Fabrication of conductive paper coated with PEDOT: preparation and characterization

Conductive polymers have been studied extensively because of their attractive physical properties, such as conductivity, luminescent performance, and dielectric property. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most employed conductive polymers for applications, such as a buffer layer of organic electroluminescent devices, due to its high conductivity and electrical stability. In this study, we fabricated a conductive paper coated with PEDOT by direct polymerization onto a paper sheet. The conductive paper exhibited the electrical conductivity of 1.8?S/cm. Scanning electron microscopy images of the conductive paper showed two structures: thin polymer membranes attached to cellulose fibers at the surfaces, and thick polymer sheets extended through the void spaces between the fibers in the inner layers. Consequently, strong interactions between the PEDOT and the cellulose fibers enhanced mechanical properties of the conductive paper. Electron probe X-ray microanalysis (EPMA) revealed distribution elemental maps of carbon, oxygen, sulfur, chlorine, and iron on the conductive paper.     

Effect of glycerol on electrical conducting of chitosan/polyaniline blends

Chitosan (Cs) and polyaniline (PANI) were studied in this article for possible application as conductive and flexible films. Cs is a biodegradable polymer, that presents interesting properties as film applications. Otherwise, PANI is a semiconductor polymer with a wide range of applications. The films were produced by casting adding 30% glycerol and glutaraldehyde. The morphology, thermally, chemical structure, and electrical properties of films were obtained. Results showed the casting technique becomes possible to obtain self-standing films, with a chemical structure identical to precursor materials. Glutaraldehyde reacted to amine groups of terminal PANI chains, acting in the increase of electric conductivity and decrease of sheet resistance. The plasticizing effect of glycerol increased the spacing between Cs chains and facilitated the PANI dispersion. Therefore, glycerol and glutaraldehyde proved to be extremely efficient in increasing the electrical conductivity of blends.     

Piezoresistive effect in spin-coated polyaniline thin films

Polymeric materials have been replacing other materials in various applications, from structural to electronic components. In particular, since the discovery of conducting polymers, the use of these materials is growing up in the manufacture of electronic components, such as organic light-emitting diodes, organic electrodes, energy storage devices and artificial muscles, among others. On the other hand, examples of sensors of conductive polymers based on the piezoresistive effect, with large potential for applications, are not sufficiently investigated. This work reports on the piezoresistive effect of an intrinsically conductive polymer, polyaniline, which was prepared in the form of thin films by spin coating on polyethylene terephthalate substrates. The relationship between electrical response and mechanical solicitations is presented for different preparation conditions. The values of the gauge factor ranges from 10 to 22 for different samples and demonstrates the viability of these materials as piezoresistive sensors.     

Development of Conductivity of Acrylic Polymer Using Ionic Liquids Incorporated with Zinc Oxide Nanoparticles

In this study, we synthesized antistatic and ultraviolet-resistant acrylic films with a combination of ionic liquids and ZnO nanoparticles for the prevention of static electricity and ultraviolet instability. ZnO and two different ionic liquids such as 1-ethyl-2,3-dimethylimidazolium ethyl sulfate and methyl-tri-n-butylammonium methylsulfate were preferred to achieve conductive and ultraviolet-resistant acrylic films. To obtain the highest ultraviolet protection factor and the lowest surface resistivity for the acrylic film, the combined effect of ZnO nanoparticles and the ionic liquids was utilized. The surface resistivity, thermal conductivity and effusivity, thermogravimetric analysis, and ultraviolet resistivity of the films were investigated. Surface morphology of the films and distribution of ZnO were also observed by scanning electron microscopy. The acrylic polymer exhibits higher ultraviolet resistance and lower transmission even in the low content of ZnO nanoparticles as compared with the neat polymer. The film consisting of methyl-tri-n-butylammonium methylsulfate ionic liquid showed the highest electrical conductivity performance even after 150 days. Consequently, ZnO nanoparticles are determined to be influential on ultraviolet-resistant properties, whereas ionic liquids are efficient on electrical conductivity performance of the acrylic polymer.     

