Electroconductive Films Research Articles

Sandwich-Structured Carbon Nanotube Composite Films for Multifunctional Sensing and Electrothermal Application.

Electro-conductive films with excellent flexibility and thermal behavior have great potential in the fields of wearable electronics, artificial muscle, and soft robotics. Herein, we report a super-elastic and electro-conductive composite film with a sandwich structure. The composite film was constructed by spraying Polyvinyl alcohol (PVA) polymers onto a buckled conductive carbon nanotube-polydimethylsiloxane (CNTs-PDMS) composite film. In this system, the PVA and PDMS provide water sensing and stretchability, while the coiled CNT film offers sufficient conductivity. Notably, the composite film possesses high stretchability (205%), exceptional compression sensing ability, humility sensing ability, and remarkable electrical stability under various deformations. The produced CNT composite film exhibited deformation (bending/twisting) and high electro-heating performance (108 °C) at a low driving voltage of 2 V. The developed CNT composite film, together with its exceptional sensing and electrothermal performance, provides the material with promising prospects for practical applications in wearable electronics.

Fabrication of Conductive Tissue Engineering Nanocomposite Films Based on Chitosan and Surfactant-Stabilized Graphene Dispersions.

Chitosan (CS)/graphene nanocomposite films with tunable biomechanics, electroconductivity and biocompatibility using polyvinylpyrrolidone (PVP) and Pluronic F108 (Plu) as emulsion stabilizers for the purpose of conductive tissue engineering were successfully obtained. In order to obtain a composite solution, aqueous dispersions of multilayered graphene stabilized with Plu/PVP were supplied with CS at a ratio of CS to stabilizers of 2:1, respectively. Electroconductive films were obtained by the solution casting method. The electrical conductivity, mechanical properties and in vitro and in vivo biocompatibility of the resulting films were assessed in relation to the graphene concentration and stabilizer type and they were close to that of smooth muscle tissue. According to the results of the in vitro cytotoxicity analysis, the films did not release soluble cytotoxic components into the cell culture medium. The high adhesion of murine fibroblasts to the films indicated the absence of contact cytotoxicity. In subcutaneous implantation in Wistar rats, we found that stabilizers reduced the brittleness of the chitosan films and the inflammatory response.

Polysaccharide‐based electroconductive films for controlled release of ciprofloxacin

AbstractHereby, fabrication of hyaluronic acid/gelatin/sodium alginate (HA/Gel/SA) polymeric films, which contain electroconductive poly(3,4ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) particles, is studied for drug release applications. The characterization of synthesized PEDOT:PSS and HA/Gel/SA‐(PEDOT:PSS) films is verified by using FT‐IR and RAMAN spectroscopy. Conductivity values of the films containing 0, 4, and 6% v/v PEDOT:PSS are found via a four‐point probe technique to determine the optimum composition of the films for the targeted field. Additionally, swelling, mechanical, and cytotoxicity tests are carried out according to the related methods. Ciprofloxacin (CIP), which is a commonly used antibiotic, is loaded into the polymeric matrix and its release behavior is investigated. All results indicate that the incorporation of PEDOT:PSS increases the mechanical performance and decreases the burst release of drug resulted in more sustained release profile. The HA/Gel/SA‐(PEDOT: PSS) formulation is clearly a promising drug carrier that also supports cell viability due to its high cytocompatibility.

Model system of cross-linked PEDOT:PSS adaptable to an application for an electrode with enhanced water stability

We herein report a synthetic route to electro-conductive films with enhanced water stability involving cross-linking poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) with bisphenol A diglycidyl ether (DGEBA). The reaction was confirmed by Fourier-transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. Furthermore, evaluation of the surface resistance, transmittance and roughness of the films was also conducted. As a consequence of quantitative analysis of the water stability of the films by measurement of the surface resistance, as well as transmittance of the films after immersion in buffer solution (pH = 7.4), it was determined that the PEDOT:PSS film with 0.5% DGEBA displayed a remarkable improvement in water resistance without any reduction in the initial electrical properties and transmittance of the films. The PEDOT:PSS film, which was reacted with DGEBA also exhibited significant improvement in thermal stability at 180 °C. Our study proposes a promising method for development of an electrode applicable to biological environments, where contact with water is often unavoidable.

