Effect of synthesis parameters on the electrical conductivity of polypyrrole‐coated poly(ethylene terephthalate) fabrics

The effects of pyrrole, anthraquinone‐2‐sulphonic acid (AQSA) and iron(III) chloride (FeCl₃) concentrations, reaction time and temperature on the electrical conductivity of polypyrrole (PPy)—coated poly(ethylene terephthalate) (PET) fabrics were investigated. With an increase in both the AQSA and FeCl₃ concentrations, resistivity decreased to a point beyond which higher concentrations led to increased surface resistivity. Erosion of the polymer coating, in dynamic synthesis from continual abrasion, manifested as an exponential increase in the resistance of the coated textile substrate. This was not encountered in static synthesis conditions. Temperature affected the degree of surface and bulk polymerisation. The effect of polymerisation temperature on conductivity was negligible. Conductive polymer coating on textiles through chemical polymerisation enabled a smooth coherent film to encase individual fibres, which did not affect the tactile properties of the host substrate. The optimum FeCl₃/pyrrole and AQSA FeCl₃/pyrrole molar ratios were found to be 2.22 and 0.40 respectively. Copyright © 2003 Society of Chemical Industry     

Surface structure of conductive polypyrrole‐containing composites

The surface structures of polypyrrole/silicon crosslinked poly( styrene/butyl acrylate/hydroxyethyl acrylate) (PSBH) conductive composite films were investigated by X‐ray photoelectron spectroscopy and scanning electron microscopy. It was found that the conductive composite films were of a “sandwich” structure, and the surfaces greatly differ in chemical compositions and phase morphologies from the bulk. The Si and N contents exhibit opposite gradient change with the measured depth of the two surface layers in the composite films, namely, the decrease in Si content and the increase in N content with increase in the depth of the surface layers. However, the N^δ+/N ratios in polypyrrole decreased with the measured depth of the conductive composite film. It was also found that the conductive composite film based on silicon crosslinked matrix exhibits more environmental stable than that based on linear matrix. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 95–101, 1999     

Polypyrrole/polyaniline conductive films obtained electrochemically on polycarbonate‐coated platinum electrodes

In this study, two‐component free‐standing films were obtained by coating a polycarbonate (PC)‐coated Pt electrode first with polypyrrole (PPy) in an organic medium and then polyaniline (PAn) in an aqueous medium using an electrochemical technique. The amount of PPy and PAn contained in the films was controlled by varying the electrolysis time. The PC/PPy/PAn films were characterized by cyclic voltammetry, conductivity, FTIR and UV–visible spectrophotometry, and thermogravimetric analysis. The resistance change of the films was determined in the temperature range of ?15 to 120 °C and their temperature sensor properties were investigated. © 2002 Society of Chemical Industry     

Enhancement in electrical conductive property of polypyrrole‐coated cotton fabrics using cationic surfactant

Recently, great efforts have been made to gain highly conductive fabrics for smart textiles and flexible electromagnetic shielding materials. Different from the conventional chemical synthesis method, fibrillar polypyrrole was synthesized on the cotton fabrics via a simple chemical polymerization process with micelles of cationic surfactant (cetyltrimethylammonium bromide, CTAB) as soft template. The modified cotton fabric exhibited excellent electrical conductivity and electromagnetic interference shielding effectiveness due to the formation of fibrillar polypyrrole on the fiber surface. Electrical conductivity of fabric surface were studied by four‐probe resistivity system. The highly conductive fabric with surface conductivity of 5.8 S cm^?1 could be obtained by changing cationic surfactant concentration. The electromagnetic interference shielding effectiveness (EMI SE) of the modified fabrics was evaluated by the vector network analyzer instrument. Compared with the sample without using surfactant, the EMI SE value of PPy‐coated cotton fabrics increased by 28% after using 0.03 M CTAB as soft template. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43601.     

Development of conductive cotton fabrics for heating devices

Recent developments in the area of textiles to make fabrics more functional have led to synthesizing “intelligent fabrics.” This can be achieved by making the fabrics electrically conducting. In the present study it is reported that the cotton fabrics, when impregnated with polypyrrole, achieve enhanced level of conduction. The method of diffusion of pyrrole, followed by polymerization using iron chloride as oxidant, was used. The different levels of conduction were achieved by varying the contents of monomer in the bath from 0.01 to 0.1M during the synthesis. The conductivity could be enhanced from the initial value of 10^?12 to 10¹ S/cm. It is shown that when a fixed voltage is applied to such a modified piece of cloth, the heat generated is up to 1000 W/m² depending on the percentage of pyrrole present. Such fabrics can be used as heating pads and integrated into the apparel to keep the wearer warm enough using a portable 9.0‐V battery. Being flexible and breathable, such fabrics have better comfort properties (compared with conventional heating pads). It can find applications in dresses for army personnel and old‐age patients. Such conductive fabrics can also find applications in many areas such as electromagnetic interference shielding, gas sensors, and temperature indicators. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4690–4695, 2006     

