导电聚合物纳米线的制备及气敏性能研究

首次采用简单的浸润多孔氧化铝(AAO)模板法制备了导电聚合物聚-3,4-乙烯二氧噻吩(PE-DOT)纳米线.导电聚合物溶液浸润AAO模板后,PEDOT吸附于孔道壁并进一步聚合生成导电聚合物纳米线.紫外-可见光-近红外光谱(UV-vis-NIR spec-trum)分析表明生成的纳米线处于掺杂态.采用四探针仪分析了导电聚合物纳米线的导电性能,结果显示纳米线电导率相比普通PEDOT材料有数量级增加,且表现出良好的掺杂/脱掺杂能力.研究了导电聚合物纳米线的气体敏感性能,发现其对挥发性醇类,尤其对甲醇在较低浓度下表现出优异的敏感性,对5×10-6甲醇气体的响应时间约为10～20s,测试可重复性超过20次,达到饱和吸附时的气体浓度明显大于普通PEDOT材料.表明PEDOT纳米线不仅提供了较大表面积供气体分子吸附,而且纳米线中导电通道取向一致,从而体现出较好的气体敏感性能.     

γ-PGA生物纳米涂层的制备与性能研究

首先对生物大分子γ-聚谷氨酸(γ-PGA)进行自组装,制备γ-PGA自组装胶束粒子,利用Zeta电位及纳米粒度分析仪,原子力显微镜(AFM)对胶束粒子的基本性能进行表征。接着以γ-PGA自组装胶束粒子溶液为电解液,通过电沉积技术,在镁合金表面制备γ-PGA生物纳米涂层材料。采用全反射傅里叶变换红外光谱仪(ATR-FT-IR),X射线衍射仪(XRD),超景深显微镜,扫描电子显微镜(SEM)对涂层样品进行表征。研究结果表明,γ-PGA自组装胶束粒子的流体动力学直径约为221.1nm,所制备的生物纳米涂层材料可降低镁合金的腐蚀速率,且经乙二胺化学交联后涂层的防护性能将得到进一步改善。本文直接使用未改性的γ-PGA为组装基元制备胶束粒子,为γ-PGA的组装提供了一种简便方法,同时利用电诱导将其固定在金属基材表面制备生物纳米涂层材料,进一步拓宽了基于γ-聚谷氨酸自组装胶束粒子的应用领域。     

导电聚合物有序超薄膜成膜性能的研究

采用LB膜诱导沉积法制备PEDOT高度有序导电聚合物薄膜,采用的工艺是将十八胺(ODA)与聚3,4-乙烯二氧噻吩/聚苯乙烯磺酸(PEDOT-PSS)先形成ODA包裹PEDOT-PSS纳米粒子的组装体,然后再将其铺展于气/液界面,制备PEDOT-PSS复合LB膜。实验表明,PEDOT-PSS纳米粒子对单分子层具有包裹作用,形成了稳定的复合单分子膜;不同膜压下制备的膜表面形貌不同,较高膜压下得到颗粒紧密排列的薄膜,亚相温度23℃、PEDOT-PSS浓度1×10-3mol/L、压缩速率5mm/min、拉膜速率为1mm/min的条件下薄膜具有较好的成膜性能。     

LaFeO_3纳米纤维的制备及其气敏特性研究

采用静电纺丝方法制备了LaFeO3纳米纤维,利用电子扫描显微镜(SEM)、X-射线衍射(XRD)对其进行表征。所合成的LaFeO3纳米纤维材料作为敏感材料制作烧结型旁热式气敏元件,测试其气敏特性。结果表明,基于LaFeO3纳米纤维的气体传感器对于乙醇气体的最佳工作温度为200℃,对于浓度为500×10-6的乙醇气体,灵敏度为46,LaFeO3纳米纤维材料对乙醇具有快速的响应恢复速度。     

铁酸钬与铁酸钐纳米晶的制备及其甲醛敏感特性研究

用固相反应法制得钙钛矿型复合氧化物铁酸钬(HoFeO_3)与铁酸钐(SmFeO_3)纳米粒子。用X射线衍射仪和透射电镜对产物进行了表征,探讨了煅烧条件对产物的影响,并研究了其纯相材料对甲醛的敏感特性。结果表明:分别在1000℃和950℃煅烧反应物料2h即可获得纯相HoFeO_3和SmFeO_3纳米粒子;HoFeO_3与SmFeO_3元件分别在其最佳工作温度315℃和270℃下对浓度为20×10-6甲醛气体的灵敏度分别为20.4和3.8,响应-恢复时间分别为25s和10s、20s和18s,具有一定的应用价值。     

