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Fundamental understanding of carrier mobility related prebreakdown phenomena in dielectrics provides insights into high field transport phenomena as well as associated aging and onset of charge injection induced instability. A system for measuring resistive current through a dielectric film during a ramp voltage to breakdown has been developed to address the limits of conventional steady-state approaches...
TSD studies have been carried out on cellulose triacetate (CTA), Polystyrene (PS) and their laminated films to study the interfacial phenomena. Only one peak at 80 °C is observed at lower polarising temperature and field while at higher temperature and fields two peaks (at 80 °C and 160 °C) appear, when the negative voltage is applied to CTA (CTA−). The TSC study with CTA+ also gives two peaks at...
The TSD technique has been used to study the α-relaxation in Nylon terpolymer films. A well isolated peak observed at about 60 °C in the TSD spectrum suggests the onset of low frequency molecular motions in the polymer. Experimental results indicate that the induced polarization is due to dipole alingment. TSP experiments give a peak characterized by the same position and height as the TSD peak. T...
Investigation of thermally stimulated charge decay (TSCD) and of short-circuit thermally stimulated currents (TSCs) was undertaken in one-sided vacuum aluminized 25 μm thick polystyrene samples subjected to negative corona charging with corona voltages ranging from 6 to 9 kV at temperatures 40°C and above. Charge stability has been found to increase considerably in samples charged above 70°C# This...
The pyro- and piezoelectric coefficients p3 and d31, respectively, and the remanent polarization P of PVDF films drawn uniaxially and biaxially under different conditions (draw ratio, temperature) were determined in dependence on the −1 poling field up to 430 MVm−1. While the saturation value of the remanent polarization showed no essential changes, the pyro- and piezoelectric coefficients proved...
The effects of thermal stress on the breakdown behavior of biaxially oriented polypropylene (BOPP)-silica nanocomposite thin film and commercial BOPP film was evaluated with a step stress experiment in the temperature range of 50…110 °C. Weak spots were measured in thermally aged unfilled BOPP films but not in the PP-silica, which in turn displayed increasing scatter of the breakdown voltages and...
Low temperature plasma-assisted ALD-grown metal nanocomposite layers based on mixtures of ruthenium and cobalt have been investigated as potential conductive adhesion/barrier layers in thermally restrictive flexible electronics applications. While Ru∶Co metal ratios can be easily adjusted with these processes, initial samples for low thermal budget applications were processed at 200°C with a Ru∶Co...
In the present work, we report the room temperature NH3 sensing properties of Cobalt-boride nanoparticles intercalated polyaniline (Co-B-PANI) nanocomposite films. Polyaniline nanocomposite films (PNCF's) have been deposited at room temperatures by in-situ oxidative polymerization of aniline in the presence of Co-B nanoparticles. The PNCF exhibited a highly selective, sensitive and reversible response...
The use of conducting polymer (CPs) as sensitive material in the development of chemiresistors is investigated for environmental monitoring and clinical diagnostics. Much efforts, in sensor field, are directed to exploit conductive polymer (CPs) properties. A limitation common to all CPs is however the poor selectivity. The objective is therefore to tune the polymer properties to make the sensor selective...
The aim of this work is to understand the role of gamma radiation in trap creation and/or trapping and detrapping space charge mechanisms in isotactic polypropylene (iPP). The measurements are performed on 25 µm thick films: virgin polypropylene and one irradiated with gamma rays at a dose of 100 kGy. The experimental study is focused on measuring final thermostimulated discharge currents. At the...
In this work we are interested with the dynamic behavior and density of PDLCs films (Polymer Dispersed Liquid Crystals).constituted of the microdroplets of nematic liquid crystal E7 dispersed in two types of polymer matrix; Tripropylene glycol diacrylate (TPGDA) or Propoxylene-glyceryl-triacrylate (GPTA). These films are prepared by polymerization induced phases separation by electron-beam (EB) or...
Recently, high thermally conductive polymers have emerged as low cost and energy efficient alternatives to traditional use of metals in heat transfer applications. Here, we present development of ultra-high molecular weight polyethylene (UHMWPE) thin films with high thermal conductivity. The fabrication platform is based on a sol-gel process followed by mechanical drawing. After gel formation and...
In this study, the electric field-assisted alignment of graphene flakes in B-stage graphene-epoxy composite film was demonstrated. Compared with conventional electric field-induced alignment method which involves curing liquid phase polymer matrix, the electric field application on B-stage composite film with controlled viscosity can achieve graphene flake alignment without any curing reactions, thereby...
In this study, water soluble polymers such as poly vinyl alcohol (PVA) and poly vinyl pyrrolidone (PVP) were chosen as the base material for hydrogen storage with the aim of producing recyclable and water-soluble polymer-based hydrogen storage material. Initially, the polymers were acid treated using concentrated hydrochloric acid (conc. HCl) to incorporate Cl ions into the polymeric matrices. Furthermore,...
BaTiO3 (BT) with various diameters were synthesized by alkoxide route and then loaded into different polymers (poly (vinylidene fluoride) (PVDF) and polyimide (PI)) at 50 vol. % to fabricate BT/PVDF and BT/PI nanocomposite films. The effects of nanoparticles and polymer matrixes on dielectric properties were studied in a wide range of frequency from 10−2 Hz to 106 Hz. A significant low-frequency dielectric...
Poly(aryl ether ether ketone) (PEEK) is one of the primary candidates for a high temperature capacitor dielectric as a result of its outstanding mechanical strength and thermal stability. However, its breakdown strength is unsatisfactory (∼400 MV/m) and high field (>100 MV/m) volumetric resistivity at elevated temperature is largely unknown. In this work, the inter-relationship among crystallinity,...
A flexible implantable micro temperature sensor has been proposed and fabricated on a polymer capillary by surface micromachining. The dynamic temperature response of the sensor when used in the hyperthermia is simulated and analyzed. The micro sensor has been successfully fabricated by our developed cylindrical projection lithography system. Platinum film is used as the sensing element material considering...
This paper focuses on the preparation and characterization of hybrid organic-inorganic epoxy systems obtained through the application of a Layer by Layer (LbL) assembly on a UV-cured epoxy coating. To this aim, a mixture 90/10 (wt.%) of 3,4-epoxycyclohexylmethyl-3′,4″-epoxy-cyclo-hexane carboxylate (CE)/diglycidylether-terminated polydi-methyl-siloxane (GTPDMS) was subjected to LbL deposition of 10...
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