Prakt. Met. Sonderband 38 (2006) 473 
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Fig. 2: Self-cleaning of Lotos plant leaves. A water droplet rolls over the non- 
wettable surface (left), the particulate matter (middle) adheres top the drop of 
water as it rolls over the non-wettable surface (right). 
As pointed out earlier each case of adhesion is unique and has to be treated 
hich separate in order to design a surface with superior, long-lasting antiadhesive 
sed properties. Manufacturing of antiadhesive surfaces has therefore to be flexible and 
rely upon well-known technologies. Moreover, as pointed out previously, a 
ri.e. biomimetical transfer of surface properties seem to be favourable. For this purpose 
several micro- and nanostructuring technologies can be used. Some microstructures 
hich can be achieved by flame spraying or sand blasting of aluminum and stainless steel 
A samples in order to achieve the samples microstructure. Subsequently the samples 
2 is can be nanostructured by electrochemical methods. Thereafter the hierachially 
stuctured surfaces are coated with tetraether lipids — a biomolecule which is believed 
cture to be very durable since they are isolated from microorganisms which live under 
3,4] harsh conditions (acidic and at high temperatures). Moreover, since they form a part 
of the cell membrane (which is responsible for protective and regulatory tasks in 
microorganisms) they are very likely to fullfil one of the most important demands that 
is put upon antiadhesive surfaces by industrial users: the long-term durability. For an 
accurate biomimetic transfer we have to rely upon a stable coating since the coating 
cannot be regenerated if damaged in the same way as living organisms such as 
plants regenerate the surface. Moreover, tetraetherlipids self-assemble readily on 
substrates and can also be used in combination with other biomolecules or 
nanoclusters in order alternate properties [6, 7, 8]. 
Several antiadhesive surfaces have been developed and tested in research 
laboratories but mostly those surfaces fail when tested for months or years outdoors - 
exposed to rain, sun, snow, hail, wind and shifting temperatures. Nature represents 
the worst conditions one can ever think of — also for this reason it is important to think 
“biomimetically” i.e. to consider biomimetical transfer of properties, structure or 
compounds from nature in order to meet the requirements of the same. One of the 
technological processes which is close to the structuring of biological surfaces is 
0s 
electrochemical structuring. In both cases self-assembly or self-organisation of the 
structural components (wax and metal) play an important role. Figure 3 show a 
typical non-wettable copper surface and an SEM graph of the dentritic structure of 
the electrodeposited copper. By comparing the structures shown in figure 1 and 3 it is 
‚mer evident that the copper surface structure represents an example of biomimetical 
transfer of structures. 
the 
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