High-performance, fluorescent, UV-shielding, triboelectric, super-flexible polyurea elastomers via strong π–π stacking of pyrene and hydrogen bonding strategies

Abstract

It is a challenge to develop polyurea with high-performance and multifunctionality because the integration of functions often comes at the expense of mechanical properties. This work synthesized a novel diisocyanate with a pyrene side chain, followed by reacting with poly(propylene oxide) diamine to prepare polyurea elastomers (PPU-x). Herein, thanks to the strong π–π stacking effect between pyrene groups and the anchoring effect of the amino group, the maximum tensile strength of PPU-x reached 41.4 MPa. The large conjugate structure of pyrene groups also gave PPU-x outstanding fluorescence and UV shielding performance. More noteworthy is the fact that graphene can be well dispersed in PPU-x with such high polarity via π–π interactions, which caused the dielectric constant of graphene-modified PPU-x nanocomposites to be three times that of PPU-0.3. Furthermore, this nanocomposite was used to make a triboelectric nanogenerator. Under the action of 0.5 N, the output voltage can reach 80 V, which is expected to be used to monitor weak signals of the human body. This work opens up a new strategy for the development of high-performance polyurea and its graphene-modified multifunctional polyurea nanomaterials with wide potential applications.