ANTIFOULING PERFORMANCE OF NOVEL MARINE ANTIFOULING COATINGS IN TROPICAL SOUTHEAST ASIA
Abstract
Field Static Immersion testsWe will provide static immersion field testing for materials from ONR Coatings Program, for upto a maximum of 100 panels. We will work with relevant partners in ONR program to determinebest test method to apply depending on the nature of the antifouling material, to obtainappropriate information of its antifouling capabilities to drive further technology development.This would include estimates of fouling coverage, species composition [ASTM D6990 ~ 05(Standard Practice for Evaluating Biofouling Resistance and Physical Performance of MarineCoating Systems)], and ease of fouling removal (water jet cleaning and relevant ASTM eg.D5618 ~ 94 tests).In addition, where relevant, biofilm fingerprinting may be conducted to elucidate the antimicrobialproperties. This aspect is of growing interest to better understand the role of slime inantifouling performance.2. Laboratory AssaysWith the restriction in the use of biocides, next generation environmentally benign antifoulingcoatings will increasingly employ foul-release properties to reduce marine growth. Tubewormfouling is a problem for novel foul release antifouling coatings.We have observed high numbers of spirorbid tubeworms settling on foul-release materialsdeployed at our test site. While they are small (diameter 1-2 mm), the adhesion strength iscomparable with Serpulid tubeworms of equivalent size. However, spirorbids offer two possibleadvantages for antifouling testing: their disc shape makes it easier to study biomechanics of foulreleasefrom surfaces; and the adults broods larvae which settle within hours of release, thuseliminating the need to culture larvae. Because of their small size, only small samples of materialwill be required to obtain statistically useful data.The research on antifouling properties of fouling release materials has largely focused onbarnacle and mussel research models, but the tubeworm adhesion process is different. Recentstudies by the Hadfield lab (University of Hawaii Manoa) suggest an interactive relationshipwith marine biofilms, which may account for variation in the ease of removal from foul-releasingcoatings. Most of the research conducted on serpulid tubeworms has focused on the settlementbehaviour of the serpulid worm, Hydroides elegans, in Hawaii and Hong Kong. TropicalSoutheast Asian studies have mostly been taxonomic. Our research team recently developed abioassay using local serpulid tubeworm, Spirorbranchus krausii (Chan et al. 2014) collectedfrom local mangroves. However, serpulid worm larvae require 7-10 days culture before they arecompetent to settle.Besides taxonomy, very little else has been published about Spirorbidae in tropical waters,probably a result of their small size. However, we have observed that these organisms are oftenamong the first settlers on coatings which are about to fail, suggesting that they are relativelyresilient opportunistic fouling species. This first ~dusting~ of minute tubeworms over the surfacecompromises surface antifouling properties, potentially providing foothold for subsequentsettlement of large macrofouling organisms.In this study, we aim to (a) identify common spirorbid species found on foul release materialsdeployed at the test site; (b) develop a simple bioassay for evaluating antifouling materials usingthe Spirorbid worms; and (c) preliminary measurement of adhesion strength in controlled flowcondition for a range of foul-release materials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 23, 2016
- Source ID
- N000141613122
Entities
People
- Serena Lay-Ming Teo
Organizations
- National University of Singapore
- Office of Naval Research
- United States Navy