Siegfried Bauer

Siegfried Bauer
Johannes Kepler University Linz | JKU · Institute of Experimental Physics

Univ. Prof. Dr.

About

360
Publications
102,737
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
21,828
Citations
Introduction
Skills and Expertise

Publications

Publications (360)
Article
Full-text available
Embedded sensors are key to optimizing processes and products; they collect data that allow time, energy, and materials to be saved, thereby reducing costs. After production, they remain in place and are used to monitor the long‐term structural health of buildings or aircraft. Fueled by climate change, sustainable construction materials such as woo...
Article
Full-text available
Paper-Based Sensors iSens are flexible, foldable, and translucent paper-based sensors. The porous substrates consist of a fiber structure that is highly permeable to liquids. Interdigital electrodes made of ultrathin copper are individually designed by one step laser ablation. This iSens platform, presented by Martin Kaltenbrunner and co-workers in...
Article
Nature offers bionic inspirations for elegant applications of mechanical principles such as the concept of snap buckling, which occurs in several plants. Exploiting mechanical instabilities is the key to fast movement here. We use the snap-through and snap-back instability observed in natural rubber balloons to design an ultrafast purely mechanical...
Article
Full-text available
Biodegradable and biocompatible elastic materials for soft robotics, tissue engineering or stretchable electronics with good mechanical properties, tunability, modifiability or healing properties drive technological advance, and yet they are not durable under ambient conditions and do not combine all the attributes in a single platform. We have dev...
Article
Full-text available
Stretchable Electronics The image, provided by Martin Kaltenbrunner and co‐workers (article number 2000065), shows magnetic interfaces serving not only as mechanical but also as electrical connectors in stretchable electronics. These connectors are safeguarded by a controlled release mechanism, preventing failure in every‐day operation and allow a...
Article
Full-text available
Wearable healthcare devices monitor the condition of patients outside the hospital and hence increase treatment capacity and resources. At the same time, patients benefit from wireless data transmission and conformable device designs, speeding up the rehabilitation process and integration into normal daily activities. Yet, the successful implementa...
Cover Page
Full-text available
The image representing article number 2000467 by Martin Kaltenbrunner and co‐workers shows the mixing of the two phases that form a polyHIPE, a process in which UV‐curable monomers and an electrolyte solution are brought together, to form a highly porous, ion conductive structure. The use of such polyHIPEs as high‐performance separators in stretcha...
Article
Full-text available
Powering soft embodiments of robots, machines and electronics is a key issue that impacts emerging human friendly forms of technologies. Batteries as energy source enable their untethered operation at high power density but must be rendered elastic to fully comply with (soft) robots and human beings. Current intrinsically stretchable batteries typi...
Article
Full-text available
Rapid energy‐efficient movements are one of nature's greatest developments. Mechanisms like snap‐buckling allow plants like the Venus flytrap to close the terminal lobes of their leaves at barely perceptible speed. Here, a soft balloon actuator is presented, which is inspired by such mechanical instabilities and creates safe, giant, and fast deform...
Article
Full-text available
Explosion of ping‐pong balls that is caused by the rapid inflation of an elastomer membrane. The illustrated ultrafast actuation is based on a plant‐inspired mechanical instability that occurs in natural rubber and can be remotely triggered, presented in article number 1903391 by Martin Kaltenbrunner and co‐workers. These new types of high‐speed so...
Article
Full-text available
Flexible circuits: anodization makes them all! A simple concept of scanning head-guided anodization is shown to be highly expandable to fabricate various electronic components. A team led by Professor Siegfried Bauer from Johannes Kepler University Linz, Austria develops a universal and patternable printing protocol of anodic oxides for a full rang...
Conference Paper
Full-text available
We present RESi (Resistive tExtile Sensor Interfaces), a novel sensing approach enabling a new kind of yarn-based, resistive pressure sensing. The core of RESi builds on a newly designed yarn, which features conductive and resistive properties. We run a technical study to characterize the behaviour of the yarn and to determine the sensing principle...
Article
Expensive equipment is often considered a prerequisite for good science. But the development of technology that is affordable and accessible to many could help promote a greater diversity of scientific thinking.
Article
In this paper, we describe the design, fabrication and functional principle of microfluidic diodes – devices for directional liquid transport. They are passive (i.e., need no external energy input) and are capable of unidirectional water transport even vertically against gravity, i.e. they prevent backflow of liquid. In designing the devices with a...
Article
Full-text available
The article “Fluidic Diode” for Passive Unidirectional Liquid Transport Bioinspired by the Spermathecae of Fleas, written by Gerda Buchberger, Alexander Kogler, Agnes Weth, Richard Baumgartner, Philipp Comanns, Siegfried Bauer, Werner Baumgartner, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on...
Article
Full-text available
We present a device for passive unidirectional liquid transport. The capillary channels used are bioinspired by the shape of the spermathecae (receptaculum seminis) of rabbit fleas (Spilopsyllus cuniculi) and rat fleas (Xenopsylla cheopis). The spermatheca is an organ of female fleas that stores sperm until suitable conditions to lay eggs are found...
Article
