Artis Linarts

Inversely polarised ferroelectric polymer contact electrodes for triboelectric-like generators from identical materials

Although it is known that triboelectric nanogenerators (TENGs) based on ferroelectric polymer films show better performance, the origin of this enhancement remains poorly understood. To date, it has been accepted that enhancement is observed due to shift of the “effective work function” of the ferroelectric polymer insulator, which in turn enhances electron transfer between the TENG electrodes. The present study reveals that this view is incorrect and, in reality, the enhancement is observed due to induction driven by piezoelectric charges. Furthermore a novel piezoelectric-electrostatic generator (PEEG) has been constructed from inversely polarised polyvinylidene films, which exhibits higher performance than TENGs for mechanical energy conversion to electricity.

Polymer/Nanographite Composites for Mechanical Impact Sensing

The purpose of this chapter is to give a review of the polymer/nanographite composite (PNGC) materials specially developed for applications in mechanical strain and pressure sensors that can be used for design of flexible sensing systems. Our recent achievements in design, processing, and investigation of physical properties of elastomer and nanostructured carbon composites as prospective materials for mentioned sensors are also presented. In the beginning, theoretical principles of tunneling percolation theory and piezoresistivity have been described. We discuss the most suitable polymer matrices and electrically conductive nanographite fillers for sensitive PNGC. Preparation methods of mechanically sensitive PNGC have been considered. Different particularly produced and tested polymer/nanographite composites are overhauled and possible advantages and disadvantages of PNGC in different possible applications are analyzed.

The dependence of piezoresistivity of elastomer/nanostructured carbon composites on dynamic mechanical load frequency

The aim of this article is to determine piezoresistive sensitivity of elastomer nanostructured carbon composites at dynamic loading tests and show the piezoresistive effect correlations to various frequencies of applied mechanical force in a manner that could provide a parameter of the highest detectible dynamic load frequency. This parameter is crucial when determining sensors usability in possible applications. There are only few articles on conductive polymer composite sensitivity in dynamic mechanical loading tests.With this article we are trying to estimate the values of dynamic loading frequencies in which sensor would be functional.

Design Principles for Building a Soft, Compliant, High Spatial Resolution Tactile Sensor Array

High-density tactile arrays are required to measure tactile properties, including forces and torques, contact shape and location, and dynamic slip, for dexterous gripping and manipulation tasks performed by robots and humans through haptic interfaces. However, in all current tactile sensing solutions, there is a trade-off between spatial resolution, flexibility, softness and manufacturing cost. In this work, a new design is proposed for a low cost, soft and malleable tactile sensing system with high spatial resolution that can be reshaped and applied to any surface, and that reduces the number of individual sensing elements, eliminates the need for any electronics within the sensing area and removes the need to time-division multiplex between sensor elements, allowing fully-parallel processing of transducer readings. Here the design is an orthogonal placement of conductive rubber strips with a pressure-dependant resistance. A basic algorithm for estimating the pressure at the intersection of each pair of orthogonal sensing strips is also described. The algorithm was tested with a simulated stimulation by two spherical stimuli onto a 16 \( \times \) 16 grid (16 horizontal strips overlaid with 16 vertically strips) – the estimated pressure profile correlates well with the simulated stimulus (\( r \) = 0.86). A 5 \( \times \) 5 grid prototype was built and was tested by stimulating with a spherical stimuli – the estimated pressure profile correlates well with the real stimulus (\( r \) = 0.92). Various design and algorithm improvements are suggested to overcome ambiguity in the estimated pressure profile due to the underdetermined nature of the system.