Growing Self-Organising Polymer Pelts
Polymer pelts are suitable for many different applications from coatings that adhere well and are easy to remove to highly sensitive biodetectors. Researchers at KIT, together with scientists in the USA, have now developed a cost-effective process that enables customised polymer nanofibres to grow on a solid substrate.
Surfaces with specially aligned fibres commonly occur in nature and perform different functions such as sensing, adhering and self-cleaning. For example, gecko feet are covered with millions of hairs that allow them to stick to surfaces and quickly let go again. Replicating such surfaces from man-made materials will open up new prospects for different applications, but production methods for polymer pelts on solid bases have been costly to date. Furthermore, the size, shape and alignment of the fibres can only be controlled to a limited extent with conventional methods such as extrusion or production in an electric field (electrospinning).
Liquid crystal layer with reactive molecules
Researchers at the Institute of Functional Interfaces (IFG) of Karlsruhe Institute of Technology (KIT), the University of Michigan, the University of Wisconsin-Madison and Cornell University in Ithaca, New York, have now developed a simple and cost-effective process that allows polymer pelts to grow in a self-organised way. The scientists presented the new method in the journal "Science": they first wet a carrier with a thin layer of liquid crystals and then vapour-deposited activated molecules onto it. These reactive monomers penetrate the liquid crystalline layer and grow from the substrate into the liquid in the form of fine fibres.
As a result, polymer nanofibres are created that can be customised in length, diameter, shape and arrangement. The complex yet precisely structured polymer pelts formed by the fibres are promising for many different applications, especially for biological detectors, coatings with new properties and bioinstructive surfaces that interact with their environment. This also includes surfaces with dry adhesion properties similar to those of gecko feet. However, adhesion in nanofibres is due to a special spatial arrangement of the atoms in the molecules.