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Periodic Report Summary 2 - SEAFRONT (Synergistic Fouling Control Technologies)

Project Context and Objectives:
Marine biofouling, the unwanted colonization of marine organisms on surfaces immersed in seawater has a huge economic and environmental impact in terms of maintenance requirements for marine structures, increased vessel fuel consumption, operating costs, greenhouse gas emissions and spread of non-indigenous species. The SEAFRONT project will aim to significantly advance the control of biofouling and reduce hydrodynamic drag by integrating multiple technology concepts such as surface structure, surface chemistry and bio-active/bio-based fouling control methodologies into one environmentally benign and drag-reducing solution for mobile and stationary maritime applications. In parallel, a combination of laboratory-based performance benchmarking and end-user field trials will be undertaken in order to develop an enhanced fundamental/mechanistic understanding of the coating-biofouling interaction, the impact of this on hydrodynamic drag and to inform technology development and down-selection of promising fouling control solutions. This project aims to facilitate a leap forward in reducing greenhouse gas emissions from marine transport and the conservation of the marine ecosystem by adopting a multidisciplinary and synergistic approach to fouling control.

The overall objectives of the SEAFRONT project are both measurable and challenging.

1. Cost-effective coatings solutions with reduced environmental footprint as determined by comparative life cycle and eco-efficiency assessment*
* Measurable parameters for evaluation include: total resource consumption, VOC, toxicity and environmental fate, non-fossil derived carbon content and greenhouse gas emissions during in-service lifetime.

2. 50% improvement in biofouling deterrence (% coverage) and/or biofouling release (% release at a given speed over time).

As compared to latest state of the art commercial Intersmooth7460HS SPC (Biocide-based coating) and Intersleek900 (Fouling release coating) reference controls.

3. Hydrodynamic drag reduction resulting in a consequent 5% improvement in operating efficiency as compared to that offered by Intersleek900.

In parallel, as an integral ethos within the project, a strong fundamental/mechanistic understanding and new performance predictive test methods will be developed to feedback and inform technology evolution and down-select promising coating solutions for end-user field trials.
Project Results:
An executive summary of the work performed and the main results are described below for each work package.

WP1: Surface structure-based biofouling control technologies.
T1.1.1: Samples of the standard formulation of Intersleek 1100SR could not be used directly with Fraunhofer’s riblet producing procedure. Interaction between the resin, the solvent and the mould caused poor sample removal resulting in unacceptable pattern fidelity.
Two alternative nearly solvent-free formulations were developed: one with only the solvent removed (causing a viscosity increase) and the second with solvent removed and adjustment of the thixotrope package so as to maintain the viscosity comparable with that of the standard paint. Both examples are thermoset coatings where crosslinking is brought about by catalyst initiated condensation cure.

T1.1.2: The work largely focused on the development of a suitable procedure to emboss the elastomeric fouling-release material provided by IP which deviates from the standard riblet manufacturing process applied to the UV-curable paint system from Fraunhofer. The second step was to apply the test coatings to the Taylor-Couette cylinders for measurement of skin friction (WP4.2).

T1.1.3: DUTP has performed fully resolved numerical simulations for flow over (possibly) drag reducing surface textures. The progress made so far is twofold. Firstly, several numerical simulations of turbulent flow over shark skin blade riblets have been performed to validate our numerical approach. Secondly, a start has been made with the investigation of a possibly next generation drag reducing texture with riblets arranged in a herringbone pattern.

T1.2.1: The production of several thermoresponsive coatings has been achieved within WP1. These include a number of poly(oligoethylene glycol methacrylate) (p(OEGMA)) samples and samples of poly N-isopropylacrylamide (p(NIPAM)) for comparison. In addition, a number of examples of materials possessing upper critical solution temperatures (UCSTs) are being developed, including systems based on poly(acrylonitrile-co-acrylamide) (p(AN-co-AAm)) and poly(N-acryloyl glycinamide) (p(NAGA)). Strategies have been developed to improve adhesion of the coatings to carrier substrates to enable anti-biofouling testing to be performed. Equipment has also been developed to facilitate cycling of the temperature to induce repeated CST transitions during anti-biofouling assessment.

