Characterization of new surface morphologies in a hydrogen-bonded multilayer system

This work presents an analysis of surface morphology changes in poly(acrylic acid)/polyacrylamide (PAA/PAAm) hydrogen-bonded multilayers. These changes were induced by immersion of the films in aqueous solutions of poly(allylamine hydrochloride), or PAH, at different levels of pH. Positive charges on PAH are attracted to negative charges on PAA, forming ionic bonds and locally decreasing the hydrophilicity of the multilayer. The degree of ionization for each polyelectrolyte, controlled by the pH of the treatment solution, determines the molecular conformations and the extent of electrostatic interactions. These factors, in turn, determine the resulting morphology of the film. Different surface morphologies appeared in four different pH regimes. Highly acidic solutions retained the film's original smooth surface, but wrinkled, honeycomb, or globular morphologies appeared as the pH increased. The three different surface morphologies correlate with the linear, pearl necklace, and globular conformations of PAH.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• Kunz, Allison (Allison L.)

Advisor dc:contributor.advisor

• Michael F. Rubner.

• Materials Science and 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/1721.1/43801

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/43801