Preparation of polyaniline/nylon conducting fabric by layer‐by‐layer assembly method

In this article, layer‐by‐layer assembly technology was used to prepare polyaniline (PANI)/nylon conducting fabrics. PANI/nylon conductive composite fabrics were prepared by deposition of polyanion (PSS) and polycation (aniline cation) alternately. The pretreatment with PSS was discussed. The influence of the reaction time, aniline concentration, acid concentration and assembly time on the conductivity, and K/S values of composite fabric was studied. The optical reaction condition of assembly should be: the concentration of PSS was 20 g/L, the PSS‐treated nylon immersion in blended bath for 24 min, ammonium persulfate 0.1 mol/L, aniline 0.1 mol/L, p‐toluene sulfonic acid 0.3 mol/L. In the end, the conductive composite fabrics were characterized by fourier transformed Infrared‐attenuated total reflection spectroscopy and compared with pure nylon fabrics. At the same time, scanning electron microscopy, atomic force microscope (AFM), thermogravimetric analysis (TG), and mechanical properties were studied. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Dendrimer‐encapsulated Pt nanoparticles/polyaniline nanofibers for glucose detection

A novel amperometric glucose biosensor based on self‐assembling glucose oxidase (GOx) and dendrimer‐encapsulated Pt nanoparticles (Pt‐DENs) on nanofibrous polyaniline (PANI) was described. PANI nanofibers were synthesized via an interfacial polymerization method. A sulfonated polyelectrolytes‐poly(sodium 4‐styrenesulfonate) (PSS) was used to form the negative PANI/sulfonated polyelectrolyte complex, which had good disperse in aqueous solution. GOx was immobilized on the PANI/PSS surface by alternatively assembling a cationic Pt‐DENs layer and an anionic GOx layer. The unique sandwich‐like layer structure (Pt‐DENs/GOx/Pt‐DENs/PANI/PSS) formed by self‐assembling provides a favorable microenvironment to keep the bioactivity of GOx and to prevent enzyme molecule leakage. The fabricated Pt‐DENs/GOx/Pt‐DENs/PANI/PSS electrode exhibited excellent response performance to glucose with a detection limit of 0.5 μM, wide linear range from 10 μM to 4.5 mM, short response time within 5 s, improved sensitivity of 39.63 μA/(mM cm²), and good stability (85% remains after 20 days). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of polyaniline coated polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) microparticles and the further fabrication of hollow polyaniline microspheres

In this article, the microparticles of polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) (PS‐PSS) coated by polyaniline (PANI) were prepared and hollow PANI microspheres were further obtained by dissolving the core. First, surface‐sulfonated monodispersed PS was prepared by copolymerization of sodium 4‐styrenesulfonate (SSS) and styrene with dispersion polymerization method. Then aniline was polymerized on the surface of the surface‐sulfonated PS (PS‐PSS) by chemical oxidative polymerization. After purification, we prepared core‐shell (PS‐PSS)/PANI particles. Hollow PANI microspheres were prepared by dissolving the plastic PS core of the (PS‐PSS)/PANI particles in chloroform. The growth process of PANI on the surface of PS‐PSS particles was investigated and the hollow PANI microspheres were characterized. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Fabrication and properties of solution‐cast polyaniline/carboxymethylchitin blend films

Blend films consisting of polyaniline in emeraldine base form (PANI EB) dispersed in partially cross‐linked carboxymethylchitin (CM‐chitin) were prepared by solution casting, and characterized for their physical, thermal, and electrical properties. Homogeneous and mechanically robust blend films were obtained having PANI EB contents up to 50 wt % in the CM‐chitin matrix. FTIR spectra confirm intimate mixing of the two blend components. The thermal stability of the blend films increased with increase of PANI EB content, suggesting the formation of an intermolecular interaction, such as hydrogen bonding, between PANI EB and CM‐chitin chains. The addition of PANI EB into the pure CM‐chitin film resulted in a decrease in electrical conductivity of the films owing to disruption of ionic conduction of the CM‐chitin structure. After doping the blend films by immersion in HCl solution, the electrical conductivity of the HCl‐doped films increased with increase of the PANI EB content to a maximum value of the order of 10^?3 S/cm at 50 wt % PANI EB content. The electrical conductivity of the blend films was also dependent on the HCl concentration as well as on the type of acid dopant. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Application of poly(diphenolic acid‐phenyl phosphate)‐based layer by layer nanocoating in flame retardant ramie fabrics