T1.2.2: Three different systems have been investigated. Two of these are based on thermoresponsive hydrophilic materials with a lower critical solution temperature (LCST), which switch from a flat to a structured surface (photoembossing) or vice versa (patterned photo-crosslinking). The third coating is based on an omniphobic perfluorinated coating made from fluorogel elastomers. The addition of the swelling agent significantly improves the omniphobic properties of the fluorogel elastomers and decreases cyprid settlement by a factor of 4 compared to the unswollen coatings.

WP2: Surface chemistry based biofouling control technologies
WP2.1: Innovative zwitterionic materials – Concerning the first task aimed to determine a structure-property relationship for anti-biofouling zwitterionic surfaces UNEW-SCL prepared 41 different zwitterionic or pseudo-zwitterionic polymer coatings on glass substrates. Preliminary studies on barnacle cyprid settlement allowed to select some prototypes based on the sulfobetaine moiety and LMA (lauryl methacrylate) as co-monomer which were ‘scaled-up’ and the required number of replicates submitted to UNEW-MST for systematic studies on their antifouling properties. Neutral and charged pseudo-zwitterionic coatings were also prepared in order to investigate the influence of an excess of charge on the anti-biolfouling properties. The preliminary biological results (diatom settlement assay) show that the coatings with a net positive or negative charge possess the best antifouling performance.

T2.1.2, aiming at the combination of fouling release and fouling deterrent, is also on track. In the second half 2014 SSP prepared several PFPE derivatives and UNEW-SCL synthesized a number of zwitterionic intermediates. By June 2015 an overall number of 29 different samples were prepared and delivered to International Paint.

WP2.2: Fluoro-functionalized particles
In T2.2.1, Fluorosilane modified silica nanoparticles, SSP delivered three different PFPE silanes to be used by Fraunhofer to prepare hydrophobic silica (nano)particles. Fraunhofer tested several methods and selected the best suited ones for the functionalization of silica particles to get both hydrophobic (fluorinated) and hydrophilic (PEGylated) particles. Fraunhofer managed to prepare four different types of fluoro-functionalized particles and two types of polyethyleneglycol-functionalized silica particles.
In T2.2.2, Fluoroelastomeric particles, SSP provided to IP a water based latex of fluoroelastomeric particles, namely Tecnoflon® TN, which contains 70% of a terpolymer of VDF/TFE/HFP (vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene) obtained by emulsion polymerization without use of surfactants. SSP prepared and delivered to International Paint also two samples of low molecular weight fluoroelastomeric polymers (Tecnoflon® N215/U and Tecnoflon® 935) to be used as ingredients of coating formulations. Success has been made with preparing coatings from waterborne terpolymer latexes and solvent borne dipolymers.

WP2.3: Domain-structured materials creating ultra lubricious surfaces
SSP prepared and provided 6 PFPE derivatives differing for functional end groups and functionality degree. Fraunhofer received all the six samples and made preliminary formulations into model coatings based on different polymers. 49 different coating systems were formulated and 45 of them were manufactured and applied to steel, glass or aluminum substrates and cured. For further investigation, eight of the 45 coating systems were selected. IP received only the α,ω-PFPE diols. High gloss, low roughness coalesced films with a lubricous feel were prepared.

WP3: Bio-based and bio-active biofouling control technologies.
Three of the four tasks in this work package have started. In WP3.1, characterization of the three initially selected bio-active compounds Selektope®, chitosan and quaternary ammonium salts (QAS) has been performed and a preliminary risk assessment was carried out. All three bioactives exhibit acceptable risk ratios in the marine environment with the exception of QAS in the sediment compartment. In WP3.2, samples have been produced with immobilized polyglycerols, QAS, Selektope, and chitosan. Initial characterization of these samples has been performed and for some of them also the results of the settlement assays performed in WP4.3 are already available. In WP3.3, work has initially focused on dissolving the two bio-based polymers, PHA and chitosan, in appropriate organic solvents. Albeit repeated trials with lower molecular weights and finer particle sizes the problem could not be overcome to achieve satisfactory results and both compounds will most likely have to be chemically modified in order to make them suitable as polymeric binders. Therefore, an alternative approach has been investigated to use PHA and chitosan as additives in self-polishing antifouling paints. WP4.3 aims at demonstrating that immobilization of a bioactive has no detrimental effect on antifouling performance. This task is about to start.

