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dc.contributor.authorGalhenage, Teluka Pasan
dc.description.abstractBiofouling has been an economically and environmentally costly problem to mankind ever since they set sail. Biofouling causes frictional drag leading to slow vessel speeds, and increased fuel costs. Antifouling (AF) coatings containing biocides have been used for decades, however, since some biocides have shown undesired effects towards the environment, a non-toxic solution to combat fouling is desired. Subsequently, fouling release (FR) coatings quickly gained acceptance as a non-toxic approach to contend with biofouling. Unlike AF coatings, FR coatings not necessarily prevent settlement of organisms, they permit weak adhesion which is easily released by water shear or light grooming. The siloxane-polyurethane (SiPU) coatings based on the concept of self-stratification is a non-toxic and durable approach to prepare FR coatings. In this work, several approaches were considered to optimize surface properties of SiPU coatings. Incorporation of phenyl-methyl silicone oils led to improved FR properties towards several marine organisms in laboratory assays and in ocean field immersion. Enhancement in FR properties may be attributed to slowly exuding silicone oil providing surface lubricity, weakening the adhesion of marine organisms. Addition of diphenyldimethyl siloxane in to SiPU coatings at different ratios resulted in micro-scale surface topographical features which negatively affected microfouling-release while several coatings displayed good FR performance towards macrofouling organisms. In another study, decreasing the acid group content helped to improve FR performance towards barnacles, but FR performance towards diatoms were compromised. Novel amphiphilic siloxane-polyurethane (AmSiPU) coatings from polyisocyanate pre-polymers modified with polydimethyl siloxane and polyethylene glycol displayed excellent FR properties towards several marine organisms during laboratory assays. These AmSiPU coatings show promise as contenders to commercial FR standards. Initial development of SiPU coatings with hydrophilic surfaces showed promise, as the coatings showed rapidly rearranging surfaces with comparable FR performance to commercial standards which claim hydrophilic surface properties. During freshwater field immersion trials, SiPU coatings displayed excellent mussel FR performance up to 3 years. Surface analysis suggested that solvent content affected self-stratification and morphology of SiPU coatings. The SiPU coating system is a highly tunable, tough, environmentally friendly, and practical FR solution which can evolve along with non-toxic commercial marine coatings.en_US
dc.publisherNorth Dakota State Universityen_US
dc.rightsNDSU Policy 190.6.2
dc.titleSurface Optimization of Siloxane-Polyurethane Marine Coatings for Improved Fouling-Release Propertiesen_US
dc.typeDissertationen_US
dc.date.accessioned2018-12-16T16:58:34Z
dc.date.available2018-12-16T16:58:34Z
dc.date.issued2016en_US
dc.identifier.urihttps://hdl.handle.net/10365/29092
dc.subject.lcshSiloxanes.en_US
dc.subject.lcshFouling.en_US
dc.subject.lcshCoating processes.en_US
dc.description.sponsorshipOffice of Naval Research (Grant number N00014-12-1-0482)en_US
dc.description.sponsorshipSSPCen_US
dc.description.sponsorshipValparen_US
dc.description.sponsorshipAmerican Coatings Associationen_US
dc.description.sponsorshipNorth Dakota State University. College of Science and Mathematicsen_US
dc.rights.urihttps://www.ndsu.edu/fileadmin/policy/190.pdf
ndsu.degreeDoctor of Philosophy (PhD)en_US
ndsu.collegeScience and Mathematicsen_US
ndsu.departmentCoatings and Polymeric Materialsen_US
ndsu.programCoatings and Polymeric Materialsen_US
ndsu.advisorWebster, Dean C.


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