Soluble,Antibaterial, and Anticorrosion Studies of Sulfonated Polystyrene/Polyaniline/Silver Nanocomposites Prepared with the Sulfonated Polystyrene Template

In this work, multifunctional sulfonated polystyrene/polyaniline/silver (SPS /PANI /Ag) nanocomposites are prepared through using sulfonated polystyrene (SPS ) spheres as templates and utilizing polyvinylpyrrolidone (PVP ) as reducing agent and stabilizing agent. Our method is an environmentally friendly method because no toxic reagents are added during the preparation process. Fourier transform infrared spectrum (FTIR ), field emission scanning electron microscopy (FESEM ), and energy disperse spectroscopy (EDX ) results confirmed the formation of PS spheres, SPS spheres, SPS /PANI nanocomposites, and SPS /PANI /Ag nanocomposites. Powder X‐ray diffraction (XRD ) patterns indicate that the obtained Ag nanoparticles are crystalline. Solubilities measurements show that SPS /PANI /Ag nanocomposites have improved solubilities when compared to pure PANI in common organic solvents and deionized water. Antibacterial studies show that SPS /PANI /Ag nanocomposites can greatly inhibit the growth of Escherichia coli and Staphylococcus aureus . Anticorrosion studies show that the incorporation of SPS /PANI /Ag nanocomposites in waterborne alkyd resin can greatly promote the anticorrosive efficiency of waterborne alkyd resin.     

One-step route to the fabrication of highly porous polyaniline nanofiber films by using PS-b-PVP diblock copolymers as templates

We report a new method to control both the nucleation and growth of highly porous polyaniline (PANI) nanofiber films using porous poly(styrene-block-2-vinylpyridine) diblock copolymer (PS-b-P2VP) films as templates. A micellar thin film composed of P2VP spheres within a PS matrix is prepared by spin coating a PS-b-P2VP micellar solution onto substrates. The P2VP domains are swollen in a selective solvent of acetic acid, which results in the formation of pores in the block copolymer film. PANI is then deposited onto the substrates modified with such a porous film using electrochemical methods. During the deposition, the nucleation and growth of PANI occur only at the pores of the block copolymer film. After the continued growth of PANI by the electrochemical deposition, a porous PANI nanofiber film is obtained.     

Constructing magnetic polyaniline/metal hybrid nanostructures using polyaniline/Fe3O4 composite hollow spheres as supports

Polyaniline (PANI)/Fe₃O₄ composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production.     

Synthesis of hierarchical Polystyrene/Polyaniline@Au nanostructures of different surface states and studies of their catalytic properties

We synthesized hierarchical Polystyrene/Polyaniline@Au(PS/PANI@Au) catalysts through a seeded swelling polymerization and in-situ reduction procedure. PS/PANI@Au catalysts possess a core of PS as seed and template, a PANI shell with fibers and uniform gold nanoparticles on the surface. The configuration changes of the PANI chains resulting from the doping/ dedoping procedure led to various loading amounts of Au nanoparticles. Reduction of 4-nitrophenol was chosen as the probe reaction to evaluate the catalytic activity of supported Au nanocatalysts. The catalytic results indicated that dedoping treatment of the PS/PANI supports provides stronger coordinative ability to metal nanoparticles as well as more –N= groups, which results in a better catalytic performance towards the reduction of 4-nitrophenol.     

Enhancing dielectric and mechanical behaviors of hybrid polymer nanocomposites based on polystyrene,polyaniline and carbon nanotubes coated with polyaniline

The dielectric and mechanical properties of hybrid polymer nanocomposites of polystyrene/polyaniline/carbon nanotubes coated with polyaniline(PCNTs) have been investigated using impedance analyzer and extensometer. The blends of PS/PANI formed the heterogeneous phase separated morphology in which PCNTs are dispersed uniformly. The incorporation of a small amount of PCNTs into the blend of PS/PANI has remarkably increased the dielectric properties. Similarly, the AC conductivity of PS/PANI is also increased five orders of magnitude from 1.6 × 10~(-10) to 2.0 × 10~(-5) S·cm~(-1) in the hybrid nanocomposites. Such behavior of hybrid nanocomposites is owing to the interfacial polarization occurring due to the presence of multicomponent domains with varying conductivity character of the phases from insulative PS to poor conductor PANI to highly conductive CNTs. Meanwhile, the tensile modulus and tensile strength are also enhanced significantly up to 55% and 160%, respectively, without much loss of ductility for three phase hybrid nanocomposites as compared to the neat PS. Thereby, the hybrid nanocomposites of PS/PANI/_P CNTs become stiffer, stronger and tougher as compared to the neat systems.     

On the structure and electrical conductivity of polyaniline/polystyrene blends prepared by an aqueous‐dispersion blending method

This article describes electrically conductive polymer blends containing polyaniline‐dodecyl benzene sulfonic acid (PANI‐DBSA) dispersed in a polystyrene (PS) matrix or in crosslinked polystyrene (XPS). Melt blending of previously mixed, coagulated, and dried aqueous dispersions of PANI‐DBSA and PS latices lead to high conductivities at extremely low PANI‐DBSA concentrations (∼0.5 wt % PANI‐DBSA). In these blends, the very small size of the PANI‐DBSA particles and the surface properties (with surfactants used) of both the PANI and polymer particles play a major role in the PANI‐DBSA particle structuring process. The PANI‐DBSA behavior is characteristic of a unique colloidal polymeric filler with an extremely high surface area and a strong interaction with the matrix, evidenced by a significantly higher glass‐transition temperature of the matrix. The effect of the shear level on the conductivity and morphology of the PS/PANI‐DBSA blends was studied by the production of capillary rheometer filaments at various shear rates. An outstanding result was found for XPS/PANI‐DBSA blends prepared by the blending of aqueous XPS and PANI‐DBSA dispersions. Some of these blends were insulating at low shear levels; however, above a certain shear level, smooth surface filaments were generated, with dramatically increased and stable conductivities. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 611–621, 2001     

Inverse‐Opal Conducting Polymer Monoliths in Microfluidic Channels

Inverse opal monolithic flow‐through structures of conducting polymer (CP) were achieved in microfluidic channels for lab‐on‐a‐chip (LOC) applications. In order to achieve the uniformly porous monolith, polystyrene (PS) colloidal crystal (CC) templates were fabricated in microfluidic channels. Consequently, an inverse opal polyaniline (PANI) structure was achieved on‐chip, through a two‐step process involving the electrochemical growth of PANI and subsequent removal of the template. In this work the effect of CP electropolymerisation time on these structures is discussed. It was found that growth time is critical in achieving an ordered structure with well‐defined flow‐through pores. This is significant as these optimised porous structures will allow for maximising the surface area of the monolith and will also result in well‐defined flow profiles through the microchannel.     

Fabrication, morphology and thermal degradation behaviors of conductive polyaniline coated monodispersed polystyrene particles

This study describes the preparation of polyaniline (PANI) coated on the surface of monodispersed 400 nm polystyrene (PS) particles by in situ chemical oxidative polymerization. The monodispersed 400 nm PS particles served as cores were synthesized using the emulsion polymerization. Both images observed by field-emission scanning electron microscopy and transmission electron microscopy show the presence of a thin PANI layer uniformly coated on the surface of PS particle. The electrical conductivity of various amounts of PANI-coated PS particles is significantly increased about 13 orders of magnitude compared to that of the pristine PS particles. Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) were used to investigate the thermal stability and thermal degradation behavior of PS and PANI-coated PS particles. Both DSC and TGA curves revealed that the coating of a thin PANI layer on the surface of PS can drastically increase the thermal stability of PS matrix. TGA isothermal degradation data illustrate that the activation energy of the PANI-coated PS particle is larger than that of PS. This phenomenon can be attributed to the incorporation of PANI coating on the surface of PS particle caused a decrease in the degradation rate and an increase in the residual weight for the PANI-coated PS particle.     

