Shape Memory and Self-Healing Nanocomposites with POSS–POSS Interactions and Quadruple Hydrogen Bonds

Abstract

The organic–inorganic nanocomposites were constructed via polyhedral oligomeric silsesquioxanes (POSS)–POSS interactions and supramolecular quadruple hydrogen bonds. First, a double-decker silsesquioxane (DDSQ) was functionalized with two trithiocarbonate groups. Thereafter, the functionalized DDSQ was used to mediate the radial copolymerization of butyl acrylate (BA) with 2-ureido-4[1H]-pyrimidinone acrylate (UPyA). The reversible addition–fragmentation chain transfer (RAFT) polymerizations afforded the organic–inorganic hybrids with the architecture that a single POSS cage was embedded in the middle of a P(BA-co-UPyA) copolymer chain. The morphological investigation showed that the organic–inorganic hybrids were microphase-separated; the POSS (viz., DDSQ) cages were aggregated into the microdomains with diameter 10–20 nm. It was found that the organic–inorganic nanocomposites simultaneously had shape memory and self-healing properties. The shape memory and self-healing properties can be regulated with the supramolecular quadruple bonding interactions. The shape memory properties are attributable to the formation of physical cross-linking in the materials, whereas the self-healing properties are responsible for the introduction of dynamic noncovalent bonds (viz., quadruple hydrogen bonds). The self-healing properties can be utilized to reprogram the original shapes of the shape memory nanocomposites.