Electrospinning of sacrificial nanofibers for the creation of a self-healing nanovascular network and its effect on the properties of an epoxy matrix

Composites, whose use has increased significantly the last decades due to their excellent properties, are prone to failure over time, like any other material. Self-healing materials are being developed to extend their lifetime. Today, most self-healing systems are based on the introduction of microcapsules. Although a lot of progress has been made, the effect of introducing such healing feature on the mechanical properties of the neat material is mainly overlooked, with the microcapsules creating potential artefacts in the neat matrix material. The use of a nanovascular network may show a better solution to apply self-healing systems. Therefore in the present paper we created a nanovascular network by pullulan sacrificial electrospun nanofibers, analysed the flexural properties and compared them to those of the neat matrix material as well as reported microcapsule-based materials. A detailed parameter analysis of the electrospinning process allowed for the production of tailored pullulan nanofibers. The introduction of the pullulan nanofibers showed no effect on the strength and modulus of the neat epoxy. On removal of the pullulan, the properties of the resultant nanovascular epoxy matrix system were somewhat reduced relative to the neat epoxy with an effect in proportion to the volume fraction and the diameter of the channels. However very interesting, the decrease of the mechanical properties of the nanovascular epoxy is far lower than on the introduction of microcapsules and opens potentials for a more appropriate introduction of self-healing systems in composite materials.

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