Poly(diphenolic acid‐phenyl phosphate) [poly(DPA‐PDCP)], obtained from diphenolic acid (a well‐known biomass chemical), was used together with polyethylenimine (PEI) to construct a flame retardant surface coating for ramie fabric using layer‐by‐layer self‐assembly. Attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR) and scanning electron microscope (SEM) equipped with an energy dispersive X‐ray spectrometer (EDX) were used to confirm the successful formation of layer by layer assembly. Assessment of the thermal and flammability properties for poly(DPA‐PDCP)/PEI‐coated ramie fabrics showed that the thermal stability, flame retardancy, and residual char were enhanced as the concentration of poly(DPA‐PDCP) and the BL number in the LbL process increased as well as the treatment of KH550 was applied. SEM and EDX analysis of the char residue confirmed further the intumescent flame retardant mechanism. This work demonstrated the great potentials of poly(DPA‐PDCP)/PEI flame retardant nanocoating constructed by LbL assembly method in the application of ramie fabric. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44795.     

Layer‐by‐layer films based on charge transfer interaction of ϕ‐conjugated poly(dithiafulvene) and incorporation of gold nanoparticles into the films

Layer‐by‐layer (LBL) self‐assembled ultrathin films were prepared via consecutively alternating immersion of substrates into solutions of electron donor, poly(dithiafulvene) (PDF), and electron acceptor, poly(hexanyl viologen) (6‐VP). The charge transfer (CT) interaction formed at solid–liquid interfaces between the backbones of the electron acceptor and donor polymers was the driving force of the alternative deposition. The sandwich heterostructure of the LBL film led to electrical anisotropy in the directions parallel and perpendicular to the film surfaces. Incorporation of gold nanoparticles into the LBL films was investigated by reducing gold ions with the PDF layers already deposited on the film surfaces, or depositing PDF‐protected gold colloidal solution as the electron donor layers directly. The influence of the gold nanoparticles on the electrical anisotropy of the LBL films was also illustrated in this research. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1608–1615, 2007     

Preparation and properties of conductive polyaniline/poly‐ω‐aminoundecanoyle fibers

Historically, polyaniline (PANI) had been considered an intractable material, but it can be dissolved in some solvents. Therefore, it could be processed into films or fibers. A process of preparing a blend of conductive fibers of PANI/poly‐ω‐aminoundecanoyle (PA11) is described in this paper. PANI in the emeraldine base was blended with PA11 in concentrated sulfuric acid (c‐H₂SO₄) to form a spinning dope solution. This solution was used to spin conductive PANI / PA11 fibers by wet‐spinning technology. As‐spun fibers were obtained by spinning the dopes into coagulation bath water or diluted acid and drawn fibers were obtained by drawing the as‐spun fibers in warm drawing bath water. A scanning electron microscope was employed to study the effect of the acid concentration in the coagulation bath on the microstructure of as‐spun fibers. The results showed that the coagulating rate of as‐spun fibers was reduced and the size of pore shrank with an increase in the acid concentration in the coagulation bath. The weight fraction of PANI in the dope solution also had an influence on the microstructure of as‐spun fibers. The microstructure of as‐spun fibers had an influence on the drawing process and on the mechanical properties of the drawn fibers. Meanwhile, the electrically conductive property of the drawn fibers with different percentage of PANI was measured. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1458–1464, 2002     

Improved hemocompatibility of silk fibroin fabric using layer‐by‐layer polyelectrolyte deposition and heparin immobilization

Silk fibroin has long been used as implantable surgical sutures and it has acceptable mechanical properties and patency rates in animal models and in clinical end‐uses. However, fibroin has been shown to be hemolytic and can cause damage to red blood cells. So to be used as an implantable vascular prosthesis its hemocompatibility needs to be improved. This study has taken two sequential steps to address this problem. First, to create a positively charged layer on the fibroin fibers' surface, a 1.5 and 2.5 bilayers polyelectrolyte surface deposition layer‐by‐layer technique was used with the positive counterion poly(allylamine hydrochloride) and the negative counterion poly(acrylic acid). Second, negatively charged low molecular weight heparin was then immobilized on these positively charged self‐assembled surfaces. The presence of the heparin was confirmed with Alcian Blue staining and a toluidine blue assay, and the increased roughness and hydrophilicity of the modified surfaces were characterized by scanning electron microscopy, contact angle measurements, and atomic force microscopy. In addition, a negligible hemolytic effect, reduced protein adsorption, and a higher concentration of free hemoglobin measured by a kinetic clotting time test were found to be enhanced with the use of 2.5 bilayers compared to the 1.5 bilayers self‐assembly technique. Given the success of these preliminary results, it is anticipated that this novel approach of surface modification and heparin immobilization will demonstrate long‐term patency during future animal trials of small caliber silk fibroin vascular grafts. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40772.     

