Ultra-Stretchable LENR/PEDOT:PSS/CuSO4Hydrogel for Self-Powered, High-Sensitivity Human–Computer Interaction Touchpads N. S. Fatinah Khairul Nidzham, Huda Salah Kareem, Nurul Hayati Yusof, Nurfarhanim Abu Bakar, Nurdiana Nordin ACS Applied Electronic Materials, 2025 Human–computer interaction (HCI) devices demand materials that are simultaneously flexible, conductive, and mechanically resilient. Here, we report an ultrastretchable and conductive hydrogel based on liquid epoxidized natural rubber (LENR), poly(acrylamide- co -acrylic acid), PEDOT:PSS, (labeled as LENR composite hydrogels) and CuSO 4, engineered to deliver balanced electrical and mechanical performance for next-generation HCI systems. Spectroscopic and thermal analyses confirmed the formation of a robust hybrid network, with enhanced π–π interactions and increased hydroxyl content at optimal PEDOT:PSS loading. Among the synthesized hydrogels, the CuSO 4 -doped LENR/p(AAm- co -AA)/20%PEDOT:PSS ( 2b ) formulation demonstrated the best balance of properties, achieving conductivity of 97.1 Ω –1 ·cm –1, resistivity of 0.0103 Ω·cm, capacitance of 37 ± 4 mF, and toughness of 2.20 × 10 9 J·m –3 . The hydrogel also exhibited mechanoresponsive strain sensitivity with a gauge factor of ∼4.9 and >90% recovery after repeated deformation cycles. Comparative benchmarking confirmed that these values outperform or rival state-of-the-art conductive hydrogels, surpassing PEDOT:PSS/natural rubber (15–40 Ω –1 ·cm –1 ) and PEDOT:PSS/ionic liquid elastomers (∼80 Ω –1 ·cm –1 ), while approaching the capacitance of advanced in situ-functionalized PEDOT:PSS hydrogels (40–50 mF). The integration of the optimized hydrogel into a self-powered touchpad, utilizing carbonized Kapton electrodes and PET substrates, demonstrated reliable triboelectric charge generation and highly sensitive, reproducible touch responses. This study presents LENR/PEDOT:PSS/CuSO 4 hydrogels as a sustainable and multifunctional platform for flexible, adaptive, and high-performance HCI technologies, with future potential for self-calibrating systems through machine learning-assisted signal optimization.
Towards 3D compositional control of addressable biofunctional sites within a microfluidic environment 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2017, 2020
Monitoring in situ electrodeposition of Chitosan in a compact microfluidic channel with Nuclear Magnetic Resonance (NMR) 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2018, 2018