MWCNTs/CB waterborne conductive smart coating for damage monitoring of composites: Design, fabrication, characterization, and verification

To avoid the additional damage caused by conductive films embedded between layers of composites and to decrease the complexity of sensing structure manufacturing, a novel conductive smart coating for structural health monitoring is developed. This coating can be applied onto the surface of composite products. Also, a design principle for conductive coatings is proposed to provide design guidelines for sensor materials. A conductive coating with multiwall carbon nanotubes and carbon black is fabricated to verify the design principles. Besides, coating-related properties such as resistance change, conductivity, and failure strain are characterized through experiments. The damage to composite laminates with various thicknesses at tensile and different impact loads is analyzed to verify the monitoring effect of the coating. Additionally, to determine the damage location, a damage localization prototype is proposed. The results of this paper provide a reference and a design method for the engineering application of coated sensors and damage monitoring.