Carbon Nanotube-based Microscale Capacitive Flow Sensors
Abstract
Micro-scale flow sensors present several advantages over traditional flow sensing
methods, including minimal flow disruption, high spatial resolution, and low unit
cost. Many existing micro-scale thermal and piezo flow sensors struggle with temperature drift and require complicated fabrication processes. This thesis details
the development of a 60 μm by 60 μm by 50 μm drag-based capacitive flow sensor
constructed from vertically aligned carbon nanotube forests. The construction
of a thermal chemical vapour deposition system for sensor synthesis is also de-
tailed. Manual manipulation of the sensor with an atomic force microscope probe
was found to produce a full scale signal of ∼30 fF, measured by an AD7746 integrated circuit. A flow experiment producing wall shear stresses from 1 to 95 Pa
did not produce a measurable output. With more development, such a sensor
would provide a low-cost, highly configurable device for all manner of flow sensing
applications.