AbstractThe detection of possible impacts in carbon-fiber-reinforced plastic (CFRP) structures is important for the evaluation of structural integrity of CFRP. Sol–gel-based sensitive coatings for impact detection on CFRP substrates have been developed and investigated by University of Aveiro (UAVR). The coatings are based on hybrid sol–gel formulations with tunable mechanical properties, i.e., brittleness adjusted for a defined range of impact energy. This sensitive layer allows the identification and location of mechanical impacts under visible light and without supplementary tools or conditions for its detection. A systematic study was performed to enhance the coating response for the defined impact threshold. A set of different parameters such as composition, fillers, curing conditions, surface roughness, and chemistry of the surface were tested and optimized.