Inkjet-Electrospray Hybrid Printing:Understanding the Processing-Structure Relationship

The ability to create thin films of functional materials addresses vital technological needs for many applications, including: flexible electronics, bio-sensing, optical coatings, energy conversion/harvesting, and data storage. As one of the dominant thin film manufacturing techniques, printing of materials underpins multi-billion dollar industries. However, the current printing methods have reached a fundamental limit that has inhibited innovation in thin film processing. The overarching goal of this research is to provide the much-needed knowledge for creating a high-resolution, scalable technique that can achieve mass production of printed patterns using a variety of functional inks. The new technique will provide manufacturers with a unique tool to print novel materials for industrial applications and consumer products. The success of this research will lay the groundwork for changing the paradigm of thin film processing and will have an impact on accelerating manufacturing innovation in the United States. In addition, the integration of undergraduate and graduate students into this research will provide industry with the highly qualified and experienced personnel they need to expand the commercial use of thin film additive manufacturing. This project aims to combine inkjet technology and electrospray printing to create a hybrid printing technique that provides the advantages of photolithography and traditional printing, namely, high feature resolution, material versatility, material conservation, and control over microstructure. Using electrospray, dry colloidal material is delivered to the surface of inkjet-printed sacrificial rivulets to form colloidal monolayers. The monolayers are subsequently transferred to the substrate upon complete evaporation of the rivulets to create self-assembled, close-packed nanoparticle monolayers. Unique mechanical, electrical, and optical properties can emerge in the monolayers by controlling the deposit structure on the length scale of an individual particle. This research will integrate computational modeling and experimental approaches to discover the fundamental relationships among the process parameters, printing dynamics, and final deposit structure. Advanced imaging techniques will be used to characterize the time evolution of this complex system and the final deposits. A novel two-way coupled Lagrangian particle tracking-lattice Boltzmann model will be developed to provide fundamental insight into the electrospray of nanoparticles, the physico-chemical hydrodynamics of the evaporating rivulet, and the self-organization of particles at the interface and subsequent deposition. With a greater understanding of this hybrid printing process, the research team will design and build an integrated hybrid printhead that encompass an inkjet nozzle and electrospray emitter for scalable processing.

The ability to create thin films of functional materials addresses vital technological needs for many applications, including: flexible electronics, bio-sensing, optical coatings, energy conversion/harvesting, and data storage. As one of the dominant thin film manufacturing techniques, printing of materials underpins multi-billion dollar industries. However, the current printing methods have reached a fundamental limit that has inhibited innovation in thin film processing. The overarching goal of this research is to provide the much-needed knowledge for creating a high-resolution, scalable technique that can achieve mass production of printed patterns using a variety of functional inks. The new technique will provide manufacturers with a unique tool to print novel materials for industrial applications and consumer products. The success of this research will lay the groundwork for changing the paradigm of thin film processing and will have an impact on accelerating manufacturing innovation in the United States. In addition, the integration of undergraduate and graduate students into this research will provide industry with the highly qualified and experienced personnel they need to expand the commercial use of thin film additive manufacturing. This project aims to combine inkjet technology and electrospray printing to create a hybrid printing technique that provides the advantages of photolithography and traditional printing, namely, high feature resolution, material versatility, material conservation, and control over microstructure. Using electrospray, dry colloidal material is delivered to the surface of inkjet-printed sacrificial rivulets to form colloidal monolayers. The monolayers are subsequently transferred to the substrate upon complete evaporation of the rivulets to create self-assembled, close-packed nanoparticle monolayers. Unique mechanical, electrical, and optical properties can emerge in the monolayers by controlling the deposit structure on the length scale of an individual particle. This research will integrate computational modeling and experimental approaches to discover the fundamental relationships among the process parameters, printing dynamics, and final deposit structure. Advanced imaging techniques will be used to characterize the time evolution of this complex system and the final deposits. A novel two-way coupled Lagrangian particle tracking-lattice Boltzmann model will be developed to provide fundamental insight into the electrospray of nanoparticles, the physico-chemical hydrodynamics of the evaporating rivulet, and the self-organization of particles at the interface and subsequent deposition. With a greater understanding of this hybrid printing process, the research team will design and build an integrated hybrid printhead that encompass an inkjet nozzle and electrospray emitter for scalable processing.