Ion transport and structure of layer-by-layer assemblies

Layer-by-layer (LbL) films of various architectures were examined as potential solid state electrolytes for electrochemical systems (e.g. batteries and fuel cells). The relationship between materials properties and ion transport within LbL films was investigated in three systems, described below. The observed structure and properties aid in the design of tunable ultra thin electrolytes. The thermal and mechanical properties of PEO/PAA films were evaluated, aided by a new peel-away technique. Results indicated that the glass transition temperature (Tg) of PEO/PAA films decreases with increasing assembly pH, but when assembled in the presence of salt, the Tg, remains constant. Results indicate that the degree of inter- and intramolecular PAA hydrogen bonding, evidenced by FTIR spectroscopy, controls the observed Tg. The ionic conductivity was found to increase with increasing charge carrier concentration (doping during assembly) and with humidity. Maximum room temperature dry conductivity was -108 S cm-1. Polymer-clay nanocomposites were investigated for structural and transport anisotropy. LPEI/Laponite/PEO films demonstrated an oriented structure where clay nanoplatelets lay parallel to the substrate and assembly in sheets with polymer in-between.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Lutkenhaus, Jodie Lee

Advisor dc:contributor.advisor

• Paula T. Hammond.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/39346

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/39346