scholarly journals Carbon Black/PDMS Based Flexible Capacitive Tactile Sensor for Multi-Directional Force Sensing

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 628
Author(s):  
Yinlong Zhu ◽  
Xin Chen ◽  
Kaimei Chu ◽  
Xu Wang ◽  
Zhiqiang Hu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Carbon Black ◽  
Dielectric Layer ◽  
Composite Layer ◽  
Material Design ◽  
Tactile Sensor ◽  
Tangential Direction ◽  
Force Sensing ◽  
Contact Compliance ◽  
The Individual

Flexible sensing tends to be widely exploited in the process of human–computer interactions of intelligent robots for its contact compliance and environmental adaptability. A novel flexible capacitive tactile sensor was proposed for multi-directional force sensing, which is based on carbon black/polydimethylsiloxane (PDMS) composite dielectric layer and upper and lower electrodes of carbon nanotubes/polydimethylsiloxane (CNTs/PDMS) composite layer. By changing the ratio of carbon black, the dielectric constant of carbon black/PDMS composite layer increases at 4 wt%, and then decreases, which was explained according to the percolation theory of the conductive particles in the polymer matrix. Mathematical model of force and capacitance variance was established, which can be used to predict the value of the applied force. Then, the prototype with carbon black/PDMS composite dielectric layer was fabricated and characterized. SEM observation was conducted and a ratio was introduced in the composites material design. It was concluded that the dielectric constant of carbon sensor can reach 0.1 N within 50 N in normal direction and 0.2 N in 0–10 N in tangential direction with good stability. Finally, the multi-directional force results were obtained. Compared with the individual directional force results, the output capacitance value of multi-directional force was lower, which indicated the amplitude decrease in capacity change in the normal and tangential direction. This might be caused by the deformation distribution in the normal and tangential direction under multi-directional force.

Atomistic prediction on the configuration- and temperature-dependent dielectric constant of Be0.25Mg0.75O superlattice as a high-κ dielectric layer

2021 ◽  
Author(s):  
Gyuseung Han ◽  
In Won Yeu ◽  
Kun Hee Ye ◽  
Seung-Cheol Lee ◽  
Cheol Seong Hwang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dft Calculations ◽  
Bond Length ◽  
Dielectric Layer ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Temperature Dependent ◽  
High Dielectric

Through DFT calculations, a Be0.25Mg0.75O superlattice having long apical Be–O bond length is proposed to have a high bandgap (>7.3 eV) and high dielectric constant (∼18) at room temperature and above.

scholarly journals Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

2021 ◽  
Vol 16 (2) ◽  
pp. 138-147
Author(s):  
S. A. Syrbu ◽  
M. S. Fedorov ◽  
E. A. Lapykina ◽  
V. V. Novikov
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Anisotropy ◽  
Specific Electrical Conductivity ◽  
Conductivity Anisotropy ◽  
Independent Molecules ◽  
System Properties ◽  
The Individual

Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %. 

A novel functional polyurethane as a dielectric layer for organic thin-film transistors

2018 ◽  
Vol 42 (13) ◽  
pp. 10969-10975
Author(s):  
Xuesong Wang ◽  
He Wang ◽  
Yao Li ◽  
Ting Xu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Layer ◽  
Thin Film Transistors ◽  
High Dielectric Constant ◽  
Organic Thin Film Transistors ◽  
Organic Thin Film ◽  
High Dielectric

A polyurethane material with a high dielectric constant was used to regulate the grain size of p-6P.

A Method to Resolve the Properties of Individual Phases in Carbon-Black-Loaded Elastomer Blends

1991 ◽  
Vol 64 (2) ◽  
pp. 234-242
Author(s):  
R. F. Bauer ◽  
A. H. Crossland
Keyword(s):  
Carbon Black ◽  
Large Deformation ◽  
Polymer Phase ◽  
Stress Strain ◽  
Strain Behavior ◽  
Stress Behavior ◽  
Strain Relationship ◽  
Deformation Stress ◽  
The Individual ◽  
Vulcanization Process

Abstract Properties of the individual phases in a 70/30 carbon-black-loaded BR/NR blend could be successfully resolved using large deformation stress-strain modelling. Since the dispersed NR phase of the example had a lower modulus than the continuous BR phase, the interaction between the blend phases could be modelled by a simple parallel coupling arrangement. The stress behavior of each individual carbon-black-loaded polymer phase was then determined with respect to strain using a specially derived stress-strain relationship. The blend components also have to be characterized with respect to state-of-cure by empirically establishing how the parameters in the stress-strain relationship vary with respect to cure. The properties of the phases in the blend are then determined by finding the combination of component parameters which precisely reproduce the stress-strain behavior of the blend. In the demonstration example of this paper, there was evidence of a significant amount of curative migration between phases during the vulcanization process.

scholarly journals Variability in swelling of spruce (Picea abies [L.] Karst.) wood with the presence of compression wood

2008 ◽  
Vol 53 (No. 6) ◽  
pp. 243-252 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
P. Horáček
Keyword(s):  
Compression Wood ◽  
Longitudinal Direction ◽  
Tangential Direction ◽  
Transverse Plane ◽  
Opposite Wood ◽  
Sample Tree ◽  
Swelling Coefficient ◽  
Hygroscopic Material ◽  
The Individual ◽  
Shape Changes

Wood is a hygroscopic material that is affected by shape changes. The aim of this study was to analyse the variability of wood swelling in the individual anatomic directions. Wood swelling was examined on a sample tree containing compression wood. With regard to the presence of compression wood, the sample tree was divided into the following three zones: the compression wood zone (CW), the opposite wood zone (OW), and two side wood zones (SWL and SWR). The results show that the wood containing compression wood swells less at the transverse plane (in the radial and tangential direction). Conversely, the swelling of compression wood in the longitudinal direction is higher. The same proportion was established in the swelling coefficient that grew proportionally to the increasing wood density in all anatomic directions. The proportion of compression wood manifested its effects in different ways. Transversely (in the radial and tangential direction) the swelling coefficient decreased proportionally to the increasing percentage of compression wood, longitudinally, however, the opposite was the case.

Sign in / Sign up

Export Citation Format

Share Document