Enhanced mechanical properties of multilayer nano‐coated electrospun nylon 6 fibers via a layer‐by‐layer self‐assembly

We reported the mechanical properties of the polyelectrolyte multilayer nano‐coated electrospun fiber mats with different number of layers. Multilayer nano‐coatings composed of layers of PSS and PAH were successfully deposited onto electrospun nylon 6 fibers via layer‐by‐layer self‐assembly. Compared with pure nylon 6 fibers, the morphology of polyelectrolyte multilayer coated nylon 6 fibers was uniform and smooth. The mechanical properties of polyelectrolyte multilayer coated random and aligned nylon 6 fibers were remarkably enhanced. Moreover, it was found that the higher degree of alignment resulted in higher tensile strength, suggesting the combined effects of the alignment, the surface nanocoating and the formation of internal networks of polyelectrolytes on nylone 6 fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrically conducting polyaniline‐PBMA composite films obtained by extrusion

Poly(n‐butyl methacrylate) (PBMA)–polyaniline (PANI) composite films were obtained by extrusion by use of two methods: the first method consisted of polymerizing a thin layer of PANI, with Cl^? as dopant, on the extruded film of PBMA; the second method was based on blends of PBMA and PANI produced by the extrusion of the two polymers by using dodecylbenzene sulfonic acid (DBSA) as dopant. The thermal properties, electrical conductivity, and morphology of the composite films obtained were measured. The sensitivity of the composites films as detectors of hydrogen peroxide and ammonia was evaluated. The change in the electrical resistance on exposure to different aqueous solutions of these components shows a linear behavior. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 179–183, 2003     

Hollow PUA/PSS/Au microcapsules with interdependent near‐infrared/pH/temperature multiresponsiveness

In this work, smart hollow microcapsules made of thermal‐/pH‐dual sensitive aliphatic poly(urethane‐amine) (PUA), sodium poly(styrenesulfonate) (PSS), and Au nanoparticles (AuNPs) for interdependent multi‐responsive drug delivery have been constructed by layer‐by‐layer (LbL) technique. The electrostatic interactions among PUA, PSS, and AuNPs contribute to the successful self‐assembly of hollow multilayer microcapsules. Thanks to the shrinkage of PUA above its lower critical solution temperature (LCST) and the interaction variation between PUA and PSS at different pH conditions, hollow microcapsules exhibit distinct pH‐ and thermal‐sensitive properties. Moreover, AuNPs aggregates can effectively convert light to heat upon irradiation with near‐infrared (NIR) laser and endow the hollow microcapsules with distinct NIR‐responsiveness. More importantly, the NIR‐responsive study also demonstrates that the microcapsule morphology and the corresponding NIR‐responsive drug release are strongly dependent on the pH value and temperature of the media. The results indicate that the prepared hollow PUA/PSS/Au microcapsules have the great potential to be used as a novel smart drug carrier for the remotely controllable drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43008.     

Interfacial polymerization of morphologically modified polyaniline: from hollow microspheres to nanowires

BACKGROUND: Polyaniline (PANI) has attracted much attention in many fields due to its chemical and physical properties, and different nanostructures of PANI changing from one‐dimensional to three‐dimensional have been obtained. By changing the concentration of cetyltrimethylammonium bromide (CTAB), the morphology of hydrochloric acid‐doped polyaniline could be changed from one‐dimensional nanoneedles or nanowires with a network structure (50–100 nm in diameter) to three‐dimensional hollow microspheres (ca 400 nm in outer diameter) via combining interfacial polymerization and self‐assembly process. RESULTS These different nanostructures of PANI were proved using scanning electron and transmission electron microscopies. A plausible mechanism of the formation of the changeable nanostructures of PANI may be different from that of interfacial polymerization without surfactant or a traditional homogenous reaction system using CTAB as surfactant. CONCLUSION The results obtained from Fourier transform infrared spectrometry, X‐ray diffraction and the four‐probe method showed that the molecular structure of PANI does not change with increasing CTAB concentration, but crystallinity and conductivity of PANI increase with surfactant concentration. Copyright © 2007 Society of Chemical Industry     

