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CNT-Polyimide Nanocomposite Piezoresistive Thin Film Devices for Strain and Pressure Measurement

LI, QIUYAN (2015) CNT-Polyimide Nanocomposite Piezoresistive Thin Film Devices for Strain and Pressure Measurement. Master's Thesis, University of Pittsburgh. (Unpublished)

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In this thesis, piezoresistive thin film devices made of carbon nanotube (CNT)-polyimide (PI) nanocomposite were fabricated and characterized. Based on the percolation threshold, the CNT-PI nanocomposites with five different CNT weight ratios were chosen and made by suspension mixture method. The CNT-PI nanocomposite suspensions were deposited on the polyimide substrate by a drop-on-demand piezoelectric inkjet printer to fabricate piezoresistive thin film devices. The electrical impedance and the strain of the nanocomposite thin films under uniaxial tension and uniform pressure were characterized, and the strain sensor gauge factors were calculated. The temperature and humidity effect on the performance of the nanocomposite thin film devices were evaluated: the temperature coefficient was measured and the methods for temperature compensation were proposed; the resistance changes of the nanocomposites with humidity variation were monitored, and Parylene C thin film coating was used to eliminate or reduce the humidity effect. The piezoresistive nanocomposite thin film devices are used for pressure measurements. Finally, the sensitivities of the CNT-PI nanocomposite of different geometrical shapes under different types of load were defined and the values of sensitivities were evaluated by experiments. The inkjet printing method showed its advantages over the traditional thin film fabrication methods for its ability to precisely control the geometry and the uniformity of the nanocomposite thin film. The research results demonstrated that CNT-PI piezoresistive nanocomposite devices are promising candidates for flexible strain/pressure sensing applications.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorWang, Qing-Mingqiw4@pitt.eduQIW4
Committee MemberSlaughter, Williamwss@pitt.eduWSS
Committee MemberSmolinski, Patrickpatsmol@pitt.eduPATSMOL
Date: 8 June 2015
Date Type: Publication
Defense Date: 9 March 2015
Approval Date: 8 June 2015
Submission Date: 9 March 2015
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 94
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering and Materials Science
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Nanocomposite, piezoresistive, inkjet printing, strain gauge
Date Deposited: 08 Jun 2015 18:14
Last Modified: 15 Nov 2016 14:26


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