Abstract:In this work, stretchable magnetic sensorics is successfully established by combining metallic thin films revealing a giant magnetoresistance effect with elastomeric materials. Stretchability of the magnetic nanomembranes is achieved by specific morphologic features (e.g. wrinkles), which accommodate the applied tensile deformation while maintaining the electrical and magnetic integrity of the sensor device. The entire development, from the demonstration of the world-wide first elastically stretchable magnetic sensor to the realization of a technology platform for robust, ready-touse elastic magnetoelectronics with fully strain invariant properties, is described. The prepared soft giant magnetoresistive devices exhibit the same sensing performance as on conventional rigid supports, but can be stretched uniaxially or biaxially reaching strains of up to 270% and endure over 1,000 stretching cycles without fatigue. The comprehensive magnetoelectrical characterization upon tensile deformation is correlated with in-depth structural investigations of the sensor morphology transitions during stretching.With their unique mechanical properties, the elastic magnetoresistive sensor elements readily conform to ubiquitous objects of arbitrary shapes including the human skin. This feature leads electronic skin systems beyond imitating the characteristics of its natural archetype and extends their cognition to static and dynamic magnetic fields that by no means can be perceived by human beings naturally.Various application fields of stretchable magnetoelectronics are proposed and realized throughout this work. The developed sensor platform can equip soft electronic systems with navigation, orientation, motion tracking and touchless control capabilities. A variety of novel technologies, like smart textiles, soft robotics and actuators, active medical implants and soft consumer electronics will benefit from these new magnetic functionalities. Michael Melzer: Stretchable MagnetoelectronicsOutline 4

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This work presents a technique for the study and measurement of the interfacial energies of solid–liquid–gas systems. The instrument and the evaluation method for the measurements obtained by it, allow the analysis of the energy changes of sessile drops submitted to microgravity. A mathematical model based on the thermodynamic of wetting is applied to evaluate the interfacial energies as a function of the drop shape changes due to the effect of the release of gravitation during the experiment. The presented model bases on the thermodynamic equilibrium of the interfaces and not on the balance of bi-dimensional tensors on the contour line. For this reason, the model does not follow Young’s equation as the current surface wetting characterization techniques usually do.

All textile materials, having periodic surfaces, show horizontal and vertical repetitive unities. For this reason, different length scales have to be taken into account by interpreting topographic data measured. In this study, a topographical characterization method for textile materials at different length scales is presented and justified. The topographical study of textile materials using different length scales permits us to characterize the surfaces considering their specific morphologies due to the type of weave, yarn and filament/ fibers separately. The use of a scale concept to characterize textile surfaces seems to be a new skill that helps to correlate textile parameters, topography, and topographical changes with interface phenomena such as spreading, wetting, capillary penetration, and soil release.

These studies aimed to investigate in detail changes on cellulose surfaces treated with low pressure oxygen plasma at various exposure times. Modifications of cellulose films were studied in respect to topography effects by means of atomic force microscopy and scanning electron microscopy. Chemical effects of plasma treatment were studied using X-ray photoelectron spectroscopy and X-ray diffractometry. Results show that the topographical evolution of the surfaces to rougher ones is not at all gradual. Local maxima of fractionation and the surface size regularity were investigated using surface fractal analysis and Wenzel roughness factors, respectively. It was shown, that plasma treatments decompose the cellulose material by formation of highly functionalized molecules. Such plasma-initiated and supported reactions taking place on the sample surface. The bulk phase and in particular, the crystalline domains are not influenced by plasma treatments. The studies provide useful information to understand the plasma reaction on amorphous and crystalline regions of cellulose surfaces and allow to predict effects of the plasma treatment on physical and chemical properties of much more complex cellulose systems such as cotton fibres and fabrics.