EAGER: Direct Ink Writing of Molecularly Patterned Polyionic Actuators

这一早期概念探索性研究(EARGER)奖将支持将展示3D打印聚合物材料的研究，聚合物材料通过其体积传输电荷，同时充当人造肌肉，将热能转化为机械功。这项研究设想的一个关键突破是能够在聚合物网络中对齐离子物种，其中它们的组织可以在打印过程中指定，但在打印后仍然容易使用刺激进行重新配置。实现这一点可以使多功能部件的制造能够影响一系列技术部门。具有可变的机械、电子和离子属性的可打印材料可以实现结构的新颖设计，例如a)用于自由形式电池的可调电解液，b)用于软机器人的能够自我报告其驱动状态的传感材料，以及c)可以主动调节其与微生物/生物制剂的相互作用的响应性生物材料。为了实现这一目标，有关过程参数如何影响聚合物网络中带电物种的配置的基本问题仍有待回答。这项研究将通过材料合成、制造工艺的优化、表征技术和机械设计来解决这些问题。这项研究将探索支持3D打印离子液晶弹性体(LCE)可逆驱动的结构-性能-性能映射。考察了由介晶型丙烯酸酯和离子扩链剂组成的LCE在直接墨水写入(DIW)过程中挤出参数的影响。工作重点将集中在测量印刷过程中施加的剪应力对分子排列的均匀性的影响，表征分子结构对所产生的性质的作用，并将这些表征利用于对刺激做出反应的自由形式的人造肌肉。LCE主链上的离子基团对分子有序状态稳定性的影响将作为组成、分子结构和加工历史的函数进行探索。与标准液晶单体兼容的离子单体将被合成以产生3D可打印油墨。研究了油墨的组成和DIW的印刷参数，以测量液晶的赋存有序性、相稳定性和结构。所产生的样本将因其对刺激的响应、它们感知变形/应变的能力以及它们与自由形式的软机器人体系结构的集成而被表征。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This EArly-concept Grant for Exploratory Research (EAGER) award supports research which will demonstrate 3D printing of polymeric materials that transport charges through their bulk, while simultaneously functioning as artificial muscles, which convert thermal energy into mechanical work. A key breakthrough envisioned by this research is the ability to align ionic species within a polymer network, where their organization can be dictated during the printing process but remain susceptible to reconfiguration using stimuli thereafter. Accomplishing this can enable the manufacturing of multifunctional components that could impact an array of technological sectors. Printable materials with mutable mechanical, electronic, and ionic properties may enable novel designs of structures like a) tunable electrolytes for freeform batteries, b) sensory materials for soft robots that can self-report their actuation state, and c) responsive biomaterials that can actively modulate their interaction with microbial/biological agents. To achieve this goal, fundamental questions on how process parameters affect the configuration of charged species within a polymer network remain to be answered. This research will address these issues using material synthesis, optimization of manufacturing processes, characterization techniques, and mechanical design. This research will explore the structure-property-performance mappings that underpin reversible actuation in 3D-printed, ionic liquid crystalline elastomers (LCE). The effect of extrusion parameters applied during direct ink writing (DIW) of LCE composed of mesogenic acrylates and ionic chain extenders will be examined. Efforts will focus on measuring the influence of the shear stresses imposed during the printing process on the homogeneity of the molecular alignment, characterizing the role of the molecular structure on the resulting properties, and harnessing these characterizations in freeform artificial muscles that respond to stimuli. The effect of the ionic groups in the backbone of the LCE on the stability of the molecularly ordered state will be explored as a function of the composition, molecular structure, and the processing history. Ionic monomers compatible with canonical liquid crystalline monomers will be synthesized to create 3D printable inks. The composition of the inks and the DIW printing parameters will be studied to measure the endowment of the liquid crystalline order, phase stability and structure. The resulting samples will be characterized for their actuation in response to stimuli, their ability to sense deformation/strain, and their integration into freeform soft robotic architectures.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.