Publication Date

12-2022

Date of Final Oral Examination (Defense)

10-18-2022

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Mechanical Engineering

Department

Mechanical and Biomechanical Engineering

Major Advisor

Zhangxian Deng, Ph.D.

Advisor

Dave Estrada, Ph.D.

Advisor

Gunes Uzer, Ph.D.

Abstract

Piezoelectric poly(vinylidene fluoride-co-trifluoroethylene), or PVDF-trFE, builds up significant electrical charges on its surface when stressed. By correlating the mechanical force with the resulting electrical charges or voltages, researchers have developed flexible, broadband, and biocompatible force sensors. PVDF-trFE force sensors are traditionally fabricated via spin coating or solvent casting, which result in large waste production and experience difficulties in forming complex geometries. To tackle these challenges, I leveraged a commercial direct ink writing system (nScrypt microdispenser) to additively manufacture PVDF-trFE force sensors. I first synthesized an unprecedented piezoelectric ink that is compatible with a commercial ink writing system at Boise State University, specifically the nScrypt microdispenser, by dissolving PVDF-trFE powders into a cosolvent system consisting of methyl ethyl ketone and dimethyl sulfoxide. The ink composition and substrate surface properties were optimized simultaneously to ensure consistent and uniform printing. Postprocessing procedures, including air-drying, thermal curing, electrical poling and non-contact corona poling were then investigated to facilitate polymerization and beta phase transformation in the printed PVDF-trFE films. With the knowledge acquired from these investigations, I prototyped a piezoelectric force sensor consisting of printed PVDF-trFE films and printed silver electrodes. From justifying the methods for sensor fabrication, unprecedented prototypes of PVDF-trFE sensor arrays were investigated.

DOI

https://doi.org/10.18122/td.2042.boisestate

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