不同微观形貌所引起的聚二氧乙撑噻吩的光电性能改变

通过无模板法并以功能掺杂酸樟脑磺酸作为掺杂剂，分别在过硫酸铵和三氯化铁为氧化剂的情况下，制得了直径为50-150nm的纳米球形的聚二氧乙撑噻吩（PEDOT）和直径为80-150nm的纳米棒状的PEDOT。由于三氯化铁的氧化还原势能远低于过硫酸铵使得氧化的速率降低，使PEDOT的生长能够更好的依照由单体和掺杂剂组成的柱状胶束而进行所产生的。两种不同微观形貌的PEDOT表现出了明显不同的光电性能．     

纳米Zr粒子改性环氧涂层的耐腐蚀性能

使用纳米Zr粒子和环氧树脂制备出纳米复合环氧涂料,用透射电镜(TEM)、X射线衍射光谱(XRD)对纳米Zr粒子进行了表征,并测试了不同含量纳米Zr粒子涂层力学性能。根据盐雾试验和电化学阻抗谱(EIS)试验结果研究了纳米Zr粒子对涂层耐腐蚀性能的影响。结果表明,在10%纳米Zr粒子涂层中水的扩散系数为6.0×10-6cm2/s,比其它涂层降低了一个数量级。适量的惰性纳米Zr粒子在涂层中均匀分散产生的物理屏蔽作用,提高了涂层的耐腐蚀性能。     

多孔Ag/ZnO的生物模板法合成及气敏性能研究

以油菜花粉为模板合成了Ag/ZnO纳米颗粒,采用X射线衍射仪、扫描电子显微镜等手段对样品进行了结构形貌表征,并测试了其气敏性能。结果表明,所得产物为直径30~50nm左右的六方纤锌矿结构,Ag/ZnO纳米粒子在相对低的工作温度(270℃)下,对100×10~(-6)的丙酮气体的灵敏度达到了38.2(约为ZnO的10倍),其响应和恢复时间分别为3和36s。     

Pd掺杂纳米ZnO的燃烧法制备及性能研究

以酒石酸为燃料,硝酸锌为氧化剂,采用溶液燃烧法制备了Pd(0~7%(原子分数))掺杂纳米Zn O。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和荧光光谱仪对产物了进行表征,重点讨论了掺杂对Zn O气敏性能的影响。结果表明,在330℃测试条件下,纯Zn O和7%(原子分数)Pd掺杂Zn O气敏元件对体积分数为5.0×10-5的乙醇气体灵敏度分别为21.4和11.2;元件对5.0×10-5丙酮气体的灵敏度分别为2.0和8.8。Pd掺杂显著提高了元件对乙醇和丙酮气体的选择性。     

反胶束体系中聚吡咯/氯化银纳米复合粒子的合成与表征

利用阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)形成的反胶束作为微反应器合成了聚吡咯-氯化银(PPy/AgCl)纳米复合粒子.考察了吡咯/硝酸银、正己醇/水的比例的变化对PPy/AgCl纳米复合粒子的粒径大小和粒子形貌的影响,并利用TEM、SEM、FTIR、XRD和激光光散射粒度分析仪对产物进行了表征.结果显示,PPy/AgCl纳米粒子的粒径在40-60nm之间,改变合成条件可以进行自组装.FTIR和XRD显示复合物中含有PPy.因氯化银的存在,导致复合物的红外光谱向低波数方向移动.该实验结果同时表明,反胶束法可以有效地应用于有机/无机纳米复合粒子的制备.     

Poly(acrylonitrile-co-itaconic acid)–poly(3,4-ethylenedioxythiophene) and poly(3-methoxythiophene) nanoparticles and nanofibres

This work aimed to produce poly(acrylonitrile-co-itaconic acid) (P(AN-co-IA)) nanocomposites with poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3-methoxythiophene) (PMOT). An anionic surfactant sodium dodecyl benzene sulphonate was used in emulsion polymerization for nanocomposite production. Incorporations of PEDOT and PMOT on the nanoparticles were characterized by scanning electron microscopy (SEM), atomic force microscopy, Fourier transform infrared-attenuated total reflectance spectroscopy and ultra-violet spectroscopy. These nanoparticles were blended with PAN and the blends were electrospun to produce P(AN-co-IA)–polythiophene-derivative-based nanofibres, and the obtained nanofibres were characterized by SEM and energy dispersive spectroscopy. In addition, electrochemical impedance studies conducted on nanofibres showed that PEDOT and PMOT in matrix polymer P(AN-co-IA) exhibited capacitive behaviour comparable to that of ITO–PET. Their capacitive behaviour changed with the amount of electroactive polymer.     

