Date of Graduation

Fall 2015

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Saibal Mitra

Keywords

iCVD, PTFE, free radicals, HFPO, PFOSF

Subject Categories

Materials Science and Engineering

Abstract

Initiated Chemical Vapor Deposition (iCVD) is a surface polymerization technique that is different from other traditional chemical vapor deposition (CVD) techniques. iCVD is carried under a vacuum without the use of solvents, therefore eliminating contaminations. An initiator and a monomer are metered into a vacuum reactor chamber. Inside the reaction chamber is an array of resistively heated filaments and a cooled substrate stage. Monomer species adsorb on to the cooled substrate surface underneath the filament array. The thermal energy from the resistively heated filaments breaks the bonds in the initiator molecule, generating free radicals. These generated free radicals chemisorb to the monomer initiating an in situ free radical polymerization reaction which results in the formation of a polymer thin film. The overall objective of this research was to assemble a custom-built iCVD reactor and use it to grow polytetrafluoroethylene (PTFE) thin films. Perfluoro-1-octanesulfonyl fluoride (PFOSF) was used as the initiator while hexafluoropropylene oxide (HFPO) was used as the monomer. HPFO is well known for its good thermal decomposition. Nichrome filaments were resistively heated at temperature less than 400 ˚C and substrate surface cooled between 10 ˚C and 35 ˚C. Various characterization techniques such FTIR, XPS, SEM, and EDX were performed on as-deposited iCVD PTFE thin films. FTIR spectra of iCVD PTFE showed that the as-deposited iCVD thin films are spectroscopically identical to bulk PTFE.

Copyright

© Edgar Kiprop Kosgey

Open Access

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