Shape memory and self-healing materials from supramolecular block polymers

Shape memory thermoplastics are an important class of engineering polymers with smart characteristics. A series of diblock polymers, polymethylmethacrylate-b-poly(butylacrylate-co-2-acrylamido-2-methyl- 1-propanesulfonic acid) (PMMA-b-P(BA-co-AMPS)) with varying molecular weights and compositions were conveniently synthesized. The monomer selection as well as the design of molecular architecture facilitated microphase separation in the prepared polymers, leading to two networks formed by the vitrified PMMA domain and the supramolecular interactions from the AMPS component, respectively. As a result, these block polymers exhibited excellent shape memory property (shape recovery ratio: 95%). Besides, the materials were also mechanically tough with an outstanding breaking strain of around 500% and a high tensile strength over 10 MPa. Furthermore, these shape memory polymers (SMPs) were built merely relying on physical interactions, retaining the thermal processability of engineering thermoplastics: it was facile to melt compound the materials into various desired shapes (dog-bone, disk, and film, etc.). More importantly, the prepared SMPs also showed exceptional self-healing capability under ambient conditions, benefited from the supramolecular interactions (ionic interactions) within the polymer network. This work elucidates a new path towards fabricating multifunctional low-cost shape-memory materials for a host of industrial applications. (C) 2017 Elsevier Ltd. All rights reserved.