Resistivity Ρs Research Articles

Preparation and Characterization of PA6-PEG/Li High Performance Static Dissipation Composites

A copolymer of PA6 (polyamide 6) and PEG (polyethylene glycol) was synthesized by a condensation reaction. The optimal reaction conditions were determined as the following: a reaction temperature of 255°C, –0.04 MPa vacuum, and a condensation time of 40 min. A series of novel PA6-PEG/Li composites were developed by melt blending the PA6-PEG copolymer (10 wt-% PEG) with three different kinds of colourless lithium salts (LiCl, C18H35LiO2, LiAc). FT-IR, NMR, thermogravimetric (TGA), electronic universal testing, and resistivity analyses were employed to investigate the comprehensive properties of the copolymers and composites. The results of FT-IR and 1H NMR analyses revealed that the PEG was copolymerized with PA6 successfully. TGA results indicated that the decomposition temperature of the PA6-PEG copolymer was above 350°C. Resistivity testing revealed that the surface resistivity (Rs) of the copolymer decreased from 1 × 1014 to 5.67 × 109 Ω square–1 with an increase of the content of PEG. The PA6-PEG/LiCl composite showed an excellent static dissipation performance of 2.71 × 108 Ω square–1.

The Effect of the SiC Content on Electrical Properties of SiC Anti-Corona Coating for Generator

In this research, the anti-corona lacquer with different SiC content was fabricated. The surface resistivity of the lacquer at different voltage levels was measured, and the effect of the SiC content on electrical properties of SiC anti-corona coating was investigated. The results showed that the initial surface resistivity ρs decreased with increasing mass ratio of SiC to resin, while the non-linear coefficient β varied the opposite way. The surface resistivity was improved by adding suitable amount of graphite, which suited the requirements of multiple sections anti-corona structure.

Preparation and characterization of composite coatings containing a quaternary ammonium salt as an anti-static agent

Abstract The main aim of the present study is to manufacture antistatic sheets with high transparency and high electrical conductivity by dip coating. Here, we used coating solutions consisting of a quaternary ammonium salt, a urethane acrylate oligomer, a photoinitiator, and a mixture of solvents which contains a water-soluble high boiling solvent of monobutyl glycol ether, 2-butoxyethanol. The coating solutions were deposited on polymethyl methacrylate (PMMA) substrates, which were subjected to a two-step drying process at 23 °C and at 60 °C, and subsequently cured by ultraviolet radiation. We have examined the effect of the concentration of the water-soluble monobutyl glycol ether, relative humidity (RH) at the first step, and drying time on the electrical conductivity, contact angle, and optical transmittance and haze of the coated layers. The surface electrical resistivity (ρs) monotonically decreased with the concentration of the monobutyl glycol ether, RH, and drying time. The water contact angle of the surface of the coated layers increased with decrease in ρs. These results strongly suggest a migration and fixation of the quaternary ammonium salt at the air/layer interface during the drying process. The coated PMMA sheet prepared under the optimal condition showed fairly good performance in terms of the optical and electrical properties.

Prepatation and characterization of poly(ether-block-amide)/metal-salt antistatic composites

ABSTRACTPolyether diol and end-capped diisocyanates were first employed in a step-growth addition polymerization with amidogen terminated Polyamide-6 to synthesis segmented poly(ether-block-amide) (APEBA) with organized molecular chain structure. Colorless salts were mixed with the copolymers to develop solid polymer electrolyte (SPE). Chemical structures of composites were characterized by infrared-spectroscopic analysis (FTIR). Thermal behaviors were studied by differential scanning calorimetery (DSC) and thermo gravimetric analyzer (TGA). The APEBA elastomer showed excellent antistatic properties in decreasing the surface resistivity (Rs), which decreased to 107.78Ω cm−2 when the doping-salt content approaches 2.5 phr. Also, Rs exhibits humidity-independency and enduring-existence.

Shape memory-based tunable resistivity of polymer composites

A conductive composite in bi-layer structure was fabricated by embedding hybrid nanofillers, namely carbon nanotubes (CNTs) and silver nanoparticles (AgNPs), into a shape memory polyurethane (SMPU). The CNT/AgNP-SMPU composites exhibited a novel tunable conductivity which could be facially tailored in wide range via the compositions or a specifically designed thermo-mechanical shape memory programming. The morphologies of the conductive fillers and the composites were investigated by scanning electron microscope (SEM). The mechanical and thermal measurements were performed by tensile tests and differential scanning calorimetry (DSC). By virtue of a specifically explored shape memory programming, the composites were stretched and fixed into different temporary states. The electrical resistivity (Rs) varied accordingly, which was able to be stabilized along with the shape fixing. Theoretical prediction based upon the tunneling model was performed. The Rs–strain curves of the composites with different compositions were well fitted. Furthermore, the relative resistivity and the Gauge factor along with the elongation were calculated. The influence of the compositions on the strain-dependent Rs was disclosed. The findings provided a new avenue to tailor the conductivity of the polymeric nano-composites by combining the composition method and a thermo-mechanical programming, which may greatly benefit the application of intelligent polymers in flexible electronics and sensors fields.

