Melt‐processed polyaniline nanofibers/LDPE/EAA conducting composites

The melt‐processable polyaniline nanofibers doped with superfluous dodecylbenzenesulfonic acid (PANI‐DBSA) were synthesized using the interfacial polymerization and thermal doping technique. Conducting composites composed of PANI‐DBSA nanofibers, low‐density polyethylene (LDPE), and ethylene‐acrylic acid copolymer (EAA) as compatibilizer were prepared by melt processing. The effects of PANI‐DBSA nanofibers on the electrical conductivity, and mechanical properties, and morphological structure of the composites were investigated. As a result, the conducting composites had lower percolation threshold (4 wt%) due to the easy formation of conducting paths for fibrillar‐like PANI‐DBSA in the LDPE matrix, which was also confirmed by the frequency dependence of the real part of the AC conductivity. The Scanning electron microscopy (SEM) images indicated that the PANI‐DBSA nanofibers were dispersed uniformly in the matrix. The mechanical properties of the composites were improved at the low PANI‐DBSA load (about 1 wt%), but they were deteriorated at high PANI‐DBSA content. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Aqueous dispersions of DBSA‐doped polyaniline: One‐pot preparation,characterization, and properties study

Aniline was polymerized in the presence of dodecylbenzene sulfonic acid (DBSA) as a functionalized protonic acid, in an aqueous medium to directly synthesize polyaniline (PANI)‐DBSA particles. DBSA acted as a dopant and a surfactant with stabilizing PANI‐DBSA dispersions by formation of strong hydrogen bonds. The NH⁺…SO interactions between the PANI chains and the DBSA appeared at 1026 cm^?1 in Fourier transform infrared (FTIR) spectrum. Elemental analysis was used to determine the degree of sulfonation (S/N ratio) of PANI chains and resulted that the sulfur‐to‐nitrogen ratio is 0.35. Thermogravimetric analysis (TGA) technique was used to analyze thermal properties of the particles and resulted that the synthesized PANI‐DBSA particles have high thermal stability. The moisture, DBSA and PANI contents of the PANI‐DBSA were estimated from TGA curve, and then the number of aniline repeating units doped with one DBSA molecule was approximately calculated. X‐ray diffraction (XRD) analysis confirmed that a chemical crosslinking reaction occurs between the PANI chains during thermal treatment of PANI‐DBSA. The morphology of PANI‐DBSA powder was investigated by scanning electron microscopy technique and showed that the PANI particles develops from round particles to a smooth surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synergistic effect of polyaniline and multiwalled carbon nanotube on the microstructure and the electric property in PP/PANI/MWNT composites

In this article, the volume conductivity of polypropylene (PP)/polyaniline (PANI)/multiwalled carbon nanotube (MWNT) composites was detected. When the ratio of PANI protonated with dodecylbenzene sulphonic acid (PANI‐DBSA) to MWNT is 2 to 3 and 3 to 17, the volume conductivity of the two composites is much higher than that of composites filled with solely PANI‐DBSA or MWNT. The synergistic effects of PANI‐DBSA and MWNT on the microstructure and the electric property of PP/PANI/MWNT composites were carefully analyzed by scanning electron microscope (SEM) and transmission electron microscopy. The SEM results illuminate that the dispersion and the continuity of the composites filled with PANI‐DBSA and MWNT are far better than that filled with only PANI‐DBSA or MWNT. Especially, the dispersion and continuity of PP/PANI/MWNT 5, in which the ratio of PANI‐DBSA to MWNT is 3 to 17, are the best among all the composites. When PANI‐DBSA is introduced in PP/PANI/MWNT composites, the size of agglomerated particles decreases, and the dispersion of conductive particles is improved evidently. Therefore, there is a synergistic action of PANI‐DBSA and MWNT, which is used to improve the dispersion of conductive particles and the volume conductivity of the PP/PANI/MWNT composites. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Polyaniline–nylon 6 composite nanowires prepared by emulsion polymerization and electrospinning process

Polyaniline (PANI) nanoparticles doped with the dodecylbenzene sulfonic acid (DBSA) were prepared and these nanoparticles were electrospun with nylon 6 as matrix material into fiber web. Depending on the contents and concentrations of PANI and nylon 6, either nylon 6 nanofibers (～96 nm) or PANI‐nylon 6 composite nanofibers (～12 nm) were obtained. The electrical conductivity of PANI(DBSA)–nylon 6 electrospun fiber web was lower than that of PANI(DBSA)‐nylon 6 film because of the low crystallinity of the PANI(DBSA)–nylon 6 composite electrospun fiber web. However, it showed that the PANI–nylon 6 composite nanofibers would have applications as the nanowires for connecting the microelectromechanical system (MEMS). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1277–1286, 2006     

