Dimethyl Sulfoxide–Enhanced Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) Hydrogels for Flexible and Conductive Sensors

Conductive hydrogels are promising materials for flexible and wearable sensors owing to their high conductivity, stretchability, and biocompatibility. However, the insulating nature of poly(styrene sulfonate) (PSS) in poly(3,4-ethylenedioxythiophene) (PEDOT) limits charge transport. Dimethyl sulfoxide (DMSO) has been used to enhance conductivity by modifying hydrogen bonding interactions. In this research, we incorporated DMSO into PEDOT:PSS hydrogels to improve conductivity. Fourier transform infrared spectroscopy confirmed that DMSO replaced hydrogen bonds between PEDOT and PSS, as shown by the disappearance of the SO₃⁻ and S⁺ peak at 1150 cm⁻¹ and the emergence of a −SO₂H and O⁻ peak at 1300 cm⁻¹. Electrical measurements showed that resistance decreased from 200 to 40 kΩ, reaching 20% of its initial value. However, further DMSO addition led to conductivity saturation. These findings demonstrate that DMSO effectively enhances PEDOT:PSS hydrogels by improving charge transport. The enhanced conductivity makes these hydrogels suitable for wearable sensors, biomedical monitoring, and flexible electronics. Future research will focus on optimizing mechanical properties and stability for real-world applications.