Polyaniline − carbon nanohorn composites as thermoelectric materials

Thermoelectric materials can convert heat into electricity when a temperature gradient is present. The investigation of conductive polymers such as polyaniline (PANI ) and poly(3,4‐ethylenedioxythiophene) as active materials for thermoelectric generators in the room temperature range is gaining interest because of several key advantages offered by these materials. The relative ease of solution processing, their mechanical stability and flexibility together with low density and low thermal conductivity make conductive polymers suitable for integration in a thermoelectric generator. Polymers offer remarkably low thermal conductivity values but modest Seebeck coefficient and electrical conductivity. In this work, polymer/inorganic nanocomposites of PANI with carbon particles such as single wall carbon nanohorns (SWCNHs ) were prepared via solution mixing of the precursors in order to increase the electrical conductivity by means of polymer matrix/nanohorn electronic junctions. The electrical conductivity and Seebeck coefficient were estimated on PANI /SWCNH films and pressed pellets and through‐plane thermal conductivity was determined on films. The thermal stability of PANI /SWCNH composites was evaluated by means of TGA /DSC coupled with residual gas analysis. It was found that a proper concentration of SWCNHs in PANI ?(+/?)‐camphor‐10‐sulfonic acid (CSA) film was effective in increasing the electrical conductivity without decreasing the Seebeck coefficient. © 2017 Society of Chemical Industry     

Electric‐field‐induced layer‐by‐layer fabrication of stable second‐order nonlinear optical films

BACKGROUND: Second‐order nonlinear optical (NLO) films have been made using electric field poling polymer and Langmuir–Blodgett techniques with non‐centrosymmetric structures that exhibit relatively high values of nonlinear susceptibility (χ²), but the shortcomings of insufficient temporal or mechanical stability have restricted their potential applications. In this study, electric‐field‐induced layer‐by‐layer assembly was investigated as an effective technique to prepare low molecular weight chromophoric (LMWC) molecules of high degree of self‐ordering and density in NLO films. RESULTS: A new and stable LMWC molecule, 2‐({4‐[4‐(2‐carboxy‐2‐cyanovinyl)‐Z‐phenylazo]‐phenyl}‐methylamino)‐ethyl acid (DRCB), was first designed and synthesized successfully. The chromophore possesses two negative groups, one at each end, and still retains molecular polarity after ionization. DRCB was successfully assembled with polycationic diazoresin using the electric‐field‐induced layer‐by‐layer assembly method to construct stable organic second‐order NLO multilayer films. Upon UV irradiation, the interaction between multilayers was converted from an electrostatic interaction to covalent bonds. CONCLUSION: Due to the DC electric field effect in the assembly process, in addition to introducing the stable chromophore molecule and the covalent crosslinking structure in the films, the second‐order NLO films fabricated using the method described have large second harmonic generation response, good thermal stability and excellent chemical stability, which offer potential advantages for device applications. Copyright © 2009 Society of Chemical Industry     

Preparation of conductive polyaniline/nylon‐6 composite films by polymerization of aniline in nylon‐6 matrix

Polyaniline (PANI)/Nylon‐6 composite films were prepared by oxidative polymerization of aniline (ANI) inside host Nylon‐6 film. Such a composite has the desired electro‐active and mechanical properties to serve as a self‐standing functional unit. Comparative studies on sorption of ANI by Nylon‐6 matrix from various ANI containing media were conducted revealing superior ANI uptake from neutral ANI solution in water. ANI content was measured to be as high as 12%. Spectroscopic measurements showed that hydrogen bonding seemed to play important role in ANI sorption by Nylon‐6 matrix. Polymerization was monitored using atomic force microscopy and conductivity measurements. The morphology studies showed the appearance of PANI nanodomains on Nylon‐6 surface in the early stages of the polymerization. Eventually the domains coalesced during polymerization forming a continuous PANI layer. The conductivity measurements confirmed the change of the morphology from isolated islands to continuous conducting surface by drastic increase in conductivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Facile preparation of multifunctional poly(amide‐imide)/polyaniline films: Combining self‐cleaning,self‐extinguishing,and conductive

Recently, multifunctional films are of particular interest to scientists owing to their diversified properties. Here, we demonstrated that self‐cleaning, self‐extinguishing, and high conductive films were fabricated by simple solvent‐casting method from poly(amide‐imide)/polyaniline composites. The multifunctional films exhibited controllable water contact angles varying from 65° to 120° and high electrical conductivities of over 40 S m^?1. Moreover, due to the improved hydrophobicity, the multifunctional films showed self‐cleaning characteristics and were used to collect the dust powders easily and perfectly during the dispensed water droplet rolling off the solid surface. Furthermore, the self‐extinguishing property of the multifunctional films was confirmed by thermogravimetric analysis. The special film composition and morphology are the two important aspects that induce such unusual properties. The polyaniline content can strongly influence the morphology of the composite films, which in turn display different hydrophobicities and conductivities. POLYM. ENG. SCI., 59:E33–E43, 2019. © 2018 Society of Plastics Engineers     

