Confinement Effects and Active Nanostructure Control in Amphiphilic Systems

提案编号：CBET：0730392首席研究员：Arijit BoseUniversity/Institution：University of Rhode Island题目：两亲系统中的限制效应和主动纳米结构控制智力价值这个项目是一个实验项目，旨在了解系统地增加三维和二维限制条件下两亲自组装过程的后果。由于排除体积熵效应在高度受限的领域变得显着，它们可以大大有助于热力学管理的形成有组织的纳米结构在两亲性系统。该项目提出了一个假设，即这些排除的体积效应以及与边界表面的长程相互作用的熵贡献可以在有限的情况下产生一系列在散装系统中不存在的平衡形态。建议的实验遵循最近的结果，在我们的实验室中，我们已经观察到，对于CTAB/HDBS模型阴阳离子系统，由聚苯乙烯乳胶球产生的三维限制显着降低了在填充珠之间的空隙空间中形成的囊泡的大小。这些结果表明，近定量协议与一个简单的热力学模型，占两个热力学和自由体积熵贡献吉布斯自由能的变化。在拟议的研究中，一系列的模型两亲性系统和限制表面被故意选择为从基本上不吸收的表面活性剂分子的强烈吸收。将使用小角中子散射（SANS）、低温透射电子显微镜（cryo-TEM）和动态光散射来评价和了解纳米结构形态。他们将利用封闭系统中的高比表面积以及边界之间的小长度尺度来主动控制纳米结构。这些实验将为三维和二维约束条件下两亲系统的微观结构演变提供重要的新认识。更广泛的影响这项研究将有助于为开发几种技术提供基础，其中软胶体材料通过高度受限的领域，包括血管和皮肤中药物递送载体的命运，使用表面活性剂驱油、去污剂和胶束增强超滤从页岩中回收油。这项工作为研究生提供了一个机会，获得SANS和cryo-TEM的经验，这是一个不寻常的组合。本科生将获得冷冻TEM的经验。这项研究的内容将直接纳入PI为学生和行业参与者定期教授的“界面和胶体现象进展”课程。为了让更多的学生接触到电子显微镜，新的TEM抵达我们的校园将是互联网启用。互联网电子显微镜将通过URI开发的外展计划提供给当地高中学生和科学教师。此外，PI将在夏天在他的实验室接待一名少数民族高中生，从事一个独立的子项目。通过该计划提供的教师指导已经通过私人捐款资助，成功地鼓励高中生考虑科学和技术职业。他们将与我们的NSF资助的东北研究生教育联盟和教授（NEAGEP）计划密切合作，为这个项目招募一名代表性不足的学生。URI是NEAGEP的成员，并在校园内有一个计划，以积极解决代表性不足的少数民族学生在科学，数学和工程（SME）获得博士学位的短缺。URI在毕业生中有一个工作人员管理的中小企业招聘和保留单位。

Proposal Number: CBET: 0730392 Principal Investigator: Arijit BoseUniversity/Institution: University of Rhode IslandTitle: Confinement Effects and Active Nanostructure Control in Amphiphilic Systems Intellectual merit This project is an experimental program to understand ramifications to the amphiphilic self-assembly process under conditions of systematically increasing three- and two-dimensional confinement. Because excluded volume entropic effects in highly confined domains become significant, they can contribute strongly to the thermodynamics governing the formation of organized nanostructures in amphiphilic systems. The project proposes hypothesize that entropic contributions from these excluded volume effects as well as long-range interactions with bounding surfaces can produce a range of equilibrium morphologies in confined situations that are not present in bulk systems. The proposed experiments follow recent results in our laboratory, where we have observed that for a CTAB/HDBS model catanionic system, three-dimensional confinement produced by polystyrene latex spheres dramatically reduces the size of vesicles formed in the void spaces between the packed beads. These results show near quantitative agreement with a simple thermodynamic model that accounts for both enthalpic and free volume entropic contributions to the change in Gibbs free energy. In the proposed research, a range of model amphiphilic systems and confinement surfaces are deliberately chosen to vary from essentially non-absorbing to strongly absorbing for the surfactant molecules. Small Angle Neutron Scattering (SANS), Cryogenic Transmission Electron Microscopy (cryo-TEM), and dynamic light scattering to evaluate and understand nanostructure morphology will be used. They will exploit the high specific surface area available in confined systems as well as the small length scale between boundaries for active control of nanostructures. These experiments will provide important new understanding of microstructure evolution in amphiphilic systems underconditions of three- and two-dimensional confinement.Broader Impact This research will help provide a fundamental basis for the development of several technologies where soft colloidal materials are passed through highly constrained domains, including the fate of drug delivery vehicles in blood vessels and in the skin, recovery of oil from shale using surfactant flooding, detergency and micellar enhanced ultrafiltration. The work provides an opportunity for graduate students to gain experience in SANS and cryo-TEM, a combination that is unusual. Undergraduates will get experience with cryo-TEM. Contents from this research will be incorporated directly into a 'Advances in Interfacial and Colloidal Phenomena' course taught regularly by the PI for students and industry participants. In order to expose more students to electron microscopy, the new TEM arriving on our campus will be internet-enabled. The internet electron microscope will be offered to local high school students and science teachers through an outreach program being developed at URI. In addition, the PI will host a minority high school student in his laboratory over the summer, to work on an independent sub-project. The faculty mentorship provided through this program, already funded through private donations, has been successful in encouraging high school students to think about careers in science and technology. They will work closely with our NSF-funded Northeast Alliance for Graduate Education and the Professoriate (NEAGEP) program to recruit an underrepresented student for this project. URI is a member of NEAGEP and has a program in place on campus to proactively address the shortage of underrepresented minority students receiving Ph.D.s in the sciences, mathematics and engineering (SME). URI has a staffed administrative SME Recruitment and Retention Unit within the Graduate.