Environmental Engineering Reference
In-Depth Information
Adhesion between two surfaces depends on the surface properties of the materials
mainly the surface energy. The surface chemistry can be manipulated and thus, so
can the interfacial interactions between the two surfaces by nano-scale surface design.
Gaub and co-workers [63] showed experimentally how non-covalent interactions
of the polymer surface can be manipulated by applying externally an electric
potential. This electric glue is reversible. Such examples include a combination of
neutral polyethylene glycol, 2,2-ionene (containing a positively charged backbone)
and a negatively charged biopolymer (DNA) where three of the four bases contains
primary amines. Applications of such designs include biosensors, reversible adhesion
of materials and so on. It should be possible to design surface layers, which could be
bound to the main body/hull using electric energy and which could later be peeled
off, after it has been highly fouled, by manipulating the electric potential.
6.2.2 Polymeric Composites
The marine industry widely uses reinforced polymeric composite materials in boats,
ships, submersibles, offshore structures, and has done so for several decades-this
includes new ways to use existing materials and in using new materials for new
applications. A life cycle assessment of composite structures, in order to better
understand and appreciate the environmental impact of their use, is also required,
namely the concept of 'Cradle to Grave' needs to be part of the design paradigm.
6.2.3 Nanotechnology and Bio-nanotechnology
Using nanotechnology, materials can be made to be stronger, lighter, more durable,
more reactive, or to be better electrical conductors. Nanotechnology can help in
developing materials, which prevent adhesion of marine organisms or fouling and
also possess self-polishing behaviour. The chemistry and topography of the material
surface affects the response of living systems to it. Most of the biomolecules have not
only the recognition power (speciic binding) but also have a tendency to physically
adsorb onto a solid substrate without speciic receptor recognition (non-speciic
adsorption). Therefore, materials need to be designed that will have enhanced speciic
binding and reduced non-speciic binding. Design of surface chemistry and micro or
nanofabrication techniques can help to achieve this. Both self-assembled monolayers
and polymer brushes have attracted considerable attention in achieving such goals
and can help in manipulating biofouling.
