Amphibious Polymer Materials with High Strength and Superb Toughness in Various Aquatic and Atmospheric Environments

Abstract Herein, the fabrication of amphibious polymer materials with outstanding mechanical performances, both underwater and in the air is reported. A polyvinyl alcohol/poly(2‐methoxyethylacrylate) (PVA/PMEA) composite with multiscale nanostructures is prepared by combining solvent exchange and thermal annealing strategies, which contributes to nanophase separation with rigid PVA‐rich and soft PMEA‐rich phases and high‐density crystalline domains of PVA chains, respectively. Benefiting from the multiscale nanostructure, the PVA/PMEA hydrogel demonstrates excellent stability in harsh (such as acidic, alkaline, and saline) aqueous solutions, as well as superior mechanical behavior with a breaking strength of up to 34.8 MPa and toughness of up to 214.2 MJ m⁻³. Dehydrating the PVA/PMEA hydrogel results in an extremely robust plastic with a breaking strength of 65.4 MPa and toughness of 430.9 MJ m⁻³. This study provides a promising phase–structure engineering route for constructing high‐performance polymer materials for complex load‐bearing environments.