GOALI/Collaborative Research: Autonomous Thermomechanical Fabrication of 3D Structures using Heat-Responsive Polymers

通过使预成型体受到非接触刺激（如热）来自主制造宏观聚合物物体具有重要的技术意义。例如，它提供了根据需要将预制件（以简单、紧凑的几何形状制造）转换为目标形状的能力。它还提供了同时将大量零件转换成目标形状的能力，通过使用全局应用的刺激来触发它们。因此，无需额外开销即可实现大规模生产。这项学术与工业联络资助机会（GOALI）奖支持基于热响应聚合物分子水平嵌入设计的3D结构自组装的基础研究。研究结果有助于在生物医学等应用领域催生新技术，在生物医学领域，植入物可以被部署成所需的形状，并根据需要使用外部刺激进行重塑。第一个研究目标是建立应变场的时空演化（导致三维螺旋结构的产生）与可控参数（向列取向和温度）之间的关系。为了达到这个目的，交联的，丙烯酸酯基液晶聚合物的扭曲向列构型将被合成。自由悬浮的聚合物样品将在不同的向列取向（相对于样品的中平面从0到45°）和温度（从玻璃化转变温度到接近热分解温度）下进行热处理。这些样品中应变场的演变将使用基于表征的图像分析进行原位测量。第二个研究目标是确定位移（预先施加在样品上）对扭转，弯曲应变场的时空演变的影响（支撑3D棱柱形和分层超螺旋形状的创建）。将对样品施加各种位移（高达样品长度的20%）。扭转、弯曲应变场的时空演变将使用基于表征的成像分析来测量。

Autonomously fabricating macro-scale polymeric objects by subjecting a preform to a non-contact stimulus such as heat holds significant technological implications. For instance, it offers the ability to transform a preform (fabricated in simple, compact geometries) into target shapes on demand. It also offers the ability to simultaneously transform a large number of parts into target shapes by triggering them en masse using a globally applied stimulus. Hence, mass manufacturability emerges without an additional overhead. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research on the self-assembly of 3D structures based on designs embedded at the molecular level in heat-responsive polymers. Research results can help spawning new technologies in applications such as biomedicine, where implants can be deployed into desired shapes and reshaped as-needed using an external stimulus.The first research objective is to establish the relationship between the spatiotemporal evolution of strain fields (leading to the creation of 3D helical structures) and controllable parameters (nematic director orientation and temperature). To achieve this objective, crosslinked, acrylate-based liquid crystalline polymers in twisted nematic configurations will be synthesized. Freely suspended polymer samples will be subjected to heat treatment with varying nematic director orientation (ranging from 0 to 45° with respect to the mid-plane of samples) and temperature (ranging from the glass transition temperature to close to the thermal decomposition temperature). The evolution of strain fields in these samples will be measured in situ using image analysis based characterization. The second research objective is to establish the effect of the displacement (preimposed on the sample) on the spatiotemporal evolution of torsional, bending strain fields (underpinning the creation of 3D prismatic and hierarchically supercoiled shapes). Various displacements (up to 20 percent of the length of the samples) will be imposed to samples. Spatiotemporal evolution of torsional, bending strain fields will be measured using imaging analysis based characterization.