择方法，因为它对与优化本体液体的粘性性质相关的适当胶体和分子长度尺度敏感。因此，获得世界一流的SANS设施对该方案至关重要。该方法是生成将在CO2中形成蠕虫状胶束的亲CO2表面活性剂。该策略是将最近在CO2表面活性剂设计方面的突破[1]与某些有机添加剂和无机抗衡离子诱导缠结的跨越系统的线状胶束的能力[2]结合起来。这种方法的可行性已经通过之前在ISIS进行的定量限SANS实验得到了证明。学生将在ISIS接受样品制备相关化学技术和SANS方法学的培训。自组装结构将由ISIS的高压SANS（TSII上的LOQ和SANS 2d）使用现有的，即将投入使用的专用HP-SANS高压电池进行研究。匹兹堡大学的合作者Enick和Beckman教授将研究高压粘度特性（附录1）。1)设计的亲CO2分子稳定二氧化碳包水微乳液J. Eastoe，S. Gold，S.Rogers，P. Wyatt，D. C. Steytler，A.Gurgel，R.K. Heenan，X. Fan，E.J. Beckman和R.M. Enick，Angewandte Chemie，2006，45，3675- 3677。杨，胶体与界面科学新观点，2002，7，276-281.

The project will deliver complex fluids based on dense CO2, incorporating designed self-assembly structures for modifying viscosity and surface tension of CO2. In the medium term, these systems have potential to improve carbon capture technologies, as well as to enhance industrial processing applications of CO2 as a solvent. Small-angle neutron scattering (SANS) is the method of choice for determining shapes and sizes in these complex fluids systems, since it is sensitive to the appropriate colloidal and molecular length scales relevant for optimizing viscous properties of the bulk liquid. Therefore, access to world-class SANS facilities is essential for the programme. The approach is to generate CO2-philic surfactants that will form worm-like micelles in CO2. The strategy is to marry up recent breakthroughs in CO2 surfactant design [1], with the ability of certain organic additives and inorganic counterions to induce entangled system-spanning thread-like micelles [2]. Feasibility for this approach has been demonstrated by previous SANS experiments on LOQ at ISIS.The student will be trained in relevant chemical techniques for sample preparation and in SANS methodology at ISIS. The self-assembly structures will be investigated by High-Pressure SANS at ISIS (LOQ and SANS 2d on TSII) using existing, and soon to be commissioned, dedicated HP-SANS high-pressure cells. High-pressure viscosity properties will be studied by collaborators Professors Enick and Beckman of the University of Pittsburgh (Appendix 1). 1) Designed CO2-philes Stabilize Water-in-Carbon Dioxide MicroemulsionsJ. Eastoe, S. Gold, S.Rogers, P. Wyatt, D. C. Steytler, A.Gurgel, R.K. Heenan, X. Fan, E.J. Beckman and R.M. Enick, Angewandte Chemie, 2006, 45, 3675-3677.2) Viscoelastic worm-like micelles and their applicationsJ. Yang, Current Opinion in Colloid and Interface Science, 2002, 7, 276-281.