Full-text available
Controlling the size and shape of semiconducting nanocrystals advances nanoelectronics and photonics. Quantum-confined, inexpensive, solution-derived metal halide perovskites offer narrowband, color-pure emitters as integral parts of next-generation displays and optoelectronic devices. We use nanoporous silicon and alumina thin films as templates f...
Article
Full-text available
Introducing methods for instant tough bonding between hydrogels and antagonistic materials—from soft to hard—allows us to demonstrate elastic yet tough biomimetic devices and machines with a high level of complexity. Tough hydrogels strongly attach, within seconds, to plastics, elastomers, leather, bone, and metals, reaching unprecedented interfaci...
Article
A dielectric elastomer transducer is a deformable capacitor, and is under development as a sensor, actuator, or generator. Among various geometric configurations, laterally-constrained transducer, also known as pure-shear transducer, is easy to implement and effective to couple mechanical force and electrical voltage. This analytical study reveals...
Article
Full-text available
Tuning the band gap of semiconductors via quantum size effects launched a technological revolution in optoelectronics, advancing solar cells, quantum dot light-emitting displays, and solid state lasers. Next generation devices seek to employ low-cost, easily processable semiconductors. A promising class of such materials are metal-halide perovskite...
Article
Large-bandwidth, low-operation-voltage, and uniform organic amplifiers are fabricated on ultrathin foils. By the integration of short-channel OTFTs and AlOx capacitors, organic amplifiers with a bandwidth of 25 kHz are realized, demonstrating the highest gain-bandwidth product (GBWP) reported to date. Owing to material and process advancements, clo...
Article
Full-text available
We present light-point localization by transparent, flexible, thin sensor surfaces based on only two functional polymers: a thin film of pyroelectric poly(vinylidene fluoride) (PVDF) combined with large-area polymer electrodes made of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS). One of the electrodes is resistive to en...
Article
Full-text available
Toy bricks are an ideal platform for the cost-effective rapid prototyping of a tabletop tensile tester with measurement accuracy on par with expensive, commercially available laboratory equipment. Here, a tester is presented that is not only a versatile demonstration device in mechanics, electronics, and physics education and an eye-catcher on exhi...
Article
Full-text available
Toy bricks are an ideal platform for the cost-effective rapid prototyping of a tabletop tensile tester with measurement accuracy on par with expensive, commercially available laboratory equipment. Here, a tester is presented that is not only a versatile demonstration device in mechanics, electronics, and physics education and an eye-catcher on exhi...
Chapter
Ferroelectrets are used in capacitive piezoelectric sensors. When a force is applied to such a sensor, an electrical signal is generated. We first describe the equivalent circuit representation of a ferroelectret sensor element and proceed with the coupling of the sensor element to a measurement device. Based on the governing equations for the meas...
Chapter
This chapter presents a brief overview on sensor and transducer applications of piezoelectric and electrostrictive polymers. Piezoelectric and electrostrictive polymers are smart electromechanical materials which have already found commercial applications in various transducer configurations. Novel applications may arise in the emerging fields of a...
Chapter
Ferroelectrets are used in capacitive piezoelectric sensors. When a force is applied to such a sensor, an electrical signal is generated. We first describe the equivalent circuit representation of a ferroelectret sensor element and proceed with the coupling of the sensor element to a measurement device. Based on the governing equations for the meas...
Chapter
This chapter presents a brief overview on sensor and transducer applications of piezoelectric and electrostrictive polymers. Piezoelectric and electrostrictive polymers are smart electromechanical materials which have already found commercial applications in various transducer configurations. Novel applications may arise in the emerging fields of a...
Article
Full-text available
Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this fiel...
Conference Paper
Full-text available
The Texas Horned lizard has the ability to harvest moisture from ambience with its skin and to transport water directionally to its snout; at the same time water is hindered to flow in opposite direction. We present a passive microfluidic device for directional liquid transport which is inspired by this natural role model. To this end, we deduce a...
Article
Full-text available
Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highl...
Article
Full-text available
Moisture-harvesting lizards such as the Texas horned lizard (Iguanidae: Phrynosoma cornutum) live in arid regions. Special skin adaptations enable them to access water sources such as moist sand and dew: their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport i...
Article
Low density energy sources, like wind and solar energy, are widely available and they are increasingly used for electricity conversion worldwide. Ambient energy sources with even lower energy densities are universally available and could equally be converted into electricity with large scale special purpose converter systems. This work discusses a...
Article
Full-text available
Glassy metallic Hf thin films were obtained using electron beam deposition at room temperature due to the low energy received by Hf atoms during the film formation process. The amorphous nature of the Hf films suggested by XRD was confirmed by low temperature electrical conductivity measurements where a negative temperature coefficient of resistivi...
Article
Full-text available
