Self-assembling nacre-like high-strength and extremely tough polymer composites with new toughening mechanism

•A macroscopic polymer composite with nanoscale structure was successfully fabricated with record mechanical strength, including ultra-high fracture strain of 1180%, tensile strength of 55.4 MPa, and toughness of 506.9 MJ/m3.•A new toughening mechanism utilizing non-affine flow of molecular networks is established, which can improve the tensile properties of PET by more than 2 times.•A nacre-like biomimetic toughening mechanism is self-integrated into the composite during stretching for synergistic toughening.