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Computational Study of Ionic Polymers: Multiscale Stiffness Predictions and Modeling of the Electromechanical Transduction

Gao, Fei (2010) Computational Study of Ionic Polymers: Multiscale Stiffness Predictions and Modeling of the Electromechanical Transduction. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Ionic polymer transducers (IPTs) represent a relatively new class of active (¡®smart¡¯) materials, which can function as highly sensitive mechanical sensors as well as actuators. An IPT is made of an ionic polymer membrane sandwiched between two conductive electrodes. They generate controllable strain when applying a low voltage (<5 V) across their thickness and generate measurable currents due to extremely small mechanical strain. IPTs are cost effective and often have superior sensing capabilities compared to other active materials such as piezoelectrics. However, this novel class of transducers has not been widely employed mainly because the mechanism of IPT sensing is not clearly understood. In this dissertation, the mechanical properties of ionic polymers, the ionomer morphology, and the fundamental mechanism responsible for the electromechanical sensing responses of IPTs are studied. A multiscale model for the prediction of material stiffness is presented. The results give access to a fundamental material parameters currently inaccessible via experimentation, namely local stiffness. Subsequently the sensing mechanism of stream potential is hypothesized. It is argued that the mechanism of streaming potential, unlike prior hypotheses, is able to systematically explain generalized experimentally observed sensing phenomena, such as the observation of an optimum conductive particulate volume fraction in the interpenetrating electrode region of the transducer. Moreover, it is argued that coupling the exploration of local stiffness and streaming potential is prerequisite to gaining insight into subtler experimental sensing phenomena such as experimentally observed variations in sensing due to variations in IPT architecture.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Gao, Feifeg13@pitt.eduFEG13
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairWeiland, Lisa Mlmw36@pitt.eduLMW36
Committee MemberAkle,
Committee MemberLee, Jung-Kunjul37@pitt.eduJUL37
Committee MemberWang, Qing-Mingqiw4@pitt.eduQIW4
Committee MemberClark, William Wwclark@pitt.eduWCLARK
Date: 25 June 2010
Date Type: Completion
Defense Date: 6 April 2010
Approval Date: 25 June 2010
Submission Date: 24 March 2010
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Ionic Polymer; Sensing; Streaming Potential; Ionomer Morphology; Modeling
Other ID:, etd-03242010-104052
Date Deposited: 10 Nov 2011 19:32
Last Modified: 15 Nov 2016 13:37


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