Effects of magnesium chloride polluted soils on underground Q235 steel pipelines

Abstract This paper discusses the effects of soils polluted with different magnesium chloride (MgCl2) contents on the corrosion of Q235 low-carbon steel pipelines. The material has a yield strength of 235 MPa. The following major parameters were considered in the experimental study to analyze MgCl2 polluted soils: degree of saturation Sr, electrical resistivity ρs, oxidation reduction potential Eh7 and corrosion potential Ecorr. The corrosion properties of Q235 steel samples buried in soils, such as corrosion behavior of macrographs and scanning electronic microscopy (SEM) photos, chemical elements components of corrosive products by energy dispersive spectrometer (EDS), corrosion weight loss mcor, corrosion rate vcor, and dynamic equation of mcor, were studied in detail. Based on the statistical analysis results obtained from this study, MgCl2 has a significant impact on ρs, while MgCl2 has lesser effects on other parameters. Corrosion macro and micro behaviors of Q235 steel were revealed. The vcor of Q235 steel decreases with the increase of corrosion time (t), while it increases with MgCl2 contents. The dynamic equation for mcor and the pollution impact factor β for Q235 steel in MgCl2 polluted soils are proposed. Lastly, a developed multi-linear regression equation for vcor is recommended.

Nanostructured V2O5 thin films deposited at low sputtering power

Vanadium pentoxide (V2O5) films were deposited on cleaned silicon (Si) and glass substrates by reactive dc magnetron sputtering at different sputtering powers (50–70W) at room temperature (RT). Microstructural, morphological, topological, optical and electrical properties of the films were studied by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), atomic force microscopy (AFM), UV–vis spectroscopy and four point probe method (FPP) respectively to analyze the impact of the sputtering power on the properties of V2O5 films. The average grain size of the films increased from 77 to 90nm on increasing the sputtering power and also all the deposited films showed characteristic peaks in the range 920–970cm−1 in Fourier transform infrared spectroscopy (FT-IR) spectrum corresponding to the V2O5. The optical bandgap and electrical resistivity of the films were found to be decreased while increasing the sputtering power. Four probe electrical resistivity measurements show the typical semiconductor behavior of the deposited film. The film deposited at 70W sputtering power at RT exhibited a temperature coefficient of resistance (TCR) of −1.22%/°C and resistivity (Rs) of 22Ωm. The low sputtering power used and room temperature deposition of the V2O5 films in the present investigation is suitable for complementary metal oxide semiconductor (CMOS) fabrication.

Antistatic effects of ionic liquids for polyether-based polyurethanes

Mobility of component anions of ionic liquids (ILs) was found to be a most effective factor to enhance antistatic properties of polyether-based polyurethanes (PUs). Then, the antistatic effects were discussed with Kamlet-Taft parameters (hydrogen bond acidity: α and basicity: β) of the added ILs. A strong correlation was found between β value and surface resistivity (Rs) of the PUs containing the ILs. On the contrary, α value was found to have a weak influence on the Rs. Since there was a weaker interaction between polyether chains and anions than cations, antistatic effects of the ILs were weaken by fixing the component anions into the PUs. This strongly suggests that effective antistatic effects are supported by the anion migration of ILs.

The Quantitative Description of Tight Sand Reservoir Fracture in Sulige Gas Field

The Sulige gas field is a typical tight sand reservoir, Ordos Basin, the fracture development degree directly affects the development of the natural gas, especially affects the volume fracturing effect of horizontal well and the deliverability of the natural gas, the appropriate method to describe the fracture is very important. At present, outcrop, core and FIM are general methods to describe the fracture development degree, but they have inherent shortages. In the Sulige gas field, a few of cores and poor representativeness can not illustrate the fracture distribution in well bore, and imaging logging data are especially absent. Su53 gas field was used as an example in the Sulige gas field, during the research of the fracture, based on fractal theory, through using the amplitude difference data between deep investigate double lateral resistivity (Rd) and shallow investigate double lateral resistivity (Rs), and other conventional logging data, in combination with the response characteristics of fracture in the logging curve, reservoir fracture was quantitatively identified by the analysis method of R / S , the relationship between fractal dimension value and fracture density was quantitatively analyzed , the vertical heterogeneity of fracture distribution was analyzed, and the relationship between fractal dimension value of fracture and initial deliverability of gas well was researched. The results which were tested by the data of drilling cores and productions available, indicate that the method of R / S is feasible to quantitatively describe the fracture development degree; the relationship between fractal dimension value and fracture density is positively relative, fractal dimension value is bigger, the fracture is more developed; there is a good corresponding relationship between fractal dimension value and deliverability of gas well, fractal dimension value decreases with a decrease of deliverability. Key words: Fractal; R / S analysis; Logging curve; Tight sand reservoir fracture; Fracture description

