Dynamic Bonds and Mechanical Properties of Tough Hydrogels: Medical Device and Gel Electrolyte Applications

背景资料。动态键，即可以由外部刺激以可逆方式释放的物理或化学键，是智能软材料最基本的构建块。虽然单个动态键可以被认为是弱的，但坚韧的水凝胶(断裂能~10000 J/m2)已经通过聚集氢键或离子对来实现，这也使得可逆粘着和自愈成为可能。尽管具有重要的技术意义和经验上的成功，但目前对这些动态键团簇与韧性水凝胶的机械性能之间的相关性的了解还处于起步阶段。这个问题在一定程度上是因为现有实验工具的能力有限。 解决方案。方案1的总体目标是建立微通道悬臂梁传感器，其振动由激光多普勒振动仪监测，作为研究(水)凝胶中动态键的标准工具。该方法是为生物传感中的超灵敏检测而建立的，其另外两个优点是皮升样本量和振动模式的多样性。短期目标(3年)是验证微通道悬臂技术作为定量微观流变学工具的有效性。在中长期计划中(5年及以后)，与聚合物化学家、密度泛函理论专家和力学理论家的合作将使动态键的特征(如单/簇键强度和缔合/解离动力学)与动态力学性质(复杂模数的时间分辨演化)之间建立定量关联。 应用程序。为了补充我目前在生物医学设备和电池凝胶电解液方面的研究计划，计划2是关于粘性水凝胶的分子设计。近期和中期(5年)的目标是研制出既能快速使用又能按需释放的止血凝胶垫。长期目标(超过5年)是将伤口敷料或可植入生物电子设备集成到粘性水凝胶平台上，用于先进的医疗设备，这将通过汇聚我的整个研究活动来实现。 冲击力。在软材料的所有学科中，对动态键及其对机械性能的影响的基本了解是巨大的。粘性和坚韧水凝胶的分子设计可以转化为橡胶、粘合剂和涂层等传统技术，以及生物医疗设备、药物输送和软机器人等新兴技术领域。拟议的DG补充了我的整个研究计划，成为一个具有强大科学基础的自我一致的统一。在我独特的、高度跨学科的研究项目中培训的HQP将具备未来社会对工程师所需的素质，在未来社会，学科之间的融合是关键。来自拟议的DG的科学/技术发现和训练有素的HQP将发展加拿大和世界的学术界和工业界。

BACKGROUND. Dynamic bonds, physical or chemical bonds that can be released by external stimuli in a reversible way, are the most fundamental building block for smart soft materials. While individual dynamic bond may be considered as weak, tough hydrogels (fracture energies of ~10,000 J/m2) has been realized by clustering hydrogen bonds or ionic pairs, which also enables reversible adhesion and self-healing. Despite of the technological importance and empirical successes, current understanding on the correlation between these dynamic bond clusters and the mechanical properties of tough hydrogels at its infancy. This problem is partly because of limited capability of existing experimental tools. SOLUTION. Overall objective of PROGRAM 1 is to establish microchannel cantilever sensor, whose vibration being monitored by laser Doppler vibrometer, as a standard tool for studying the dynamic bonds in (hydro)gels. Established for ultrasensitive detection in biosensing, the two additional merits of the method are picoliter sample size and the variety of vibration modes. The short-term objective (3 years) is to validate the microchannel cantilever technology as a tool for quantitative microrheology. In mid- to long-term plan (5 years and beyond), collaborations with polymer chemists, density functional theory experts, and mechanics theoretician will make quantitative correlations between the characteristics of dynamic bonds (such as individual/clustered bond strength and association/dissociation kinetics) and dynamic mechanical properties (time-resolved evolution of complex moduli). APPPLICATION. With a purpose to complement my current research programs on biomedical devices and battery gel electrolytes, PROGRAM 2 is on molecular design of sticky hydrogels with tunable adhesion. The short- to mid-term objective (5 years) is to fabricate hemorrhage suppressing gel pad that can apply quickly and then release on demand. Long-term objective (beyond 5 years) is to integrate wound-dressing or implantable bioelectronics on the sticky hydrogel platform for advanced healthcare devices, which will be realized by converging my whole research activities. IMPACT. Fundamental understanding on dynamic bonds and its impact to mechanical properties is tremendous across all disciplines of soft materials. Molecular design of sticky and tough hydrogels can be translated to traditional technologies such as rubbers, adhesives, and coatings, as well as to emerging technological areas of biomedical devices, drug delivery, and soft robotics. The proposed DG complements my entire research program to become a self-consistent unity with strong scientific foundation. HQPs trained in my unique and highly interdisciplinary research program will have qualities required for engineers in future society, where convergence between disciplines is the key. Scientific/technological discovery and trained HQPs from the proposed DG will evolve academia and industry in Canada and in the world.