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at the Science Center Straubing, have succeeded in retaining this plant-derived movement when the respective plant has been replaced by an artificial petrification process.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
Decoding cement's shape promises greener concrete
08.12.2016 | Rice University
Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D
08.12.2016 | DOE/Brookhaven National Laboratory
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences