Construction
In the engineering/machine and building industry, materials such as steel, wood and concrete do not only need to show an excellent long-term stability, but they also need to be sustainable and environmentally friendly.
The successful application of construction materials requires a good knowledge of their mechanical and chemical properties, as well as their long-time performance. Key is a profound understanding of these properties from the macro down to the nano scale. Often experiments are combined with theoretical modelling in order to derive underlying physical principles.
The list below gives a flavour of the diversity of competences that are united in the MaP community.
In order to improve the reliability and performance of wood products, we are attempting to modify the wood cell walls in a way that will reduce their capacity to admit water. Treated wood should swell and shrink less, be dimensionally stable and should be more durable in the long term. To this end, we are studying how the optimization of materials in nature (e.g. heartwood formation in trees) could be transferred to the technological realm (biomimetics), making use of nanotechnology procedures and polymer chemistry.
Polymeric foams can be electrically poled by the application of a high electric field, resulting in a remnant charge separation within the gas filled voids as a consequence of electric breakdown. Poled foams show ferroelectric and piezoelectric behaviour and can potentially be used as actuators/sensors, e.g. in acoustic noise reduction or as large area medical pressure sensor. In collaboration with the Nonmetallic Inorganic Materials research group, a novel foaming technology is applied to polymers and the resulting porous structures investigated with respect to their electromechanical properties.
Single-walled carbon nanotubes (SWNT) are exciting molecular nanostructures for the development of nano electromechanical systems (NEMS). Before SWNTs can find wide use, fundamental challenges need to be solved. These challenges include the exploration, the development and the characterization of processes for a reproducible integration of carbon nanotubes (CNTs). Therefore our projects are aimed at the control of the location and the size of catalytic particles for the direct integration of SWNTs; the development and evaluation of an integrated process flow; and the demonstration and characterization of SWNTs as active elements in electro mechanical transducers and gas sensors.
Nanocoil structures consist of bilayer ribbons 20 to 40nm thick that can be precisely designed to coil at a variety of pitches and with single or dual chirality into helical structures. The MSRL has demonstrated ultrasensitive environmental sensors with this structure, as well as novel linear-to-rotary motion converters for creating precise rotary motion at the nanoscale. An interesting use of this technology is as artificial bacterial flagella that mimic natural bacterial flagella in both size and shape and are capable of swimming in a similar helical fashion at comparable speeds. The group has recently demonstrated the first artificial bacterial flagella, and continues to develop novel motion mechanisms at the nanoscale.
Energy relaxation and transition energy fluctuations of quantum systems are sensitive probes for materials properties. To improve coherence times of solid state quantum systems we explore, for example, the effect of materials and fabrication processes on quality factors of microwave frequency resonators fabricated using high purity Aluminum and Niobium thin films evaporated on low loss dielectric substrate materials such as Silicon, Sapphire (Al2O3) and GaAs. Materials are characterized from room temperature down to ultra-low temperatures of 0.01 Kelvin.