Effect of the Polyamide Type on the Physical Properties of Layered Polyaniline Composite Films

2020 ◽  
Vol 13 (3) ◽  
pp. 227-232

Abstract: The present work deals with the investigation of the dielectric properties of layered polyamide/polyaniline films and their correlation to the microstructure. A thin polyaniline (PANI) layer was polymerized in the subsurface of polyamide films. The dielectric relaxation spectroscopy was used to compare the electrical behaviour of flexible polyamide 6 (PA6) and polyamide 12 (PA12) surfaces loaded with PANI nanoparticles, while the roughness was investigated by the contact angle technique. Relatively high dielectric constants were recorded for PA12/PANI films compared to PA6/PANI ones due to the hydrophobic nature of the PA12 matrix. This also explained the wettability enhancement observed for PA12/PANI films up to 12 wt.% of aniline absorbed concentration, while PA6/PANI films needed no more than 9 wt.% to reach maximum wettability. This behavior was in good correlation with the microstructure of the films. SEM micrographs showed uniform surfaces for both films formed above these respective concentrations, where wettability started to decrease. The films of PA/PANI seemed to be good candidates as dielectric layers in flexible electronics. Keywords: Polymer, Polyamide, Polyaniline, Dielectric constant, Optical gap. PACS: 78.20.-ei, 78.20.-c, 68.60.-p, 82.35.Lr.

2012 ◽  
Vol 496 ◽  
pp. 263-267
Author(s):  
Rui Li ◽  
Jian Zhong Pei ◽  
Yan Wei Li ◽  
Xin Shi ◽  
Qun Le Du

A novel all-polymeric material with high dielectric constant (k) has been developed by blending poly (vinylidene fluoride) (PVDF) with polyamide-6 (PA6). The dependence of the dielectric properties on frequency and polymer volume fraction was investigated. When the volume fraction of PA6 is 20%, the dielectric property is better than others. The SEM investigations suggest that the enhanced dielectric behavior originates from significant interfacial interactions of polymer-polymer. The XRD demonstrate that the PA6 and PVDF affect the crystalline behavior of each component. Furthermore, the stable dielectric constants of the blends could be tuned by adjusting the content of the polymers. The created high-k all-polymeric blends represent a novel type of material that are simple technology and easy to process, and is of relatively high dielectric constant, applications as flexible electronics.


2011 ◽  
Vol 239-242 ◽  
pp. 2655-2658
Author(s):  
Heng Feng Li ◽  
Guo Wen He ◽  
Jun Li ◽  
Jun Chen ◽  
Jiang Cong Chen

A series of polyimide composites with various mass fractions of multi-walled carbon nanotubes (MWNTs) were prepared by in situ polymerization. MWNTs were treated with an acid mixture and sulfoxide chloride in turn to increase the chemical compatibility of carbon nanotubes with the polyimide matrix. The modified MWNTs are dispersed homogeneously in the matrix while the structure of the PI and MWNTs structures are stable in the preparation process. The composite films hold preferable thermal stability as same as the pure PI. The dielectric constants of the composites decreased with the increasing frequency and increase sharply with the adding of MWNTs.


2009 ◽  
Vol 1161 ◽  
Author(s):  
Zuhal Tasdemir ◽  
Gullu Kiziltas

AbstractThe goal of this research is to develop a process suitable for producing monolithic conformal substrates with a spatial arrangement of material cells according to a particular design creating novel material systems, useful for many multi- functional electronic and Radio Frequency devices. In this study, MCT ceramics (Mg-Ca-Ti-O systems) and organic binders (polymer solution) are mixed and fabricated as films through a process called tape casting to compromise between high dielectric constant and flexibility. Prior to optimizing the process, several characterization studies are carried out: Commercial spray dried MCT powders (Transtech Inc.) with dielectric constant k=70 and k=20 were analyzed as pressed and produced into tape cast films. Dielectric properties are then measured by an Agilent 16451B material analysis kit and their microscopic behavior is examined by scanning electron microscopy. Results show that flexible composite films show a maximum dielectric constant of ε∼22 unlike their powder pressed form with ε ∼16 but their loss behavior deteriorates when compared with their sintered form and a loss tangent factor of 0.001. The difference is attributed to the air content vs. polymer presence of the material in powder pressed form. Also, these substrates naturally are no longer flexible; hence studies are focused on their tape cast form. The potential of these dielectric shades to serve as candidate constituents for producing monolithic textured polymer-ceramic-composites with controllable loss is studied further. Four properties are of prime importance: tunability of dielectric constants to achieve miniaturization, flexibility via low temperature processing of polymers and loss controllability.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1541 ◽  
Author(s):  
Yongchang Jiang ◽  
Zhao Zhang ◽  
Zheng Zhou ◽  
Hui Yang ◽  
Qilong Zhang

