Date of Award

11-7-2007

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Electrical and Computer Engineering

First Advisor

LaVern A. Starman, PhD

Abstract

The purpose of this research is to investigate the Piezo-Electrochemical Transducer (PECT) effect in intercalated graphite as a possible mechanism of actuation for micro-electromechanical systems (MEMS). This dissertation presents the results of research into the PECT effect in H2SO4-intercalated graphitized carbon fibers, including both electrical and mechanical characteristics of this effect. PECT fibers achieve up to 1.7% strain at 1.4 V of applied potential. In contrast, the piezoelectric material polyvinylidene difluoride (PVDF) generates only 0.01% strain and polysilicon thermal expansion between 0.02 and 0.06% strain depending on the thermal conductivity of the particular polysilicon that the actuators are fabricated in. This work concludes that PECT carbon fiber actuators achieve two orders of magnitude better strain than PVDF piezoelectric actuators and polysilicon thermal expansion in the same voltage range of operation. In addition to this highly improved strain, the devices, after an initial peak power consumption of 227 micronW, a PECT device uses only 260 nW to hold actuation. Although slow operation and unpractical intercalants are serious drawbacks to PECT actuators, the characteristics of strain and power consumption presented in this dissertation prove that PECT actuators, given some minor modifications, prove to be a competitive alternative to current MEMS actuators.

AFIT Designator

AFIT-DEE-ENG-08-03

DTIC Accession Number

ADA481116

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