@article{shahariar_kim_soewardiman_jur_2019, title={Inkjet Printing of Reactive Silver Ink on Textiles}, volume={11}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.8b18231}, abstractNote={Inkjet printing of functional inks on textiles to embed passive electronics devices and sensors is a novel approach in the space of wearable electronic textiles. However, achieving functionality such as conductivity by inkjet printing on textiles is challenged by the porosity and surface roughness of textiles. Nanoparticle-based conductive inks frequently cause blockage/clogging of inkjet printer nozzles, making it a less than ideal method for applying these functional materials. It is also very challenging to create a conformal conductive coating and achieve electrically conductive percolation with the inkjet printing of metal nanoparticle inks on rough and porous textile and paper substrates. Herein, a novel reliable and conformal inkjet printing process is demonstrated for printing particle-free reactive silver ink on uncoated polyester textile knit, woven, and nonwoven fabrics. The particle-free functional ink can conformally coat individual fibers to create a conductive network within the textile structure without changing the feel, texture, durability, and mechanical behavior of the textile. It was found that the conductivity and the resolution of the inkjet-printed tracks are directly related with the packing and the tightness of fabric structures and fiber sizes of the fabrics. It is noteworthy that the electrical conductivity of the inkjet-printed conductive coating on pristine polyethylene terephthalate fibers is improved by an order of magnitude by in situ heat-curing of the textile surface during printing as the in situ heat-curing process minimizes the wicking of the ink into the textile structures. A minimum sheet resistance of 0.2 ± 0.025 and 0.9 ± 0.02 Ω/□ on polyester woven and polyester knit fabrics is achieved, respectively. These findings aim to advance E-textile product design through integration of inkjet printing as a low-cost, scalable, and automated manufacturing process.}, number={6}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Shahariar, Hasan and Kim, Inhwan and Soewardiman, Henry and Jur, Jesse S.}, year={2019}, month={Feb}, pages={6208–6216} }
 @inproceedings{shahariar_soewardiman_jur_2017, title={Fabrication and packaging of flexible and breathable patch antennas on textiles}, DOI={10.1109/secon.2017.7925306}, abstractNote={Textile antennas are prone to damage and change their shape and RF (radio frequency) characteristics over time. However, typical hydrophobic coatings or encapsulation layers, such as polyurethane, acrylate, or films, make textile antennas rigid and air impermeable. This work details the approach of using a polyurethane web as an encapsulation and lamination layer for screen-printed microstrip patch antennas on textile fabrics. Integrating the polyurethane web into the textile antennas makes the printed antennas flexible, air permeable, and durable. Further improvements are made by introducing a novel porous patch antenna design to enhance the flexibility and air-permeability for printed antennas. Antennas were designed and modeled using the ANSYS HFSS simulation software and compared with fabricated experimental results. Results show the fully packaged printed antenna have good impedance matching even under different bent conditions. The antennas were also analyzed before and after rinsing with heavy flow of water for 2 minutes to determine the effect of wetting.}, booktitle={Southeastcon 2017}, author={Shahariar, H. and Soewardiman, H. and Jur, J. S.}, year={2017} }