DMREF/Collaborative Research: Conductive Protein Nanowires as Next Generation Polymer Nanocomposite Fillers

可拉伸电子产品有潜力在通信、医疗、安全等领域实现新的技术创新。软填料、软基纳米复合材料是大多数可拉伸电子应用的理想材料。传统的纳米复合材料将薄、硬、脆的导电材料（如金属纳米线或碳纳米管）嵌入可拉伸的弹性聚合物中，这些聚合物提供电子功能，但由于机械不匹配而在拉伸循环中失效。这个设计材料革命和工程我们的未来（DMREF）奖支持研究的理解，开发和制造一类新的软电子产品。这项工作是一种协同计算-实验研究方法，旨在了解导电蛋白质纳米线中基本的加工-微观结构-性能关系，并设计纳米级蛋白质线，使其成为高导电性的机械软填料，与宿主聚合物性能相匹配，从而创造出卓越的纳米复合材料。蛋白质-聚合物相互作用的计算将为合成和制造具有增强弹性和导电性的蛋白质基纳米复合材料提供信息，这将通过先进的显微镜、电子和机械测试得到证实。这项研究融合了微生物学、高分子化学、材料加工、电子学和分子建模等学科，形成了一个强大的反馈回路。该奖项还支持教育活动，强调传统上在STEM领域未被充分代表的群体的参与，包括为期数天的创新、团队建设、工作与生活平衡和创业系列研讨会，通过这些研讨会，参与者获得成为科学家、工程师和企业家所需的信心和技能，从而促进未来的经济和社会进步。这项工作有可能使美国走在柔性电子开发的前沿，同时培训下一代劳动力以保持这种竞争优势。软电子技术的发展需要一种新兴的填充物，这种填充物既要具有高导电性，又要与基体保持化学和机械上的相容性。导电蛋白质纳米线或毛是蛋白质基软电子元件的导电元件。粗粒度模型的分子模拟将调查毛氨基酸序列和暴露的表面肽残基与软材料化学的相互作用，以创建一个数据丰富的系统，为软聚合物基质中的毛填料建立基本的设计原则。导电毛丝固有的水分散特性使得设计、表征和生产大块毛丝聚合物纳米复合材料和具有均匀填料的静电纺毛丝聚合物纳米纤维垫成为可能。先进的电子和扫描探针显微镜将询问毛的结构和电子特性，并提供一个反馈回路，以完善分子模型。毛毛定向团聚成束和静电纺毛毛弹性体纤维也将使研究这种新的纳米复合材料平台的可扩展性。分子模型最终将揭示表面肽序列，提高新的毛菌菌株和毛聚合物纳米复合材料的可加工性和功能，并通过流变学、显微镜、运输和拉伸测试方法进行验证。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。

Stretchable electronics have the potential to enable new innovations in technologies for communications, healthcare, security and beyond. Soft-filler, soft-matrix nanocomposites are desired for most stretchable electronics applications. Conventional nanocomposites embed thin, hard, and brittle conductive materials such as metal nanowires or carbon nanotubes into stretchable elastic polymers, which provide electronic function, but fail during stretching cycles due mechanical mismatch. This Designing Materials to Revolutionize and Engineer our Future (DMREF) award supports research for the understanding, development and manufacture of a new class of soft electronics. This work is a collaborative computational-experimental research approach to understanding the fundamental processing-microstructure-property relationships in conductive protein nanowires, and to design nanoscale protein wires to be highly conductive, mechanically soft fillers that match the host polymer properties to create a superior nanocomposite. Calculations of protein-polymer interactions will inform the synthesis and fabrication of protein-based nanocomposites with enhanced elasticity and conductivity, which will be confirmed by advanced microscopy, electronic, and mechanical testing. This research merges disciplines including microbiology, polymer chemistry, materials processing, electronics, and molecular modeling in a powerful feedback loop. This award also supports educational activities which emphasize participation from groups traditionally underrepresented in STEM, including a multi-day workshop series on innovation, team building, work-life balance, and entrepreneurship through which participants gain the confidence and skills necessary to succeed as scientists, engineers, and entrepreneurs, thus promoting future economic and societal advancement. This work has the potential to bring the U.S. to the forefront of flexible electronics development, while training the next generation workforce to maintain this competitive advantage.Advancing soft electronics requires a nascent class of filler that exhibits high conductivity yet remains chemically and mechanically compatible with the host matrix. Conductive protein nanowires or pili function as the conducting element of protein-based soft electronics. Molecular simulations with coarse-grained models will survey the interplay of pili amino acid sequences and exposed surface peptide residues with soft materials chemistry to create a data-rich system that establishes foundational design principles for pili fillers in soft polymer matrices. The inherent aqueous dispersion properties of conductive pili enable the design, characterization, and production of both bulk pili-polymer nanocomposites and electrospun pili-polymer nanofiber mats with well-distributed filler. Advanced electron and scanning probe microscopy will interrogate the structural and electronic properties of the pili and provide a feedback loop that refines the molecular models. Directed agglomeration of pili into bundles and electrospun pili-elastomer fibers will also enable studies on the scalability of this new nanocomposite platform. Molecular models will ultimately unveil surface peptide sequences that improve processability and functionality of new pili strains and pili-polymer nanocomposites that are validated by rheology, microscopy, transport, and tensile testing methods.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.