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

可伸缩电子产品有可能在通信、医疗保健、安全等领域实现新的技术创新。软填充、软基纳米复合材料是大多数可伸缩电子应用所需要的。传统的纳米复合材料将金属纳米线或碳纳米管等薄、硬、脆的导电材料嵌入到可拉伸的弹性聚合物中，提供电子功能，但在拉伸循环中由于机械失配而失败。这一设计材料革命性和工程我们的未来(DMREF)奖支持理解、开发和制造新类别的软电子产品的研究。这项工作是一种协作性的计算-实验研究方法，旨在了解导电蛋白质纳米线的基本加工-微结构-性能关系，并设计纳米级蛋白质纳米线，使其成为高度导电、机械柔软的填料，与宿主聚合物的性能相匹配，从而创造出优异的纳米复合材料。蛋白质-聚合物相互作用的计算将有助于合成和制备具有增强弹性和导电性的蛋白质基纳米复合材料，这将得到先进的显微镜、电子和机械测试的证实。这项研究融合了微生物学、聚合物化学、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中代表性较低的群体的参与，包括为期数天的关于创新、团队建设、工作与生活平衡和创业的系列研讨会，通过这些研讨会，参与者获得作为科学家、工程师和企业家取得成功所需的信心和技能，从而促进未来的经济和社会进步。这项工作有可能将美国带入柔性电子产品开发的前沿，同时培训下一代劳动力以保持这一竞争优势。先进的软电子产品需要一种新生的填充剂，这种填充剂具有高导电性，但在化学和机械上与主机基质保持兼容。导电蛋白质纳米线或菌毛是基于蛋白质的软电子的导电元件。粗粒模型的分子模拟将考察菌毛氨基酸序列和暴露的表面多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，建立软聚合物基质中菌毛填充物的基本设计原则。导电菌毛固有的水分散性使其能够设计、表征和生产具有均匀填充物的块状菌毛-聚合物纳米复合材料和电纺菌毛-聚合物纳米纤维垫。先进的电子和扫描探针显微镜将询问菌毛的结构和电子性质，并提供一个反馈回路来完善分子模型。将菌毛定向凝聚成束和电纺的菌毛弹性体纤维也将使对这种新的纳米复合平台的可扩展性的研究成为可能。分子模型最终将揭开表面多肽序列的面纱，改善新的菌毛菌株和菌毛-聚合物纳米复合材料的加工性和功能性，并通过流变学、显微镜、传输和拉伸测试方法进行验证。该奖项反映了NSF的法定使命，并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。

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.