CAREER: Extrusion-based Additive Manufacturing of Sustainable Thermoplastics via Enzyme Encapsulation and Microfluidic Structuring of Hierarchical Composites

热塑性塑料的增材制造（AM）为消费电子、汽车、航空航天和医疗等行业生产零件提供了一个庞大且不断增长的市场。随着需求的不断增加，有必要推进增材制造科学，以创造加工和材料，不仅要实现性能、效率和成本的平衡，而且要特别解决对环境的影响。该学院早期职业发展（Career）奖支持新型增材制造工艺的基础研究，该工艺将可持续塑料复合材料与热保护生物成分和导电填料相结合。该方法将利用微流体打印技术的创新，使材料的精确热塑性加工结合各种独特的材料特性。一旦完成，该项目将为各种性能驱动应用的材料选择提供信息，加速可降解塑料和环境传感器等材料的广泛采用和商业可行性。该项目的核心工作是为各种学生群体建立教育和推广活动，包括那些在这些研究领域历史上代表性不足的学生群体。特别是，该项目将为农村高中和部落大学生开发交互式动手三维打印体验，并将可持续的分层聚合物增材制造研究整合到蒙大拿州立大学的课程中。这项跨学科研究的总体目标是整合制造，材料科学和化学，使新型多材料热塑性复合材料结构结合功能性生物制剂，如酶和导电填料。在这项事业的努力中有两个研究重点。首先是了解制造增材制造长丝所需的条件，这种长丝可以成功地封装热敏生物衍生的酶成分，从而在热塑性加工成最终复合材料时基本保留其生物活性。热屏蔽的数量将通过分析完整复合材料样品的环境可降解性来量化，这些样品是通过定制设计的用于熔丝制造的打印头通过材料挤压的微流体控制制造的。第二个重点是利用所开发的方法探索导电元件的加工和性能，分层构建多材料系统。一种创新的微流体技术，通过工程增材制造打印头将材料与精确的局部结构和热控制相结合，将用于更好地了解所需的工艺条件。此外，拓扑优化和微流体建模将结合实验来确定加工参数空间。这两项研究工作的高潮将是一个增材制造的生物基被动传感器的成功演示，该传感器可以根据湿度进行生物降解。该项目由民用、机械和制造创新部门（CMMI）和刺激竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Additive manufacturing (AM) of thermoplastics serves a large and growing market to produce parts for industries such as consumer electronics, automotive, aerospace and medical, etc. As the demand continues to increase, there is a need to advance the science of AM to create processing and materials that not only achieve a balance of performance, efficiency and cost, but especially also address impacts on the environment. This Faculty Early Career Development (CAREER) award supports fundamental research into novel AM processes combining sustainable plastic composite blends with thermally-protected biological components and electrically conductive fillers. The approach will leverage innovations in microfluidic print technologies, which enable precise thermoplastic processing of materials to combine a variety of unique material properties. Once completed, the project will inform materials selection for a variety of performance-driven applications, accelerating widespread adoption and commercial viability of such materials as degradable-by-design plastics and environmental sensors. At its central effort, this project will establish education and outreach activities for a variety of student groups, including those historically underrepresented in these areas of research. In particular, this project will develop interactive hands-on three-dimensional printing experiences for rural high school and tribal college students and integrate additive manufacturing research of sustainable, hierarchical polymers into curricula at Montana State University.The overarching goal of this interdisciplinary research, integrating manufacturing, materials science and chemistry, is to enable novel multi-material thermoplastic composite structures that incorporate functional biologics, such as enzymes, and electrically conductive fillers. There are two research thrusts in this CAREER endeavor. The first is to understand the conditions needed to create additive manufacturing filaments that can successfully encapsulate heat-sensitive biologically derived enzymatic constituents, such that their biological activity is substantially retained upon thermoplastic processing into final composites. The amount of thermal shielding will be quantified by analyzing the environmental degradability of complete composite samples manufactured via microfluidic controls of material extrusions through custom-design print-heads for fused filament fabrications. The second thrust is to explore the processing and properties of electrically-conductive components using the developed methods to hierarchically structure multi-material systems. An innovative microfluidic technique, based on combining materials with precise local structural and thermal control through engineered AM print-heads, will be utilized to better understand the required process conditions. Further, topology optimization and microfluidic modeling will be used in conjunction with experiments to determine processing parameter space. The culmination of these two research efforts will be a successful demonstration of an additively manufactured bio-based passive sensor that biodegrades in response to humidity. This project is jointly funded by the division of Civil, Mechanical and Manufacturing Innovation (CMMI) and the Established Program to Stimulate Competitive Research (EPSCoR).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.