Integrating charge mobility, stability and stretchability within conjugated polymer films for stretchable multifunctional sensors

Conjugated polymers (CPs) are promising semiconductors for intrinsically stretchable electronic devices. Ideally, such CPs should exhibit high charge mobility, excellent stability, and high stretchability. However, converging all these desirable properties in CPs has not been achieved via molecular design and/or device engineering. This work details the design, synthesis and characterization of a random polythiophene (RP-T50) containing similar to 50 mol% of thiophene units with a thermocleavable tertiary ester side chain and similar to 50 mol% of unsubstituted thiophene units, which, upon thermocleavage of alkyl chains, shows significant improvement of charge mobility and stability. Thermal annealing a RP-T50 film coated on a stretchable polydimethylsiloxane substrate spontaneously generates wrinkling in the polymer film, which effectively enhances the stretchability of the polymer film. The wrinkled RP-T50-based stretchable sensors can effectively detect humidity, ethanol, temperature and light even under 50% uniaxial and 30% biaxial strains. Our discoveries offer new design rationale of strategically applying CPs to intrinsically stretchable electronic systems.

Automated summary

A novel random polythiophene (RP-T50) material was designed, which showed significantly improved charge mobility and stability upon thermal annealing, while generating wrinkles in the polymer film to enhance its stretchability. The RP-T50-based stretchable sensor exhibited outstanding performance in detecting various environmental parameters under different stretching conditions.