Electroconductive hyaluronic acid/gelatin/poly(ethylene oxide) polymeric film reinforced by reduced graphene oxide

AbstractNovel electroconductive polymeric films with enhanced mechanical performance were fabricated by encapsulating reduced graphene oxide (RGO) at different concentrations (0–50 vol %) into a hyaluronic acid/gelatin/poly(ethylene oxide) (HyA/Gel/PEO) polymeric structure. The obtained RGO‐reinforced polymeric films were characterized by Fourier transform infrared and scanning electron microscopy analyses. Mechanical performances were measured with a universal mechanical testing machine. The results verified that the RGO reinforcement significantly enhanced the mechanical performances of the films. To determine the biocompatibility of the polymeric films, L929 (murine fibroblast) cell lines were used. The water uptake capacities were measured using swelling tests. A four‐probe method was used to measure conductivity characteristics. The conductivity results indicated that HyA/Gel/PEO film containing 20 vol % RGO has the highest average electrical conductivity (1.832 × 10−6S/cm). All of the results demonstrated that the obtained electroconductive films could be used in biomedical fields in the future, especially in controlled drug release systems and tissue engineering. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 46905.

Facile Preparation of Starch-Based Electroconductive Films with Ionic Liquid

Here, we discovered that starch could be straightforwardly processed into optically transparent electroconductive films by compression molding at a relatively mild temperature (55 or 65 °C), much lower than those commonly used in biopolymer melt processing (typically over 150 °C). Such significantly reduced processing temperature was achieved with the use of an ionic liquid plasticizer, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). A higher [C2mim][OAc] content, lower processing temperature (55 °C), and/or higher relative humidity (RH) (75%) during the sample postprocessing conditioning suppressed the crystallinity of the processed material. The original A-type crystalline structure of starch was eliminated, although small amounts of B-type and V-type crystals were formed subsequently. The starch crystallinity could be linked to the mechanical properties of the films. Moreover, the processing destroyed the original lamellar structure of starch, and the amorphous starch processed with [C2mim][OAc]/wa...

Electroconductive films based on amino-substituted tetraphenylporphyrins and their metal copper complexes

Amino-substituted tetraphenylporphyrins (5,10,15,20-tetrakis(4′-aminophenyl)porphyrin, 5-(4′-aminophenyl)–10,15,20-triphenylporphyrin) and their copper complexes in dichloromethane and ethanol were electropolymerized by the cyclic voltammetry method and their electrochemical properties were studied. The polyporphyrin films obtained by electro-oxidation transmit electricity and possess semiconductor properties of different types. The poly-5,10,15,20-tetrakis(4′-aminophenyl)porphyrin films obtained from different solvents are similar to each other in chemical composition but different in morphology. The polyporphyrin film surface morphology was studied by AFM microscopy.

New Reflectable Materials on the Basis of Polyimides

Electroconductive and reflective metallized polyimide films have been prepared by heterogeneous chemical modification of polyimide surface. By carrying out the chemical reactions <em>in situ</em> in the modified layers of polyimide surface, thereby a metal phase strongly impregnated into the polyimide surface is obtained. The steps of chemical modification have been studied on the model compound – poly(amic acid) on the basis of pyromellite dianhydride and oxydianiline, which forms insoluble sodium or potassium poly(amicacid) salts (polyamate). Metallization of Kapton HN & JP (from DuPont) and Upilex S films have been carried out and the films have been characterized by XRD, XRFD, and measurements of reflectivity in the visible range and surface resistivity at elevated temperatures. It is shown that reflectivity coefficients of silvered films are 90-92% and surface resistivity is about 0.5 Ω.