Preparation and characterization of polyaniline/polysulfone nanocomposite ultrafiltration membrane

Novel nanocomposite membrane was prepared through the filtration of polyaniline (PANI) nanofiber aqueous dispersion with polysulfone (PS) ultrafiltration (UF) membrane. Scanning electron microscope (SEM) images showed that PANI nanofiber layer was formed on the PS membrane surface. Atomic force microscopy (AFM) analysis indicated that the nanocomposite membrane had rougher surface than the PS substrate membrane. Compared with the PS substrate membrane, the nanocomposite membrane had much better permeability for the good hydrophilicity of PANI nanofiber layer, and had almost the same rejection performance. In addition, the nanocomposite membrane had positive surface potential under acidic condition because PANI could be protonated easily by acid. During the filtration of BSA solution, the nanocomposite membrane showed much better antifouling performance than the substrate membrane for the hydrophilicity and steric hindrance effect of its nanofiber layer. Moreover, under acidic solution condition, strong electrostatic repulsion between PANI nanofibers and BSA existed and improved membrane antifouling performance further.     

Nanocomposite and nanoporous polyaniline conducting polymers exhibit enhanced catalysis of nitrite reduction

Nanostructured polyaniline (PANI) conducting polymer films were prepared on electrochemically pretreated glassy carbon electrodes, which were previously modified with multilayers of polystyrene (PS) nanoparticles with a diameter of 100 nm. PANI was electropolymerised and grown through the interstitial spaces between the PS nanoparticles, which formed a nanocomposite film of PANI and PS nanoparticles on the electrode surface. Furthermore, a nanoporous PANI film was fabricated through the removal of the PS nanoparticles by dissolution in toluene. As a result of their nanostructure, both of the PANI films (before and after removal of the PS nanoparticles) exhibited enhanced electrocatalytic behaviour towards the reduction of nitrite relative to bulk-PANI films; however, partial collapse or shrinkage may have occurred with the removal of the nanoparticles and could have resulted in a less enhanced response. Under optimised conditions, the nanocomposite-film-modified electrode exhibited a fast response time of 5 s and a linear range from 5.0 x 10(-7) to 1.4 x 10(-3) M for the detection of nitrite; the detection limit was 2.4 x 10(-7) M at a signal-to-noise ratio of 3.     

聚苯乙烯-b-聚丙烯酸模板剂成核段长度对聚苯胺尺寸及性能的影响

以两亲性嵌段共聚物为模板是构筑导电聚合物纳米结构并对其形貌尺寸进行调控的有效方法之一。 嵌段共聚物成核段长度的变化对其胶束化行为有显著影响,进而也会改变受限于其胶束形貌的导电聚合物的形貌尺寸。 形貌尺寸的变化必然导致导电聚合物电化学性能变化。 本文欲通过嵌段共聚物模板诱导实现对聚苯胺(PANI)形貌尺寸的调控并使其电化学性能得到优化,采用可逆加成-断裂链转移自由基聚合(RAFT)法成功合成了嵌段共聚物聚苯乙烯-b-聚丙烯酸PS_x-b-PAA₇₀(x=38、64、101)并以其胶束为“模板”制备了窄相对分子质量分布的PANI。 在成核段(PS)长度较短时,模板诱导形成的棒状PANI颗粒,直径为100~200 nm。当 x=101时PANI呈现空间网状结构,其放电比容量高于其它样品,在电流密度为1 A/g时,其放电比容量可达386.71 F/g。     

Synthesis and properties of silica/polystyrene/polyaniline conductive composite particles