Antibacterial property on Gram‐positive bacteria of polypyrrole‐coated fabrics

Antibacterial activity against Gram‐negative bacteria of polypyrrole‐coated fabrics has been demonstrated in the past. In this work, biocidal efficacy of polypyrrole has been evaluated against Gram‐positive bacteria on textiles with different polypyrrole loading. Excellent bacterial reduction (≥99%) was found on cotton fabrics containing more than ～9 wt % of polypyrrole. Polypyrrole loading can be greatly reduced in presence of silver. Silver‐containing fabrics used in this work alone does not guarantee a complete biocidal effect, but the addition of just 2 wt % of polypyrrole showed a bacteria reduction of 99%. Moreover, stability to different washing procedures of the antibacterial activity was evaluated. Fabrics were characterized by scanning electron microscopy, energy dispersive X‐ray analysis, and infrared spectroscopy. Stability of the coating was assessed by abrasion tests. PPy showed excellent fastness to abrasion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41670.     

Dopants dependent ion sensitivity of polypyrrole‐modified electrode: Case of pH sensing

The polypyrrole (PPY)‐modified electrode made through electropolymerization of pyrrole monomer is found sensitive to different cations depending on the dopants present within microstructure of polymeric domain. When p‐toluenesulfonate (PTS) anion is doped, the modified electrode is sensitive to proton whereas, under similar conditions, in the presence of tetraphenylborate (TPB) anion, the same is sensitive to zinc ion. A comparative study on ion sensing behavior of PPY‐modified electrodes is reported in this communication. The electro‐polymerization of PTS‐doped PPY‐modified electrode, made under both potentiodynamic and potentiostatic conditions, are studied. The modified electrode is characterized by scanning electron microscopy and cyclic voltammetry and compared with those recorded for TPB‐doped PPY‐modified electrode made under similar conditions. The results based on scanning electron microscopy and cyclic voltammetry suggested; (i) dependence of microstructure based on mode of electropolymerization; (ii) dopant‐dependant ion sensitivity of PPY‐modified electrode, (iii) variation in the redox behavior of the PPY‐modified electrode based on dopants and mode of electropolymerization. Typical results on pH sensing together stability of PPY‐based pH sensor are reported and compared with those recorded for polyaniline (PANI)‐based pH sensor. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of composites of polyethylene with polypyrrole‐coated wollastonite

Composite sheets of polyethylene and polypyrrole‐coated wollastonite were prepared by extrusion and compression molding. Four compatibilizers were also evaluated, poly(ethylene‐co‐methyl acrylate) (EMA), maleated polyethylene (MAPE), poly(ethylene‐co‐vinyl alcohol) (EVOH), and poly(vinyl alcohol) (PVOH). The composite materials were characterized using X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy (SEM), Raman spectroscopy, and mechanical properties determined by tensile tests. SEM micrographs showed that significantly improved interactions occurred between the PE matrix and polypyrrole‐coated wollastonite particles in the presence of EMA, MAPE, and EVOH. Raman spectroscopy confirmed that the polypyrrole coating on the wollastonite particles was not thermally degraded during melt processing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of polypyrrole‐au coated SiO2@poly(4‐vinylpyridine) composites

Microspheres with silica as core and poly(4‐vinylpyridine) (P4VP) as shell were synthesized. AuCl ions were bound by P4VP chains to form the complex, which acted both as an oxidant of pyrrole monomers and as a source of Au atoms. By vapor phase polymerization, the PPy and Au nanoparticles were simultaneously formed on the surfaces of SiO₂@P4VP microspheres. The core‐shell structure was confirmed by transmission electron microscopy. The surface morphologies of the composites were observed by scanning electron microscopy. The molecular structures of composites were characterized in detail by Raman spectra, X‐ray diffraction, and X‐ray photoelectron spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Introducing all‐polyamide composite coated fabrics: A method to produce fully recyclable single‐polymer composite coated fabrics

Novel all‐polyamide composite (APC) has been developed to replace traditional coated fabrics with good interfacial adhesion and enhanced recyclability. The composite is fully recyclable since it contains no other materials except polyamide. APC was prepared by partially dissolving a polyamide fabric by treatment with a film‐forming polyamide solution. The effect of the polyamide solution concentration and gelling time on tensile and viscoelastic properties of APCs was investigated to explore the optimum processing parameters for balancing the good interfacial adhesion. The composite properties were studied by dynamic mechanical thermal analysis (DMTA), tensile testing and scanning electron microscopy (SEM). The results showed a good adhesion between the coating and the fabric. A new method was introduced to convert a low value added textile waste to a high value‐added product. The composite is tunable, in terms of having a dense or a porous top‐layer depending on the end‐use requirements. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42829.     

