Tribological and mechanical characterizations of polyelectrolyte multilayer nanoassemblies

Over the last decade, the sequential layer-by-layer assembly of oppositely charged polyelectrolytes has received much interest for the deposition of film architectures, ranging from tens to hundreds of nanometers in thickness, that can be precisely tuned as a function of the processing conditions. The resulting polyelectrolyte multilayer (PEM) constructs are being investigated as biomaterials, photonic structures, electrochemical devices, and separation membranes. There is a distinct lack of literature, however, on the friction-and-wear behavior of these nanocoatings, and their exploitation in systems with tribological problems of practical relevance. In addition, their mechanical properties, crucial for the success of almost all applications being studied, have not been systematically characterized. This thesis focuses on the elucidation of the tribological and mechanical properties of PEMs composed predominantly of weak polyelectrolytes--poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA). In general, the friction coefficients of PAH/PAA PEM-coated substrates were at least marginally higher than those exhibited by their uncoated counterparts, in the absence of substrate wear. The films, however, demonstrated a significant capacity for wear prevention of underlying substrates in the dry state, and also in the presence of bovine calf serum, used to simulate joint synovial fluid. In the latter case, a significant decrease in wear rates, in tests using a clinically relevant number of cycles and articulation pattern, pointed to the efficacy of PEM-coated systems for wear reduction in total joint replacement prostheses; wear particle- induced implant loosening remains a major cause of revision surgeries.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Pavoor, Prem Venkatachalam

Advisor dc:contributor.advisor

• Robert E. Cohen and Anuj Bellare.

• 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/1721.1/31176

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/31176