Self‐Healing Materials: Progress in Self‐Healing Fiber‐Reinforced Polymer Composites (Adv. Mater. Interfaces 17/2018)

Abstract

With the potential for small-scale damage to grow or coalesce under subsequent loading, FRP structures incorporate high safety factors to account for this defect sensitivity to ensure they will remain load bearing throughout their service life. This paradigm has resulted in many research groups worldwide exploring and devel-oping the concept of self-healing or self-repair being applied to FRPs, with the aim of achieving autonomous structural recovery via an embedded functionality, to address damage formation in its early stages before the integrity of the structure is compromised. In principle, this could reduce the structural redundancy and fully realize the mass saving associated with using FRP composite materials. This paper sets out to review the current state of the art in applying self-healing/self-repair to high-performing advanced fiber-reinforced polymer com-posite materials. Our definition of an advanced fiber-reinforced polymer composite material for this work is as follows: • A nominal fiber volume fraction, V f > 30%. • A nominal matrix modulus, E > 500 MPa. Our review discusses what has been achieved to date, the ongoing challenges which have arisen in implementing self-healing into FRPs, how considerations for industrialization and large-scale manufacture must be considered from the outset, where self-healing may provide the most benefits (with respect to current FRP approaches to design), and how a func-tionality like self-healing can be validated for application in real structures. A significant proportion of self-healing studies have focused on assessing the healing efficiency of the system in bulk poly-mers, liquid (or low fiber volume) polymers, particulate com-posites, or low-volume fraction fiber-reinforced materials with inferior mechanical properties. [1,2] Comparatively, limited research has been undertaken on self-healing in advanced FRP composite materials, specifically based on systems com-monly used in industry or those that possess high-performance characteristics. Two broad categories of self-healing systems can be found in the available literature: [3] i) intrinsic self-healing systems, which can heal a crack through interactions (physical or chemical) at the molecular level; ii) extrinsic self-healing systems, which This paper sets out to review the current state of the art in applying self-healing/self-repair to high-performing advanced fiber-reinforced polymer composite materials (FRPs). A significant proportion of sel…