PEDOT-Au nanocomposite films for electrochemical sensing of dopamine and uric acid

In this work, conducting polymer impregnated gold nanoparticles are synthesized through a sequence of chemical and electrochemical routes. The nanocomposite film is characterized using UV-vis, FTIR spectroscopy, and SEM techniques to study the formation of oxidized PEDOT and Au0. The advantages of these films are demonstrated for sensing biologically important compounds such as dopamine and uric acid in presence of excess ascorbic acid, one of the major interferants in the detection of DA and UA (mimicking the physiological conditions), with superior selectivity and sensitivity when compared to the polymer film alone. Simultaneous determination is realized at 115 mV and 246 mV for DA and UA, respectively. The PEDOT matrix is recognized to be responsible for the peak separation (selectivity) while also favouring catalytic oxidation of the above compounds and the nanometer-sized gold particles allow nanomolar sensing of DA and UA (sensitivity). Thus, it is possible to detect nanomolar levels of DA and UA in presence of excess of AA. The combined effect of Au nanoparticles and the PEDOT matrix is rationalized that the Aunano surrounded by a "hydrophobic sheath (PEDOT)" tending to reside within these hydrophobic regions of PEDOT, thus favouring the selectivity and sensitivity of the DA/UA detection. This new generation of nanocomposites is expected to enhance the value of electroanalytical techniques, as it is possible to tune their properties suiting the analytical needs.     

Conducting polymer‐coated, palladium‐functionalized multi‐walled carbon nanotubes for the electrochemical sensing of hydroxylamine

Electrochemical sensors of hydroxylamine were fabricated on glassy carbon electrodes (GCEs) by the electropolymerization of 3,4‐ethylenedioxypyrrole (EDOP) and 3,4‐ethylenedioxythiophene (EDOT) on palladium (Pd) nanoparticles attached to thiolated multi‐walled carbon nanotubes (MWCNTs), denoted as PEDOP/MWCNT‐Pd/GCE and PEDOT/MWCNT‐Pd/GCE. The sensors were characterized by field emission scanning electron microscopy and electrochemical impedance spectroscopy. They showed strong catalytic activity toward the oxidation of hydroxylamine. Cyclic voltammetry and amperometry were used to characterize the sensors' performances. The detection limits of hydroxylamine by PEDOP/MWCNT‐Pd/GCE and PEDOT/MWCNT‐Pd/GCE were 0.22 and 0.24 μM (S/N = 3), respectively. The sensors' sensitivity, selectivity, and stability were also investigated.     

Design of multicomponent microgels by selective deposition of nanomaterials

In the present paper a method for the targeted deposition of different nanomaterials on aqueous microgels is described. In the first stage poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods are introduced into the microgel structure by in situ oxidative polymerization. In the second stage hydrogen tetrachloroaurate is used to transform PEDOT chains to an oxidized state in the microgel structure, leading to the fixation of chloroaurate anions on the surface of the PEDOT nanorods. The reduction of chloroaurate ions induces the formation of gold nanoparticles (AuNPs) predominantly located on the PEDOT surface. Obtained microgel/PEDOT/AuNP hybrid particles with different nanoparticle loadings exhibit superior colloidal stability and temperature sensitivity. The microgel/PEDOT/AuNP hybrid microgels exhibit extraordinary catalytic activity in aqueous media.     

Synergistic catalytic effect of a composite (CoS/PEDOT:PSS) counter electrode on triiodide reduction in dye-sensitized solar cells

Inorganic/organic nanocomposite counter electrodes comprised of sheetlike CoS nanoparticles dispersed in polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene (CoS/PEDOT:PSS) offer a synergistic effect on catalytic performance toward the reduction of triiodide for dye-sensitized solar cells (DSSCs), yielding 5.4% power conversion efficiency, which is comparable to that of the conventional platinum counter electrode (6.1%). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry measurements revealed that the composite counter electrodes exhibited better catalytic activity, fostering rate of triiodide reduction, than that of pristine PEDOT: PSS electrode. The simple preparation of composite (CoS/PEDOT:PSS) electrode at low temperature with improved electrocatalytic properties are feasible to apply in flexible substrates, which is at most urgency for developing novel counter electrodes for lightweight flexible solar cells.     