Effects of chlorinated polypropylene on the hydrogen‐bond and electric property of polypropylene/chlorinated polypropylene/polyaniline composites: FTIR analysis

In this article, the volume resistivity of polypropylene (PP)/chlorinated polypropylene (CPP)/polyaniline (PANI) composites was detected. The results show that thevolume resistivity of PP/CPP/PANI composites decreases with increasing CPP content, and there exists a minimum volume resistivity. The relationship between volume resistivity of the PP/CPP/PANI composites and CPP content can be explained by Fourier‐transform infrared spectra (FTIR). Effects of CPP on the formation of the intermolecular and innermolecular hydrogen‐bond in the PP/CPP/PANI composites were carefully investigated by FTIR. An iterative least‐squares computer program was adopted to obtain the best FTIR fit curves of the PP/CPP/PANI composites by varying the wavenumber (ν), width at half‐height (w_1/2), and area (S) of several bands. The obtained semiquantitative results illuminate that the intermolecular and innermolecular H‐bonded interaction of the PANI‐DBSA is weakened by the introduction of CPP; the interactional strength between PANI‐DBSA and CPP increases with increasing CPP content, and there exists a maximum, which is favorable to disperse well PANI‐DBSA in PP/CPP/PANI composites and improve the conductive property of the PP/CPP/PANI composites. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Polymerization of anilinium/DBSA in the presence of clay particles: Catalysis and encapsulation

This paper describes polymerization of anilinium‐DBSA complex to PANI‐DBSA (DBSA doped polyaniline) in an aqueous dispersion in the presence of mica or talc clays. It is found that the clay presence significantly accelerates the polymerization kinetics by metal ions, such as Fe⁺² ions, present in the clays. Polymerization occurs preferentially on the clay particles' surface, causing their encapsulation with PANI‐DBSA shells. Further coating with PANI‐DBSA takes place on the already coated particles with thin PANI‐DBSA shells by an autoacceleration effect of anilinium‐DBSA polymerization by PANI. It is suggested that the catalytic/autoacceleration effect dominating in the coating process of clay particles with PANI‐DBSA can be extended to other particle/coating systems, which are already under investigation.     

Facile preparation of conductive paint made with polyaniline/dodecylbenzenesulfonic acid dispersion and poly(methyl methacrylate)

We investigated an easy way to prepare industrially a conductive paint made with polyaniline (PANI)/dodecylbenzenesulfonic acid (DBSA) dispersion and poly(methyl methacrylate) (PMMA) in organic media. First, water‐dispersible PANI doped with DBSA was chemically synthesized with aniline sulfate using ammonium persulfate in water, and the resulting PANI/DBSA was readily extracted from the reaction medium with a mixture of toluene and methyl ethyl ketone (MEK) (toluene:MEK = 1:1 (v/v)), which is useful for industrial applications. The obtained PANI/DBSA organic dispersion was mixed with PMMA organic solution to give the corresponding PANI/DBSA conductive paint containing PMMA. A film prepared with the resulting PANI/DBSA conductive paint was found to possess relatively good conductivity and low surface resistivity for a conductive paint utilized for an electrostatic discharge even at low PANI/DBSA content in the PANI/DBSA–PMMA composite film (the conductivity and the surface resistivity were 9.48 × 10^?4 S cm^?1 and 3.14 × 10⁶ Ω cm^?2, respectively, when the feed ratio of PANI/DBSA:PMMA was 1:39 (w/w)). Furthermore, it was found that the conductivity of the film composed of PANI/DBSA–PMMA composite can be readily and widely controlled by the PANI/DBSA content of the composite or by the amount of DBSA used during the PANI/DBSA synthesis. The highest conductivity of PANI/DBSA–PMMA composite film (7.84 × 10^?1 S cm^?1) was obtained when the feed ratio of PANI/DBSA:PMMA was 1:4 (w/w). Copyright © 2007 Society of Chemical Industry     

Effect of aniline‐formaldehyde resin on the reduced conjugation length of doped polyaniline: Thermal studies

