<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-20T13:09:17Z</responseDate><request verb="GetRecord" identifier="oai:dspace.mit.edu:1721.1/39537" metadataPrefix="dim">https://dspace.mit.edu/server/oai/request</request><GetRecord><record><header><identifier>oai:dspace.mit.edu:1721.1/39537</identifier><datestamp>2026-06-11T15:41:14Z</datestamp><setSpec>com_1721.1_7582</setSpec><setSpec>com_1721.1_7581</setSpec><setSpec>col_1721.1_131022</setSpec></header><metadata><dim:dim xmlns:dim="http://www.dspace.org/xmlns/dspace/dim" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.dspace.org/xmlns/dspace/dim http://www.dspace.org/schema/dim.xsd">
   <dim:field mdschema="dc" element="contributor" qualifier="advisor" lang="en_US">Edwin L. Thomas and Ian W. Hunter.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="author" lang="en_US">Pytel, Rachel Zimet</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="other" lang="en_US">Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.</dim:field>
   <dim:field mdschema="dc" element="contributor" qualifier="department">Massachusetts Institute of Technology. Department of Materials Science and Engineering</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="accessioned">2009-01-23T14:49:44Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="available">2009-01-23T14:49:44Z</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="copyright" lang="en_US">2007</dim:field>
   <dim:field mdschema="dc" element="date" qualifier="issued" lang="en_US">2007</dim:field>
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   <dim:field mdschema="dc" element="identifier" qualifier="oclc" lang="en_US">174039933</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.</dim:field>
   <dim:field mdschema="dc" element="description" lang="en_US">Includes bibliographical references (leaves 183-204).</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="abstract" lang="en_US">We seek to improve polypyrrole and other conducting polymer actuators by discovering and exploiting the connection between nanoscale transport events and macroscale active strain. To this end we have used diffraction and electron microscopy to investigate the microstructure of polypyrrole. and propose a new description consisting of disordered polypyrrole chains held together by small crystalline bundles, around which solvent and counterions are randomly distributed. We utilize different modes of deformation to impart orientational texture to polypyrrole films, and show that by controlling polymer chain conformation and packing at a sub-micron level a conducting polymer actuator can be engineered that shows a significantly larger macroscopic electroactive response. We also alter the synthesis and doping conditions to produce films with widely varying surface morphologies, allowing us to control the rate of electroactive response. Our detailed understanding of polypyrrole morphology at different lengthscales provides valuable insight to the mechanisms of polypyrrole actuation, and has helped us process polypyrrole more intelligently for improved electroactive devices.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="statementofresponsibility" lang="en_US">by Rachel Zimet Pytel.</dim:field>
   <dim:field mdschema="dc" element="description" qualifier="degree" lang="en_US">Ph.D.</dim:field>
   <dim:field mdschema="dc" element="format" qualifier="extent" lang="en_US">204 leaves</dim:field>
   <dim:field mdschema="dc" element="language" qualifier="iso" lang="en_US">eng</dim:field>
   <dim:field mdschema="dc" element="publisher" lang="en_US">Massachusetts Institute of Technology</dim:field>
   <dim:field mdschema="dc" element="rights" lang="en_US">M.I.T. theses are protected by 
copyright. They may be viewed from this source for any purpose, but 
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   <dim:field mdschema="dc" element="rights" qualifier="uri" lang="en_US">http://dspace.mit.edu/handle/1721.1/7582</dim:field>
   <dim:field mdschema="dc" element="subject" lang="en_US">Materials Science and Engineering.</dim:field>
   <dim:field mdschema="dc" element="title" lang="en_US">Artificial muscle morphology : structure/property relationships in polypyrrole actuators</dim:field>
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   	&lt;Title>Artificial muscle morphology : structure/property relationships in polypyrrole actuators&lt;/Title>
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   	&lt;PublicationDate>2007&lt;/PublicationDate>
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   	&lt;Abstract>We seek to improve polypyrrole and other conducting polymer actuators by discovering and exploiting the connection between nanoscale transport events and macroscale active strain. To this end we have used diffraction and electron microscopy to investigate the microstructure of polypyrrole. and propose a new description consisting of disordered polypyrrole chains held together by small crystalline bundles, around which solvent and counterions are randomly distributed. We utilize different modes of deformation to impart orientational texture to polypyrrole films, and show that by controlling polymer chain conformation and packing at a sub-micron level a conducting polymer actuator can be engineered that shows a significantly larger macroscopic electroactive response. We also alter the synthesis and doping conditions to produce films with widely varying surface morphologies, allowing us to control the rate of electroactive response. Our detailed understanding of polypyrrole morphology at different lengthscales provides valuable insight to the mechanisms of polypyrrole actuation, and has helped us process polypyrrole more intelligently for improved electroactive devices.&lt;/Abstract>
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