GOALI: Large-Scale Structures in Colloids with Moderate-Range Attractions

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。[05:35 . 51]具有吸引粒子间势的胶体粒子从基础和应用的角度来看都是重要的。迄今为止，大部分研究都集中在具有短程吸引力的胶体上，这种胶体可能形成有吸引力的胶体玻璃或网状凝胶。然而，最近的研究表明，在具有中等范围引力的系统中，可能会形成一种包含稳定致密颗粒团簇的新相。这些令人兴奋的结果强调了吸引力范围作为确定吸引胶体相行为的附加参数的重要性。在这个GOALI项目中，我们将对各种吸引相互作用如何影响胶体分散体中的大规模结构（包括有限大小团簇的聚集和形成）有一个基本的了解，并将这些知识应用于开发改进的调色剂配方。我们将自己限制在由桥链引起的吸引力以及颗粒聚合物尺寸比为0(1)的系统中。我们的研究与以前的工作不同，我们将使用小角散射来量化粒子间势，并使用散射和成像技术来探索结构。该提案的主要目标是：1。开发一个可以调整引力范围的模型系统，并利用小角中子散射表征粒子间势；2. 利用超小角中子散射（USANS）、动态光散射、共聚焦显微镜和透射电镜探测静止系统中的大尺度结构和聚集；3. 研究剪切对团簇形态和流变性能的影响；和4。通过研究生实习和施乐公司研究人员提供的工业互动，测试我们的发现在工业相关系统中的可扩展性。施乐公司对胶体聚合在碳粉生产中的应用很感兴趣，并将作为该目标的工业合作伙伴。通过促进研究成果转化为工业相关技术，并通过扩大参与该项目的研究生和本科生的培训经验，施乐作为合作伙伴将增加价值。施乐公司的员工将积极参与，在定期的研究小组会议上提供意见和建议，安排学生实习来评估研究对碳粉生产的适用性，为部分工作提供资金支持，并参加工业短期课程。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).0853551BhatiaColloidal particles with attractive interparticle potentials are important from both a fundamental and applications standpoint. Much of the research to date has focused on colloids with short-range attractions, which may form either attractive colloidal glasses or networked gels. However, recent studies have shown that a new phase containing stable dense clusters of particles may be formed in systems with moderate-range attractions. These exciting results underscore the importance of the range of attraction as an additional parameter to explore in determining the phase behavior of attractive colloids. In this GOALI project, we will develop a fundamental understanding of how the range of attractive interactions impacts large-scale structure in colloidal dispersions, including aggregation and formation of finite sized clusters, and apply this knowledge to develop improved toner formulations. We confine ourselves to systems in which the attractions arise from bridging chains and in which the particle polymer size ratio is O(1). Our study distinguishes itself from previous work in that we will both quantify the interparticle potential using small angle scattering and explore structure using scattering and imaging techniques. The main objectives of the proposal are to: 1. Develop a model system where the range of attraction can be tuned, and characterize the interparticle potential using small angle neutron scattering; 2. Probe large scale structure and aggregation in systems at rest using ultra-small angle neutron scattering (USANS), dynamic light scattering, confocal microscopy, and TEM; 3. Investigate the effect of shear on cluster morphology and rheology; and 4. Test the extensibility of our findings to industrially relevant systems, through graduate student internships and industrial interactions provided by researchers at Xerox Corporation. Xerox Corporation is interested in applications of colloidal aggregation to toner production and will serve as the industrial partner for this GOALI. Inclusion of Xerox as a partner will add value by facilitating transfer of the research results into an industrially relevant technology and by broadening the training experiences of graduate and undergraduate students involved in the project. Xerox personnel will actively participate by providing comments and suggestions at regular research team meetings, by arranging student internships to evaluate the applicability of the research to toner production, by providing funds in support of portions of the work, and by participating in an industrial short course.