Collaborative Research: Surface and Actuation Kinetics of Stimulus-Responsive Hydrogels

杜克大学和华盛顿大学的研究人员合作研究了刺激响应性水凝胶(SRH)的表面和驱动动力学。这些材料是聚合物凝胶，在可逆的相变过程中，体积和表面的物理化学性质会发生很大的变化。SRH有可能克服目前使用电磁或压电致动器的微致动器和传感设备的一些基本限制。SRH的总体特征指向生物兼容的设备，以最小的功率输入操作，并提供现有伺服机构难以实现的运动范围。拟议的工作将结合实验、理论和计算，目标是推进基于这些多功能材料的技术。将在杜克大学进行的实验将包括：1)使用新的光学-机械装置光学测量SRH中的体积位移变化；2)使用平行圆盘流变仪测量SRH的摩擦学；以及3)使用胶体探针显微镜绘制精细的、空间分辨的力附着和摩擦力图。与这些努力相结合，华盛顿大学的研究人员将开发物理上一致的整体和界面本构模型。最后，一些实验的数值模拟将在这两个机构进行，以关联材料参数并获得与SRH合理设计的预测能力。

AbstractA collaborative effort between researchers at Duke University and Washington University is supported to investigate the surface and actuation kinetics of stimulus responsive hydrogels (SRHs). These materials are polymer gels that exhibit a large change in volume and surface physiochemical properties during a reversible phase transition. SRHs have the potential to overcome some of the fundamental limitations of micro-actuation and sensing devices that currently use electromagnetic or piezoelectric actuators. The overall characteristics of SRHs point toward devices that are biocompatible, operate with minimal power input, and provide a range of motion that is difficult to achieve with existing servomechanisms. The proposed work will combine experiment, theory, and computation with the goal of advancing technologies based on these multifunctional materials. Experiments to be conducted at Duke will include: 1) optical measurements of volume displacement changes in SRHs using a novel optical-mechanical setup; 2) tribological measurements of SRHs using a parallel-disk rheometer; and 3) fine-grained, spatially resolved force adhesion and friction force maps using colloidal probe microscopy. In conjunction with these efforts, researchers at Washington University will develop physically consistent bulk and interfacial constitutive models. Finally, numerical simulations of some of the experiments will be conducted at both institutions to correlate material parameters and gain predictive capabilities for rational design with SRHs.