WP4: Characterization, fundamental understanding and performance prediction.
Work has progressed according to plan with regard to physico-chemical (WP4.1; Fraunhofer and UNEW-SCL) and biological characterisation (WP4.3; UNEW-MST) of commercial benchmarking coatings supplied by International Paint viz. Intersleek (700, 900 and 1100 SR), Intersmooth (7460 and 7465 Si) and Intercept 8000 LPP. Toxicity testing of coatings has been straightforward except for the biocidal systems, which kill the test larvae. The solution arrived at is to utilise a flow-through test rig to examine effects on growth of biofilm. This amendment has been incorporated into a revised biological testing workflow. Both sets of data – biological and physico-chemical – have been compiled into databases. The analytical and assay procedures developed/refined are now being applied to surfaces prepared under WPs 1–3. After initial problems with loss of cylinders in the post for the Taylor-Couette (T-C) measurements (WP4.2), a hydrodynamic analysis of drag reduction has been made (DUTP) of standard and IS1100SR riblet coatings prepared by Fraunhofer, albeit the results are still preliminary. Impressive drag reduction has been recorded though it is cautioned that these data have yet to be corrected for an apparent positive rotation number that amplifies the drag reduction. Method development in WP4.4 has progressed well. Automated tracking algorithms have been developed and a prototype version of the cyprid tracking programme that automatically tracks multiple larvae and classifies their settlement behaviour was demonstrated. A pressure drop section for the UNEW-MST flow cell has also been designed. WP4.5 comprises the Training Associate (TA) programme, microbially-influenced corrosion and microbial fouling. A combination of bi-annual project meetings, regular Skype/video meetings and hands-on training courses have been organized (co-ordinated by Prof Anders Blomberg, UGOT) to facilitate communication amongst TAs and partner laboratories, and to enhance interdisciplinary skills. Progress on the individual projects of the TAs is proceeding according to plan with results reported under WPs 1 and 4. T4.5.1 performed a pilot study using RNA sequencing (RNA-seq) in order to identify genes expressed in specific stages along the settlement process. The final outcome of these studies will provide a set of “reporter genes” expressed during exploration of different surfaces enhancing understanding of the settlement process and providing new tools and targets for antifouling research. In T4.5.2, biocorrosion resistance of mild steel by three standard (benchmark) coatings – Intershield 300, Intershield 300-HS and Interseal 670HS – has been investigated using a range of tests: accelerated corrosion, adhesion, and electrochemical. All three benchmark coatings showed good adhesion but Intershield-300 performed best with respect to resisting water absorption, possibly indicative of superior corrosion resistance. Under T4.5.3, sample handling and biofilm DNA extraction methodologies have been developed and applied to compare biofilm developed on biocidal versus fouling-release coatings exposed in Hartlepool Marina. The methods developed have successfully highlighted that the two types of coating have broadly similar taxa, though with significant differences at the species level.

WP5: Benchmarking & Performance Monitoring In situ.
The end user requirement matrix has been completed highlighting the minimum and desirable requirements for application, performance, product features and product usage (T5.1.1 and T5.1.2). Coated fishnets (nylon coupons, commercial fouling release and commercial biocidal) have been tested at the VAL test site (T5.2.2). Flat panel coupons have been deployed at International Paint raft sites (T5.3.1 and T5.3.3), at the sea bed and sea surface from Minesto infrastructure and under dynamic conditions on the Princes Royal research vessel using the custom built strut device. Development of the data acquisition devices is underway (T5.3.2); the system design of the data acquisition system has been completed, covering both the electronic aspects and the software specification. Suitable sensors have been selected, and their suitability has been verified through simple field deployments. The processor board and other components have also been selected and the code has been written. The software, protocols, Goal & Scope, Function of the product and Functional Unit for the LCA have been established and the boundaries of the assessment are being defined (WP5.4). Technical partners will be provided with information templates so as to being gathering data for the LCA and LCIA and identifying the missing data sources.

