Investigating the effect of ultrasonic irradiation on preparation and properties of conductive nanocomposites

In the present study, the ultrasonic irradiation technique was employed as a new approach to prepare 0-3-dimensional polyaniline/ZnO shell-core composite particles. By taking advantage of the multiple effects of ultrasound, one can break down the aggregates of nanocrystalline ZnO particles. The polymerization of aniline proceeded while the nanoparticles were redispersed by ultrasound, and the synthesized polyaniline deposited on the ZnO particle, which formed polyaniline-coated nanocrystalline composite particles. The material was characterized by using transmission electron microscopy, XRD, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA). With increased ZnO content, the H-bonding interaction is strengthened and the characteristic peaks of benzoid and quinoid are shifted. X-ray photoelectron spectroscopy (XPS) shows that the ratio of the number of Zn and N atoms (Zn/N) on the surface is lower than that in the bulk. This is strong evidence for a PANI-encapsulated ZnO nanoparticles structure. The conductivity of the composites obtained through ultrasonic irradiation decreases with increasing ZnO content. Ultrasonic irradiation contributes to the increase in the conductivity compared with conventional stirring. Photocatalytic properties of PANI/ZnO nanocomposites were examined by degrading Reactive Black 5 (RB5) dye under visible light irradiation.     

Preparation and Gas Sensing Performance of Hierarchical Porous ZnO-based Materials with Sunflower Rods as a Biological Template

A graded porous structure SnO2/ZnO composite was prepared with sunflower rods as a biological template. The prepared samples were subjected to phase analysis by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffractiometry(XRD) and X-ray photoelectron spectroscopy(XPS).ZnO sample was a pure phase of hexagonal wurtzite, and the template had been completely removed. The surface of the sample presented a honeycomb-like structure of a sunflower rod template, which was formed by interconnecting the porous channels, and had a smaller average size and exhibited n-n heterojunction at tlie n-type ZnO interface. Compared with that of pure ZnO, the response of the hierarchical porous structure SnO2/ZnO composite to 100 mg/L w-butanol reached a maximiuTi of 40.61 at 240℃, about 2.7 times higher than that of pure ZnO. Its response time and recovery time are 6 and 3 s, respectively, which are also better than those of pure ZnO. SnO2/ZnO composite exhibits good gas selectivity, which is related to the improvement of the structure and the forming of n-n heterojunctions of the material.     

Platinum-modified polyaniline/polysulfone composite film electrodes and their electrocatalytic activity for methanol oxidation

The polyaniline/polysulfone (PAN/PSF) composite films were prepared by electropolymerization, and then platinum was deposited into this composite film to obtain the platinum-modified polyaniline/polysulfone(Pt/PAN/PSF) composite film electrodes. Their component, morphology and structure were characterized by FTIR spectra, scanning electron microscopy and energy dispersive X-ray spectroscopy. The results show that the composite film has a bi-layer structure with asymmetrical pores, and the platinum particles are homogeneously dispersed in the modified film electrodes. The cyclic voltammetry and electrochemical impedance spectroscopy techniques were applied to investigate the electrochemical properties and the electrocatalytic activity of the modified film electrodes, which show a promotive action for methanol oxidation and the methanol oxidation under a diffusion-controlled process.     

A comparative study on wear and friction characteristics of phenolic composite coatings filled with different morphologies ZnO

In this paper, different morphologies ZnO (disk‐like, rod‐like, and nanoparticles) were introduced into phenolic composite coatings to comparatively investigate the tribological properties. The structural and morphological characterization was conducted with Raman spectroscopy, X‐ray diffraction, and scanning electron microscopy. The tribological performances of composite coatings were evaluated using ring‐on‐block tester under dry condition at room temperature. Experimental results indicated that composite coatings filled with 1 wt% ZnO micro‐disks possessed the optimal tribological performances. It was attributed to the strong interfacial interaction between ZnO micro‐disks and phenolic matrix induced by their specific polar structure. Moreover, different loads and sliding speeds were employed to further evaluate the tribological performances of ZnO micro‐disks/phenolic composite coatings. The outcome revealed that ZnO micro‐disks were potential anti‐wear fillers under harsh condition.     

