@article{chen_hua_ling_liu_chen_ju_gao_mills_tao_yin_2023, title={An airflow-driven system for scalable production of nano-microfiber wrapped triboelectric yarns for wearable applications}, volume={477}, ISSN={["1873-3212"]}, url={https://doi.org/10.1016/j.cej.2023.147026}, DOI={10.1016/j.cej.2023.147026}, journal={CHEMICAL ENGINEERING JOURNAL}, author={Chen, Yu and Hua, Jie and Ling, Yali and Liu, Yang and Chen, Mingtai and Ju, Beomjun and Gao, Wei and Mills, Amanda and Tao, Xiaoming and Yin, Rong}, year={2023}, month={Dec} }
 @article{knowles_ju_sennik_mills_jur_2023, title={Simulation techniques for smart textile predictive design}, volume={1266}, ISBN={["*****************"]}, ISSN={["1757-8981"]}, DOI={10.1088/1757-899X/1266/1/012008}, abstractNote={Abstract
               Smart textiles must combine both textile and electronic systems into one product. This presents challenges as each industry has their own design and evaluation standards that are not compatible with one another. As such, smart textile designers tend to rely heavily on the production and iteration of physical prototypes to create a product that meets the specified design criteria. One emerging tool in the apparel industry that has potential to shorten the prototyping cycle is 3D CAD for textiles, also known as 3D garment simulation. While typically used for apparel design and e-commerce, this work presents two case studies that demonstrate how 3D garment simulation can be used as a tool for predictive design of smart textile products. In particular, how strain-dependent properties such as resistance and contact pressure can be predicted and how designs can be optimized to achieve certain performance metrics.}, journal={8TH INTERNATIONAL CONFERENCE ON INTELLIGENT TEXTILES & MASS CUSTOMISATION}, author={Knowles, Caitlin G. and Ju, Beomjun and Sennik, Busra and Mills, Amanda C. and Jur, Jesse S.}, year={2023} }
 @article{youn_knowles_ju_sennik_mathur_mills_jur_2023, title={Simulation-Based Contact Pressure Prediction Model to Optimize Health Monitoring Using E-Textile Integrated Garment}, volume={23}, ISSN={["1558-1748"]}, url={https://doi.org/10.1109/JSEN.2023.3293065}, DOI={10.1109/JSEN.2023.3293065}, abstractNote={Advancements in wearable technology have integrated textile sensors into garments for long-term electrocardiogram (ECG) monitoring. However, optimizing biosignal quality, motion artifacts, and wearer comfort in electronic textiles (E-textiles) remains challenging. While designing appropriate contact pressure (CP) is crucial, there is a lack of guidance on proper material selection and sizing for achieving the desired CP. This article presents a novel CP prediction model that utilizes three-dimensional garment simulation (3DGS) to optimize knit textiles for health monitoring. First, a stress test method is devised in the simulator to examine the reliability of simulated stress. Based on understanding the simulated stress mechanism, the CP model is developed using simulation parameters. The model is validated against experimental CP values, exhibiting high accuracy ( ${R}^{{2}}= {0.9}$ ). The effectiveness of the CP model is validated through the demonstration of a customized ECG armband incorporating screen-printed dry electrodes on knit fabrics. Analyzing ECG signals, CP, and applied strains validates the benefits of strategically selected materials and sizing. Specifically, the knit sample with 90% polyester and 10% spandex (S-10) for the 15%–20% range and the knit sample with 85% polyester and 18% spandex (S-18) for the 10%–15% strain range significantly enhance ECG quality, resulting in higher signal-to-noise ratios (SNR) of 33.45 (±1.72) and 34.57 (±0.84)−36.61(±1.81), respectively. These design parameters achieve the desired CP range of 1–1.5 kPa, optimizing the functionality and comfort of the ECG armband. The CP model sets a benchmark for the strategic manufacturing of health monitoring garments by integrating digital technology.}, number={16}, journal={IEEE SENSORS JOURNAL}, author={Youn, Seonyoung and Knowles, Caitlin G. and Ju, Beomjun and Sennik, Busra and Mathur, Kavita and Mills, Amanda C. and Jur, Jesse S.}, year={2023}, month={Aug}, pages={18316–18324} }
 @article{li_reese_ingram_huddleston_jenkins_zaets_reuter_grogg_nelson_zhou_et al._2022, title={Textile-Integrated Liquid Metal Electrodes for Electrophysiological Monitoring}, volume={7}, ISSN={["2192-2659"]}, url={https://doi.org/10.1002/adhm.202200745}, DOI={10.1002/adhm.202200745}, abstractNote={AbstractNext generation textile‐based wearable sensing systems will require flexibility and strength to maintain capabilities over a wide range of deformations. However, current material sets used for textile‐based skin contacting electrodes lack these key properties, which hinder applications such as electrophysiological sensing. In this work, a facile spray coating approach to integrate liquid metal nanoparticle systems into textile form factors for conformal, flexible, and robust electrodes is presented. The liquid metal system employs functionalized liquid metal nanoparticles that provide a simple “peel‐off to activate” means of imparting conductivity. The spray coating approach combined with the functionalized liquid metal system enables the creation of long‐term reusable textile‐integrated liquid metal electrodes (TILEs). Although the TILEs are dry electrodes by nature, they show equal skin‐electrode impedances and sensing capabilities with improved wearability compared to commercial wet electrodes. Biocompatibility of TILEs in an in vivo skin environment is demonstrated, while providing improved sensing performance compared to previously reported textile‐based dry electrodes. The “spray on dry—behave like wet” characteristics of TILEs opens opportunities for textile‐based wearable health monitoring, haptics, and augmented/virtual reality applications that require the use of flexible and conformable dry electrodes.}, journal={ADVANCED HEALTHCARE MATERIALS}, author={Li, Braden M. and Reese, Brandon L. and Ingram, Katherine and Huddleston, Mary E. and Jenkins, Meghan and Zaets, Allison and Reuter, Matthew and Grogg, Matthew W. and Nelson, M. Tyler and Zhou, Ying and et al.}, year={2022}, month={Jul} }
 @article{li_ju_zhou_knowles_rosenberg_flewwellin_kose_jur_2021, title={Airbrushed PVDF-TrFE Fibrous Sensors for E-Textiles}, volume={3}, ISSN={["2637-6113"]}, url={https://doi.org/10.1021/acsaelm.1c00802}, DOI={10.1021/acsaelm.1c00802}, abstractNote={The low-temperature processing, inherent flexibility, and biocompatibility of piezoelectric polymers such as poly(vinylidene fluoride) (PVDF)-based materials enable the creation of soft wearable sensors, energy harvesters, and actuators. Of the various processing techniques, electrospinning is the most widely adopted process to form PVDF nanofiber scaffolds with enhanced piezoelectric properties such that they do not require further post-processing such as mechanical drawing, electrical poling, or thermal annealing. However, electrospinning requires long periods of time to form sufficiently thick PVDF nanofiber scaffolds and requires extremely high voltages to form scaffolds with enhanced piezoelectric properties, which limits the number of usable substrates, thus restricting the integration and use of electrospun PVDF scaffolds into wearable textile platforms. In this work, we propose a facile processing technique to airbrush PVDF–trifluoroethylene (TrFE) nanofiber scaffolds directly onto textile substrates. We tune the polymer concentration (4, 6, and 8 wt %) and the spray distance (5, 12.5, and 20 cm) to understand their effects on the morphology and crystal structure of the fibrous scaffolds. The characterization results show that increasing the polymer wt % encourages the formation of fibrous morphologies and a β-phase crystal structure. We then demonstrate how the airbrushed PVDF–TrFE scaffolds can be easily integrated onto conductive inkjet-printed nonwoven textile substrates to form airbrushed piezoelectric textile devices (APTDs). The APTDs exhibit maximum open-circuit voltages of 667.1 ± 162.1 mV under tapping and 276.9 ± 59.0 mV under bending deformations. The APTDs also show an areal power density of 0.04 μW/cm2, which is 40× times higher compared to previously reported airbrushed PVDF scaffolds. Lastly, we sew APTDs into wearable textile platforms to create fully textile-integrated devices with applications in sensing a basketball shooting form.}, number={12}, journal={ACS APPLIED ELECTRONIC MATERIALS}, publisher={American Chemical Society (ACS)}, author={Li, Braden M. and Ju, Beomjun and Zhou, Ying and Knowles, Caitlin G. and Rosenberg, Zoe and Flewwellin, Tashana J. and Kose, Furkan and Jur, Jesse S.}, year={2021}, month={Dec}, pages={5307–5326} }
 @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={AbstractPressure sensors for wearable healthcare devices, particularly force sensitive resistors (FSRs) are widely used to monitor physiological signals and human motions. However, current FSRs are not suitable for integration into wearable platforms. This work presents a novel technique for developing textile FSRs (TFSRs) using a combination of inkjet printing of metal‐organic decomposition silver inks and heat pressing for facile integration into textiles. The insulating void by a thermoplastic polyurethane (TPU) membrane between the top and bottom textile electrodes creates an architectured piezoresistive structure. The structure functions as a simple logic switch where under a threshold pressure the electrodes make contact to create conductive paths (on‐state) and without pressure return to the prior insulated condition (off‐state). The TFSR can be controlled by arranging the number of layers and hole diameters of the TPU spacer to specify a wide range of activation pressures from 4.9 kPa to 7.1 MPa. For a use‐case scenario in wearable healthcare technologies, the TFSR connected with a readout circuit and a mobile app shows highly stable signal acquisition from finger movement. According to the on/off state of the TFSR with LED bulbs by different weights, it can be utilized as a textile switch showing tactile feedback.}, 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} }