Composites can be divided into three groups based on their matrix materials, namely polymer, metal and ceramic. Composite materials fail due to micro cracks. Repairing is complex and almost impossible if cracks appear on the surface and interior, which minimizes reliability and material life. In order to save the material from failure and prolong its lifetime without compromising mechanical properties, self-healing is one of the emerging and best techniques. The studies to address the advantages and challenges of self-healing properties of different matrix materials are very limited; however, this review addresses all three different groups of composites. Self-healing composites are fabricated to heal cracks, prevent any obstructed failure, and improve the lifetime of structures. They can self-diagnose their structure after being affected by external forces and repair damages and cracks to a certain degree. This review aims to provide information on the recent developments and prospects of self-healing composites and their applications in various fields such as aerospace, automobiles etc. Fabrication and characterization techniques as well as intrinsic and extrinsic self-healing techniques are discussed based on the latest achievements, including microcapsule embedment, fibers embedment, and vascular networks self-healing.

An antibacterial filter was developed using Poly Vinylidene Fluoride (PVDF) nanofibres using electrospinning method blended with silver nanoparticles (AgNO₃) of varying weight percentages of filler. Polypropylene (PP) non woven substrate was used as base material for collecting the nanofibres. It also acted as a barrier to protect the fibres. UV visible spectroscopy and FTIR confirmed the uniform dispersion of silver nanoparticles throughout the nanofibres. The experiment was designed using Box Behnken statistical tool through three different variables namely, Polypropylene non woven sheets (GSM), electrospinning time (hours), concentration of silver (wt %) in fifteen runs. Surface morphology was analysed using SEM and AFM. Thermo gravimetric Analysis was performed for the analyses of mass decomposition of the material. Bacterial filtration efficiency and antibacterial activity studies were tested against S.aureus and E.coli for both PVDF +0wt% Ag fibres and PVDF-Ag nanofibres. This research shows the bacterial filtration efficiency for the prepared PVDF-Ag nanofibres as 99.86%. The prepared nanofilter was shown providing greater possibilities towards the application for clean air management.