@article{han_dong_2018, title={Electrohydrodynamic Printing for Advanced Micro/Nanomanufacturing: Current Progresses, Opportunities, and Challenges}, volume={6}, ISSN={["2166-0476"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85057826433&partnerID=MN8TOARS}, DOI={10.1115/1.4041934}, abstractNote={The paper provides an overview of high-resolution electrohydrodynamic (EHD) printing processes for general applications in high-precision micro/nanoscale fabrication and manufacturing. Compared with other printing approaches, EHD printing offers many unique advantages and opportunities in the printing resolution, tunable printing modes, and wide material applicability, which has been successfully applied in numerous applications that include additive manufacturing, printed electronics, biomedical sensors and devices, and optical and photonic devices. In this review, the EHDs-based printing mechanism and the resulting printing modes are described, from which various EHD printing processes were developed. The material applicability and ink printability are discussed to establish the critical factors of the printable inks in EHD printing. A number of EHD printing processes and printing systems that are suitable for micro/nanomanufacturing applications are described in this paper. The recent progresses, opportunities, and challenges of EHD printing are reviewed for a range of potential application areas.}, number={4}, journal={JOURNAL OF MICRO AND NANO-MANUFACTURING}, author={Han, Yiwei and Dong, Jingyan}, year={2018}, month={Dec} }
 @article{cui_han_huang_dong_zhu_2018, title={Electrohydrodynamic printing of silver nanowires for flexible and stretchable electronics}, volume={10}, ISSN={["2040-3372"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85045850487&partnerID=MN8TOARS}, DOI={10.1039/c7nr09570h}, abstractNote={A silver nanowire (AgNW) based conductor is a promising component for flexible and stretchable electronics. A wide range of flexible/stretchable devices using AgNW conductors has been demonstrated recently. High-resolution, high-throughput printing of AgNWs remains a critical challenge. Electrohydrodynamic (EHD) printing has been developed as a promising technique to print different materials on a variety of substrates with high resolution. Here, AgNW ink was developed for EHD printing. The printed features can be controlled by several parameters including AgNW concentration, ink viscosity, printing speed, stand-off distance, etc. With this method, AgNW patterns can be printed on a range of substrates, e.g. paper, polyethylene terephthalate (PET), glass, polydimethylsiloxane (PDMS), etc. First, AgNW samples on PDMS were characterized under bending and stretching. Then AgNW heaters and electrocardiogram (ECG) electrodes were fabricated to demonstrate the potential of this printing technique for AgNW-based flexible and stretchable devices.}, number={15}, journal={NANOSCALE}, author={Cui, Zheng and Han, Yiwei and Huang, Qijin and Dong, Jingyan and Zhu, Yong}, year={2018}, month={Apr}, pages={6806–6811} }
 @article{han_dong_2018, title={Fabrication of self-recoverable flexible and stretchable electronic devices}, volume={48}, ISSN={["1878-6642"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046344028&partnerID=MN8TOARS}, DOI={10.1016/j.jmsy.2018.04.011}, abstractNote={In this paper, we developed an EHD printing process for the fabrication of high-resolution self-recoverable flexible and stretchable electronics using low-melting-point metal inks. Three different metal inks were tested for their printability on four different substrates separately to demonstrate the capability of EHD printing technology. EHD printing enables low-cost direct fabrication of metallic conductors with sub-50 μm resolution, which represents a promising way to create electronic features with metallic conductivity and excellent flexibility and stretchability. When properly designed, the EHD printed electronics provided a stable resistance under hundreds of bending cycles and many stretching and releasing cycles with high tensile strain, which demonstrates their good flexibility and stretchability in electronics applications. The printed electronics was capable of self-healing under low temperature treatment to recover from failures without sacrificing its electrical properties. Moreover, a high-resolution capacitive sensor array was designed and fabricated. A Finite Element Analysis (FEA) model was developed to study the performance of the designed touch sensor. The results from FEA model agreed well with experimental results, which demonstrated the high-resolution capability of the EHD printing for the direction fabrication of flexible and stretchable devices.}, journal={JOURNAL OF MANUFACTURING SYSTEMS}, author={Han, Yiwei and Dong, Jingyan}, year={2018}, month={Jul}, pages={24–29} }
 @article{han_dong_2017, title={Design, modeling and testing of integrated ring extractor for high resolution electrohydrodynamic (EHD) 3D printing}, volume={27}, number={3}, journal={Journal of Micromechanics and Microengineering}, author={Han, Y. W. and Dong, J. Y.}, year={2017} }
 @article{han_dong_shih_wang_2016, title={Design of Integrated Ring Extractor for High Resolution Electrohydrodynamic (EHD) 3D Printing}, volume={5}, ISSN={["2351-9789"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000387592400079&KeyUID=WOS:000387592400079}, DOI={10.1016/j.promfg.2016.08.070}, abstractNote={This paper presents an integrated ring extractor design in electrohydrodynamic (EHD) printing, which can overcome the standoff height limitation in the EHD printing process, and improve printing capability for 3D structures. Standoff height in EHD printing will affect printing processes and limit the height of the printed structure when the ground electrode is placed under the substrate. In this work, we designed and integrated a ground ring electrode with the printing nozzle to achieve a self-working printer head, which can start and maintain the printing process without the involvement of the substrate. We applied FEA method to model the electrostatic field distribution and strength to direct the ring extractor design, which has the similar printing capability with the system using substrate as the ground electrode. We verified the ring electrode design by experiments, and the results from experiments demonstrated a good match with results in the FEA simulation. We have characterized the printing processes using the integrated ring extractor, and successfully applied newly designed ring extractor to print polycaprolactone (PCL) 3D structures.}, journal={44TH NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE, NAMRC 44}, author={Han, Yiwei and Dong, Jingyan and Shih, A and Wang, L}, year={2016}, pages={1031–1042} }
 @article{han_wei_dong_2015, title={Droplet formation and settlement of phase-change ink in high resolution electrohydrodynamic (EHD) 3D printing}, volume={20}, ISSN={["2212-4616"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000367634700007&KeyUID=WOS:000367634700007}, DOI={10.1016/j.jmapro.2015.06.019}, abstractNote={This paper presents a modeling framework to model the droplet formation and settlement on substrate of phase-change ink in high resolution electrohydrodynamic (EHD) printing process, which can successfully produce sub 10-μm droplet footprints and 3D microstructure. We have used Finite Element Analysis (FEA) to develop the model for droplet formation and droplet settlement. Two important competitive forces in EHD printing, electrostatic force and surface tension force are modeled by FEA. The droplet size is obtained by balancing the electrostatic force and surface tension of the pending droplets at the tip of the meniscus under different printing conditions. With the results from FEA analysis about the charge on a droplet and electrostatic field distribution, the droplets in-flight velocity and impact velocity on the substrate are derived numerically. With the derived impact velocity, the droplet spreading and settlement on the substrate is also modeled by FEA. The results from FEA models are compared with the experimental measured droplet dimensions at different process conditions to validate the developed model, which demonstrate very good agreement between the experimental results and model prediction. We have successfully applied EHD printing process for phase-change wax material, which is widely used in 3D printing or additive manufacturing for supporting and model material, to achieve high resolution sub 10-μm 3D structures.}, journal={JOURNAL OF MANUFACTURING PROCESSES}, author={Han, Yiwei and Wei, Chuang and Dong, Jingyan}, year={2015}, month={Oct}, pages={485–491} }