Pollack, Kevin A (2014-12). Multiply Complex, Non-Toxic, Anti-Fouling Surfaces Designed for Marine and Biomedical Applications. Doctoral Dissertation.
Thesis
Biofouling, the undesired accumulation of biological organisms on a surface, is a problem that plagues a wide spectrum of materials. Because of the ban of heavy metal paint formulations, there has been a rapid movement towards the development of novel anti-biofouling coatings based upon various polymeric networks. The main focus of this dissertation is to design and develop unique polymeric networks that display unique heterogeneities in regards to topography, topology and chemical composition on the micro- and nano-scales that can be explored as non-toxic coatings for the deterrence of organisms in the marine environment. These materials also have potential to serve as anti-biofouling coatings for biomedical and other applications. A two dimensional array of terpolymer networks based on the crosslinking of hyperbranched fluoropolymers (HBFP) with varying concentrations of poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) were generated. Crosslinking coincides with and is followed by degrees of thermodynamically-driven phase separation within the bound network and results in a complex surface that displays dynamically-reorganizing heterogeneity in its topography, topology and chemical composition on both the nano- and the micro-scales. The coatings were characterized using atomic force microscopy (AFM), surface force spectroscopy, and static water contact angle to probe their surface properties. Because of the performance displayed in anti-biofouling testing for the terpolymer networks, a more industrially-relevant method for applying the networks was sought. Through the use of a spray coating application method, the terpolymer network could be laid down onto a Naval-approved epoxy barrier coating. The epoxy barrier coating provides functional handles to covalently bond the terpolymer network to the substrate without further modification. The coatings were then tested, through collaborations with the University of Newcastle, Florida Institute of Technology, the University of Hawaii at Manoa and California Polytechnic State University against various marine organisms and in static water immersion testing to test their viability as anti-biofouling coatings. Additionally, the ability to expand the concept the of the terpolymer networks was investigated. These studies included the use of different components for each of the three components of the system. Specifically, the use of silsesquioxanes as a hydrophobic component, zwitterions as a hydrophilic component and a bis-functional fluorinated molecule was explored using AFM, IR, static water contact angle and an anti-biofouling study against Ulva zoospores. In summary, both systems studied displayed potential as next-generation anti-biofouling coatings.