橡胶/碳纤维层压复合导电发热板的电学性能研究

研究了橡胶／碳纤维层压复合导电面状发热板的电学性能。结果表明,硫化过程对导电发热板的电阻有直接影响,不同规格导电发热板的电阻下降率不同;导电发热板具有较发的热循环稳定性,数次热循环后,室温电阻可保持恒定;其伏－安特性、表面温度－功率密度均呈现良好的线性关系;在长期通电使用下,能保持其功率的稳定性。     

Conducting property of carbon black filled poly(ethylene glycol)/poly(methyl methacrylate) composites as gas‐sensing materials

To reveal the role of crystalline polymers in carbon black (CB) filled amorphous polymer composites and improve the mechanical properties of composite films, CB/poly(ethylene glycol) (PEG)/poly(methyl methacrylate) (PMMA) composites were synthesized by polymerization filling in this work. The electrical conductive property and response to organic solvent vapors of the composites were investigated. The composites, characterized by a relatively low percolation threshold (～ 2.1 wt %), had lower resistivity than CB/PMMA composites prepared with the same method because of the different dispersion status of CB particles in the matrix polymer. The concentration and molecular weight of PEG notably influenced the electrical response of the composites against organic vapors. The drastic increase in the electrical resistance of the composites in various organic vapors could be attributed mainly to the swelling of the amorphous polymer matrix in the solvent but not to that of the crystalline polymer. These findings could help us to understand the conductive mechanism and electrical response mechanism of the composites as promising gas‐sensing materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Electroconductive Adhesives: Comparison of Three Different Polymer Matrices. Epoxy, Polyimide and Silicone

Electrically conductive organic adhesives are used in the microelectronics manufacturing industry for the attachment of silicon dies. These adhesives are composite materials which owe their conductivity to the incorporation of silver flakes. Several polymers have been formulated into electrically-conductive adhesives to meet different applications in the microelectronics industry; these are an epoxy resin, a polyimide and a silicone polymer. The purpose of this paper is to examine properties of these die-bonding adhesives in order to determine the advantages or disadvantages of these materials. This study offers a comparison of hardening chemistry, chemical purity, processing, electrical, thermal, and mechanical properties of three conductive adhesives based on an epoxy, a polyimide and a silicone polymer. We discuss correlation of composite properties with the structure of each matrix. The results indicate that the choice of the matrix is dictated by the application for which the electronic grade conductive adhesive is to be used and the desired properties for best reliability and performance.     

Electroconductive Adhesives: Comparison of Three Different Polymer Matrices. Epoxy,Polyimide and Silicone

Electrically conductive organic adhesives are used in the microelectronics manufacturing industry for the attachment of silicon dies. These adhesives are composite materials which owe their conductivity to the incorporation of silver flakes. Several polymers have been formulated into electrically-conductive adhesives to meet different applications in the microelectronics industry; these are an epoxy resin, a polyimide and a silicone polymer. The purpose of this paper is to examine properties of these die-bonding adhesives in order to determine the advantages or disadvantages of these materials. This study offers a comparison of hardening chemistry, chemical purity, processing, electrical, thermal, and mechanical properties of three conductive adhesives based on an epoxy, a polyimide and a silicone polymer. We discuss correlation of composite properties with the structure of each matrix. The results indicate that the choice of the matrix is dictated by the application for which the electronic grade conductive adhesive is to be used and the desired properties for best reliability and performance.     

Room temperature sputtering deposition of high-haze Ga-doped ZnO transparent conductive thin films on self-textured bio-based poly(ethylene 2, 5-furandicarboxylate) substrates

In this work, bio-based poly(ethylene 2,5-furandicarboxylate) (PEF) films were prepared by drop-casting method and used as substrates for depositing Ga-doped ZnO (GZO) transparent conductive thin films. Results showed that the 300-nm GZO thin films deposited on PEF substrates exhibited haze values above 65% at 550 nm without post-treatment. The high haze value was because of the large surface roughness of PEF films. The total optical transmittance and electrical properties of GZO thin films on PEF were comparable to those of GZO thin films on PET. The present study provides a simple way for the sputtering deposition of high-haze transparent conductive thin films on flexible substrates.     