Excellent biocompatible polymeric membranes prepared via layer‐by‐layer self‐assembly

Excellent biocompatible polymeric membranes were prepared by combining the antifouling property of poly(ethylene glycol) methyl ether (mPEG) and the anticoagulant property of poly(sodium p‐styrene sulfonate) (PSS). Block copolymers of poly(ethylene glycol) methyl ether‐b‐poly(sodium p‐styrene sulfonate) (mPEG‐b‐PSS) with different chain lengths were synthesized by ATRP using mPEG macroinitiator. The copolymers were then used to modify polyethersulfone (PES) membrane via layer‐by‐layer (LBL) self‐assembly technology. The chemical compositions, surface morphologies and hydrophilicity of the modified membranes were characterized, indicating that the mPEG‐b‐PSS copolymers were successfully deposited on the membranes surfaces. Then, the blood compatibility and cytocompatibility of the modified membranes were systematically investigated. The results indicated that the mPEG‐b‐PSS copolymers could improve the hydrophilicity and the resistance to protein adsorption, and had great effect on suppressing platelet adhesion, prolonging clotting times, and improving cytocompatibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41245.     

Electrochemical synthesis of poly(2‐iodoaniline) and poly(aniline‐co‐2‐iodoaniline) in acetonitrile

Poly(2‐iodoaniline) (PIANI) and poly(aniline‐co‐2‐iodoaniline) [P(An‐co‐2‐IAn)] were synthesized by electrochemical methods in acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The voltametry of the copolymer shows characteristics similar to those of conventional polyaniline (PANI), and it exhibits higher dry electrical conductivity than PIANI and lower than PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of the iodine moieties into the PANI chain. The structure and properties of these conducting films were characterized by FTIR and UV‐Vis spectroscopy and by an electrochemical method (cyclic voltametry). Conductivity values, FTIR and UV‐Vis spectra of the PIANI and copolymer were compared with those of PANI and the relative solubility of the PIANI and the copolymer powders was determined in various organic solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1652–1658, 2003     

Designed magnetic multilayer thin films fabricated via the layer‐by‐layer assembly of polycyanofullerenes

The layer‐by‐layer self‐assembly technique was used to fabricate a series of multilayer thin films with poly[4′‐(4‐methacryloyphenyl)‐2,2′:6′,2″‐terpyridine] (PmPhtpy), polycyanofullerenes, and transition metals (Ni²⁺ and Co²⁺). The polymer PmPhtpy was prepared by free‐radical polymerization, and this was confirmed by Fourier transform infrared (FTIR) and ¹H‐NMR spectroscopy. The polycyanofullerenes, which were characterized by FTIR, ultraviolet–visible (UV–vis), and ¹³C‐NMR spectroscopy, was synthesized via the bromination of fullerene and then substitution with a nucleophilic reagent [potassium cyanide (KCN)]. The optical properties of the films were measured by attenuated total reflection infrared and UV–vis spectroscopy, and the results indicate that the driving force of the fabrication of the multilayer film was the coordination interaction. The magnetic behavior was examined as a function of the magnetic field strength at 5 K and the temperature (5–300 K). The magnetic hysteresis loops of the films showed a typical S shape at 5 K; this suggested soft ferromagnetic properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40681.     

Chitosan nanocoating on cotton textile substrate using layer‐by‐layer self‐assembly technique

An attempt was made to deposit a nanocoating onto a cotton textile substrate using a layer‐by‐layer self‐assembly approach. Chitosan, a natural biopolymer with polycationic characteristic, was used as a polyelectrolyte along with poly(sodium‐4‐styrene sulfonate) as an anionic polyelectrolyte for the first time on a textile substrate using this technique. The nanocoated surface was evaluated for surface characteristics such as the contact angle and scanning electron microscopy. The effect of ultrasonication during the intermediate washing steps was explored. Ultrasonication during the washing steps clearly helped in depositing more uniform bilayers onto individual fiber surfaces; this contrasted with the deposition of a continuous coating layer, which was nonuniform and had a lot of surface cracks. The use of this novel method for depositing chitosan onto cotton imparted antimicrobial properties to the fabric without adversely affecting its flexibility, feel, or breathability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011