Extremely compliant sub-2-μm sensor films enable temperature mapping on complex 3D objects, like integrated circuits on printed circuit boards, food packages, and on human skin. In their stretchable form, these metal films withstand strains up to 275%. This imperceptible electronic foil technology platform offers new avenues for the design of compl...
Article
Electronics formed on ultrathin polymer supports are extremely lightweight, able to float on a soap bubble. On page 34, M. Drack and co‐workers describe the fabrication of this imperceptible electronic technology platform together with applications in spatio‐temporal temperature mapping of electronic circuitry, food items, or human skin. In conjunc...
Article
Full-text available
Laser ultrasonic (LUS) receivers based on photorefractive (PR) materials are contactless and adap-tive interferometers, which are used widely for materials characterization. Here, we present a simple LUS interferometer at 532 nm operating wavelength based on organic PR polymer composites (PVK/ECZ/C60) doped with the nonlinear chromophore 4-[4-(diet...
Article
Full-text available
The rapid and efficient development of soft active materials requires readily available, compact testing equipment. We propose a desktop-sized, cost-efficient, and open source radial stretching system as an alternative to commercially available biaxial and uniaxial stretching devices. It allows for doubling the diameter of an elastomer membrane whi...
Article
Ferroelectrets are flexible and conformable polymer transducer foils with a dominant longitudinal piezoelectric effect. Ferroelectrets also have a negligible transverse piezoelectric effect, which makes them ideal for the fabrication of roll- and bendable keyboards. Cellular polypropylene ferroelectrets with heteropolar charge patterns are useful f...
Article
New polymerisable photoluminescent octahedral rhenium cluster complexes trans-[{Re6Q8}(TBP)4(VB)2] (Q = S or Se; TBP – p-tert-buthylpyridine; VB – vinyl benzoate) have been synthesised, characterised and used to construct rhenium cluster-organic polymer hybrid materials. These novel polymer systems are solution-processable and the rhenium clusters...
Article
Full-text available
Clean, renewable and abundant sources of energy, such as the vast energy of ocean waves, are untapped today, because no technology exists to convert such mechanical motions to electricity economically. Other sources of mechanical energy, such as motions of people and vibrations of buildings and bridges, can potentially power portable electronics an...
Article
Dielectric elastomer minimum energy structures (DEMES) are soft electronic transducers and energy harvesters with potential for consumer goods. The temporal change in their electromechanical properties is of major importance for engineering tasks. Therefore, we study acrylic DEMES by impedance spectroscopy and by optical methods for a total time pe...
Article
Full-text available
We report on a contactless method to focus laser generated bulk and surface ultrasound waves in the thermo-elastic coupling mode by annular shaped illumination. By using a spatial light modulator (SLM) the beam profile of a pulsed picoseconds laser was shaped to annular forms flexibly and further rings with a thickness of 50 μm and a generation ene...
Article
Microelectronics dominates the technological and commercial landscape of today's electronics industry; ultrahigh density integrated circuits on rigid silicon provide the computing power for smart appliances that help us organize our daily lives. Integrated circuits function flawlessly for decades, yet we like to replace smart phones and tablet comp...
Article
Full-text available
We present two laser ultrasonic receivers based on organic photorefractive polymer composites with 2-[4-bis(2-methoxyethyl)aminobenzylidene]malononitrile (AODCST) or 2-dicyanomethylen-3-cyano-5,5-dimethyl-4-(4′-dihexylaminophenyl)-2,5-dihydrofuran nonlinear optical chromophores. Experimental results show sensitivities of the ultrasonic receivers of...
Article
This paper shows that a highly deformable capacitor made of a soft dielectric and two conformal electrodes can switch between two states discontinuously, by a first-order transition, as the total charge varies gradually. When the total charge is small, it spreads evenly over the area of the capacitor, and the capacitor deforms homogeneously. When t...
Article
Full-text available
Scientists are exploring elastic and soft forms of robots, electronic skin and energy harvesters, dreaming to mimic nature and to enable novel applications in wide fields, from consumer and mobile appliances to biomedical systems, sports and healthcare. All conceivable classes of materials with a wide range of mechanical, physical and chemical prop...
Article
Full-text available
Dielectric elastomers are used for electromechanical energy conversion in actuators and in harvesting mechanical energy from renewable sources. The electrical breakdown strength determines the limit of a dielectric elastomer for its use in actuators and energy harvesters. We report two experimental configurations for the measurement of the stretch...
Article
Skin is a large, flexible and robust organ that covers and protects the body from external damage. This multifunctional biological model is inspiring the development of electronic equivalents referred to as 'electronic skin', consisting of large-area networks of sensors that detect pressure, temperature and other environmental stimuli, and are usua...
Article
Full-text available
We demonstrate ultrathin (2 µm thick) red and orange polymer light-emitting diodes with unprecedented mechanical properties in terms of their flexibility and ability to be stretched. The devices have a luminance greater than 100 cd m–2, sufficient for a variety of optoelectronic applications including indoor displays. They can be operated as free-s...
Data
The dataset is a video file (also available here: http://youtu.be/_wcaYDxi5_8) showing the use of our screen printed, flexible, large area polymer sensors in safety systems for automotive applications. The sensors were developed within the European Project 3PLAST. The pyroelectric and piezoelectric effect of the ferroelectric polymer is utilized to...