不同衬底上ZnO:Al透明导电薄膜的性能

室温下,采用射频磁控溅射法在玻璃和聚对苯二甲酸乙二醇酯（polyethylene terephthalate,PET）上沉积了掺铝的氧化锌（ZnO：Al,AZO）透明导电薄膜。通过X射线衍射仪分析不同衬底上AZO薄膜的结构,采用四探针测试仪及紫外可见光分光光度计测试薄膜的光电性能。结果表明：沉积在两种衬底上的AZO薄膜都具有六方纤锌矿结构,最佳取向均为[002]方向;玻璃衬底和PET衬底上制备的AZO薄膜的方阻分别为19/sq和45/sq,薄膜透光率均高于90%。实验表明,柔性衬底透明导电氧化物薄膜可以代替硬质衬底透明导电薄膜使电子器件向小型化、轻便化方向发展。     

Semiconductor–Metal Transition in Poly(3,4‐Ethylenedioxythiophene): Poly(Styrenesulfonate) and its Electrical Conductivity While Being Stretched

Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film was prepared from an aqueous dispersion of the polymer treated with 5 wt% dimethylsulfoxide (DMSO) on a glass substrate and was electronically characterized in order to study its electronic properties. The electrical resistance of the polymer film was measured over the temperature range (380–10 K) using four‐point probe technique. It was noticed that the electrical resistance followed three different trends each of which was indicative of a different charge carrier transport mechanism. Each mechanism was investigated in more detail. A semiconductor to metal transition was also observed at 292 K above which dR/dT had a positive slope. Furthermore, Hall effect, electrical conductivity and sheet resistance measurements were performed on the polymer film using van der Pauw technique. The metallic behavior of PEDOT:PSS at room temperature was further evidenced by the results of these measurements. Next, stretchable knitted fabric was coated with PEDOT:PSS prepared from the polymer dispersion treated with 5 wt% DMSO. The conductive fabric was then stretched axially to different amounts of strain and was electrically characterized in both relaxed and stretched states. Despite the constant decrease in its electrical conductivity, the fabric remained electrically conductive while being stretched under increasing applied strain. POLYM. ENG. SCI., 59:1051–1056, 2019. © 2019 Society of Plastics Engineers     

Scalable,solvent-less de-bundling of single-wall carbon nanotube into elastomers for high conductive functionality

Composite fabrication techniques predominantly involve wet-synthetic protocols with organic solvents. While the resulting composite exhibits good electrical properties, their mass-production have been severely hindered due to use of excessive organic solvents. In contrast, dry-compounding methods are well-suited for industrialization but result in composites with lower electrical properties. This mutually exclusivity between (a) the fabrication process, (b) the composite properties and (c) the industrial scalability has been a major road-block for their commercialization. Addressing this obstacle, we report an electrically conductive polymer composite with long single-wall carbon nanotubes (SWCNT) as conductive fillers. The SWCNT/polymer composite possesses superior electrical properties to those achieved previously with other fillers or CNTs, obtained through dry-processes. The method involved efficient loosening of long SWCNT bundles through a biaxial shear force and subsequent kneading into the rubber matrix. The structural damage to SWCNTs was thereby minimized, as indicated by Raman spectroscopy and optical microscopy. Consequently, we achieved a SWCNT/polymer composite exhibiting ∼200 fold higher electrical conductivity than composite materials made by conventional dry-compounding methods. Finally, we demonstrate the industrial scalability of the process through the continuous, batch-production of the SWCNT-polyurethane composite sheet (12 m long and 60 mm wide) with uniform electrical conductivity (1.5 S/cm).     

Dielectric and Mechanical Behavior of Treated Paper Sheet

Abstract

The dielectric properties of different polymers, polymethyl methacrylate. polystyrene, mixture of them (1:1) and polyvinyl alcohol films were studied. Also, the dielectric and mechanical properties were measured to study the intermolecular interactions of paper sheet impregnated in the different polymers under investigation. The retained polymer on dipped paper sheet is lowest in case of mixed polymer solutions than that of each polymer solution alone. The retained polymer on paper sheet from aqueous polymer solution is lower than that dipped in organic solvent polymer solutions. The mixture of 1:1 PS and PMMA has a higher permittivity than that of each of both polymer alone. The treatment of paper sheet with polymer solutions improved their dielectric and mechanical properties, whereas the mixture of PS and PMMA is the best one for improving treated paper sheet.     

