Characterization of Spin Coated Polymers in Nano-environments as a Function of Film Thickness
Polymer applications have become more demanding as industry continuously turns to more microscopic parts. Due to the interactions of the polymer chains with the supporting surface and the air interface, the thinner films required for such applications have distinctly different properties than th...
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/34548 http://scholar.lib.vt.edu/theses/available/etd-08152001-160853/ |
| Summary: | Polymer applications have become more demanding as industry continuously
turns to more microscopic parts. Due to the interactions of the polymer chains with the
supporting surface and the air interface, the thinner films required for such applications
have distinctly different properties than those of the well-defined bulk systems. The goal
of the current research is to elucidate the behavior of ultrathin films. Two separate
studies were performed on thin films supported on silicon wafer substrates: the first
focuses on the viscoelastic cooperativity of thin films, and the second concentrates on the
morphological behavior of polymer brush films.
For the first study, polymethyl methacrylate films were spin coated onto silicon
wafers, and the film thickness was determined using ellipsometry. A series of thin films
were examined using techniques such as dielectric analysis and thermal mechanical
analysis. The theory of cooperativity, which explains polymeric behavior using the
intermolecular and intramolecular forces among polymer chains, was employed to
understand the behavior of these thin films.
Another type of thin film, a polymer brush, was investigated in the second study.
Polymer brushes are formed by chemically bonding one end of many polymer chains to a
substrate. The other ends of the chains can interact with the surrounding environment
creating a brush-like structure. Constraining one end of a polymer chain alters the
behavior of such a thin film. Polymer brushes of the di-block copolymer poly(t-butyl
methacrylate) and polystyrene were produced on silicon wafers using spin coating
techniques. The effects of both grafting density and solvent washes were analyzed using
contact angle analysis and atomic force microscopy. In addition, hydrolysis was
successfully performed on existing polymer brush samples to produce polymer brushes of
the di-block copolymer polymethyl acrylic acid and polystyrene. === Master of Science |
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