title: Chemical and physical processes in the retention of functional groups in plasma polymers studied by plasma phase mass spectroscopy.
abstract: Surface engineering of functionalised polymer films is a rapidly expanding field of research with cross disciplinary implications and numerous applications. One method of generating functionalised polymer films is radio frequency induced plasma polymerisation which provides a substrate independent coating. However, there is currently limited understanding surrounding chemical interactions in the plasma phase and physical interactions at the plasma-surface interface, and their effect on functional group retention in the thin film. Here we investigate functionalised plasma polymer films generated from four precursors containing primary amines. Using XPS and fluorine tagging with 4-(trifluoromethyl)benzaldehyde, the primary amine content of plasma polymer films was measured as a function of applied power at constant precursor pressure. The results were then correlated with analysis of the plasma phase by mass spectrometry which showed loss of amine functionality for both neutral and ionic species. Surface interactions are also shown to decrease primary amine retention due to abstraction of hydrogen by high energy ion impacts. The stability of the plasma polymers in aqueous solution was also assessed and is shown to be precursor dependent. Increased understanding of the chemical and physical processes in the plasma phase and at the surface are therefore critical in designing improved plasma polymerisation processes.
authors.affiliation: School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia.
authors.forename: Joonas
authors.initials: J
authors.lastname: Ryssy
authors.affiliation: Department of Industrial Engineering, Universidade Federal de Sao Carlos, Sorocaba Campus, Highway John Leme dos Santos, Sao Paulo, 18052-780, Brazil.
authors.forename: Eloni
authors.initials: E
authors.lastname: Prioste-Amaral
authors.affiliation: Department of Materials Engineering, Centro Federal de Educacao Tecnologica de Minas Gerais, 5253 Amazonas Avenue, Nova Suíça, 30480-000, Belo Horizonte, Brazil.
authors.forename: Daniela F N
authors.initials: DF
authors.lastname: Assuncao
authors.affiliation: Future Industries Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia and Cooperative Research Centre for Cell Therapy Manufacturing, University of South Australia, Adelaide, South Australia 5000, Australia. andrew.michelmore@unisa.edu.au.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Rogers
authors.affiliation: Future Industries Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia and Cooperative Research Centre for Cell Therapy Manufacturing, University of South Australia, Adelaide, South Australia 5000, Australia. andrew.michelmore@unisa.edu.au.
authors.forename: Giles T S
authors.initials: GT
authors.lastname: Kirby
authors.affiliation: Cooperative Research Centre for Cell Therapy Manufacturing, University of South Australia, Adelaide, South Australia 5000, Australia. andrew.michelmore@unisa.edu.au and School of Engineering, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia.
authors.forename: Louise E
authors.initials: LE
authors.lastname: Smith
authors.affiliation: Cooperative Research Centre for Cell Therapy Manufacturing, University of South Australia, Adelaide, South Australia 5000, Australia. andrew.michelmore@unisa.edu.au and School of Engineering, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Michelmore