Synthesis of nano/micro zinc oxide rods and arrays by thermal evaporation approach on cylindrical shape substrate

Nano and micro ZnO rods and arrays have been synthesized by a simple thermal evaporation approach on a cylindrical shape substrate. Most of the synthesized ZnO products are single crystalline with a hexagonal structure and grow along the [0001] direction. Individual protrusive ZnO rods and well-aligned arrays are two typical products in our work. The individual protrusive ZnO rods have diameters of 25 nm approximately 2.1 microm and lengths from several hundred nanometers to 40 microm, while in the well-aligned arrays, the diameter and length of each ZnO rod range from 60 nm to 1.2 microm and from 4 microm to 6 microm, respectively. The heating temperature and deposition position are two key points to control the diameters of the rods. The growth mechanism is discussed and proposed. The perfect crystalline ZnO rods with different scales from nanometer to micrometer are good models for the investigation of the size effect of physical and chemical properties of one-dimensional material.     

高度c轴取向的ZnO膜的低温水热法制备

在预先镀有ZnO纳米层的(0001)蓝宝石衬底上利用低温水热法制备出ZnO薄膜。SEM和XRD显示此ZnO膜是由六棱柱状阵列构成的，基于蓝宝石衬底生长，具有高度的c轴择优取向，且(0004)摇摆曲线的FWHM达到1.8°。并发现了在水热溶液中加入一定量六次甲基四胺可以调节六棱柱状ZnO尺寸比例。     

聚苯胺/聚砜复合材料的制备及其超级电容性能

通过化学聚合法,制备出盐酸掺杂聚苯胺（PANI）,将其与聚砜（PSF）溶液混合,定量滴加到玻碳电极上制得PANI/PSF复合膜电极。 采用扫描电子显微镜、红外光谱以及X射线衍射对其结构和形貌进行表征。 根据循环伏安曲线、恒电流充放电曲线和电化学阻抗,研究了其作为电极的超级电容性能。 结果表明,多孔结构的PANI/PSF复合材料具有良好的电容性能,其比电容可达到497 F/g,并且该超级电容器具有较小的内阻和较好的循环稳定性。     

顺序加料法制备聚苯胺与聚吡咯复合物及其电化学电容性能

以顺序加料原位聚合法化学氧化制备了聚吡咯(PPy)和聚苯胺(PANi)的复合物.采用SEM、红外光谱表征其结构,采用电化学工作站测试其超级电容性能.结果表明:制得的聚苯胺与聚吡咯的复合物,形成了二次结构;复合物的循环伏安特性曲线均接近于理想的矩形,恒流充放电曲线基本为线性,呈现双电层电容;PANi-PPy和PPy-PANi复合物的最高比电容分别达到227.6、195.5 F/g.     

Synthesis of polyaniline/Q-CdSe composite via ultrasonically assisted dynamic inverse emulsion polymerization

In this communication, polyaniline/CdSe quantum dots (PANI/Q-CdSe) composite was successfully synthesized via in situ ultrasonically assisted dynamic inverse emulsion polymerization. The synthesized PANI-coated Q-CdSe composite was characterized by field emission transmission electron microscopy showed that the CdSe quantum dots have an average size of around ca. 5 nm were dispersed in the PANI matrix. X-ray diffraction, Fourier transform infrared spectrum (FT-IR) and UV-visible spectrum were used to characterize the structure of the obtained PANI/Q-CdSe composite. FT-IR spectra indicated that the polymer was highly doped and existed in conducting emeraldine salt form. The obtained PANI/Q-CdSe composite showed significant improvement in the thermal behavior as indicated by TGA thermograph. The presented dynamic polymerization process is very fast and produces stable colloidal dispersion. This approach provides a one-step, simple, general, and inexpensive method for the preparation of PANI/Q-CdSe composite.     

Effect of polyaniline particle size on the properties of a polyaniline-nylon 6 composite

A method is proposed for the preparation of a conducting polyaniline-nylon 6 composite with controlled morphology of its surface. The method consists of the ammonium persulfate-induced oxidation polymerization of aniline in the presence of nylon 6. As has been established with the use of atomic force microscopy, spherical polyaniline particles are formed on the surface of nylon 6 and their sizes decrease with an increase in the duration of nylon 6 hydrothermal modification at 100° C. It is shown that a decline in polyaniline particle size in the polyaniline-nylon 6 composite enhances its reactivity with respect to KI.     