Thin electroconductive hydrogel films by in situ electropolymerization of pyrrole within polyelectrolyte multilayers

Electroconductive hydrogel (ECH) films have becoming more and more attractive in the field of electro-stimulated response systems and biosensors. Comparatively speaking, the thinner ECH films enable faster response to external stimuli. However, construction of thin ECH films with thickness at the nano-to-micrometer scale is challenging. In the present study, we reported a thin ECH film by in situ electropolymerization of pyrrole within the layer-by-layer (LbL) polyelectrolyte multilayers. Thin poly(L-lysine)/sodium hyaluronate (PLL/HA) multilayers were fabricated. Polypyrrole (PPy) was then prepared by in situ electropolymerization of pyrrole within the multilayers by the galvanostatic method. Chronopotentiometry and an electro-quartz crystal microbalance were used to follow the electropolymerization. The chemical and structural characteristics of the thin ECH film were extensively investigated. Electrical impedance spectroscopy and cyclic voltammetry measurements demonstrated that this (PLL/HA)@PPy film has good electroconductivity with impedance as low as 5 Ω. This thin ECH film could to be a highly desirable candidate for applications in implantable electro-related biomedical devices and biosensors.

57.1: WITHDRAWN: 57.2: Transparent Conductive Coatings Made by Electrochemical and Physicochemical Methods

AbstractNew methods of transparent conductive electrodes fabrication are presented. The electrochemical anodization of aluminum is a key component for methods to make metal electrodes. It allows to produce the holey aluminum electrode (method 1) and holey alumina mask as a pattern for metal electrode deposition with its further transferring to adhesive substrate (method 2). The 80% average transmission for range 300–1000nm and 10–20Ω/□ sheet resistance is achieved. Electroconductive films made of organosilicon compounds are investigated too.

Anodic processes on aluminum in aprotic electrolytes based on the tetraethylammonium tetrafluoroborate salt in acetonitrile

Anodic processes on aluminum used as a current collector in electric double-layer capacitors in a 0.1 M solution of tetraethylammonium tetrafluoroborate in acetonitrile are studied to determine its corrosion resistance. It is shown that aluminum can be anodically dissolved in an aprotic electrolyte of a supercapacitor with formation of electroconductive films on its surface.

Investigation of electroconductive films composed of polyvinyl alcohol and graphitized carbon black

Films consisting of the polymer (polyvinyl alcohol (PVA)) matrix and the filler (graphitized carbon black (CB)) were prepared and examined using TMA, contact angle, and conductivity measurements. Existence of weak interaction between the molecules of PVA and the surface of CB was established. The changes occurring in the process of the thermal treatment and the chlorination of composite films were evaluated using the contact angle measurements. The results of DC conductivity measurements were approached using a model of filler cluster formation in the polymer matrix. The model of this concept is based on the percolation theory and the fractal structure of the filler network. The films exposed to environment of a certain relative humidity and the chlorinated films were examined this way. The size of the clusters, which were formed in the matrix of PVA was determined. It was established that the change of conductivity in the process of moisture adsorption runs through the aggregation of clusters.

Electroconductive polymer films obtained by plasma polymerization of 1-amino-9,10-anthraquinone

Electroconductive polymer films obtained by plasma polymerization of 1-amino-9,10-anthraquinone

Electrochemical Properties of Electrochemically Polymerized Polypyrrole Film in the Dark and under Light Irradiation

Abstract Polypyrrole films prepared on Pt or SnO2 through electrochemical oxidative polymerization of pyrrole were characterized with respect to electroconductivity by photoelectrochemical measurements. Redox reactions of solution species such as methyl viologen, hydroquinone, oxygen, Cu2+, I−, and Br− occur on these electroconductive films. Light excitation of the film with wavelengths shorter than 550 nm results in observable cathodic photocurrent at the potential region more negative than 0.0 V vs. Ag. The polypyrrole film is a p-type semiconductor with a bandgap energy of ca. 2.2 eV and is stable during redox reactions.