Quantitative Identification of Reservoir Fracture with the Variable Scale Fractal Technique in Su53 Gas Field, Ordos Basin

Typical tight gas reservoirs in the Su53 Gas Field, Ordos Basin, are the demonstration region for deploying horizontal wells. In order to provide foundation for evaluating the volume fracturing adaptability of horizontal wells, through using the amplitude difference data between deep investigate double lateral resistivity (Rd) and shallow investigate double lateral resistivity (Rs), and other conventional logging data, in combination with the response characteristics of fracture in the logging curve, reservoir fracture was quantitatively identified with the variable scale fractal technique, the vertical heterogeneity of fracture distribution was analyzed, and the relationship between fractal dimension value of fracture and initial deliverability of gas well was researched. The results indicate that, this method is applied to quantitatively identify and evaluate the fracture development degree of single-well is feasible; the relationship between fractal dimension value and fracture development degree is positively relative, fractal dimension value is bigger, the fracture is more developed; there is a good corresponding relationship between fractal dimension value and deliverability of gas well, fractal dimension value decreases with a decrease of deliverability.

Fixation of ionic liquids into polyether-based polyurethane films to maintain long-term antistatic properties

Ionic liquids (ILs) were fixed into polyether-based polyurethane (PU) films for sustainable antistatic properties. Preliminarily, ILs were screened in terms of efficiency of antistatic effect. Surface resistivity (ρs) for IL-doped PU films changed depending the anion species, and the smallest ρs was found for the PU films containing bis(trifluoromethanesulfonyl)imide ([Tf2N])-type ILs. Then, [Tf2N]-type ILs composed of ammonium cations having hydroxyl groups were fixed into the PUs through urethane bonds. The fixation of 1000 ppm of the ILs reduced the ρs of the PU films from 2.1 × 1012 to 2.1 × 109 Ω sq−1. These IL-fixed PU films were revealed to possess high washing durability confirmed by negligible change of ρs before and after ultra-sonication treatment in methanol.

Bis(trifluoromethanesulfonyl)imide-Type Ionic Liquids as Excellent Antistatic Agents for Polyurethanes

Surface resistivity (ρs) of polyurethane (PU) films is reduced from 2.1 × 1012 to 9.4 × 1010 ohm sq−1 by addition of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][Tf2N]) for only 10 ppm. Addition of [Tf2N]-type ionic liquids (ILs) for 1 000 ppm leads to the reduction of not only ρs from 1012 to 109 ohm sq−1 but also volume resistivity (ρv) from 109 to 107 ohm cm, suggesting that the ILs are uniformly incorporated into the PU films. These PU films have ρs in the order of 109 ohm sq−1 even after methanol washing. The antistatic effects are attributed to ionic conductivity of the PU films, which is achieved by low glass transition temperatures of both PU films and [Tf2N]-type ILs. These results suggest that [Tf2N]-type ILs are excellent antistatic agents for PUs.

Structure and Magnetic Properties Investigation of CoZr and CoZrN Thin Films

nanocomposite [(Co91.5Zr8.5)- or CZN films has been prepared by reactive co-sputter deposition method. Nitrogen content plays key role to tune soft magnetic properties. Experimental observation shows that, non-magnetic nitrogen content enhances magnetization and reduces coercivity. The nanostructure is composed of Co nanoclusters embedded in CoN/ZrN matrix, revealed by high resolution transmission electron microscope study. The d-spacing of single Co nanocluster was found to be ~0.22nm corresponding to (002) phase of Cobalt. X-ray diffraction result is in agreement with cubic (400) and (622) phase of CoZr. High electrical resistivity ρs~108μΩ-cm attained corresponding to 16% N2content films. Hysteresis loop squareness depends on film thickness and coercivity squareness (S*)~0.84, obtained for ~250nm film thickness. A correlated composite nanostructure evolution is responsible for nitrogen induced magnetization and, suggests that film properties can tuned by controlling nitrogen content, in CoN/ZrN composite matrix.