A linear aniline‐formaldehyde resin (AF) complexed with different acids was successfully synthesized with the traditional way of polymerizing a novolac‐type phenolic resin. When the AF(DBSA)_1.0 (AF complexed with only HDBSA (n‐dodecyl benzene sulfonic acid)) was blended with PANI(DBSA)_0.5 (polyaniline doped only by HDBSA, the T_gs (glass transition temperatures) of the polyblends decreased with PANI(DBSA)_0.5, indicating the presence of the compatibility that can alter the doping condition of PANI(DBSA)_0.5 by changing the conjugation length. In the polyblend system, it was also confirmed when the polyblend of 50/50 showed a higher residue weight than the rest of polyblends after being heated up to 450°C. The λ_max of UV–vis spectra of PANI (DBSA)_0.5 demonstrates a red shifts indicating the secondary doping effect (increasing conjugation length) was recovered when PANI(DBSA)_0.5 was mixed with less than 50% of AF(DBSA)_0.5 (HCl)_0.5. Similar phenomenon of red shift was found for the blended samples of PANI(DBSA)_0.5/AF(DBSA)_1.0 at high temperatures. IR spectra revealed an alkyl affinity interaction is present between PANI(DBSA)_0.5 and AF(DBSA)_1.0 at room temperature and a strong and free localized polaron band appeared at high temperatures due to the recovery of secondary doping. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2120–2128, 2007     

Synthesis,characterization, and comparative study of conducting polyaniline/lead titanate and polyaniline–dodecylbenzenesulfonic acid/lead titanate composites

To study the effect of a surfactant on the properties of polyaniline (PANI)/metal oxide composites, PANI/lead titanate (PbTiO₃) composites were synthesized with different weight percentages (10, 20, 30, 40, and 50 wt %) of PbTiO₃ in both the absence and presence of dodecylbenzenesulfonic acid (DBSA) by the polymerization of aniline with ammonium persulfate as an initiator. The structural characteristics and stability, surface characteristics, and electric properties of PANI/PbTiO₃ and PANI–DBSA/PbTiO₃ were studied and compared. The interfacial interactions and thermal stability of these composites were characterized with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermogravimetry techniques. The results indicate significant changes in the physicochemical properties of the composites with the incorporation of DBSA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrical and structural analysis of conductive polyaniline/polyimide blends

Conducting films of dodecylbenzenesulfonic (DBSA)‐doped polyaniline/polyimide (PANI/PI) blends with various compositions were prepared by solvent casting followed by a thermal imidization process. Electrical and physical properties of the blends were characterized by infrared spectroscopy, an X‐ray diffraction technique, thermal analysis, a UV‐vis spectrophotometer, a dielectrometer, and conductivity measurements. The blends exhibited a relatively low percolation threshold of electrical conductivity at 5 wt % PANI content and showed higher conductivity than that of pure DBSA‐doped PANI when the PANI content exceeded 20 wt %. A lower percolation threshold and a lower compatibility was shown between the two components in the blends than those of PANI–camphorsulfonic acid/polyamic acid (PANI–CSA/PAA). A well‐defined layered structure due to the alignment of the long alkyl chain dopant perpendicular to the PANI main chain was evidenced by WAXD spectra. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2169–2178, 1999     

Investigation on the microstructure and the electric property of poly(propylene)/chlorinated poly(propylene)/poly(aniline) composites

The article presents results of studies on composites made from poly(propylene) (PP) modified with poly(aniline) (PANI) doped with dodecylbenzene sulfonic acid (DBSA) and chlorinated poly(propylene) (CPP). The volume resistivity of PP/CPP/PANI composites was detected, and the results show that the volume resistivity decreases with increasing CPP content, and there exists a minimum volume resistivity. Effects of CPP on the microstructure and crystalline structure of the PP/CPP/PANI composites and the relationship between the effects and the electric property were carefully analyzed by scanning electron microscope (SEM) and wide angle X‐ray diffraction (WAXD). The method that the specimens of SEM are polished is appropriate to investigate the morphology of conducting polymer composites. The obtained results illuminate that the area of conducting parts and insulating parts obtained from the digital analysis of the SEM image is obviously influenced by the CPP content, the parameters of the lamellar‐like structure are immediately related to CPP content and denote the dispersion of PANI‐DBSA, and the percent crystallinity and mean crystal size of PP are directly correlated with the CPP content. The increasing area of conducting parts, the increasement of layer distance, the decreasement of size and layer number of the lamellar‐like structure of PANI‐DBSA, and the increasement of the percent crystallinity and mean crystal size of PP are beneficial to the improvement of the conductive property of PP/CPP/PANI composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

PANI–LDPE composites: Effect of blending conditions

A composite based on polyaniline (PANI) and low density polyethylene (LDPE) with electrical conductivity was developed. Polyaniline was polymerized by chemical oxidation and doped with dodecyl‐benzene‐sulfonic acid (DBSA). PANI–LDPE composites were prepared via melt blending and the films were obtained by compression molding. The influence of three variables of the blending (temperature, [PANI], rotor speed) on conductivity, microstructure and mechanical properties of the composites was studied by means of statistical tools and a 2³ experimental design. The results show that the PANI concentration is the most influential variable, which mainly affects the conductivity and the elongation at break of the composites. These changes are related to the microstructure of the composites. Statistically, the other variables don't show significant influence on conductivity and mechanical properties in the studied range. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.     

