Papers by robert nawrocki
The Effects of Additive Manufacturing and Electric Poling Techniques on PVdF Thin Films: Towards 3D Printed Functional Materials
ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems
Mechanical flexibility, faster processing, lower fabrication cost and biocompatibility enable pol... more Mechanical flexibility, faster processing, lower fabrication cost and biocompatibility enable poly (vinylidene fluoride) (PVdF) to have a wide range of applications. This work investigated the use of a piezoelectric polymeric material, PVdF, in combination with 3D printing, to explore new strategies for the fabrication of smart materials with embedded functions, namely sensing. The motivation behind this research was to design and fabricate PVdF thin films that will be used to build pressure sensors with applications in active intelligent structures. In this work, 3D printed PVdF thin films with thickness values in the range of 250 to 350 μm were poled under high direct current electrical fields, which were varied from 0.4 to 12 MV/m and temperatures from 80 to 140 °C. Copper electrodes were applied, forming a standard capacitor layered structure, to facilitate poling and to collect piezoelectric output voltage. The poling process enabled the piezoelectric crystalline phase transiti...
Organic electronics Axon-Hillock neuromorphic circuit: towards biologically compatible, and physically flexible, integrate-and-fire spiking neural networks
Journal of Physics D: Applied Physics
Lessons Learned the Hard Way
2020 IEEE International Symposium on Circuits and Systems (ISCAS)
Modeling of the electrical characteristics of an organic field effect transistor in presence of the bending effects
Organic Electronics
Computer Modeling in Engineering & Sciences
Equipped with a two-dimensional topological structure, a group of masses, springs and dampers can... more Equipped with a two-dimensional topological structure, a group of masses, springs and dampers can be demonstrated to model the internal dynamics of a thin-film transistor (TFT). In this paper, the two-dimensional Mass-Spring-Damper (MSD) representation of an inverted staggered TFT is proposed to explore the TFT's internal stress/strain distributions, and the stress-induced effects on TFT's electrical characteristics. The 2D MSD model is composed of a finite but massive number of interconnected cellular units. The parameters, such as mass, stiffness, and damping ratios, of each cellular unit are approximated from constitutive equations of the composite materials, while the electrical properties of the inverted staggered TFT are characterized by utilizing an electro-mechanical coupling relation derived from the quantum mechanics. TFTs are often used in biomedical sensors/transducers attached to human skins, and, for the purpose of simulation and validation, the boundary conditions on the interface between the TFT and the human skin were modeled as a spatially distributed sinusoidal excitation with a frequency of 50 Hz, assuming the TFT thickness is more than tens of microns. The fidelity of the 2D MSD structure in the modeling of an inverted staggered TFT is verified by comparing its simulated total displacement field with that of a finite element analysis (FEA) model. The advantages of the MSD model include a dramatic reduction in memory use by up to 60% and faster computation times that are up to 80% lower. More importantly, the MSD model is better suited than FEA to many problems in accurate tissue modeling for medical applications, for which FEA is becoming a bottleneck. This work develops a novel modeling approach, which can be extended to other types of flexible thin film transistors.
Organic Electrochemical, PEDOT:PSS-Based Impedimetric Histamine Sensor
ECS Meeting Abstracts
Super‐ and Ultrathin Organic Field‐Effect Transistors: from Flexibility to Super‐ and Ultraflexibility
Advanced Functional Materials
Enhancement of Charge Transport in Polythiophene Semiconducting Polymer by Blending with Graphene Nanoparticles
ChemPlusChem
Self-Adhesive and Ultra-Conformable, Sub-300 nm Dry Thin-Film Electrodes for Surface Monitoring of Biopotentials
Advanced Functional Materials
Mechanical Engineering
The Earth is at a sociotechnical crossroads with humanity hanging in the balance – and high-tech ... more The Earth is at a sociotechnical crossroads with humanity hanging in the balance – and high-tech agriculture can help bail us out. Human population growth, increasing urbanization and rising incomes is likely to drastically increase demand for animal agriculture in the coming decades. The US Department of Agriculture (USDA) predicts the need to double global food production by 2050 as the global population increases from 7.3 billion in 2015 to 9.7 billion in 2050 as shown in Fig 1. Much of this growth will be concentrated in the world’s poorest countries where standards of living are set to rise rapidly, increasing the demand for resource-intensive meat and dairy products which has been the historical trend. At the same time, agriculture in the 21st century faces multiple challenges: it must produce more food and fiber to feed a growing population with a smaller rural labor force, produce additional feedstocks for a potentially huge bioenergy market, contribute to overall developmen...
Enhancement of Closed-Loop Gain of Organic Amplifiers Using Double Gate Structures
IEEE Electron Device Letters
Fabrication And Application Of A Polymer Neuromorphic Circuitry Based On Polymer Memristive Devices And Polymer Transistors
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Papers by robert nawrocki