Steven D. Mookhoek

Self-healing behaviour in man-made engineering materials: bioinspired but taking into account their intrinsic character

Man-made engineering materials generally demonstrate excellent mechanical properties, which often far exceed those of natural materials. However, all such engineering materials lack the ability of self-healing, i.e. the ability to remove or neutralize microcracks without (much) intentional human interaction. This inability is the unintentional consequence of the damage prevention paradigm underlying all current engineering material optimization strategies. The damage management paradigm observed in nature can be reproduced successfully in man-made engineering materials, provided the intrinsic character of the various types of engineering materials is taken into account.

X-Ray Phase-Contrast Tomography for Quantitative Characterisation of Self-Healing Polymers

X-ray phase-contrast imaging and tomography add an additional dimension to conventional x-ray methods by exploiting the x-ray refraction effects in addition to x-ray absorption in forming an image. This greatly enhances the visibility of edges, voids and boundaries within a sample. It also makes it possible to characterise weakly x-ray absorbing samples which would produce little or no contrast in conventional x-ray imaging. Here we described the application of a laboratory-based x-ray phase-contrast microscope to x-ray micro-tomography of a self-healing polymer system and the quantitative analysis of the resulting three dimensional (3D) datasets to better understand the healing and ageing processes.