Synthesis and characterization of polyaniline co-doped with nitric acid and dodecyl benzene sulfonic acid

Polyaniline (PANI) co-doped with nitric acid (HNO₃) and dodecyl benzene sulfonic acid (DBSA) was directly prepared by the chemical oxidative polymerization of aniline in an aqueous solution. When the molar ratio of HNO₃/DBSA was 0.3:7, the resulted co-doped PANI (PANI_H0.3D7) reached a maximum electrical conductivity of 7.98 S/cm. When the molar ratio of HNO₃/DBSA was 0.4:6, the resulted co-doped PANI (PANI_H0.4D6) exhibited a maximum yield of 70.09%. Thermogravimetric analysis (TGA) results illustrated that there were four weight loss stages in the co-doped PANI. These weight losses were resulted from the evaporation of moisture, HNO₃, DBSA, and PANI respectively. TGA results also indicated that approximately 10.04 and 3.32 repeating units of PANI were doped with one HNO₃ molecule and one DBSA molecule in the co-doped PANI_H0.3D7, respectively. Fourier transform infrared (FTIR) results showed that the absorption peaks of the ?C═C? and ?C_aromatic?N? stretching vibrations in the emeraldine salt (ES) PANI were all shifted to the lower wavenumbers than those in the emeraldine base (EB) PANI. It was worth noting that the morphology of PANI was strongly affected by polymerization conditions.     

DBSA掺杂聚苯胺的制备、表征及其导电性

采用过硫酸铵(APS)为氧化剂在十二烷基苯磺酸(DBSA)微胶束中化学氧化制备纳米棒状聚苯胺;DBSA既起乳化剂也起掺杂剂的作用。制备的掺杂聚苯胺用红外光谱(FTIR)、紫外光谱(UV-vis)、X-射线衍射(XRD)和扫描电镜(SEM)进行了表征;透射电镜(TEM)下首次观察到了聚苯胺的有序排列结构,晶面间距为5.99 Å。考察了掺杂剂/苯胺、氧化剂/苯胺的摩尔比和反应温度、时间等对聚苯胺电导率影响,最高电导率达到了0.72 S/cm。透射电镜怎能看到5.99     

Preparation and characterization of transparent PANI‐SIO2 hybrid conducting films

Dodecylbenzene sulfonic acid‐doped polyaniline (DBSA‐PANI) was prepared with 3‐glycidoxypropyltrimethoxysilane (GPTMS) through a sol–gel route without water and ethanol. Acetic acid was used to play both the roles of reagent and catalyst during the hydrolysis‐condensation reaction of GPTMS, which affected the structure of precursors. On the other hand, m‐cresol can adjust the acidity of solution and it was also a secondary dopant in DBSA‐PANI to enhance conductivity of hybrid films. The conductivity and visible light transmittance vary with the molar ratio of acetic acid to GPTMS and m‐cresol to GPTMS. Sheet resistance of the new hybrid films made by a dipping process reaches 5.1 kΩ/□ and visible light transmittance is higher than 75%. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Thermal dynamic processing of polyaniline with dodecylbenzene sulfonic acid

To attain an intrinsically conductive and processible polymer, polyaniline (PANI)/dodecylbenzene sulfonic acid (DBSA) blends of several compositions were processed at various elevated temperatures in a Brabender plastograph. The blends' temperatures during processing, as affected by the blends' composition and initial process temperature, were monitored. Accordingly, the process includes the following main stages: heating the blend, exothermic PANI-DBSA doping reaction accompanied by a paste to a solidlike transition, and plasticization of the resulting PANI/DBSA complex by the excess DBSA. Composition analysis of the process products sampled at the various stages showed that the initial blends, prior to their thermal processing, already consisted of partially doped PANI particles, having a core/shell structure; the core consists of PANI_base and the shell of PANI(DBSA)_0.32 complex. In addition, at the paste-to-solidlike transition, the doping reaction is completed; further mixing does not affect the complex composition, but results in conductivity reduction. The morphology of the blends sampled at the various processing stages was studied by electron microscopy. From the conductivity and processibility point of view, optimal PANI/DBSA blend composition and processing temperature were identified. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2199–2208, 1997     

