Fouling control coatings
A living problem
Marine biofouling is the undesirable colonization of ship hulls and other underwater structures by microorganisms, seaweed and larger animals such as mussels and barnacles.
For fuel driven ships, the consequences of biofouling are:
- Higher fuel consumption and associated emissions of harmful compounds (SO2, NOx, and CO2).
- More frequent dry docking with high costs and generation of toxic waste
- Translocation of invasive species
A mechanical chemical solution
To combat biofouling, fouling control coatings are used. Generally, these are based on one of two principles:
- Chemically active coatings releasing biocides (conventional antifouling)
- Low energy and flexible coatings with no or very little biocide (fouling release)
The main challenge for conventional antifouling is to design a coating with adequate release rates of biocides. Too high a release rate is not sustainable, and a rate too low leads to biofouling. The requirement is a 3-5 years dry docking interval. At the same time, the antifouling coating should provide a smooth, low drag surface during the service period.
For fouling release coatings, the main challenge is to design a smooth coating that remains essentially fouling free without the use of biocides (or very low release rates) over the entire service period. In addition, the coatings should be mechanically strong to avoid formation of cracks and other defects.
Disciplines
The disciplines involved in analysing and understanding the working mechanisms of fouling control coating systems are mainly transport phenomena, colloid and surface science, analytical chemistry, mathematical modelling, polymer chemistry, advanced characterization tools, and ship hydrodynamics.
Projects
Self-Stratifying coating (SSC) formulations are envisioned to be a sustainable alternative to multi-layered systems. These formulations are multiresinous and consist of two or more layers, with each layer serving a specific function, which spontaneously stratifies after application on the substrate and provide an undercoat and a finishing coat in one operation.
The goal of the project is to formulate a SSC for antifouling applications. Herein, different formulations are developed and characterized for self-stratification using using Fourier Transform Infrared spectroscopy – Attenuated Total Reflectance (FTIR–ATR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) analysis techniques. Moreover, theoretical models to predict the properties and interactions in these coating systems are also developed. These in turn would aid the material and substrate selection for an efficient experimental design of the SSC formulations.
The SSC technology incorporates two or more coats in one formulation. Such formulations require shorter formulation times, less raw materials, shorter processing times and can result in durable coatings due to a better interlayer adhesion strength and are hence an innovative alternative to multilayer coating formulations.
Efficient use of resources i.e. lower material consumption is ensured by adopting a one-pot formulation technique. The raw materials are utilized in optimum amounts and overcoating interval times are negligible. Therefore, research in this area enabling optimum consumption, utilization of raw materials and processing is valuable for a sustainable approach to design new coatings.
Founding
Hempel Foundation CoaST
The project runs from 1 January 2020-1 February 2023
Supervisors
- Kim Dam-Johansen
- Huichao (Teresa) Bi
- Claus Erik Weinell
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk
Fouling-control Coating
Objective
- Study the effect of the cleaning forces and frequency of cleaning on the coatings integrity.
- Develop a novel automatic cleaning fouling-control coating and evaluate the coating performance in the laboratory, such as hardness, adhesion, roughness, surface energy, coating stability, etc..
- Complete Test-site testing and Demo-site testing with the most promising coatings from the lab testing to meet the real application
Background
The settlement and accumulation of biofouling on marine structures, such as ships, seawater intakes, heat exchangers and wind turbine towers, etc., results in adverse effects on their service performance, causes economic losses, maintenance and environmental damage. For biofouling management, fouling-control coatings and in-water cleaning are widely applied for the prevention of biofouling. Automatic in-water cleaning is powerful and efficient, however during cleaning, coating damage or wear or coating detachment from the substrate is normally not avoidable due to the force applied to detach the strongly attached marine species. Therefore, robust fouling-control coatings with low-settlement of marine biofoulants and sufficient mechanical stability are needed to complement the automatic in-water cleaning.
The project
This project aims to develop coatings with appropriate properties for under-water structures undergoing automatic cleaning, i.e. low-settlement of fouling and mechanically strong: hard coatings which can stand the mechanical force and have strong adhesion to the substrate.
Funding
China Scholarship Council (CSC), the Technical University of Denmark (DTU), and the Hempel Foundation. The project runs from 15 October 2020 - 14 October 2023.
Supervisors
- Kim Dam-Johansen (main supervisor)
- Huichao (Teresa) Bi (co-supervisor)
- Claus Erik Weinell (co-supervisor)
Contact
Shujie Lin PhD student Department of Chemical and Biochemical Engineering shulin@kt.dtu.dk
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk
Objective
The objective of the project is to develop new and improved dynamic test systems for fouling control coatings. Dynamic exposure should assist in determining long-term performances, improved understanding of biofouling growth and coating selection for the specific operation.