Solution-based fabrication of a graphene–ZnO nanocomposite

Graphene-based composites represent a new class of materials with potential for many applications. Graphene can be attached to a metal, a semiconductor, or any polymer. In this work, our approach was to attach graphene to a well-known semiconductor, ZnO. We synthesized graphene–ZnO composites by a simple, low-cost, environmentally friendly solvothermal method, carrying out the reaction in different conditions in order to discover the optimum condition, and also to obtain a high-quality product. Our research demonstrated that the optimum temperature to obtain a high-quality product is 180 °C for 20 h. All obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy, electron dispersion spectrometry, X-ray photoelectron spectrometry, Raman spectroscopy, Fourier transform infrared spectrometry, UV–visible spectrophotometry, and thermogravimetric analysis. The XRD confirmed that the crystal structure of the ZnO in the nanocomposite was wurtzite type. The prepared composite was stable to 800 °C with its 80 % weight.     

石墨烯/聚苯胺复合材料的制备及应用

石墨烯/聚苯胺复合材料由于其优异的电学、热学、电化学性能和机械性能等特点,吸引了研究者们的广泛关注。本文对近几年来石墨烯/聚苯胺复合材料的发展状况进行了简单介绍,首先总结了原位聚合法、界面聚合法、自组装法、溶液共混法等不同制备方法对石墨烯/聚苯胺复合材料结构和性能的影响。由于石墨烯/聚苯胺复合材料结合了石墨烯和聚苯胺两者的优点,展现出更加优异的性能,因此本文还对其在超级电容器、传感器、燃料电池、太阳能电池等方面的应用进行了详细介绍。     

Visible-light Photochromism of Phosphomolybdic Acid/ZnO Composite

A novel photochromic hybrid ZnO was synthesized by doping with phosphomolybdic acid(PMoA). It could respond to visible light and fade in color when treated with hydrogen peroxide(H₂O₂). The microstructure and photochromic properties were investigated via X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), transmission electron microscopy(TEM), ultraviolet-visible spectroscopy(UV-Vis) and X-ray photoelectron spectroscopy(XPS). The XRD patterns show that the prepared ZnO is pure and has a hexagonal wurtzite structure. The FTIR results demonstrate the existence of a strong interaction between PMoA and ZnO. Due to PMoA doping, the rough surface morphology of ZnO became smooth, as verified by the SEM images. The TEM images illustrate that pure ZnO exhibits a polycrystalline structure with irregular morphology. PMoA was wrapped on the surface of ZnO. After visible-light irradiation, the composite changed from slight yellow to blue and returned to the original color in the presence of H₂O₂. The composite had good photosensitivity and photochromic reversibility. The photochromic process was in accord with photoinduced electrons transfer mechanism.     

Reversible encapsulation of nanometer-size polyaniline and polyaniline-Au-nanoparticle composite in starch

In this paper we report a new method of solubilization of polyaniline and polyaniline-Au-nanoparticle composite by encapsulating nanometer-size particles in starch. The solubilization was carried out in the presence of ultrasonic waves. We also report that the encapsulation was completely reversible and the dissolved polyaniline as well as the composite could be recovered by replacement with molecular iodine. In addition, the polymer particles could also replace molecular iodine from starch-iodine complex. UV-Visible and Fourier transform infrared (FTIR) spectroscopic measurements established the reversible nature of encapsulation. Transmission electron microscopic measurements showed that the sizes of the particles encapsulated in starch were on the order of 10-20 nm for both polyaniline and Au-nanoparticle-polyaniline composite particles. X-ray diffraction evidenced the presence ofAu-nanoparticles in the starch-polyaniline-Au-nanoparticle composite. Finally, we also mention here that the dissolved polyaniline could also be recovered as a precipitate by enzyme (diastage) hydrolysis of the polyaniline encapsulating starch.     

