CAREER: Telechelic triblock copolymers as a platform to design functional colloidal gels

胶体凝胶是一类独特的材料，根据加工条件的不同，其表现为固体或液体。这种灵活性使得它们对于开发下一代电池技术、实现增材制造工艺和模仿生物材料的性能至关重要。然而，在大多数凝胶中，类固体和类液体的性质相互依赖，极大地限制了它们在工业和科学应用中的实用性。为了解决这一关键的知识差距，该奖项旨在通过使用聚合物添加剂设计具有独立弹性和粘度的凝胶。这些特殊的聚合物具有末端基团，可以与分散的胶体结合，产生坚硬的固体状材料，在加工过程中容易分解，从而产生低粘度流体。这种方法将产生主要由溶剂组成的高效且具有成本效益的材料，但具有与高性能工程材料相当的机械性能。这些聚合物连接凝胶的性质将通过操纵聚合物化学来调整和优化，并使用光学显微镜和新的流变学方法进行表征。此外，该项目将开展有针对性的外展工作，重点是在STEM领域招募和留住LGBTQ+青年，以抵消持续低的参与率。拓展工作将包括与当地社区组织合作举办的实践体验研讨会，榜样介绍和指导，以及为罗德岛大学LGBTQ+学生建立一个以stem为重点的支持网络。胶体凝胶是在科学和工业应用中遇到的复杂软材料，从电池生产的浆液到组织工程的合成支架，再到3D打印的油墨。这些材料的性能主要取决于结构和动力效应之间的相互作用，这是它们涌现特性的基础。尽管许多应用需要竞争的设计约束，如强大的机械刚度和快速的传质，但大多数现有胶体系统的性质仍然是耦合的，这降低了合成的灵活性并限制了它们的设计。本实验研究一类新的流变改性剂-远旋三嵌段共聚物-旨在解耦胶体凝胶的线性和非线性力学性能。三嵌段共聚物的化学性质将被操纵，以产生扩展构象，促进桥的形成和驱动胶体自组装。此外，聚合物连接凝胶的结构和动态非均质性将被表征，这些层次性质与纳米级运输有关。最后，将使用新的流变学方案来表征聚合物连接胶体悬浮液的线性和非线性流变学，以确定高性能屈服应力流体。这些基础研究目标将被整合到罗德岛州LGBTQ+青年参与的全面教育和推广计划中。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Colloidal gels are a unique class of materials that behave like either solids or liquids depending on processing conditions. This flexibility makes them essential for developing the next generation of battery technology, enabling additive manufacturing processes, and mimicking the performance of biological materials. In most gels, however, the solid-like and liquid-like properties are dependent on each other, drastically limiting their utility in industrial and scientific applications. To address this critical knowledge gap, this award aims to design gels with independent elasticity and viscosity by using polymer additives. These specific polymers possess endgroups that bind to dispersed colloids to generate stiff solid-like materials that readily break down during processing to create low viscosity fluids. This approach will result in efficient and cost-effective materials comprised primarily of solvent but with mechanical properties comparable to high performance engineering materials. The properties of these polymer-linked gels will be tuned and optimized by manipulating polymer chemistry and characterized using optical microscopy and novel rheological procedures. Additionally, this project will engage in targeted outreach efforts focused on recruiting and retaining LGBTQ+ youth in STEM fields to offset persistently low participation rates. Outreach efforts will include hands-on experiential workshops conducted in collaboration with local community organizations, role model introductions and mentorship, and the development of a STEM-focused support network for LGBTQ+ students at the University of Rhode Island. Colloidal gels are complex soft materials encountered throughout scientific and industrial applications ranging from slurries for battery production to synthetic scaffolds for tissue engineering and to inks for 3D printing. The performance of these materials depends critically on the interplay between structural and dynamical effects that underlie their emergent properties. Although many applications require competing design constraints such as robust mechanical stiffness but rapid mass transfer, the properties of most existing colloidal systems remain coupled, reducing synthetic flexibility and limiting their design. This experimental investigation of a novel class of rheological modifiers – telechelic triblock copolymers – aims to decouple the linear and nonlinear mechanical properties of colloidal gels. The chemistry of the triblock copolymers will be manipulated to generate extended conformations that promote bridge formation and drive colloidal self-assembly. Additionally, the resulting structural and dynamic heterogeneity in the polymer-linked gels will be characterized and these hierarchical properties related to nanoscale transport. Finally, the linear and nonlinear rheology of polymer-linked colloidal suspensions will be characterized using novel rheological protocols to identify high-performance yield stress fluids. These fundamental research aims will be integrated into a comprehensive educational and outreach plan that engages LGBTQ+ youth in Rhode Island.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.