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

背景。动态键，可以通过外部刺激以可逆的方式释放的物理或化学键，是智能软材料最基本的组成部分。虽然单个的动态键可能被认为是弱的，但通过聚集氢键或离子对实现了坚韧的水凝胶（断裂能~10,000 J/m2），这也使可逆粘附和自愈成为可能。尽管具有技术重要性和经验上的成功，但目前对这些动态键簇与坚韧水凝胶力学性能之间关系的理解还处于起步阶段。造成这一问题的部分原因是现有实验工具的能力有限。解决方案。PROGRAM 1的总体目标是建立微通道悬臂式传感器，通过激光多普勒测振仪监测微通道悬臂式传感器的振动，作为研究（氢）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，它的另外两个优点是皮升样品容量和多种振动模式。短期目标（3年）是验证微通道悬臂技术作为定量微流变学的工具。在中长期计划（5年及以上）中，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（如单个/簇键强度和结合/解离动力学）与动态力学性能（复模的时间分辨演化）之间的定量关联。APPPLICATION。为了补充我目前在生物医学设备和电池凝胶电解质方面的研究项目，PROGRAM 2是具有可调粘附性的粘性水凝胶的分子设计。短期到中期目标（5年）是制造出血抑制凝胶垫，可以快速应用，然后根据需要释放。远期目标（5年以上）是将创面敷料或植入式生物电子学集成到先进医疗器械的黏性水凝胶平台上，这将通过我整个研究活动的融合来实现。的影响。对动态键及其对力学性能的影响的基本理解在软材料的所有学科中都是巨大的。粘性和韧性水凝胶的分子设计可以转化为传统技术，如橡胶、粘合剂和涂料，以及生物医学设备、药物输送和软机器人等新兴技术领域。提议的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洽统一体。在我独特的、高度跨学科的研究项目中培养的高素质人才，将具备未来社会中工程师所需要的素质，而学科之间的融合是未来社会的关键。拟议DG的科学/技术发现和训练有素的hqp将推动加拿大和世界学术界和工业界的发展。

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.