Leveraging Non-Covalent Interactions to Control the Morphology and Electrical and Mechanical Properties of Stretchable Semiconducting Composites

Abstract

Physical blending conjugated polymers (CPs) with elastomers has been established as an effective method for enhancing the stretchability of semiconductors. However, predictable control of the morphology for incompatible polymer rubber blends remains a challenge. In this work, we demonstrated the control of phase separation size of CP/elastomer composites by strategically controlling the location sites of H-bonding functional groups in CPs and elastomers, while investigating their effects on mechanical and electrical properties. We incorporated amide functional groups into a DPP-based semiconducting polymer (DPPTVT-A) and polyisobutylene-based elastomer (PIB-A) to enable inter-and intraphase hydrogen bonding (H-bonding) crosslinks within CP/elastomer composites. Along with their nonamide counterparts, we fabricated four different CP/elastomer composites, DPPTVT-A/PIB-A, DPPTVT-A/PIB, DPPTVT/PIB-A, and DPPTVT/PIB, with dual-, uni-, and non-H-bonding crosslinks and compared their phase behavior and electronic and mechanical properties. The location of the H-bonding greatly influenced the property of the semiconducting rubber as characterized by scattering, spectroscopy, and electrical characterization. Importantly, we found that creating a H-bonding cross-link into both domains of CP/elastomer composites can not only improve energy dissipation upon stretching but also maintain the electrical performance when applying high tensile stress. This work provides a comprehensive study of the morphology of CP/elastomer composites, offering valuable insights into the future design of stretchable CP/elastomer composites.

Modulating Aggregation Structure and Properties of Conjugated Polymers via Ester Additives

“…Stretchable semiconductor polymers have garnered significant attention due to their ability to maintain excellent electrical performance under mechanical deformation. − They can be applied in wearable and implantable devices, such as skin-like electronics, bioelectronics, and medical diagnostics . In these applications, stretchable transistors serve as the primary components for constructing electronic units. ,− Polymer semiconductors, due to their excellent mechanical properties, solution processability, and chemical tunability, have emerged as promising candidates for the fabrication of stretchable transistors. − …”

“…However, discovering suitable materials requires iterative synthesis of polymers and device optimization. In order to improve the mechanical flexibility, ductility, and processability of polymers, multicomponent system strategies are widely used. ,− When appropriately selected elastomers are used, thin films can generate nano-confinement effects, significantly improving the tensile properties of polymers . However, this method requires specific thin film structures to achieve the desired vertical phase separation morphology.…”