A study on novel waterproof and moisture‐permeable poly(vinylidene fluoride) micropore membrane‐coated fabrics

The feasibility of PVDF (polyvinylidene fluoride), as a novel waterproof and moisture‐permeable material, to substitute PTFE (polytetrafluoroethylene) for manufacturing civil high‐performance textiles was discussed. The work was focused on the design of casting solution composition (including solvent, additives, and polymer), possible methods to produce durably binded coated micropore membrane fabrics as well as their influences on membrane properties. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 801–807, 2001     

Synthesis and magnetorheological characteristics of ribbon‐like,polypyrrole‐coated carbonyl iron suspensions under oscillatory shear

One of the crucial problems of classical magnetorheological (MR) fluids is their high rate of sedimentation. This disadvantage may be substantially eliminated using core‐shell particles. The aim of this study is to prepare spherical carbonyl iron (CI) particles coated with conducing polymer polypyrrole (PPy) with ribbon‐like morphology. Scanning electron microscopy proved the formation of the ribbon‐like layer onto CI particles while Fourier transform infrared spectroscopy confirmed the chemical structure of PPy. The magnetic properties observed via vibrating sample magnetometer showed decreased magnetization saturation of core‐shell‐structured particles due to the existence of non‐magnetic surface layer. MR measurements performed under oscillatory shear flow as a function of the applied magnetic flux density, temperature, and particle concentration showed that core‐shell particle‐based MR suspension exhibits sufficient MR performance for practical applications. Moreover, the suspension stability is promoted significantly when core‐shell particles are used as a dispersed phase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Experimental studies on electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester

This work deals with development, characterization, and performance of an electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester. An attempt was made to optimize the polymerization process to achieve highest level of electro‐conductivity of this fabric. The essential characteristics of this electro‐conductive fabric were examined and its electromagnetic shielding performance was evaluated. Polythiophene powder was also synthesized and analyzed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical,thermal, and microwave properties of conducting composites of polypyrrole/polypyrrole‐coated short nylon fibers with acrylonitrile butadiene rubber

Pyrrole was polymerized in the presence of anhydrous ferric chloride as oxidant and p‐toluene sulfonic acid as dopant. Polypyrrole‐coated short nylon fibers were prepared by polymerizing pyrrole in the presence of short nylon fibers. The resultant polypyrrole (PPy) and PPy‐coated nylon fiber (F‐PPy) were then used to prepare rubber composites based on acrylonitrile butadiene rubber (NBR). The cure pattern, direct current (DC) conductivity, mechanical properties, morphology, thermal degradation parameters, and microwave characteristics of the resulting composites were studied. PPy retarded the cure reaction while F‐PPy accelerated the cure reaction. Compared to PPy, F‐PPy was found to be more effective in enhancing the DC conductivity of NBR. The tensile strength and modulus values increased on adding PPy and F‐PPy to NBR, suggesting a reinforcement effect. Incorporation of PPy and F‐PPy improved the thermal stability of NBR. The absolute value of the dielectric permittivity, alternating current (AC) conductivity, and absorption coefficient of the conducting composites prepared were found to be much greater than the gum vulcanizate. PPy and F‐PPy were found to decrease the dielectric heating coefficient and skin depth significantly. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Resistivity of conductive polymer–coated fabric

Preparation of conductive polymer–coated fabrics was carried out by admicellar polymerization. By this method, a thin layer of conductive polymers (polypyrrole, polyaniline, and polythiophene) was formed on cotton and polyester fabrics by a surfactant template. The effects of monomer concentration, oxidant to monomer ratio, and addition of salt on the resistivity of the resulting fabrics were studied. The results showed that the apparent surface and volume resistivity decreased with an increase in monomer concentration in the range 5–15 mM, but was not strongly dependent on the oxidant to monomer ratio over the range of 1 : 1 to 2 : 1. Addition of 0.5M salt was found to reduce the resistivity significantly. The lowest resistivity obtained was with polypyrrole‐coated fabric, with resistivity around 10⁶ ohm. SEM micrographs of the treated fabric surface showed a filmlike polymer coating, confirming that the fabrics were successfully coated by admicellar polymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2629–2636, 2004     