Delineating shallow saline groundwater zones from Southern India using geophysical indicators

A geophysical survey was conducted over an industrial belt encompassing 80 functional leather factories in Southern India. These factories discharge untreated effluents which pollute shallow groundwater where electrical conductivity (EC) value had a wide range between 545 and 26,600 μS/cm (mean, 3, 901 μS/cm). The ranges of Na(+) and Cl(-) ions were from 46 to 4,850 mg/L (mean, 348 mg/L) and 25 to 10,390 mg/L (mean, 1,079 mg/L), respectively. Geoelectrical layer parameters of 37 vertical electrical soundings were analyzed to demarcate fresh and saline water zones. However, the analysis not did lead to a unique resolution of saline and fresh waters. It was difficult to assign a definitive value to the aquifer resistivity of any area. Thus, geophysical indicators, namely longitudinal unit conductance (S), transverse unit resistance (T), and average longitudinal resistivity (Rs), were calculated for identifying fresh and saline waters. Spatial distributions of S, T, and R s reflected widely varying ranges for the saline and fresh water zones. Further, the empirical relation of formation factor (F) was established from pore-water resistivity and aquifer resistivity for fresh and saline aquifers, which may be used to estimate local EC values from the aquifer resistivity, where well water is not available.

Preparation of antistatic and antimicrobial polyethylene by incorporating of comb-like ionenes

The comb-like ionenes with aliphatic side chains were prepared and blended with a low density polyethylene (LDPE) for enhancing the antistatic and antimicrobial properties. The resulting blends were well characterized, particularly based on the surface resistivity (ρs) which revealed the antistatic properties of LDPE/ionene blends. The results showed that the values of ρs decreased 1–5 orders of magnitude after the ionenes were added. Various influencing factors on ρs, including ionene structures, ionene content, and humidity were investigated in detail. Furthermore, the surface and inner structures of resulting blends were characterized by ATR-FTIR and SEM along with water contact angle measurements. The antimicrobial activities of the ionenes and the blended sheets were assessed based on the minimal inhibitory concentration (MIC) values against E. coli and the growth inhibition of E. coli determined by means of a membrane adhering-colony counting method. The results indicated that the ionene with 4-carbon side chains had the lowest MIC value (7.8 μg/mL) and the corresponding blend reached 99.9 % of growth inhibition.

Curing kinetics, thermal, mechanical, and dielectric properties based on o‐cresol formaldehyde epoxy resin with polyhedral oligomeric (N‐aminoethyl‐γ‐amino propyl)silsesquioxane

The curing reaction and kinetics of o‐cresol formaldehyde epoxy resin (o‐CFER) with polyhedral oligomeric silsesquioxane of N‐aminoethyl‐γ‐amino propyl group (AEAP‐POSS) were investigated by differential scanning calorimetry (DSC). The thermal, mechanical, and dielectric properties of o‐CFER/AEAP‐POSS nanocomposites were investigated with thermogravimetric analysis (TGA), torsional braid analysis (TBA), tensile tester, impact tester, and electric analyzer, respectively. The results show that the activation energy (E) of curing reaction is 58.08 kJ/mol, and the curing reaction well followed the Šesták‐Berggren (S‐B) autocatalytic model. The glass transition temperature (Tg) increases with the increase in AEAP‐POSS content, and reaches the maximum, 107°C, when the molar ratio (Ns) of amino group to epoxy group is 0.5. The nanocomposites containing a higher percentage of AEAP‐POSS exhibited a higher thermostability. The AEAP‐POSS can effectively increase the mechanical properties of epoxy resin, and the tensile and impact strengths are 2.84 MPa and 143.25 kJ m−2, respectively, when Ns is 0.5. The dielectric constant (ε), dielectric loss factor (tan δ), volume resistivity (ρv), and surface resistivity (ρs) are 4.98, 3.11 × 10−4, 3.17 × 1012 Ω cm3, and 1.41 × 1012 Ω cm2, respectively, similarly at Ns 0.5. Copyright © 2009 John Wiley & Sons, Ltd.

