As composites are used increasingly in structural components, novel techniques for detecting micro-scale damage are required. Their nanoscale size and high aspect ratio allow carbon nanotubes to create electrically conductive pathways that enable sensing. In this work, carbon nanotubes are deposited onto glass fabric using electrophoretic deposition to create hierarchical composites. Polyethylenimine functionalized carbon nanotubes are deposited from an aqueous dispersion using an electric field. Symmetric cross-ply composites are investigated as a model system to demonstrate the ability to detect incipient damage and transverse microcracks. The specimens are subjected to tensile loading, and a resistance increase is observed because of two key mechanisms—A reversible change in nanotube-nanotube tunneling gaps due to elastic straining of the network and a permanent severing of paths in the conducting network due to formation of transverse cracks in the 90° plies. By analyzing the electrical response, the damage state can be identified. Acoustic emission sensors are used to validate the results. The strength and Young’s modulus of the composites with integrated carbon nanotubes are similar to the control specimens. Crack density measurements using edge replication reveal that transverse cracking can be suppressed, demonstrating multi-functionality with improved damage tolerance and integrated sensing.

Nanocomposites containing nanoscale materials offer exciting opportunities to encode nanoscale features into macroscale dimensions, which produces unprecedented impact in material design and application. However, conventional methods cannot process nanocomposites with a high particle loading, as well as nanocomposites with the ability to be tailored at multiple scales. A composite architected mesoscale process strategy that brings particle loading nanoscale materials combined with multiscale features including nanoscale manipulation, mesoscale architecture, and macroscale formation to create spatially programmed nanocomposites with high particle loading and multiscale tailorability is reported. The process features a low‐shrinking (<10%) “green‐to‐brown” transformation, making a near‐geometric replica of the 3D design to produce a “brown” part with full nanomaterials to allow further matrix infill. This demonstration includes additively manufactured carbon nanocomposites containing carbon nanotubes (CNTs) and thermoset epoxy, leading to multiscale CNTs tailorability, performance improvement, and 3D complex geometry feasibility. The process can produce nanomaterial‐assembled architectures with 3D geometry and multiscale features and can incorporate a wide range of matrix materials, such as polymers, metals, and ceramics, to fabricate nanocomposites for new device structures and applications.