The "MiFAS - Microstructured Fiber Surfaces" project has won a at the Swiss Technology Awards presentation and a special prize in the category "Inventing the future", donated by the cantons of St Gall and Thurgau. A condition of the award is that the project be exhibited at the Hanover Trade Fair from April 11th to 15th 2005.

The properties of functional textiles are frequently based on the specific surface structure of the individual synthetic fibre. The fibre surface is structured on the spinning machine, but for technical reasons longitudinal structuring has only been possible up until now.

Working jointly with the Paul Scherrer Institute (PSI), Empa has now developed a simple apparatus with which the surface of synthetic fibres can also be transversely structured by embossing the structure onto the synthetic fibre. A sophisticated system ensures that the embossing effectively covers the entire fibre surface. A patent application has been filed for the principle.

The embossing system is subject to continuous further development. For example, it is still not possible to connect the system directly to a fibre spinning machine since the process is still too slow. Apart from perfecting the system, another aim is to make the important step from microstructuring to nanostructuring.

Improving functionality means creating new embossing patterns. Research is therefore being carried out to establish which type of structuring produces which properties. The following areas, for example, are being investigated

• Colour and shimmer effects. Fashion aspects aside, these also have potential uses in safety applications.
• Capillary action: Important for the development of textiles designed to absorb a lot of liquid or where quick drying is desirable. The aim is to improve moisture transport by giving the fibres a special capillary structure.
• Friction: Fibres with good adhesion properties, for example in fibre-reinforced concrete where the structuring of the fibres provides better anchorage in the mortar, thereby endowing the concrete with greater tensile strength.
• Cell growth: Certain surface structures can promote cell growth. This can be crucial for success in medical textiles.
• Lotus effect: This is designed to produce a “self-cleaning effect”.

Apart from all these functionalities, the technology could also be boosted by one of its commercial properties. Marked fibres in clothing would allow manufacturers of branded articles to make their products virtually impossible to copy or at least make them clearly distinguishable from cheap copies.

Rémy Nideröst

Contact: Marcel Halbeisen, marcel.halbeisen@empa.ch