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at the Science Center Straubing, have succeeded in retaining this plant-derived movement when the respective plant has been replaced by an artificial petrification process.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
New approach to revolutionize the production of molecular hydrogen
22.05.2017 | Technische Universität Dresden
Photocatalyst makes hydrogen production 10 times more efficient
19.05.2017 | Kobe University
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...
22.05.2017 | Event News
17.05.2017 | Event News
16.05.2017 | Event News
22.05.2017 | Materials Sciences
22.05.2017 | Life Sciences
22.05.2017 | Physics and Astronomy