In this study, silica/polystyrene/polyaniline (SiO₂/PS/PANI) conductive composite particles were synthesized by four sequential reactions. The nanosized SiO₂ particles were synthesized from tetraethoxysilane (TEOS) by a sol–gel process with water as the solvent medium, followed by a surface modification with triethoxyvinylsilane; then the surface modified SiO₂ particles were used as seeds to synthesize SiO₂/PS composite particles with soapless seeded emulsion polymerization. Finally, the SiO₂/PS particles were used as seeds to synthesize the SiO₂/PS/PANI conductive composite particles. The sol–gel process of SiO₂, the effect of surface modification, and several other factors that influenced polymerization of styrene in the soapless seeded emulsion polymerization will be discussed. Either potassium persulfate (KPS) or 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as the initiator to synthesize the uniform SiO₂/PS particles successfully, and the cross‐section morphology of the SiO₂/PS particles was found to be of a core–shell structure, with SiO₂ as the core, and PS as the shell. The SiO₂/PS particles were well dispersed in many organic solvents. In the following step to synthesize SiO₂/PS/PANI conductive composite particles, sodium dodecyl sulfate (SDS) played an important role, specifically, to absorb aniline onto the surfaces of the SiO₂/PS particles to carry out the polymerization of aniline over the entire surface of the particles. The conductivity of the SiO₂/PS/PANI composite particles approached that of semiconductive materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 342–354, 2005     

Polyaniline/Au composite hollow spheres: synthesis, characterization, and application to the detection of dopamine

Polyaniline (PANI)/Au composite hollow spheres were successfully synthesized using polystyrene/sulfonated polystyrene core/shell gel particle templates. The PANI shell thickness and the number of Au nanoparticles decorating the PANI could be controlled effectively by adjusting the experimental conditions. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres. Furthermore, PANI/Au composites were immobilized on the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI/Au-modified GCEs showed one pair of redox peaks and high catalytic activity for the oxidation of dopamine. The possible formation mechanism of the PANI/Au composite hollow spheres was also discussed.     

RECTIFYING EFFECT OF POLYANILINE(PANI)/N-TYPE POROUS SILICONE HETEROJUNCTION*

Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell,were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of thepreparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. Therectifying parameters of Al/PS-PANI/Au cell were determined to be γ= 1 .8×10~1～ 1 .0×10~5 for the rectifyingratio at 3V, n = 3 ～12 for the ideal factor,j_0 = 8.0×10~(-5)～5.6×10~(-2) mA/cm~2 for the reversed saturated currentdensity, and φ_b = 0.67～ 0.83 V for the barrier height, respectively. The best rectifying heterojunction diodemade between PANI and n-type PS with higher rectifying factor (γ= 1 .0×10~5 at 3V ), output current (>1500mA/cm~2 at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS beforeevaporating Al electrode.     

原位溶液聚合聚苯胺与聚苯乙烯溶液共混复合材料的制备及表征

以DNSA掺杂剂,在醇(或酮)-水介质中采用原位溶液聚合法制备出了聚苯胺,以溶液共混法制备出了聚苯胺/聚苯乙烯复合材料,采用红外光谱、热失重、元素分析、扫描电镜对产物进行了表征。结果显示：掺杂的聚苯胺电导率最高为0.65 S/cm,优于常用的DBSA,具有一定实用价值和理论意义。该复合材料表面电阻率最低为101Ω/□数量级,并在一定范围内可调,可用于电磁屏蔽,适合于聚合物表面使用。     

Hemoglobin-glucose oxidase catalyzed polymerization of aniline： Electrochemical study and application

A new method for the formation of electroactive polyaniline (PANI) biocatalyzed by hemoglobin coupled with glucose oxidase in neutral medium on the polystyrene nanospheres (PS) modified glassy carbon electrode, was investigated. The bio-polymerized PANI formed on the PS was confirmed by the obvious increase of the diameter of the particles on the scanning electron microscopy image. The cyclic voltammetric behavior of the PANI was also investigated. PANI produced an oxidative peak at 0.28 V and a reductive peak at 0.23 V. Based on the glucose-dependent bio-polymerization, a new electrochemical protocol for the estimation of glucose was developed. The square wave voltammetric response of PANI deposited on the modified electrode increased linearly with glucose concentration in the range of 0.1-10.0 μmol/L. The efficient performance of hemoglobin-oxidase biocatalyzed polymerization of aniline provides a new concept for the synthesis of nanomaterials, and a general protocol for the development of the biosensors.     

聚苯胺纳米线电导率的尺寸效应

在前期工作的基础上, 利用导电原子力显微镜法测量单根聚苯胺纳米线的电导率, 探讨了聚苯胺纳米线(PANI nanowine)电导率的尺寸效应, 发现尺寸效应与纳米线的有序性有关.     

