Characterization of plasma-polymerized polyethylene glycol-like films

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Please use this identifier to cite or link to this item: http://hdl.handle.net/1853/31789

Title: Characterization of plasma-polymerized polyethylene glycol-like films
Author: Pathak, Shantanu Chaturvedi
Abstract: A parallel-plate capacitively-coupled plasma deposition system was designed and built for the growth of polyethylene glycol-like films. Deposition rate, bonding structure and dissolution and swelling behavior was characterized as a function of input RF power, reactor pressure and substrate temperature to provide information on the relationship between input plasma parameters and film properties. For the conditions studied in this thesis, deposition rates increased at increasing input powers and operating pressures and decreasing substrate temperatures. The PEG-like coatings resembled higher molecular weight solution-polymerized PEG films with a higher crosslinked structure. Manipulation of plasma deposition conditions allowed control of film crosslink density and resulted in tunable dissolution and swelling properties of the PEG-like polymer. At higher applied powers, lower operating pressures, and higher substrate temperatures, films had a higher crosslink density, thus leading to slower dissolution rates and smaller extents of swelling. Void space openings of swelled-state, PEG-like films were determined using electrophoretic drift and diffusion-controlled transport of fluorophore-tagged PAMAM dendrimers into the bulk of the coating. PAMAM dendrimers were used because of their well-defined sizes and negatively-charged succinamic acid surface groups as a means to probe pore sizes of the plasma films. It was estimated that the upper bound of pore size diameters in the plasma polymer was approximately equal to ~5.5-6.0 nm. Positron annihilation lifetime spectroscopy was used to determine average pore sizes and was estimated to equal ~0.60-0.65 nm.
Type: Dissertation
URI: http://hdl.handle.net/1853/31789
Date: 2008-09-25
Publisher: Georgia Institute of Technology
Subject: Barrier film
Plasma polymerization
Stent
Biomedical materials Research
Medical instruments and apparatus
Thin films
Department: Chemical Engineering
Advisor: Committee Chair: Dr. Dennis W. Hess; Committee Member: Dr. Clifford L. Henderson; Committee Member: Dr. J. Carson Meredith; Committee Member: Dr. L. Andrew Lyon; Committee Member: Dr. Mark R. Prausnitz
Degree: Ph.D.

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