Background
Static immersion have commonly been used to evaluate the performance of marine coating prior to application on ship hulls. The results obtained statically have provided well-established data, however, the hydrodynamic stress present on moving ships is neglected. Using dynamic testing will contribute to obtaining more realistic results, thus improving the development and evaluation of state of the art fouling control coatings.
The Project
Establish the next generation of dynamic test methods for fouling control coatings.
Increase the traditional output from dynamic test to high throughput by big sample capacity and extensive data monitoring on both conventional antifouling coatings and fouling release coatings.
Increase the reliability of data through obtaining additional datasets and more data points with a higher precision and accuracy. (Datasets: surface roughness, seawater temperature, salinity, rotational speed, cracking, polishing- and leaching rate, and biofouling growth etc. on several samples)
Funding
The Hempel Foundation and the Technical University of Denmark (DTU). The project runs from 1 May 2021 - 30 April 2024.
Supervisors
- Kim Dam-Johansen (main supervisor)
- Søren Kiil (co-supervisor)
- Claus E. Weinell (co-supervisor)
Contact
Mads Olsen PhD student Department of Chemical and Biochemical Engineering madols@kt.dtu.dk
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk
Objective
The objective of the project is to develop new and improved dynamic test systems for fouling control coatings. Dynamic exposure should assist in determining long-term performances, improved understanding of biofouling growth and coating selection for the specific operation.
Background
Static immersion have commonly been used to evaluate the performance of marine coating prior to application on ship hulls. The results obtained statically have provided well-established data, however, the hydrodynamic stress present on moving ships is neglected. Using dynamic testing will contribute to obtaining more realistic results, thus improving the development and evaluation of state of the art fouling control coatings.
The Project
Establish the next generation of dynamic test methods for fouling control coatings.
Increase the traditional output from dynamic test to high throughput by big sample capacity and extensive data monitoring on both conventional antifouling coatings and fouling release coatings.
Increase the reliability of data through obtaining additional datasets and more data points with a higher precision and accuracy. (Datasets: surface roughness, seawater temperature, salinity, rotational speed, cracking, polishing- and leaching rate, and biofouling growth etc. on several samples)
Funding
The Hempel Foundation and the Technical University of Denmark (DTU). The project runs from 1 May 2021 - 30 April 2024.
Supervisors
- Kim Dam-Johansen (main supervisor)
- Søren Kiil (co-supervisor)
- Claus E. Weinell (co-supervisor)
Contact
Morten Lysdahlgaard Pedersen Student Students s144163@student.dtu.dk
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk
Objective
Use inspiration from nature to find more sustainable and environmentally friendly solutions to marine bio-fouling challenges. Formulation of new coatings. Characterization of their mechanical properties in the lab and fouling protection under real exposure conditions on a fleet in the harbor of Hundested.
Background
Marine bio-fouling of ships and ocean infrastructures is problematic in an economical and safety point of view. However, many of the present technologies suffer from their durability, mechanical stability and environmental friendliness.
The project
The project focuses on technology inspired by bio-surfaces or natural biocides alone or in combination with other biocides, in order to lower the net environmental impact.
Funding
The Hempel Foundation and the Technical University of Denmark (DTU). The project runs from 1 November 2020- 31 October 2023.
Supervisors
- Kim Dam-Johansen (main supervisor)
- Claus Erik Weinell (co-supervisor)
- Markus Schackmann, University of Applied Sciences, Esslingen (co-supervisor)
Contact
Marcel Butschle PhD student Department of Chemical and Biochemical Engineering mabut@kt.dtu.dk
Contact
Kim Dam-Johansen Professor, Head of Department Department of Chemical and Biochemical Engineering Phone: +45 45252845 KDJ@kt.dtu.dk
The present project aims at designing a transparent, anti-fouling coating for use on solar cells and sensors on underwater drones or unmanned underwater vehicles (UUV). Overall, the goal of the coating is to maintain 80% UV and visible light transmission, while staying essentially free of seawater bio-fouling for at least three months of static immersion.
The main technical approaches involve formulating to proper application and film formation, following the transparency development during seawater immersion and evaluating the long term bio-fouling resistance in real seawater at sites in Denmark and USA.
To reach a prototype product in the two years available, coating formulation optimization will be an ongoing and recurring activity throughout the project. If successful for the present target application (transparency and bio-fouling resistance), the new coating formulation may be further developed to also ensure optical transparency, where close to 100 % light transmission is required.
Funding
Office of Naval Research (ONR) - US Navy. The project runs from 1 September 2021- 30 August 2023.
Supervisors
- Narayanan Rajagopalan
- Søren Kiil (PI)
Contact
Narayanan Rajagopalan Researcher Department of Chemical and Biochemical Engineering naraj@kt.dtu.dk
Contact
Søren Kiil Professor Department of Chemical and Biochemical Engineering Phone: +45 45252827 sk@kt.dtu.dk