WP6: Full scale in-situ demonstration.
Technology scale has not begun as it is awaiting progress form the technology WP’s, the output of which can then be transformed into scaled up material to be used for full scale in-situ, in-service application and implementation. Partner HLAG have committed vessels to be included in a test patch program, initially using commercial coatings as a benchmarking activity and latterly prototype coatings for in-service evaluation. Partner BLUE have deployed the first of two full scale devices in 2015 to assess turbine designs and efficiencies and tethering and mounting designs both of which will have the body of the device coated with Intersleek1100SR. Three coastal vessels have been included in the vessel trial program, 9 benchmarking coatings have been applied in a Latin square design on the starboard and port sides.

WP7: Dissemination, standardisation & exploitation.
At the start of the SEAFRONT project many press releases have been published in newspapers, marine magazines and specialist journals. Partners of SEAFRONT attended several conferences and presented first results of SEAFRONT in presentations and posters. The project website with a public and project internal part has been launched in February 2014. First papers of the SEAFRONT project have been submitted to scientific journals and one has already been published.
Potential Impact:
By considering the complex mechanism of biofouling and the fact that antifouling coatings have to be effective against a diverse range of over 4000 fouling organisms, it is suggested that further advances in this field requires an alternative strategy:
1. Combinations of multiple (novel) approaches/technologies into one coating solution rather than considering single technologies in isolation;
2. Considerable improvement of the fundamental understanding of biofouling and biocorrosion mechanisms so as to feedback and inform intelligent technology and advanced test method development.

Both concepts will be explored in this project through a process of parallel interdisciplinary studies combining, biology, genomics, biotechnology, chemistry and advanced surface characterisation techniques. This synergistic approach will ultimately result in the down-selection of promising technology combinations for which, after formulation and scale up, the antifouling performance will be benchmarked in end-user field trials. The expected outcome will bring outstanding economic and environmental results.

By developing environmentally benign novel fouling control coatings with reduced drag, SEAFRONT will significantly contribute to increase the efficiency and competitiveness of both mobile and stationary maritime structures by reducing operation and life-cycle costs. As 50% of the operational costs of a transport vessel are costs of fuel, only 5% reduction of drag, as targeted in this project, will already save $3 billion fuel costs and 20 million metric tons of CO2 emissions. Environmentally benign antifouling solutions will particularly be sought for slow moving vessels (<10 knots) in order to go well beyond the state of the art commercial foul release coatings.

Extending the operational life span of fouling control coatings will save maintenance/operation costs for mobile and stationary maritime structures. Currently Daily Running Expenses (DRE) of vessels include cost of operation/ownership for $450,000 per scheduled repair period to include dry docking and other maintenance costs. Bluewater expects that novel fouling control coatings will lower the maintenance costs of marine energy devices by approximately 40% since frequent cleaning at sea, lifting of the device out of the seawater to clean it (downtime) and expensive underwater inspections will become obsolete.

Furthermore, SEAFRONT will contribute to the EU Marine Strategy Directive establishing a framework for the necessary actions to be taken in order to achieve and maintain a good environmental status in the marine environment by year 2020. The Directive states that marine strategies shall be developed and implemented in order to:
a. Protect and preserve the marine environment, prevent its deterioration or, where practical, restore marine ecosystems in areas where they have been adversely affected.
b. Prevent and reduce inputs in the marine environment with a view to phasing out pollution as defined in Article 3(8) of the Directive, so as to ensure that there are no significant impact on or risks to marine biodiversity, marine ecosystems, human health or legitimate uses of the sea.

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