Transparent Flexible Polymer Actuator with Enhanced Output Force Enabled by Conductive Nanowires Interlayer

2019 ◽  
Vol 5 (1) ◽  
pp. 1900762 ◽  
Author(s):  
Tony Hiu Tung Fook ◽  
Jin Han Jeon ◽  
Pooi See Lee
Keyword(s):  
Flexible Polymer ◽  
Output Force ◽  
Polymer Actuator

A Theoretical Study on Bending Behaviour of Conducting Polymer Actuator

2014 ◽  
Vol 553 ◽  
pp. 551-556
Author(s):  
Erin Burke ◽  
Chun Hui Yang
Keyword(s):  
Finite Element ◽  
Conducting Polymer ◽  
Applied Voltage ◽  
Rectangular Cross Section ◽  
Complex Structure ◽  
Element Analysis ◽  
Polymer Actuators ◽  
Voltage Output ◽  
Output Force ◽  
Polymer Actuator

Conducting polymer actuators are of vital importance to the future of many engineering developments in a range of different fields especially micro applications. To allow for the use of conducting polymer actuators in practical applications a reliable and accurate model to predict the applied voltage, output force and bending motion relationship must be established. In current research, we are aiming to contribute to the fundamental understanding of the mechanical behaviour of such conducting polymer actuators under a range of different conditions and material properties. To achieve this goal it is vital to formulate a model that accurately represents the relationship between the applied voltage, output force and the resulting bending displacement of the conducting polymer actuator. Two different theoretical models have been developed and compared; one consisting of an analytical solution and the other involving a range of different finite element models solved using a commercial finite element analysis package–Abaqus. A new modelling method involving the meshing of a multilayered rectangular cross section that can be used for the analysis of a beam-like model is presented with satisfactory results. This numerical method allows for the complex structure of the conducting polymer actuator to be analysed using three dimensional beam elements available in Abaqus/Standard and allowing for the principles of classic beam theory to be implemented.

A Monte Carlo Study of Flexible Polymer Chain Conformations in Restricted Volumes. I. A Model for Insoluble Blocks Conformations in Swollen Cores of Multimolecular Spherical Block Copolymer Micelles

1993 ◽  
Vol 58 (10) ◽  
pp. 2290-2304 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Block Copolymer ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Micellar Systems ◽  
Flexible Polymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Chain Conformations ◽  
Chain Lengths

Monte Carlo simulations of chain conformations in a restricted spherical volume at relatively high densities of segments were performed for various numbers of chains, N, and chain lengths (number of segments), L, on a tetrahedral lattice. All chains are randomly end-tethered to the surface of the sphere. A relatively uniform surface density of the tethered ends is guaranteed in our simulations. A simultaneous self-avoiding walk of all chains creates starting conformations for a subsequent equilibration. A modified algorithm similar to that of Siepmann and Frenkel is used for the equilibration of the chain conformations. In this paper, only a geometrical excluded volume effect of segments is considered. Various structural and conformational characteristics, e.g. segment densities gS(r), free end densities gF(r) as functions of the position in the sphere (a distance from the center), distributions of the tethered-to-free end distances, ρTF(rTF), etc. are calculated and their physical meaning is discussed. The model is suitable for studies of chain conformations is swollen cores of multimolecular block copolymer micelles and for interpretation of non-radiative excitation energy migration in polymeric micellar systems.

Frequency Modulation of Motor Unit Discharge Has Task-Dependent Effects on Fluctuations in Motor Output

2005 ◽  
Vol 94 (4) ◽  
pp. 2878-2887 ◽  
Author(s):  
Carol J. Mottram ◽  
Evangelos A. Christou ◽  
François G. Meyer ◽  
Roger M. Enoka
Keyword(s):  
Motor Unit ◽  
Frequency Modulation ◽  
Discharge Rate ◽  
Motor Output ◽  
Unit Discharge ◽  
Rate Of Increase ◽  
Output Force ◽  
Position Task ◽  
Motor Unit Discharge ◽  
Target Force