共聚物酸掺杂接枝聚苯胺的研究

采用核壳乳液聚合方法合成了以甲基丙酸甲酯、甲基丙烯酸和丙烯酸丁酯三元共聚物酸为核,聚苯胺为壳的导电高分子复合物。复合物的电导率随着聚苯胺含量的增加而升高。用粒径分析仪、ＴＥＭ、ＦＴ－ＩＲ和ＤＳＣ对复合材料进行了表征。结果表明形成了核壳结构,由于共聚物酸起到了掺杂剂的作用,使制得的复合物能在环己酮、四氢呋喃等普通有机溶剂中有好的溶解性。     

Fabrication of zinc oxide nanowires/polymer composites by two‐photon polymerization

We present an approach to fabricate ZnO nanowires/polymer composite into three‐dimensional microstructures, based on two‐photon polymerization direct laser writing, a fabrication method that allows submicrometric spatial resolution. The structural integrity of the structures was inferred by scanning electron microscopy, while the presence and distribution of ZnO nanowires was investigated by energy dispersive X‐ray, Raman spectroscopy, and X‐ray diffraction. The optical properties of the produced composite microstructures were verified by imaging the characteristic ZnO emission using a fluorescence microscope. Hence, such approach can be used to develop composite microstructures containing ZnO nanowires aiming at technological applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014 , 52, 333–337     

Biomimetic Preparation of Magnetite/Chitosan Nanocomposite via In Situ Composite Method ——Potential Use in Magnetic Tissue Repair Domain

IntroductionMagnetite (Fe3O4) is widespread in the environ-ment although it is thermodynamically unstable with re-spect to hematite(α-Fe2O3) in the presence of oxygen.It has been widely used for targeted delivery ofdrugs[1], in MRI reagents[2], hyperther…     

Zein films with ZnO and ZnO:Mg quantum dots as functional nanofillers: New nanocomposites for food package with UV-blocker and antimicrobial properties

The preparation of a new nanocomposite by combining zein and quantum dots (QDs) was the main interest of the present work. By the sol-gel method, colloidal ethanolic dispersions of zinc oxide (ZnO) particles and ZnO particles doped with magnesium (II) (ZnO:Mg) were obtained, sized 4.26 and 3.65 nm, respectively, as determined by UV–Vis spectroscopy. The prepared QDs were used as nanofillers in order to obtain zein-based nanocomposite films, which displayed good visual appearance, homogeneity, and transparency. The presence of QDs increased the hydrophobicity and reduced, up to three times, the amount of water uptake of the composite films when compared to pure zein. Those effects were more pronounced for ZnO:Mg QDs. TEM, FTIR, and fluorescence microscopy analysis indicated that zein interacts more effectively with ZnO:Mg than with ZnO. In addition, and most importantly, the presence of QDs in the films showed an important advantage when compared to those of pure zein: the extended UV-blocking in the absorbance spectra. The antimicrobial assays demonstrated that the ZnO NPs, loaded into zein films, are promising antibacterial materials since the inhibition of growth of S. aureus reached (96.5 ± 4.9)% at 44.8 wt% of ZnO NPs. Therefore, the nanocomposites show promising features for the development of food packaging, UV protective films, and for the development of new and sustainable materials.     

Spherical Polarization Body: Synthesis of Monodisperse Micron‐Sized Polyaniline Composite Particles

A new method to synthesize uniform polyaniline‐coated composite microparticles was contrived considering the surface reactivity and porous structure of substrate polymer particles. It was found that the pore diameter together with the epoxy functional group plays a crucial role in controlling the structure of polyaniline shell. The polyaniline composite particles produced in this study are believed to find great applicability in piezoelectronics and as electro‐rheological fluids.     

Investigations of polyaniline-platinum composites prepared by sodium borohydride reduction

Two procedures were applied for the preparation of polyaniline (PANI)-Pt composites in aqueous solutions using sodium borohydride as the reducing agent. The first one involved reduction of Pt ions originating from PtCl₄ conducted in the presence of PANI. The second was a two-step method in which doping of PANI with Pt-containing anions was followed by their reduction. The composites containing various amounts of Pt were obtained. They were characterized by X-ray diffraction, X-ray photoelectron and IR spectroscopies. This allowed to establish differences in the efficiency of both methods of composite preparation. It was also found that the composites show mainly redox activity in catalytic isopropyl alcohol conversion.