Systematic evaluation of the preparation of conducting PANI/ABS blends

Films of blended poly(acrylonitrile‐butadiene‐styrene) (ABS) and polyaniline (PANI) were produced by codissolving both components in a common organic solvent, which was then evaporated. The influence of the preparation conditions on the properties of the blends was analyzed by factorial design. The factors evaluated were the PANI content in the blend, the m‐cresol to chloroform solvent ratio, the dopant used (dodecylbenzenesulfonic acid (DBSA) or camphor sulfonic acid) and its concentration, and the acrylonitrile content in the ABS. The responses analyzed were the flexibility and electrical conductivity of the blends. The results showed that the PANI content in the blend and the acrylonitrile content in the ABS were the major factors influencing both of the assessed responses. The dopant affected only the conductivity, DBSA being preferred for the development of more conductive PANI/ABS blends. The solvent ratio did not have any influence, owing to the uniform expanded coil conformation expected for PANI molecules at the studios ratios. After the best conditions had been established, a percolation threshold study was performed that pointed to a low threshold of 3 wt % PANI necessary in the blend, giving a flexible blend with a conductivity of 3 S/cm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polyaniline/PVAc blends: Variation with time of structure and conductivity of films cast from aqueous dispersions

Recently, a polymerization process of Anilinium‐Dodecyl Benzene Sulfonic Acid (DBSA) complex in an aqueous dispersion was developed in our laboratories. Simple mechanical mixing of the aqueous PANI–DBSA dispersion with a PVAc aqueous latex leads to highly conductive blends at low PANI–DBSA contents. The percolation threshold of the dried films is extremely low (∼0.5 wt %). The combined aqueous PVAc/PANI–DBSA dispersions exhibit a gradually decreasing electrical conductivity accompanied by a gradually increasing viscosity, with the storage time. However, an aged cast film from these blends maintains its electrical conductivity with time. These phenomena are associated with acidic hydrolytic reactions of the ester group, resulting in the formation of vinyl acetate–vinyl alcohol copolymer and evolution of acetic acid, and also the interaction of the DBSA surfactant with the PVAc, causing swelling and disintegration of PVAc particles. A chemical structural model describing these changes with storage time is suggested. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 760–766, 2001     

Reactive processing and evaluation of butadiene–styrene copolymer/polyaniline conductive blends

Blending is an important way to obtain materials based on intrinsically conductive polymers and conventional plastics and rubber materials. Much research has been carried out to determine the best performance of materials be used for electrostatic dissipation and electromagnetic interference shielding. Mechanical mixing, codissolution, and in situ polymerization have been used to prepare these materials. The method used depends on the host polymer and its thermal stability and acid attack resistance. Homogeneity and miscibility are properties that should be controlled during blend preparation. In this study, we prepared a conductive thermoplastic elastomer material based on butadiene–styrene copolymer (SBR) and polyaniline (PANI) doped with dodecylbenzene sulfonic acid (DBSA) and poly(styrene sulfonic acid) (PSS). PSS also acted as compatibilizer between PANI and SBR. PANI was doped by reactive processing with DBSA and PSS to produce the conductive complex PANI–DBSA–PSS. This complex was mixed with 90, 70, and 50% (w/w) SBR in a counterrotatory internal mixer. Conductivity tests, swelling studies, thermal analysis, and mechanical property and reflectivity testing were done, and the results show a strong dependence on PANI concentration and the ratio between PANI–DBSA and PSS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 681–685, 2006     

不同酸掺杂聚苯胺的电化学聚合及性能

采用循环伏安（CV）法在镀金PET膜上分别聚合了硫酸（H2SO4）、十二烷基苯磺酸（DBSA）、硫酸-十二烷基苯磺酸掺杂的聚苯胺（PANI）膜,对比研究了掺杂酸种类对PANI结构和性能的影响。结果表明,SO42?、DBSA?可以随聚合过程进入PANI分子链;H2SO4掺杂的PANI具有较高的电导率,但是在空气中的稳定性较差;大分子的DBSA使PANI优先产生单螺旋的纤维,提高了PANI在平行分子链方向上的结晶度和在空气中的稳定性;相对于单一酸掺杂,复合酸掺杂的PANI在酸溶液中电扫描表现出优良的循环伏安特性,在保持较高电导率的同时,提高了PANI在空气中的稳定性。