Conductive layers in diamond formed by hydrogen ion implantation and annealing

High conductivity is extremely difficult to obtain in diamond due to its wide band gap and low solubility of dopands. The goal of the investigation was to form a conductor inside HPHT synthetic diamond plates with initial high sheet resistivity ρs (∼1012Ω/sq) for 400μm thickness. We used metastable character of diamond structures relative to the graphitization of defective layers formed by 50keV hydrogen molecular ions at high fluence Φ=(1−13)×1016cm−2 ion implantation. High temperature (HT) (500–1600°C) and vacuum or high pressure (VP/HP) (3×10−3/4×109Pa) thermal annealing were chosen to provide the annealing regimes where the graphitic carbon is the most stable phase. Sheet resistance, dropped down up to nine orders of magnitude (ρs∼103Ω/sq), as well as Raman spectroscopy, and AFM measurements were used to determine electrical, optical and geometrical properties of multilayered heterostructures formed in the set of experiments. Temperature dependences of the conductivity show, that after highest fluencies and annealing temperatures the conductivity is quasimetallic and electronic system is above metal–insulator transition (MIT). At lower fluences and/or annealing temperatures the system is under MIT with the transport of charge carriers being well described by variable range hopping (VRH) mechanism with variable decay length of wave function for localized states. Two or three order of magnitude differences in the conductivity in VP and HP annealed samples are attributed with the higher dimensions of graphite nanocrystals in the case of vacuum annealing. This suggestion coincides with Raman spectra and optimum hopping length for carrier jumps in VRH model for conductivity in the buried layers.

Annealing Temperature Effects on ${\rm YBCO/LaAlO}_{3}$ and ${\rm YBCO/CeO}_{2}/{\rm Al}_{2}{\rm O}_{3}$ for Microwave Applications by TFA-MOD

YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7-x</sub> (YBCO) superconducting films can be used for microwave applications due to their low surface resistance. Both LaAlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can be considered as applicable substrates since their excellent properties for the preparation of high-quality YBCO films and for the design of microwave elements. In order to optimize the annealing temperature, the microstructure and properties were investigated for YBCO/LaAlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and YBCO/CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /r-cut Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> films prepared by trifluoroacetates metal organic deposition (TFA-MOD). The results show that the annealing temperature window is broader for YBCO films on LaAlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> substrates; while, the window is relative narrower for YBCO films on CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> substrates. The reasons were also discussed. The surface resistivity (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ) was measured for the samples with highest critical current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ). The results will provide useful information about processing effects on YBCO films using TFA-MOD for microwave applications.

Post-heat-treated spin-spray plated MnxZnyFe3−x−yO4 films exhibiting high resistivity and noise suppressing properties

Mn x Zn y Fe 3 − x − y O 4 films with a tailored microstructure were prepared by the spin-spray technique. The films were then heat treated (260°C for 3min) in a similar way to that of the reflow soldering process. The as-prepared and heat-treated films were studied for their structural, electrical, and magnetic properties. By using an oxidizing solution of CH3COONa+(NH4)2CO3+NaOH+NaNO2 (in contrast to that of CH3COONa+NaNO2 in the conventional spin spray), Mn concentration (CMn) in the film was increased and a narrow columnar structure was obtained. This structure resulted in an increased surface resistivity (ρs), thereby good noise suppressing properties even after the heat treatment. The films exhibited a high deposition rate of up to 63nm∕min with a good adhesion to the substrate. A slight decrease in the saturation magnetization (Ms) and increase in the uniaxial anisotropy field (Hk), and coercivity (Hc) were observed due to the heat treatment. The films also exhibited a decrease in imaginary permeability in the lower frequencies and the resonance frequency (fr) shifted to a higher frequency range. The film characteristics were as follows: Ms of 450–570emu∕cm3, Hc of 18–45Oe, Hk of 43–86Oe, ρs of 103–107Ω∕sq, initial permeability μ′ of 25–60, imaginary permeability μ″ of 20–38, and resonance frequency fr of 530–750MHz. The films prepared at optimum condition exhibited reflection loss (S11) less than −10dB and the transmission loss (ΔPloss) of up to 50% at 10GHz. ΔPloss exhibited uniform distribution up to 1GHz even after the heat treatment.

Annealing characteristics of electrically isolated InGaAsP devices

The authors report on the effects of fluorine implants on the sheet resistivity of n-type InGaAsP layers grown lattice matched to InP by metal organic molecular beam epitaxy. Projected range matched fluorine ions are implanted at multiple energies and single MeV energy at room temperature (RT) and 77K in both cases. Hall and resistivity measurements are carried out for the van der Pauw samples and the evolution of sheet resistivity (Rs) as a function of annealing temperature was studied in both cases. Fluorine multienergy implantation at 77K produces higher as-implanted resistivity layers of ∼107Ω∕◻ compared to RT implants. It is further observed that RT and 77K implants recover to their preimplanted sheet resistivity values as soon as they are annealed at temperatures higher than 500°C. Substrate temperature and collision cascade density due to multiple energy implants are found to play an important role to optimize the isolation process.