Supramolecular thermoplastics and thermoplastic elastomer materials with self-healing ability based on oligomeric charged triblock copolymers

Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. These dynamic supramolecular interactions can provide unique properties such as a strong decrease in viscosity upon relatively mild heating, as well as self-healing ability. In this study we demonstrate the unique mechanical properties of phase-separated electrostatic supramolecular materials based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks. In case of well-chosen mixtures and block lengths, the charged blocks are phase separated from the uncharged matrix in a hexagonally packed nanomorphology as observed by transmission electron microscopy. Thermal and mechanical analysis of the material shows that the charged sections have a Tg closely beyond room temperature, whereas the material shows an elastic response at temperatures far above this Tg ascribed to the electrostatic supramolecular interactions. A broad set of materials having systematic variations in triblock copolymer structures was used to provide insights in the mechanical properties and and self-healing ability in correlation with the nanomorphology of the materials. By mixing electrically charged polymers, a team in Belgium has created a self-healing thermoplastic polymer. Thermoplastics have a rubber-like consistency under normal conditions but become viscous when heated, allowing them to be easily molded. But a lot of energy is usually required to realize this viscous state. Now, Richard Hoogenboom from Ghent University and co-workers have created a supramolecular thermoplastic by blending two polymers carrying opposite electrical charge. The material exhibits unique mechanical properties, which stem from the strong electrostatic attraction between these different domains. The low molar mass of the polymers used mean that the supramolecular thermoplastic is easier to process than other materials with similar properties. In particular, its storage modulus can be completely restored by mild heating for two hours. Such materials are promising as self-healing coatings. Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. Here we report a novel type of supramolecular rubber based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks revealing unique mechanical properties. A broad set of materials is reported with systematic variations in triblock copolymer structures revealing insights in the mechanical properties and self-healing ability in correlation with the nanomorphology of the materials.