Polymer dielectric materials are extensively used in electronic devices. To enhance the dielectric constant, ceramic fillers with high dielectric constant have been widely introduced into polymer matrices. However, to obtain high permittivity, a large added amount (>50 vol%) is usually needed. With the aim of improving dielectric properties with low filler content, satellite–core-structured Fe2O3@BaTiO3 (Fe2O3@BT) nanoparticles were fabricated as fillers for a poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix. The interfacial polarization effect is increased by Fe2O3 nanoparticles, and thus, composite permittivity is enhanced. Besides, the satellite–core structure prevents Fe2O3 particles from directly contacting each other, so that the dielectric loss remains relatively low. Typically, with 20 vol% Fe2O3@BT nanoparticle fillers, the permittivity of the composite is 31.7 (1 kHz), nearly 1.8 and 3.0 times that of 20 vol% BT composites and pure polymers, respectively. Nanocomposites also achieve high breakdown strength (>150 KV/mm) and low loss tangent (~0.05). Moreover, the composites exhibited excellent flexibility and maintained good dielectric properties after bending. These results demonstrate that composite films possess broad application prospects in flexible electronics.


Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.


1959 ◽  
Vol 37 (1) ◽  
pp. 173-177 ◽  
Author(s):  
Martin Kilpatrick

The problem of proton mobility has been considered in H2O–CH3OH, H2O–D2O, and H2O–H2O2 solvents from the current viewpoint of the mechanism of proton mobility for aqueous solutions. Mixed solvents are more complicated in that one must consider the relative basicity and acidity of the species competing for the protons. It is concluded that for dilute solutions of HClO4, where water is replaced by hydrogen peroxide, the decrease in equivalent conductance relative to that of KCl in the same solvent mixture is due to the partial elimination of the proton transfer process.For highly acidic non-aqueous solvents of high dielectric constants such as HF, HCN, and HCOOH, the problem of the weakness of the usual "strong" acids of aqueous solution makes a direct determination of the limiting equivalent conductances difficult. In the case of anhydrous hydrogen fluoride the available experimental evidence indicates that the limiting conductance of the lyonium ion is approximately the same as that of the potassium ion but the lyate ion has a higher limiting conductance than other stable anions.The higher proton mobility in ice leads one to expect that hydrogen-bonded systems may be found where the conductivity may approach that of electronic semiconductors.


2021 ◽  
Vol 63 (4) ◽  
pp. 311-316
Author(s):  
Simon Backens ◽  
Jan Siering ◽  
Stefan Schmidt ◽  
Nikolai Glück ◽  
Wilko Flügge

Abstract Lightweight pressure vessels of type IV for hydrogen storage consist of a thermoplastic inner liner, commonly from polyethylene or polyamide. The liner is the permeation barrier against the compressed gas and must prevent the formation of cracks, also after temperature changes, for example after refueling processes. In the present work high-density polyethylene, cross-linked polyethylene, polyamide 6 and polyamide 12 were characterized by tensile tests, single notch impact tests and permeations measurements before and after a cyclic thermal aging process. The aging only lead to slight changes of mechanical properties due to post-crystallization, but to a significant decrease of permeation properties. This decrease was contributed to weakened, amorphous regions where chain splitting occurred. Considerable differences in properties resulted from different peroxide cross-linking times of polyethylene at the same temperature. A longer holding time at 200 °C led to an improvement in impact strength by a factor of more than three. However, the permeation properties decreased by about 50 %, indicating that peroxide cross-linking in the melt inhibited the formation of crystalline regions.


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