The rate of change in the fluctuations in motor output differs during the performance of fatiguing contractions that involve different types of loads. The purpose of this study was to examine the contribution of frequency modulation of motor unit discharge to the fluctuations in the motor output during sustained contractions with the force and position tasks. In separate tests with the upper arm vertical and the elbow flexed to 1.57 rad, the seated subjects maintained either a constant upward force at the wrist (force task) or a constant elbow angle (position task). The force and position tasks were performed in random order at a target force equal to 3.6 ± 2.1% (mean ± SD) of the maximal voluntary contraction (MVC) force above the recruitment threshold of an isolated motor unit from the biceps brachii. Each subject maintained the two tasks for an identical duration (161 ± 93 s) at a mean target force of 22.4 ± 13.6% MVC. As expected, the rate of increase in the fluctuations in motor output (force task: SD for detrended force; position task: SD for vertical acceleration) was greater for the position task than the force task ( P < 0.001). The amplitude of the coefficient of variation (CV) and the power spectra for motor unit discharge were similar between tasks ( P > 0.1) and did not change with time ( P > 0.1), and could not explain the different rates of increase in motor output fluctuations for the two tasks. Nonetheless, frequency modulation of motor unit discharge differed during the two tasks and predicted ( P < 0.001) both the CV for discharge rate (force task: 1–3, 12–13, and 14–15 Hz; position task: 0–1, and 1–2 Hz) and the fluctuations in motor output (force task: 5–6, 9–10, 12–13, and 14–15 Hz; position task: 6–7, 14–15, 17–19, 20–21, and 23–24 Hz). Frequency modulation of motor unit discharge rate differed for the force and position tasks and influenced the ability to sustain steady contractions.

scholarly journals ALD Deposited ZnO:Al Films on Mica for Flexible PDLC Devices

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1011
Author(s):  
Dimitre Z. Dimitrov ◽  
Zih Fan Chen ◽  
Vera Marinova ◽  
Dimitrina Petrova ◽  
Chih Yao Ho ◽  
...  
Keyword(s):  
Near Infrared ◽  
Atomic Layer ◽  
Optical Transmittance ◽  
Force Microscopy ◽  
Flexible Polymer ◽  
Layer Deposition ◽  
Polymer Dispersed ◽  
Muscovite Mica ◽  
Infrared Spectral ◽  
Continuous Bending

In this work, highly conductive Al-doped ZnO (AZO) films are deposited on transparent and flexible muscovite mica substrates by using the atomic layer deposition (ALD) technique. AZO-mica structures possess high optical transmittance at visible and near-infrared spectral range and retain low electric resistivity, even after continuous bending of up to 800 cycles. Structure performances after bending tests have been supported by atomic force microscopy (AFM) analysis. Based on performed optical and electrical characterizations AZO films on mica are implemented as transparent conductive electrodes in flexible polymer dispersed liquid crystal (PDLC) devices. The measured electro-optical characteristics and response time of the proposed devices reveal the higher potential of AZO-mica for future ITO-free flexible optoelectronic applications.

A Lightweight Soft Gripper Driven by Self-Sensing Super-Coiled Polymer Actuator

2021 ◽  
Vol 6 (2) ◽  
pp. 2775-2782
Author(s):  
Sen Wang ◽  
Hongxin Huang ◽  
Hailin Huang ◽  
Bing Li ◽  
Ke Huang
Keyword(s):  
Polymer Actuator

scholarly journals Hybrid Multisite Silicon Neural Probe with Integrated Flexible Connector for Interchangeable Packaging

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2605
Author(s):  
Ashley Novais ◽  
Carlos Calaza ◽  
José Fernandes ◽  
Helder Fonseca ◽  
Patricia Monteiro ◽  
...  
Keyword(s):  
Fabrication Process ◽  
High Signal ◽  
Wafer Level ◽  
Neural Probes ◽  
Insertion Force ◽  
Precise Integration ◽  
Flexible Cable ◽  
Flexible Polymer ◽  
Hybrid Silicon

Multisite neural probes are a fundamental tool to study brain function. Hybrid silicon/polymer neural probes combine rigid silicon and flexible polymer parts into one single device and allow, for example, the precise integration of complex probe geometries, such as multishank designs, with flexible biocompatible cabling. Despite these advantages and benefiting from highly reproducible fabrication methods on both silicon and polymer substrates, they have not been widely available. This paper presents the development, fabrication, characterization, and in vivo electrophysiological assessment of a hybrid multisite multishank silicon probe with a monolithically integrated polyimide flexible interconnect cable. The fabrication process was optimized at wafer level, and several neural probes with 64 gold electrode sites equally distributed along 8 shanks with an integrated 8 µm thick highly flexible polyimide interconnect cable were produced. The monolithic integration of the polyimide cable in the same fabrication process removed the necessity of the postfabrication bonding of the cable to the probe. This is the highest electrode site density and thinnest flexible cable ever reported for a hybrid silicon/polymer probe. Additionally, to avoid the time-consuming bonding of the probe to definitive packaging, the flexible cable was designed to terminate in a connector pad that can mate with commercial zero-insertion force (ZIF) connectors for electronics interfacing. This allows great experimental flexibility because interchangeable packaging can be used according to experimental demands. High-density distributed in vivo electrophysiological recordings were obtained from the hybrid neural probes with low intrinsic noise and high signal-to-noise ratio (SNR).

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