Enhancing mechanical properties of wet-spun PEDOT: PSS conductive fibers via molecular weight engineering of PSS

‍ABSTRACT

Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fibers with excellent electrical conductivity and stretchability are crucial for advancing wearable fiber-based electronics. However, the tensile strength and stretchability remain constrained by the hierarchical structure of PEDOT:PSS. Notably, the role of PSS molecular weight (M_w) in shaping the processability and mechanical performance of PEDOT:PSS fibers has not been explored yet. Herein, we examine the impact of PSS Mw on the process-structure–property relationship of PEDOT:PSS fibers. PSS with the higher M_w of 500 and 1000 kg mol^{− 1} were used to produce PEDOT:PSS₅₀₀ and PEDOT:PSS₁₀₀₀, compared to Clevios PH1000. Structural analysis shows that all the PEDOT:PSS solutions have a comparable PEDOT-to-PSS weight ratio. Increasing the M_w of PSS enhances solution viscosity, thereby improving fiber spinnability. The tensile strength is also improved in high M_w PEDOT:PSS fibers since the elongation at break (E_break) increases from 11.8% in PH1000 to 39.3% in PEDOT:PSS₁₀₀₀ at RH = 60%. After the DMSO/glycerol-immersed treatment, the PEDOT:PSS₁₀₀₀ fibers deliver a high conductivity of 110 S⋅cm^{− 1}.Besides, the PEDOT:PSS1000 fiber can exhibit high E_break = 48.8% at RH = 80% and still perform E_break = 13.7% even at low RH = 20%. These findings highlight the potential of tailoring PSS Mw to enhance the performance of PEDOT:PSS fibers for wearable electronics.

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KEYWORDS: PEDOT:PSS fiber, stretchability, fiber spinning, wearable electronics.