Electrically conductive composites of polyurethane derived from castor oil with polypyrrole‐coated peach palm fibers

Electrically conducting fibers were prepared through in situ oxidative polymerization of pyrrole (Py) in the presence of peach palm fibers (PPF) using iron (III) chloride hexahydrate (FeCl₃·6H₂O) as oxidant. The polypyrrole (PPy) coated PPF displayed a PPy layer on the fibers surface, which was responsible for an electrical conductivity of (2.2 ± 0.3) × 10⁻¹ S cm⁻¹, similar to the neat PPy. Electrically conductive composites were prepared by dispersing various amounts of PPy‐coated PPF in a polyurethane matrix derived from castor oil. The polyurethane/PPy‐coated PPF composites (PU/PPF–PPy) exhibited an electrical conductivity higher than PU/PPy blends with similar filler content. This behavior is attributed to the higher aspect ratio of PPF–PPy when compared with PPy particles, inducing a denser conductive network formation in the PU matrix. Electromagnetic interference shielding effectiveness (EMI SE) value in the X‐band (8.2–12.4 GHz) found for PU/PPF–PPy composites containing 25 wt% of PPF–PPy were in the range −12 dB, which corresponds to 93.2% of attenuation, indicating that these composites are promising candidates for EMI shielding applications. POLYM. COMPOS., 38:2146–2155, 2017. © 2015 Society of Plastics Engineers     

Electrochemical study of the uranium exchange by polypyrrole‐based resins

Electrochemical control of the binding of uranium ions by redox active polypyrrole resins was studied. The experimental conditions for this binding were optimized with respect to the uranium ions to be fixed, the resin, and the solution. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3473–3484, 1999     

Water vapor permeability and mechanical properties of fabrics coated with shape‐memory polyurethane

Water vapor permeable fabrics were prepared by coating shape‐memory polyurethane (PU), which was synthesized from poly(tetramethylene glycol), 4,4′‐methylene bis(phenylisocyanate), and 1,4‐butanediol, onto polyester woven fabrics. Water vapor permeability and mechanical properties were investigated as a function of PU hard‐segment content or polymer concentration of the coating solution. Water vapor permeability of PU‐coated fabrics decreased dramatically with increased concentration of coating solution, whereas only a slight change was observed with the control of PU hard‐segment content. The coated fabric showed the clear appearance of a nonporous PU surface according to SEM measurements. Attainment of high water permeability in PU‐coated fabrics is considered to arise from the smart permeability characteristics of PU. Mechanical properties of coated fabrics, although there was some variation depending on the concentration of coating solution, were primarily affected by PU hard‐segment content. Fabrics coated with PU hard‐segment content of 40% showed the lowest breaking stress and modulus as well as the highest breaking elongation, which could be interpreted in terms of the dependency of mechanical properties of coated fabrics on PU hard‐segment content and the yarn mobility arising from a difference in penetrating degree of coating solution into the fabric. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2812–2816, 2004     

Polyaniline‐coated PET conductive yarns: Study of electrical,mechanical, and electro‐mechanical properties

Intelligent and multifunctional yarns (textiles) have attracted interest because of their high potential in applications such as flexible displays, batteries, or sensors. The main objective of our research was to obtain the flexible and electrically conducting yarn based on the conductive polymer and polyethylene terephtalate (PET) yarns. Among the conductive polymers, polyaniline (PANI) is considered as a promising material and is well adapted for modifications of textile structure because of its excellent environmental, thermal, and chemical stability. Chemical PANI coating on PET yarns was performed by absorption of yarns through PANI solution. The electrical, mechanical, and electro‐mechanical properties of PET conductive yarns prepared were investigated. The environmental effects on the electrical and mechanical properties of the obtained conductive yarns were also studied. These conductive yarns are expected to be used as fibrous sensors, connection devices in smart clothing, and for electromagnetic shielding applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1252–1256, 2006     

Effects of short‐chain branches on strain‐induced polymer crystallization

We performed dynamic Monte Carlo simulations of a lattice polymer model to investigate strain‐induced crystallization behaviors of short‐chain branched polymers with variable sequence distributions, branch numbers and lengths, and their blending compositions with linear polymers. The results revealed that the branch density and distribution bring dominant effects. In the blends, there is no phase separation prior to crystallization, except that strain‐enhanced mixing is temporarily hindered by chain folding upon crystallization. Our observations shed lights onto the strain‐induced crystallization of short‐chain branched polymers. © 2018 Society of Chemical Industry