A novel class of bioinspired composite via ultrasound-assisted directed self-assembly digital light 3D printing

The advent of advanced manufacturing technologies brings about the possibilities of novel materials with potentially unprecedented material properties. Through ultrasound-assisted directed self-assembly digital light processing, we present a novel class of composite – the discontinuous interpenetrating-phase composite (d-IPC) – where the cellular filler phase is based on lines of particle assemblies, as opposed to continuous materials. Through yttria particle doping, we fully illustrate the unique microstructural-specific mechanical properties of the d-IPC. Despite being fully bulk and having a similar density (1.18 g/cm3) and strength (68 MPa) as the matrix polymer, it presents an additional plateau-deformation behaviour under large compressive strains and hence a 218% increase in specific energy absorption up to 37 J/g. The enabling mechanism is derived from the peculiar discontinuous and macroscopically aligned particle-based struts which do not contribute to a notable diminution of strength but can yet modulate high-strain deformation via induction of progressive localized failures. The concept of d-IPC is also extendable to solid fillers of all materials, morphology, and reasonable sizes, allowing the d-IPC to be highly customizable with multifunctional potentials. Through this work, we also aim to demonstrate the potentials of using advanced microstructural-controllable manufacturing techniques to achieve conceptually new and advanced composite materials.