Interfacial Chemistry Behind Damage Monitoring in Glass Fiber‐Reinforced Composites: Attempts and Perspectives

Glass Fiber Reinforced Polymers (GFRPs) are widely used in structural applications but degrade over time due to internal dam-age. Structural Health Monitoring (SHM) enables early damage detection, improving reliability and reducing maintenance costs.Traditional SHM methods are often invasive and expensive. An emerging solution involves the embedding of carbon-basedfiller like carbon nanotubes and reduced graphene oxide into GFRPs, forming conductive networks that detect damage throughresistance changes. However, poor adhesion among GF, filler, and matrix can reduce mechanical performance. Therefore, tai-loring GF and filler surface chemistry is essential to enhance durability and enable effective self-sensing properties. This reviewsummarizes the most recent efforts in modifying GF with carbon-based filler to design GFRP with improved sensing ability andmechanical performance. After a brief introduction on the role of SHM solutions in early damage detection, an overview of thecommon GF and filler used in GFRPs will be provided. Then, the most relevant GF modification strategies exploited to incor-porate carbon-based filler in GFRPs will be described, focusing on the chemical grafting approach, which allows a careful opti-mization of the fiber/matrix interface. Last, a concise summary of the key mechanical and electrical tests to evaluate interfacialadhesion and self-sensing will be supplied.