A general synthesis for PEDOT-coated nonconductive materials and PEDOT hollow particles by aqueous chemical polymerization

A method for coating functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) on nonconductive substrates in aqueous solution allows the deposition of PEDOT thin layers on various substrates, including silica and polystyrene (PS) nanoparticles, siliceous mesocellular foam, and chitosan-alginate fibers. The surface property is tuned by controlling the monomer composition in the aqueous solutions. Using appropriate organic solvents to remove the PS cores of PEDOT-coated PS nanoparticles, hollow PEDOT particles with single holes and PEDOT capsules can be formed.     

聚噻吩/碳纳米管复合物的元件制作及其气敏响应性的应用测试

本文通过化学氧化法以3,4-乙撑二氧噻吩聚合聚3,4-乙撑二氧噻吩(PEDOT),得到固体粉末样品,用液体胶水作为联体,在其掺杂功能化碳纳米管(f-CNTS)与聚噻吩,制备了复合纳米材料,并制作系列工作电极,利用自制气敏装置,应用于含甲醛的饱和汽体测试研究。测试数据表明,掺杂不同含量的碳纳米管与聚噻吩,对不同浓度的甲醛气敏响应性测试,由其电极材料的微型结构的变化,电阻规律性变化表现出不同的气敏响应性。同时,与单一种物质作用相比,复合材料膜有更好的电子传递行为,表现灵敏的响应性。     

Effects of a base coating used for electropolymerization of poly(3,4-ethylenedioxythiophene) on indium tin oxide electrode

Electropolymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) films on indium tin oxide (ITO), using a very thin PEDOT:poly(styrene sulfonate) (PEDOT:PSS) film as a base coating, was carried out in a non-aqueous solution containing the monomer, an electrolyte and propylene carbonate by a two-electrode system. For comparison, PEDOT film electrodeposited on bare ITO substrate under the same condition was also presented. The PEDOT films deposited on these two substrates were characterized by scanning electron microscopy, energy disperse X-ray spectroscopy and Raman spectroscopy. The results indicate that the PEDOT film electrodeposited on bare ITO was not uniform, while the PEDOT film electrodeposited on PEDOT:PSS/ITO has better uniformity. The compositions of the different regions of PEDOT film electrodeposited on bare ITO and PEDOT:PSS/ITO were studied and discussed. Electrochromic devices (ECDs) based on PEDOT films electrodeposited on bare ITO and PEDOT:PSS/ITO were fabricated and characterized by UV-Vis-NIR spectrophotometric study. The results show that the display contrast of the ECD based on PEDOT film electrodeposited on PEDOT:PSS/ITO was improved over that on a bare ITO substrate.     

Poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate): Correlation between colloidal particles and thin films

We deal with correlation between sizes of colloidal particles and minimum thickness of spin-coated thin films of poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) studied by a dynamic light scattering (DLS), a scanning transmission electron microscopy coupled with an energy dispersive X-ray spectroscopy (STEM-EDX), C₆₀-sputtering X-ray photoelectron spectroscopy (XPS), and an atomic force microscopy. Based on the various measurements, it was pointed out that, PEDOT/PSS colloidal dispersion contained majority of primary nanoparticles with mean diameter of 41 nm and 16 nm for BAYTRON P AG (denote P grade) or BAYTRON PH500 (denote PH grade) solutions, respectively, and small amount of clusters aggregated by the primary particles, based on the DLS measurement and STEM observation. On the other hand, PEDOT/PSS thin films with thickness of 44 nm and 16 nm were easily prepared by spin-coating on silicon wafers from the P and PH grade solutions, respectively. Results of STEM-EDX, DLS, and XPS measurements suggested that the PEDOT/PSS thin films consist of the randomly packed primary nanoparticle-“monolayer”.     

Combined electrochromic and plasmonic optical responses in conducting polymer/metal nanoparticle films

Poly(3,4-ethylenedioxithiophene)/poly(styrene sulphonate) (PEDOT/PSS) aqueous dispersions were mixed with aqueous gold nanoparticle and aqueous silver nanoparticle colloids. PEDOT/gold nanoparticles (Au NP) and PEDOT/silver nanoparticles (Ag NP) films were obtained by solvent casting the corresponding aqueous solutions. The nanocomposite films showed the optical characteristics associated with both the surface plasmon absorption resonance of the metal nanoparticles and the excitation of the bipolaron band of the conducting polymer. As an interesting application we demonstrate the use of metal nanoparticles to tune the color of PEDOT based electrochromic films from blue to violet in the case of Au NP or green in the case of Ag NP.