Scalable and multifunctional carbon nanotube-based textile as distributed sensors for flow and cure monitoring

Many manufacturing processes involve flow and cure of polymeric materials and development of sensors to detect these phenomena in situ and in real-time is important to reduce processing time and improve quality. This paper reports the development of a novel multifunctional sensor where carbon nanotubes are deposited onto a nonwoven textile to create a thin and porous areal sensor. The sensor is produced using a scalable dip-coating process and carbon nanotubes form an electrically conductive network on the fabric. Vacuum assisted resin transfer molding (VARTM) for advanced fiber composites is used to validate the sensor by using global and local distributed measurements to monitor the flow of epoxy resin. Spatial flow mapping is demonstrated using electrical impedance tomography (EIT). In a series of 2-D radial flow experiments, the EIT maps demonstrate accurate estimations for the resin flow, in terms of flow front location and shape, and is able to pinpoint dry spots and unsaturated regions. During elevated temperature cure, the sensor electrical response can be correlated directly to changes in viscosity and gelation of the epoxy. The sensor offers potential as a process sensor for flow and cure as well as for structural health monitoring. (C) 2020 Elsevier Ltd. All rights reserved.