Scalable Capillary-Driven Assembly of Asymmetric Nanoparticles via Inkjet Printing

这项拨款为研究毛细管驱动的不对称纳米粒子自组装在喷墨打印胶体悬浮液中的可扩展纳米制造提供了资金。低成本的喷墨印刷将溶液加工的功能材料输送到柔性基材上，已经成为电子和光伏卷对卷加工的革命性技术。然而，由于众所周知的咖啡渍效应，目前的技术无法产生纳米级的特征和良好控制的图案。不对称纳米颗粒可以在毛细管驱动的自组装过程中打破对称性，从而提高打印过程中的特征分辨率。两面纳米粒子（Janus nanoparticles, JNPs）是指具有两个不同表面化学成分区域的胶体粒子，在本研究中，由于取向依赖的相互作用，它将被用于促进粒子组装。该项目结合了新型纳米粒子合成、多尺度建模、原位观察和高级表征，将重点放在对JNPs与移动接触线和远离平衡的液-气界面的方向依赖相互作用的基本理解上。如果成功，这项研究的结果将导致几项技术的进步。使用JNPs作为固体表面活性剂，可以更好地控制JNPs的沉积，以避免喷墨打印结构中常见的咖啡环图案。使用JNPs作为可调的构建块将导致大量可动态切换的微型设备和智能表面。所提出的工作将有助于从蒸发胶体滴和薄膜中建立基于JNP的油墨的组装和沉积之间的重要相关性，以及JNP设计，油墨配方，加工条件和衬底性质。这些知识将潜在地使环保，大面积喷墨印刷，喷涂沉积和槽模涂层工艺用于下一代柔性电子产品的高通量生产。该项目将建立一个令人兴奋的跨学科合作，使新的课程材料，并直接受益本科研究人员和K-12教师通过德雷克塞尔？REU和RET网站，以及女性和代表性不足的少数民族学生。

This grant provides funding for the investigation of capillary-driven self-assembly of asymmetric nanoparticles in inkjet printing of colloidal suspensions for scalable nanomanufacturing. Low-cost inkjet printing for the delivery of solution-processed functional materials onto flexible substrates has become a revolutionary technology for roll-to-roll processing of electronics and photovoltaics. However, the current technology is incapable of producing nanosized features and well-controlled patterns due to the well-known coffee-stain effect. Asymmetric nanoparticles can break the symmetry during capillary-driven self-assembly and may lead to improved feature resolution during printing. Janus nanoparticles (JNPs), which refer to colloidal particles with two regions of different surface chemical composition, will be used in this study to facilitate particle assembly due to the orientation-dependent interactions. The project that combines novel nanoparticle synthesis, multiscale modeling, in-situ observation, and advanced characterization will focus on the fundamental understanding of orientation-dependent interactions of JNPs with a moving contact line and a liquid-vapor interface away from equilibrium. If successful, the results of this research will lead to several technology advancements. Using JNPs as solid surfactants, the deposition of JNPs can be better controlled to avoid coffee-ring patterns commonly encountered in inkjet-printed structures. Using JNPs as tunable building blocks will lead to a large class of dynamically switchable micro-devices and smart surfaces. The proposed work will help establish important correlations between the assembly and deposition of JNP-based inks from evaporating colloidal drops and thin films, as well as the JNP design, ink formulations, processing conditions, and substrate properties. Such knowledge will potentially enable environmentally-benign, large-area inkjet printing, spray deposition, and slot-die coating processes for high-throughput production of next generation flexible electronics. This project will build an exciting interdisciplinary collaboration, enable new course materials, and directly benefit undergraduate researchers and K-12 teachers via Drexel?s REU and RET sites, as well as women and under-represented minority students.