The Electrochemical Properties of Nanocomposite Films Obtained by Chemical In Situ Polymerization of Aniline and Carbon Nanostructures

Interactions between the π bonds in the aromatic rings of polyaniline (PANI) with carbon nanostructures (CNs) facilitate charge transfer between the two components. Different types of phenyleneamine‐terminated CNs, including carbon nano‐onions (CNOs) and single‐walled and multi‐walled carbon nanotubes (SWNTs and MWNTs, respectively), were prepared as templates, and the CN/PANI nanocomposites were easily prepared with uniform core–shell structures. By varying the ratio of the aniline monomers relative to the CNs in the in situ chemical polymerization process, the thickness of the PANI layers was effectively controlled. The morphological and electrical properties of the nanocomposite were determined and compared. The thickness and structure of the PANI films on the CNs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and infrared spectroscopy. TEM and SEM revealed that the composite films consisted of nanoporous networks of CNs coated with polymeric aniline. The electrochemical properties of the composites were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. These studies showed that the CN/PANI composite films had lower resistance than pure polymeric films of PANI, and the presence of CNs much improved the mechanical stability. The specific electrochemical capacitance of the CNO/PANI composite films was significantly larger than for pure PANI.     

Polyaniline precipitation in aqueous medium: from bulk aggregates to nanoparticles

A postsynthetic self-assembly system was designed to investigate a construction process from suspended polyaniline (PANI) molecules to condensed aggregates. The conventionally synthesized PANI was dissolved in polar solvent and introduced into acidic medium with electrolytes similar to the aniline chemical oxidative polymerization (COP) medium. In this way, reaction interference that is usually encountered in the COP process could be avoided, and influences of medium conditions including organic electrolytes on the self-assembly behaviors of PANI were studied. It was discovered that, in a static aqueous medium with moderate pH and rich electrolytes, PANI molecules composed of bulk aggregates could self-assemble into well-dispersed nanoparticles with few structural changes. Electrostatic force is considered to dominate the self-assembly of PANI molecules as compared with other noncovalent interaction or the effect of soft templates such as ionic liquid and surfactant. The results are supposed to provide better understanding on the formation mechanism of micro/nanostructured PANI.     

Elucidation of protein adsorption behavior on polymeric surfaces: toward high-density, high-payload protein templates

The elucidation of protein adsorption behavior on polymeric surfaces is very important, since their use as arrays and carriers of biomolecules is ever growing for a wide variety of bioapplications. We evaluate protein adsorption characteristics on chemically homogeneous and heterogeneous polymeric surfaces by employing polystyrene-block-polymethylmethacrylate (PS-b-PMMA) diblock copolymer, PS homopolymer, PMMA homopolymer, and PS/PMMA blend as protein templates. We also investigate distance-dependent protein adsorption behavior on the interfacial region between PS and PMMA. We observe selective protein adsorption exclusively onto PS areas for the chemically heterogeneous PS-b-PMMA and PS/PMMA blend templates. On blend films, protein adsorption is highly favored on the PS regions located near the PS:PMMA interface over that on the PS areas situated away from the interface. Protein density on PS domains is inversely proportional to the separation distance between two neighboring PS:PMMA interfaces. We also observe a higher protein density on the PS-b-PMMA than on the PS or PMMA homopolymer templates. This effect is due to the fact that chemically heterogeneous PS-b-PMMA presents periodically spaced PS:PMMA interfaces on the nanometer scale, whereas no such interfaces are present on homopolymer films. The density of protein molecules on the heterogeneous PS-b-PMMA surface is approximately 3-4-fold higher than on the homogeneous PS surface for the identical experimental conditions. These results demonstrate that self-assembling, chemically heterogeneous, nanoscale domains in PS-b-PMMA diblock copolymers can be used as excellent, high-payload, high-density protein templates. The unique advantages of the diblock copolymer may prove the spontaneously constructed protein nanotemplates to be highly suitable as functional substrates in many proteomics applications.