Development of stretchable eletrode based on PEDOT:PSS/AgNWs and elastomer

Abstract

The conducting polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is widely used as an electrode material in stretchable electronics due to its high electrical conductivity, optical transparency, and solution processability. However, its application on elastomeric substrates such as polydimethylsiloxane (PDMS) faces several critical challenges, including interfacial mismatches, poor adhesion, insufficient conductivity, and limitations in patterning resolution and electrode interconnection. This study presents a novel methodology that addresses these issues. To enhance the poor adhesion between PDMS and PEDOT:PSS, the substrate surface was treated with (3-glycidoxypropyl)trimethoxysilane (GPTMS). This process creates robust covalent bonds between the epoxy groups of GPTMS and the sulfonate groups of PSS, securely anchoring the conductive layer. High-resolution patterns of up to 10 μm were achieved via indirect patterning technique using a polyimide (PI) film as a temporary mask, overcoming photolithography limitations. Furthermore, a layer-by-layer (LBL) assembly of a PEDOT:PSS/silver nanowires (AgNWs) and a polyethyleneimine (PEI) solution was employed to ensure both high conductivity and mechanical durability. This method, leveraging strong electrostatic forces for interlayer adhesion, resulted in an optimized electrode with a low sheet resistance of 35.06 Ω/sq (5 LBL cycles). Finally, reliable electrical connections between electrodes were established using a simple water-assisted welding technique. The practical feasibility of this integrated approach was successfully demonstrated by fabricating a LED device with a serpentine electrode, which maintained stable operation under a tensile strain of up to 15%. This work establishes an effective platform for producing precisely patterned, highly conductive, and robustly interconnected stretchable electrodes, paving the way for advanced wearable electronic systems.