Studies on surface properties of polymeric coated paper material

Surface properties of a polymeric coating system have a strong influence on its performance and service life. However, the surface of a polymer coating may have different chemical, physical, and mechanical properties from the bulk. Significant progress has been made during the last three decades in the improvement of coating on materials. It has been established that polymeric blends have great potential in replacing economically many conventional materials because of their high specific strength. It is needed today, constantly, to improve the surface finish of any material for efficiency and shiny appearance in the severity of working environment. In packaging, materials having longer service lives and those are less corrosive are highly used. The effect of polymer based coating on the paper material improves its mechanical properties and flame resistance. Effect of flame retardant polymer coating illuminates the surface of the sheet. Important application of the material sheets will be for corrosion receptivity and humidity resistance of this material will certainly improve. Blends of PMM/PVDF are mainly used to improve piezoelectric properties of PVDF. In the present study we report the measurement of surface properties of thin layer of polymer blend coated on the cardboard sheet substrate material. Polymer blend solutions of PMMA/PVDF was prepared at 90/10 (w/w) proportions in miscible solvent of toluene and DMF. Thin film was prepared on the surface of cardboard by dipping the cardboard material in the solution. Thickness of the dried polymer coated paper sheet was measured to see uniformity of coating and for different concentrations. Surface properties such as flexibility index, yellowness, and gloss reflectance were also measured. The study on these polymer coated paper will help in improving the surface property of paper as well as its use in packaging. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4167–4171, 2006     

Deposition of conductive polythiophene film on a piezoelectric substrate: effect of corona poling and nano-inclusions

Electrically conductive polythiophene (PTh) nanoparticles were deposited on poly(vinylidene fluoride) (PVDF) substrate by a facile and rapid chemical oxidative deposition in an organic solvent system. The process afforded conductivity to a piezoelectric PVDF film through deposition of conductive layer on the surface in 12 min. The produced final product was transparent, flexible, conductive and piezoelectric and a good candidate to be used in organic electronics especially as a sensor and capacitor. The effect of corona poling and inclusion of nanoparticles such as nanoclay and carbon nanotubes on electrical conductivity of piezoelectric substrates were studied with high precision. Corona poling modification of substrate made it susceptible for deposition of nanoparticles on surface and meanwhile induced higher orientation and crystallinity which led to higher capacitance. Electrical conductivity of the modified films, without extra doping, was in the order of 10^?2 S/cm. Capacitance of the films was measured and the results were promising applications in flexible electronics. Surface morphology, average size, size distribution and samples surface roughness were measured by scanning electron microscopy and atomic force microscopy. It was observed that PTh surface morphology is an aggregation of globules with narrow size distribution ranging from 20 to 100 nm. EDX Technique was used to study the surface composition. The final product may find very promising applications in a wide range of organic electronics.     

Gravure printing of conductive particulate polymer inks on flexible substrates

A roto-gravure printing technique has been developed for conductive lines on paper and plastic films. Rotary-screen-printing was used to make comparative prints. The inks contained metal particles in an organic medium and were cured in temperatures of 70–120 °C, limited by the substrate durability. The following conductor line properties were characterised for different substrates: resistance, yield as a function of line width, coil inductance, folding endurance, adhesion, printed antenna properties and maximum current density. A printed resistance down to 50 mΩ/□ was obtained, with conductor lines 4–7 μm thick. Minimum line resolution and resistance were affected by smoothness of substrates. Adhesion properties were adequate for the studied components.     

