@article{ju_kim_li_knowles_mills_grace_jur_2021, title={Inkjet Printed Textile Force Sensitive Resistors for Wearable and Healthcare Devices}, volume={7}, ISSN={["2192-2659"]}, url={https://doi.org/10.1002/adhm.202100893}, DOI={10.1002/adhm.202100893}, abstractNote={Abstract}, journal={ADVANCED HEALTHCARE MATERIALS}, author={Ju, Beomjun and Kim, Inhwan and Li, Braden M. and Knowles, Caitlin G. and Mills, Amanda and Grace, Landon and Jur, Jesse S.}, year={2021}, month={Jul} }
 @article{kim_ju_zhou_li_jur_2021, title={Microstructures in All-Inkjet-Printed Textile Capacitors with Bilayer Interfaces of Polymer Dielectrics and Metal-Organic Decomposition Silver Electrodes}, volume={13}, ISSN={["1944-8252"]}, url={https://doi.org/10.1021/acsami.1c01827}, DOI={10.1021/acsami.1c01827}, abstractNote={Soft printed electronics exhibit unique structures and flexibilities suited for a plethora of wearable applications. However, forming scalable, reliable multilayered electronic devices with heterogeneous material interfaces on soft substrates, especially on porous and anisotropic structures, is highly challenging. In this study, we demonstrate an all-inkjet-printed textile capacitor using a multilayered structure of bilayer polymer dielectrics and particle-free metal-organic decomposition (MOD) silver electrodes. Understanding the inherent porous/anisotropic microstructure of textiles and their surface energy relationship was an important process step for successful planarization. The MOD silver ink formed a foundational conductive layer through the uniform encapsulation of individual fibers without blocking fiber interstices. Urethane-acrylate and poly(4-vinylphenol)-based bilayers were able to form a planarized dielectric layer on polyethylene terephthalate textiles. A unique chemical interaction at the interfaces of bilayer dielectrics performed a significant role in insulating porous textile substrates resulting in high chemical and mechanical durability. In this work, we demonstrate how textiles' unique microstructures and bilayer dielectric layer designs benefit reliability and scalability in the inkjet process as well as the use in wearable electronics with electromechanical performance.}, number={20}, journal={ACS APPLIED MATERIALS & INTERFACES}, publisher={American Chemical Society (ACS)}, author={Kim, Inhwan and Ju, Beomjun and Zhou, Ying and Li, Braden M. and Jur, Jesse S.}, year={2021}, month={May}, pages={24081–24094} }
 @article{cha_kim_lee_jang_cho_2020, title={AgNW Treated PU Nanofiber/PDMS Composites as Wearable Strain Sensors for Joint Flexion Monitoring}, volume={21}, ISSN={["1875-0052"]}, DOI={10.1007/s12221-020-0018-2}, number={11}, journal={FIBERS AND POLYMERS}, author={Cha, Sujin and Kim, Inhwan and Lee, Eugene and Jang, Eunji and Cho, Gilsoo}, year={2020}, month={Nov}, pages={2479–2484} }
 @article{shahariar_kim_bhakta_jur_2020, title={Direct-write printing process of conductive paste on fiber bulks for wearable textile heaters}, volume={29}, ISSN={["1361-665X"]}, DOI={10.1088/1361-665X/ab8c25}, abstractNote={In the printing of electronic materials for electronic textiles (e-textiles), reliability and durability of devices are of critical importance. A unique capability of a direct-write (DW) printing process is introduced that takes advantage of ink penetration in fiber bulks, owed in part to the capillary action phenomena of conductive inks on the textile. As a result of the penetration, the durability of the printed patterns improved in deformability and washability. To understand this phenomenon, the ink-to-substrate interaction of the Ag-based conductive ink on thermoplastic polyurethane (TPU) films, polyethylene terephthalate (PET) nonwoven textiles, and nylon-PET nonwoven (Evolon®) textiles are studied. Substrate properties such as surface roughness and porosity show a significant impact on the flow properties of the ink. The penetration of the conductive ink into the fiber bulk created a unique fiber-ink composite structure that is structurally more stable under mechanical deformation. Due to the high porosity and penetration to the cross-sectional direction, the patterns on the PET nonwoven textiles showed less ink spreading on the surface and higher resistance compared to a densely structured Evolon® textiles. The printed patterns were demonstrated as wearable textile heaters and showed reliable performance during mechanical deformation, wash, and cyclic heating tests. Finally, a printed heater wrap was demonstrated on the human body to explain a use case scenario for the DW process for wearable electronics.}, number={8}, journal={SMART MATERIALS AND STRUCTURES}, author={Shahariar, Hasan and Kim, Inhwan and Bhakta, Raj and Jur, Jesse S.}, year={2020}, month={Aug} }
 @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} }
 @article{kim_shahariar_ingram_zhou_jur_2019, title={Inkjet Process for Conductive Patterning on Textiles: Maintaining Inherent Stretchability and Breathability in Knit Structures}, volume={29}, ISSN={["1616-3028"]}, url={http://dx.doi.org/10.1002/adfm.201807573}, DOI={10.1002/adfm.201807573}, abstractNote={Abstract}, number={7}, journal={ADVANCED FUNCTIONAL MATERIALS}, publisher={Wiley}, author={Kim, Inhwan and Shahariar, Hasan and Ingram, Wade F. and Zhou, Ying and Jur, Jesse S.}, year={2019}, month={Feb} }
 @article{kim_cho_2018, title={Polyurethane nanofiber strain sensors via in situ polymerization of polypyrrole and application to monitoring joint flexion}, volume={27}, ISSN={["1361-665X"]}, DOI={10.1088/1361-665x/aac0b2}, abstractNote={Strain sensors made of intrinsically conductive polymers (ICPs) and nanofibers were fabricated and tested for suitability for use in wearable technology. The sensors were fabricated and evaluated based on their surface appearances, and electrical, tensile, and chemical/thermal properties. Polypyrrole (PPy) was in situ polymerized onto polyurethane (PU) nanofiber substrates by exposing pyrrole monomers to ammonium persulfate as oxidant and 2,6-naphthalenedisulfonic acid disodium salt as doping agents in an aqueous bath. The PPy treated PU nanofibers were then coated with polydimethylsiloxane (PDMS). Both pyrrole concentrations and layer numbers were significantly related to change in electrical conductivity. Specimen treated with 0.1 M of PPy and having three layered structure showed the best electrical conductivity. Regarding tensile strength, the in situ polymerization process decreased tensile strength because the oxidant chemically degraded the PU fibers. Adding layers and PDMS treatment generally improved tensile properties while adding layers created fracture parts in the stress–strain curves. The treatment condition of 0.1 M of PPy, two layered, and PDMS treated specimen showed the best tensile properties as a strain sensor. The chemical property evaluation with Fourier transform infrared and x-ray photoelectron spectroscopy tests showed successful PPy polymerization and PDMS treatments. The functional groups and chemical bonds in polyol, urethane linkage, backbone ring structure in PPy, silicon-based functional groups in PDMS, and elemental content changes by treatment at each stage were characterized. The real-time data acquired from the dummy and five human subjects with repetition of motion at three different speeds of 0.16, 0.25 and 0.5 Hz generated similar trends and tendencies. The PU nanofiber sensors based on PPy and PDMS treatments in this study point to the possibility of developing textiles based wearable strain sensors developed using ICPs.}, number={7}, journal={SMART MATERIALS AND STRUCTURES}, author={Kim, Inhwan and Cho, Gilsoo}, year={2018}, month={Jul} }