Room-Temperature\nSelf-Healable Glassy Semicrystalline\nPolymers via Ionic Aggregations

Abstract

Semicrystalline polymers constitute the largest fraction\nof industrial\nand engineering plastics but are difficult to automatically self-heal\nin their glassy state due to the frozen molecular chains. Here, we\npresent a room-temperature autonomous self-healable glassy semicrystalline\npolymer by incorporating ionic aggregations to its amorphous segments,\nwhich shows a crystalline melting temperature (<i>T</i>_m) up to 60 °C, Young’s modulus up to 1.7 GPa,\nand storage modulus up to 0.5 GPa at 25 °C. By using small-angle\nX-ray scattering (SAXS), atomic force microscopy (AFM), dynamic mechanical\nanalysis (DMA), and broadband dielectric spectroscopy (BDS), we reveal\nthat ionic aggregations exhibit independent phases and relaxation\nbehavior with a low energy barrier. This enables the relaxation and\nreconfiguration of adjacent amorphous polymer chains on the fractured\nsurface at room temperature. The resulting polymers exhibit instantons\nself-healing with a recovered tensile strength of 43.5 MPa and 97.5%\nhealing efficiency within 4 h. This work offers a promising strategy\nto extend the lifespan, increase the sustainability, and decrease\nthe cost of semicrystalline polymers. As a proof of concept, such\nroom-temperature self-healable glassy semicrystalline polymers can\nbe considerably used in 3D printing manufacturing processes, leading\nto merged interfaces and enhancing the product’s structural\nintegrity.