Ultra-strong, ultra-tough, and transparent pure poly (m-phenylene isophthalamide) (PMIA) films mediated by a highly ordered aggregation structure and hydrogen-bonded PMIA crystal structures

Lightweight, strong, and tough polymeric materials are highly sought for potential applications in flexible bioelectronics, optoelectronic devices, and aerospace fields. Among these materials, Poly (m-phenylene isophthalamide) (PMIA), a type of aromatic polyamide polymer, have been spotlighted owing to their high thermal stability and superior mechanical performance. However, there has been no research breakthrough in fabricating ultra-strength and ultra-tough pure PMIA films. Here, a novel and scalable strategy for the preparation of ultra-strength, ultra-tough, and transparent pure PMIA films mediated by a highly ordered aggregation structure and hydrogen-bonded PMIA crystal structures is reported, using a two-step uniaxial wet-drawing and high-temperature heat treatment. The resulting films exhibit a high tensile strength of 613.82 ± 28.01 MPa and a toughness of up to101.60 ± 8.14 MJ m⁻³, and these values exceed those of most previously reported materials. When normalized by weight, the specific tensile strength of the films reaches 306.91 MPa g⁻¹ cm³, surpassing that of commercial titanium alloy (257.00 MPa g⁻¹ cm³). Furthermore, it shows high transparence (86.20 % at 550 nm wavelength), resistance to alternating high and low temperatures (−196 °C to 220 °C) and fatigue resistance (222 614 ± 8223 folding-failure cycles). This work is expected to expand the potential applications of PMIA films and provides a novel perspective for designing lightweight, high-performance polymer thin-film materials.