https://scholar.dgist.ac.kr/handle/20.500.11750/815 Sat, 04 Apr 2026 14:41:58 GMT 2026-04-04T14:41:58Z https://scholar.dgist.ac.kr/handle/20.500.11750/59285 Title: Ultra-thin high-resolution transfer-printed breathable electronics for conformal wearable devices Author(s): Choi, Hyeokjoo; Lee, Dongju; Hwang, Sieun; Shin, Juhee; Bae, Jihoon; Jang, Gain; Kwon, Seokhun; Kang, Hyunil; Myeong, Jihyeon; Jeong, Youngtae; Roh, Jong Wook; Lee, Sungwon Abstract: Nanomesh electronics offer remarkable potential for biomedical and human–machine interface applications due to their conformability to nonplanar surfaces, versatile functionality, and long-term reliability. However, existing materials face significant challenges related to surface structure and chemical resistance, resulting in high electrical resistance and complex fabrication requirements. To address these challenges, we present transfer-printed nanomesh electrodes (NEs) produced by integrating fine-patterned 2D electrodes with porous nanomesh. Electrospun thermoplastic-polyurethane nanofibers provide strong adhesion to the electrodes, which generate sufficient force (95.1 mN∙cm−1) to maintain structural integrity and electrical performance. Unlike direct deposition, which requires a minimum thickness of 100nm to achieve 14.12±2 mS, transfer-printed NEs reach 16.91±8.7 mS only with 20nm. Furthermore, our electrodes demonstrate excellent durability under deformation, maintaining stable electrical performance with only a 0.53% change at a bending radius of 1mm. To validate their practical application, we demonstrate a NE-based tactile sensor, which exhibits a conductance change from 0 mS in the normal state to 130 mS upon touch. These results highlight the potential of transfer-printed NEs for next-generation e-skin with fine patterning, high conductivity, and long-term reliability. In addition, our novel method addresses the challenges of manufacturing breathable devices with functionalities extending beyond simple electrodes. Sun, 30 Nov 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59285 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59035 Title: Robust, Stretchable, and Flexible Polymer Nanofiber-Based Wearable Platform for Colorimetric and Chemiresistive Dual-Mode Ammonia Gas Sensing Author(s): Kwon, Seokhun; Choi, Hyeokjoo; Kim, Chulsoo; Shin, Juhee; Kim, Kangmin; Noh, Jihwan; Eo, Sungwoo; Lee, Seokwon; Hwang, Hyunsuk; Lee, Sungwon; Kang, Hyunil Abstract: Ammonia (NH3) is the second-most-produced chemical worldwide and has numerous industrial applications. However, such applications pose significant risks, as evidenced by human casualties caused by NH3 leaks or poisoning in confined environments. This highlights the critical need for highly portable and intuitive wearable NH3 sensors. The chemiresistive sensors are widely employed in wearable devices due to their simple structure, high sensitivity, and short response times, but are prone to malfunctioning and inaccurate gas detection because of the corrosion or failure of the sensing material under the influence of humidity, high temperatures, and interfering gas species. Addressing these limitations, a gas-sensing platform with a polymer-based nanofiber structure has been developed, providing flexibility and facilitating efficient transport of NH3 between the colorimetric (bromocresol-green-based) and chemiresistive (poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-based) sensing layers. This dual-mode design enables reliable NH3 detection. The NH3-sensing performance of each individual layer is comparable to that of the dual-mode gas-sensing platform, which operates effectively even when attached to human skin and in humid environments. Therefore, this study establishes a robust, selective, and reproducible NH3 sensor for diverse applications and introduces an innovative sensor engineering paradigm. Sun, 30 Nov 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59035 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58395 Title: Enhanced voltage and capacitance in flexible supercapacitors using electrospun nanofiber electrolytes and CuNi2O3@N-Doped omnichannel carbon electrodes Author(s): Ponnaiah, Sathish Kumar; Bae, Jihoon; Roh, Jong Wook; Min, Yuho; Lee, Sungwon Abstract: Developing functional solid polymer electrolytes (SPEs) is crucial for flexible, lightweight, and portable supercapacitors. This work presents an electrospinning approach to fabricate SPEs using poly(vinyl alcohol)-sodium chloride (PVA-NaCl) nanofibers (PNNF). CuNi2O3 nanoparticles deposited on nitrogen-doped omnichannel carbon nanofibers (CuNi2O3@N-OCCFs), coated onto a carbon cloth (CC), serve as the positive electrode, enhancing faradaic capacitance. Meanwhile, the rationally designed N-OCCFs, also coated onto CC, function as the negative electrode, providing a high-surface-area, and facilitating rapid electron transport. Comprehensive characterization revealed insights into the morphology and chemical composition of both electrodes and the PNNF electrolyte. An all-solid-state asymmetric flexible supercapacitor (AFSC) device, CuNi2O3@N-OCCFs-1.5//N-OCCFs-1.5, was assembled using PNNF as both the electrolyte and separator and evaluated against devices employing gel and aqueous electrolytes. The PNNF electrolyte enabled a wider potential window (2.2 V) compared to gel (2.0 V) and liquid (1.8 V) electrolytes. The AFSC achieved an impressive energy density of 63.6 Wh kg-1 at a power density of 1100 W kg-1, with 96.2% capacitance retention after 6000 charge/discharge cycles at 10 A g(-)1. When two devices were connected in series, they powered a red LED for 5.33 min and a blue LED for 1.43 min, demonstrating practical applicability. This study provides a simple and effective strategy for fabricating high-energy-density AFSCs with excellent cycling stability and broad potential for flexible electronics. Mon, 31 Mar 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/58395 2025-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58387 Title: High-Resolution Patterning of Breathable Polymer Nanomesh via Double-Side UV Exposure for Fabricating Micropatterned Wearable Devices Author(s): Bae, Jihoon; Song, Chong-Myeong; Ponnaiah, Sathish Kumar; Jang, Gain; Choi, Hyeokjoo; Hwang, Sieun; Shin, Juhee; Kim, Seokhwan; Do, Juha; Kim, Mijin; Kim, Yeon Woo; Kim, CheolGi; You, Chun-Yeol; Min, Yuho; Roh, Jong Wook; Kwon, Hyuk-Jun; Lee, Sungwon Abstract: Nanomesh electronics, renowned for their breathability and compatibility with long-term skin attachment, face significant challenges in achieving high-resolution micropatterning, which limits their applications in advanced devices. To address this, a method to fabricate durable, breathable, and highly conductive micropatterned nanomesh electrodes (MPNEs) with line widths as narrow as 10 mu m was developed. Using a double-side exposure technique, precise patterning was achieved on a polyimide nanomesh substrate. Silver nanowires (AgNWs) were selectively deposited via vacuum filtration, ensuring optimal alignment for enhanced conductivity. The MPNEs exhibit excellent electrical performance, achieving a sheet resistance of 3.9 Omega sq-1 at an AgNW loading of 1.6 mu g mm-2. They maintain consistent conductivity across various line widths and lengths, demonstrating high reproducibility. Mechanical testing confirmed exceptional durability under significant deformations, including bending, folding, and twisting. Furthermore, the porous structure remained breathable after AgNW deposition, preserving gas and moisture permeability. The versatility of MPNEs was demonstrated by fabricating intricate patterns such as interdigitated electrodes, multielectrode arrays, and coil antennas. These findings underscore the potential of MPNEs for advanced wearable electronics and multifunctional devices. Mon, 31 Mar 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/58387 2025-03-31T15:00:00Z