In the realm of plants, capillary forces are a widely observed impetus for actuation. They are the physical basis for the expansion of porous materials during uptake of fluid. Such materials include the cones of conifers with their readily observable movement during drying or wetting. Scientists at the Chair of Biogenic Polymers of the Technical University of Munich (TUM) located at the Science Center Straubing, have succeeded in retaining this plant-derived movement when the respective plant has been replaced by an artificial petrification process. Thereby, they laid the foundations for a new generation of sensoric materials.
"For the first time we applied a previously developed and refined 'bio-templating' process to create materials with a structure-based functionality- in cooperation with the Institute of Physics of the Austrian Montanuniversitaet Leoben and the Max-Planck-Institute for Colloids and Interfaces in Potsdam", said Dr. Daniel Van Opdenbosch, who is working at the Science Center Straubing.
Auch die versteinerte Kierfernschuppe biegt sich bei Befeuchtung gegen die Schwerkraft aufwärts und bei Trocknung wieder zurück in ihre Ausgangsposition. Bild: BP, WZS)
With this approach, one can artificially petrify pine cones, completely transforming the biological components into the technical material silica glass. Elaborate analyses at the particle accelerator BESSY II in Berlin showed that the internal structure of the pine cone was retained. Crucially, it was petrified completely and accurately – down to the smallest hierarchical level of only millionths of millimeters.
Van Opdenbosch: "We could induce the obtained samples to move in a similar manner as their biological originals during the uptake of moisture. The scales of the petrified cones move upward against gravity, and on drying back to their starting positions.
" The scientists hope that the precise templating of plant structures, and the corresponding retention of their characteristic properties, will be a pathway for the development of functional materials. Based on the current results, they say that the preparation of porous ceramic multilayer-sensors is possible with comparatively low expenditure. Such novel sensors react to changes in moisture with angular movement.
They could therefore be used to measure, switch or control in chemically or physically aggressive environments. Conventional bimetal or other bilayer actuators are, due to their composition of metals or polymers, prone to corrosion through acid- or base attacks, as well as oxidative, thermal or physical degradation. Against all of these factors, ceramic oxides, such as silica glass, are particularly resistant.
The project "Hierarchically structured porous ceramics and composites from nanocasting of plant cell walls" was carried out in the frame of the Priority Programme 1420 "Biomimetic Materials Research: Functionality by Hierarchical Structuring of Materials" funded by the German Science Community (Deutsche Forschungsgemeinschaft). The scientists published their work in the esteemed journal "Advanced Materials" (May 6th 2016, DOI-number 10.1002/adma.201600117).
Technical University of Munich
Science Center Straubing
Jan F. Turner
Phone 09421 187 163
Dr. Ulrich Marsch | Technische Universität München
Epoxy compound gets a graphene bump
14.11.2018 | Rice University
Automated adhesive film placement and stringer integration for aircraft manufacture
15.11.2018 | Fraunhofer IFAM
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences