Development of a functional sol gel coating system via encapsulation of micro-organisms

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The proposed research aims to combine the benefits of two types of technology, namely sol gel chemistry and microbiology.Sol gel technology is now recognised as a potential replacement for surface pre-treatments and coatings that are environmentally unacceptable. Such treatments include chromates which are carcinogenic and phosphates which are identified as a Risk of Hazardous Substance (RoHS). Sol gel (silane-based) coatings are non-toxic and do not contain chrome(VI) and as such are environmentally compliant.Microbial Induced Corrosion (MIC) is a form of accelerated corrosion which results when specific types of biofilm are allowed to form on a metal surface. This build up of unwanted microorganisms is known as biofouling. Over a period of time bacterial colonisation results in the formation of aggressive environments, such as hydrogen sulphide, which lead to highly localised corrosion. The most common approach to controlling biofouling and MIC is to dose the environment with biocides or coat the surfaces of the structure with paints that contain biocides. If the biocides are not contained there is a risk of environmental pollution. Certain naturally occuring bacteria are know to be able to reduce the corrosion rates of engineering metals such as steel and copper alloys. In this respect this proposal aims to incorporate suitably chosen bacteria within a sol gel coating which is then applied to the steel and Al alloy substrates in order to provide the following benefits;1. A corrosion protection system that is environmentally acceptable and non-toxic.2. A new sol-gel coating system that offers an alternative to current biocide-based corrosion protection systems.3. A coating system that self-colonises producing 'protective' bacteria that are located at the exact site requiring protection, namely at susceptible surface sites where a biofilm can develop, especially under stagnant 'low flow ' conditions.