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Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

dc.contributor.authorShearer, Jeffrey C., author
dc.contributor.authorFisher, Ellen R., advisor
dc.contributor.authorHenry, Charles, committee member
dc.contributor.authorSzamel, Grzegorz, committee member
dc.contributor.authorBailey, Travis, committee member
dc.contributor.authorBuchanan, Kristen, committee member
dc.date.accessioned2007-01-03T05:54:02Z
dc.date.available2007-01-03T05:54:02Z
dc.date.issued2013
dc.description.abstractFunctionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as -OH and -NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxCy and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2O3 supported nanoparticles. Specifically, film composition was correlated to gas-phase excited state species and the pulsing duty cycle to better understand the mechanisms of allyl alcohol deposition in our plasma systems. While these studies specifically examined supported nanoparticle substrates, some applications might require the complete functionalization of the entire nanoparticle surface. To overcome this challenge, a rotating drum plasma reactor was designed as a method for functionalizing the surface of individual Fe2O3 nanoparticles. Specifically, data show how the rotating motion of the reactor is beneficial for increasing the alcohol surface functionality of the nanoparticles when treated with pulsed allyl alcohol plasmas. Plasma copolymerization was used to deposit films rich in both oxygen and nitrogen containing functional groups using allyl alcohol and allyl amine plasma systems. Functional group retention and surface wettability was maximized under pulsed plasma conditions, and films produced under pulsed plasma conditions did not exhibit hydrophobic recovery or experience loss of nitrogen as the films aged. Plasma surface modification with N2/H2O and NH3/H2O, and plasma deposition with allyl alcohol and allyl amine, were used to increase the wettability of poly(caprolactone) scaffolds while simultaneously implanting functional groups onto the scaffold surface and into the scaffold core. While plasma deposition methods did not modify the internal core of the scaffold as much as modification methods, it afforded the ability to have higher water absorption rates after a three week aging period. Additionally, cell viability studies were conducted with N2/H2O plasma treated scaffolds and showed enhanced cell growth on plasma treated scaffolds over non plasma-treated scaffolds.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierShearer_colostate_0053A_11964.pdf
dc.identifier.urihttp://hdl.handle.net/10217/80179
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectcopolymerization
dc.subjectsurface modification
dc.subjectscaffold
dc.subjectplasma polymerization
dc.subjectpulsed plasma
dc.subjectallyl alcohol
dc.titleEnhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineChemistry
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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