CAREER: Hierarchical Structures and Tunable Mechanics of Polyelectrolyte Complex-Interpenetrating Network (PEC-IPN) Hydrogels

非技术概述：水凝胶是一种含水的聚合物网络，应用于多种领域，包括药物输送、细胞和组织工程、生物粘合剂和组织密封剂以及生物传感。该项目将创造由两个相互交织的聚合物网络组成的新型自组装水凝胶，其中一个包含永久连接，另一个包含可逆连接，通过相反带电的聚合物之间的吸引静电相互作用将其结合在一起。这些新材料将具有复杂的、分层的纳米级结构和独特的弹性、流动和粘合性能，与下一代湿式粘合剂和组织密封剂的开发相关。此外，计划中的实验将促进我们对含电荷聚合物组装的基本理解，以及可逆连接网络支持永久连接网络缓慢原位生长的机制。在更广泛的背景下，该项目将通过动手实验和演示，新课程和课程模块，以及区域研究研讨会，进一步向高中，本科生和研究生了解和欣赏聚合物和粘合材料，聚合物物理和化学，以及先进的材料表征技术，从而激励下一代聚合物科学家。同时，软材料表征技术的教程和交互式软件数据分析工具的开发将有助于教育和扩大这些技术的用户基础，并为更广泛的科学界服务。技术概述：在固化期间和固化后，制造具有可控内聚性和粘附性的水凝胶仍然是一个挑战。该项目将为创建具有正交可调体积、界面强度和韧性的聚电解质络合互穿网络（PEC-IPN）水凝胶建立设计范例。对带相反电荷的嵌段聚电解质自组装成聚电解质复合物（PEC）网络的基础研究将阐明其层次结构、链动力学和力学性能，以及在PEC水凝胶中加入小分子或聚合物添加剂后这些物理属性的演变。将各种化学上可交联的单体和聚合物前体交联，结合到PEC水凝胶中，将被证明是制造具有可控网络微结构的PEC- ipn材料的途径。此外，所提出的研究将揭示PEC- ipn水凝胶的体弹性和韧性的增强，这是由于构成PEC网络的自组装PEC结构域的应力消散而产生的。因此，具有调整体积和界面机械性能的PEC-IPN水凝胶粘合剂将被开发出来，目标是作为坚固的水下粘合剂和组织密封剂的潜在应用。同时，这项工作将有助于建立PEC自组装的知识库，类似于传统两亲嵌段聚合物组件的现有知识库。因此，拟议的研究将开发一系列多功能自组装pecc基材料，与两亲嵌段聚合物组件相媲美，但又截然不同，并扩大其应用领域，如胶束药物和基因传递载体。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智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARY:Hydrogels are water-laden polymer networks with applications in diverse areas including drug delivery, cell and tissue engineering, bioadhesives and tissue sealants and biosensing. This project will create novel types of self-assembled hydrogels composed of two interweaving polymeric networks, with one containing permanent linkages and the other comprising reversible linkages held together by attractive electrostatic interactions among oppositely charged polymers. These new materials will feature complex, hierarchical nanoscale structures and unique elastic, flow and adhesive properties, with relevance in development of the next generation of wet adhesives and tissue sealants. Furthermore, the planned experiments will advance our fundamental understanding of the assembly of charge-containing polymers and the mechanisms through which reversibly-linked networks support the slow, in-situ growth of permanently linked networks. In the broader context, this project will further the understanding and appreciation of polymeric and adhesive materials, polymer physics and chemistry, and advanced material characterization techniques to high school, undergraduate and graduate students through hands-on experiments and demonstrations, new courses and course modules, and regional research symposia, thus motivating the next generation of polymer scientists. In parallel, development of tutorials and interactive software data analysis tools for soft material characterization techniques will contribute to educate and expand the user base of these techniques and serve the broader scientific community.TECHNICAL SUMMARY:Creating hydrogels with controlled cohesive and adhesive properties, during and after curing, remains a challenge. This project will institute design paradigms for creating polyelectrolyte complex-interpenetrating network (PEC-IPN) hydrogels featuring orthogonally tunable bulk and interfacial strengths and toughness. Fundamental studies of self-assembly of oppositely charged block polyelectrolytes into polyelectrolyte complex (PEC) networks will elucidate their hierarchical structure, chain dynamics and mechanical properties, and the evolution of these physical attributes upon inclusion of small molecule or polymeric additives in PEC hydrogels. Crosslinking of diverse chemically crosslinkable monomeric and polymeric precursors, incorporated in PEC hydrogels, will be demonstrated as routes to create PEC-IPN materials with controlled network microstructures. Furthermore, the proposed studies will reveal the enhancements in bulk elasticity and toughness of PEC-IPN hydrogels that emerge from stress dissipation in the self-assembled PEC domains constituting the PEC network. Consequently, PEC-IPN hydrogel adhesives with tuned bulk and interfacial mechanical properties will be developed, targeting potential applications as robust underwater adhesives and tissue sealants. Concurrently, this work will contribute towards establishing a knowledge base for PEC self-assemblies, analogous to the existing base for traditional amphiphilic block polymer assemblies. The proposed research will thus develop a family of versatile self-assembled PEC-based materials that rival yet are distinct from amphiphilic block polymer assemblies and expand the realm of their applications such as micellar drug and gene delivery vehicles..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.