关键词: PEDOT:PSS, 电导率, 拉伸性能, 电荷屏蔽效应, 共平面性构象, 链间相互作用

Abstract:

Conductive polymer PEDOT:PSS has a wide application prospect in flexible electronic products such as wearable electronic and other fields. PEDOT:PSS has high transmittance in the visible light range, great solution processing performance and good mechanical stability. However, the conductivity and stretchability of the original PEDOT:PSS film are limited due to the fact that the conductive PEDOT is wrapped by insulating PSS and has a rigid conjugated backbone and strong interchain interaction. In order to improve the conductivity of the blended film, we use glycerin and polyvinyl alcohol as additives, and the PEDOT molecular chain conformation is changed and PEDOT:PSS phase separation is induced by the interaction between polar glycerin and PEDOT. At the same time, soft polymer PVA serves as a stretchable network, improving the stretchability of the film. Typically, the original PEDOT:PSS films are poorly stretchable, so PVA is used as a stretchable polymer network. However, because PVA is an insulating material, the conductivity of the film is extremely low. In order to improve the conductivity of the blended film, glycerin is further blended with PVA/PEDOT:PSS. Dipole interaction occur between glycerin hydroxyl group and PEDOT chain, which change the conformation of the PEDOT molecular chain and improve the planarity of the molecular chain. Meanwhile, polar glycerin induces phase separation between PEDOT and PSS, causing PEDOT regions to aggregate and form conductive pathways. Moreover, glycerin can form hydrogen bonds with PSS and PVA, reducing the interaction between polymer chains and further improving stretchability. The results show that by optimizing the content of glycerin and PVA, a stretchable conductive film with more than 100% elongation at break and 660 S/cm conductivity can be obtained.

Key words: PEDOT:PSS, conductivity, stretchability, charge screening effect, coplanar conformation, interchain interaction