Charge transport mechanisms and memory effects in amorphous TaNx thin films

Amorphous semiconducting materials have unique electrical properties that may be beneficial in nanoelectronics, such as low leakage current, charge memory effects, and hysteresis functionality. However, electrical characteristics between different or neighboring regions in the same amorphous nanostructure may differ greatly. In this work, the bulk and surface local charge carrier transport properties of a-TaN_x amorphous thin films deposited in two different substrates are investigated by conductive atomic force microscopy. The nitride films are grown either on Au (100) or Si [100] substrates by pulsed laser deposition at 157 nm in nitrogen environment. For the a-TaN_x films deposited on Au, it is found that they display a negligible leakage current until a high bias voltage is reached. On the contrary, a much lower threshold voltage for the leakage current and a lower total resistance is observed for the a-TaN_x film deposited on the Si substrate. Furthermore, I-V characteristics of the a-TaN_x film deposited on Au show significant hysteresis effects for both polarities of bias voltage, while for the film deposited on Si hysteresis, effects appear only for positive bias voltage, suggesting that with the usage of the appropriate substrate, the a-TaN_x nanodomains may have potential use as charge memory devices.     

Thin Ag films adhesive onto flexible substrates with excellent properties for multi-application

Here, thin Ag films with excellent properties were successfully prepared on flexible substrates through surface grafting and assembling followed by simple spray-assisted deposition process. The constructed molecule brushes provide the interfacial adhesion for Ag layers onto polymer substrates. The mechanical and electrical properties of the conductive Ag coated PET could be tuned by changing the spraying passes. As the electromagnetic interference shielding material, the composite PET possesses a highest shielding efficiency of 45 dB. In addition, the Ag coated PET with the thickness of 0.1 mm would maintain the 72% electrical conductivity even been folded even at a minimum diameter of 0.2 mm. It was demonstrated that uniform and fine cracks would generate when the Ag coated PET was stretching, but Ag films still retain continuous networks to maintain the high electronic conductivity even stretching to 100%. Simple finite element modeling results prove that the stress by stretching would concentrate in corner of the crack and the deformation is mainly at stress side. The Ag layers were also produced on TPU substrates to detect the stretching, showing its potential applications for strain sensors and health monitoring systems.     

Electrical conductivity of poly(3,4-ethylenedioxythiophene):p-toluene sulfonate films hybridized with reduced graphene oxide

Reduced graphene oxide-poly(3,4-ethylenedioxythiophene):p-toluene sulfonate (rGO-PEDOT:PTS) hybrid electrode films were synthesized directly on a substrate by interfacial polymerization between an oxidizing solid layer and liquid droplets of 3,4-ethylenedioxythiophene (EDOT) produced by electrospraying. The EDOT reduced the graphene oxide by donating electrons during its transformation into PEDOT:PTS, and hybrid films consisting of rGO distributed in a matrix of PEDOT:PTS were obtained. These rGO-PEDOT:PTS hybrid films showed excellent electrical conductivities as high as 1,500 S/cm and a sheet resistance of 70 Ω sq^-1. The conductivity values are up to 50% greater than those of films containing conductive PEDOT:PTS alone. These results confirm that highly conductive rGO-PEDOT:PTS hybrid films can potentially be used as organic transparent electrodes.     

Carbon black thin films with tunable resistance and optical transparency

Layer-by-layer assembly was used to produce highly conductive thin films of carbon black and polymer. Positively and negatively-charged polyelectrolytes, polyethylenimine (PEI) and poly(acrylic acid) (PAA), were used to stabilize carbon black in aqueous mixtures that were then deposited onto a PET substrate. The effects of sonication and pH adjustment of deposition mixtures on the conductivity and transparency of deposited films was studied, along with drying temperature. Sonication and oven drying at 70 °C produced films with the lowest sheet resistance (∼1500 Ω/sq), which is a bulk resistivity below 0.2 Ω cm for a 14-bilayer film that is 1.3 μm thick. These two variables improve packing and connectivity amongst carbon black particles that results in increased electrical conductivity. Increasing the pH of the PAA-stabilized mixture and decreasing the pH of the PEI-stabilized mixture resulted in transparent films due to increased polymer charge density. These pH-adjusted films have much higher sheet resistance values than their non-adjusted counterparts due to their reduced thickness and patchy deposition. Varying the number of bilayers allows both sheet resistance and optical transparency to be tailored over a broad range. Carbon black-filled thin films able to achieve these levels of resistivity and transparency may find application in a variety of optoelectronic applications.