Date of Award

8-2018

Degree Name

Master of Science in Engineering

Department

Electrical and Computer Engineering

First Advisor

Dr. Massood Z. Atashbar

Second Advisor

Dr. Bradley J. Bazuin

Third Advisor

Dr. Paul D. Fleming

Keywords

Flexible sensors, gravure printing, screen printing, temperature sensors, carbon nanotubes

Access Setting

Masters Thesis-Open Access

Abstract

This work focuses on the design, fabrication and characterization of novel flexible thermal sensors using additive print manufacturing processes. Initially, a carbon nanotube (CNT) based negative temperature coefficient (NTC) thermistor was fabricated on a flexible polyethylene terephthalate (PET) substrate using screen and gravure printing processes. The thermistor consists of two silver (Ag) electrodes deposited using screen printing process. A CNT based sensing layer was deposited using gravure printing process on the Ag electrodes. Finally, a primary polymer and a secondary Ag encapsulation layer were deposited using screen printing process. The capability of the fabricated thermistor was investigated by measuring its response towards temperatures varying from -40 °C to 100 °C, in steps of 10 °C. In addition, its stability towards relative humidity (RH) varying from 20% RH to 70% RH, in steps of 10% RH at two constant temperatures of 30 °C and 50 °C, was also studied.

Then, a fully printed nickel (Ni) based resistance temperature detector (RTD) was fabricated on a flexible polyimide (PI) substrate using screen printing process. The capability of the printed RTD was demonstrated by measuring its resistive response for temperatures varying from -60 °C to 180 °C, in steps of 20 °C and its sensing characteristics such as linearity, sensitivity and repeatability were analyzed. From the results obtained, it is evident that the fabricated thermal sensors using additive print manufacturing processes have the capability to be employed for temperature sensing applications in biomedical, automotive, robotics, and food industries.

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