University: University of Warwick  Supervisor: Dr Rachel Edwards  Start date: October 2021

As shown by the recent feasibility study, liquid crystals can be used to make a passive detection sensor for ultrasound. The sensor gives a visual image of the propagation of ultrasound through the sample; demonstration of the sensor has thus far focused on analysis of the resonant modes of a piezoelectric transducer, and visualisation of longitudinal waves passing through a sample. Regions of higher ultrasonic displacement lead to clearing of the liquid crystal sensor, which can be seen by eye. For waves travelling through a sample, any defects blocking the path will be shown by regions which do not clear. This technology could be used in a number of areas. The choice of liquid crystal material depends on the temperature of operation, and high temperature materials could be used to make high temperature sensors. Enhancement of Rayleigh waves at a defect could be used to identify surface-breaking defects under a paint without removing the paint; in fact, the sensor would be embedded as part of the paint. Or more simply, a removable sensor could be used to analyse the resonant modes of new piezoelectric transducers. The technology is at a low TRL but is ready for exploitation, offering a large number of potential avenues for a student.

Scope of Work:  

Identify key applications and temperatures of operation

Develop sensors to a higher TRL

Investigate potential for NDT


This studentship covers fees at the home/EU rate, a stipend of £16877 per annum and the full technical and professional training programme as part of the FIND CDT.