Near-infrared light-induced shape memory, self-healable and anti-bacterial elastomers prepared by incorporation of a diketopyrrolopyrrole-based conjugated polymer

Light-induced shape memory polymers are desirable since they can be stimulated by remote and spatial light control. Incorporating photothermal fillers provides a straightforward approach to realise shape memory polymers with light-responsive properties. As photoactive materials, conjugated polymers have advantages such as tunable absorption, easy modification, good photostability and biocompatibility. Diketopyrrolopyrrole-based conjugated polymers are of particular interest since they have strong absorption and high heat conversion efficiency in the near-infrared (NIR) region, which make them very promising photothermally-responsive agents. However, their potential as photothermal fillers for light-responsive shape memory polymers has rarely been explored. In this work, a diketopyrrolopyrrole-based conjugated polymer (PDPP3T) was applied as the photothermal filler to be incorporated into a shape memory elastomer matrix of polycaprolactone-co-poly(urethane/urea) (PCL-PU). With as small as 0.1 wt parts per thousand addition of PDPP3T, the resulting PCL-PU elastomer showed an obvious photothermal effect under NIR (808 nm) laser irradiation. The shape memory effect of the elastomer could be initiated and controlled efficiently by laser irradiation as well. When it was combined with a dynamic hindered urea bond in the structure, the elastomer showed more elaborate light-induced reconfigurable shape memory and self-healable effects. Additionally, the elastomer also showed a light-induced antibacterial effect due to local hyperthermia under laser irradiation, revealing further potential of photothermal elastomer materials.