可溶性DBSA掺杂PANI接枝MWNTs复合材料的结构与性能

多壁碳纳米管(MWNTs)经对苯二胺功能化后,苯胺基团以3.7%的含量通过酰胺键连接到MWNTs表面(p-MWNTs),以十二烷基苯磺酸(DBSA)为掺杂剂和乳化剂,通过原位聚合,制备了在四氢呋喃(THF)中稳定溶解的DBSA掺杂聚苯胺(PANI)接枝MWNTs(PANI-g-MWNTs)导电复合材料.采用Raman光谱、傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、紫外-可见光谱(UV-vis)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和四电极电导率仪研究复合材料的结构与性能.实验结果表明,p-MWNTs表面的苯胺基团参与原位聚合反应,使PANI与p-MWNTs通过酰胺键连接起来,形成以p-MWNTs为核、DBSA掺杂PANI为壳的纳米结构.包覆层中DBSA掺杂PANI受限生长在p-MWNTs表面,其结构规整度较纯DBSA掺杂PANI提高.DBSA掺杂PANI-g-MWNTs复合材料溶解在THF中获得31.55 mg/mL的溶解度和至少1个月的稳定性,该复合材料的室温电导率为6.23×10-1 S/cm,较纯DBSA掺杂PANI提高1个数量级.     

聚苯胺接枝多壁碳纳米管复合材料的结构与性能研究

多壁碳纳米管(MWNTs)经对苯二胺功能化后,通过原位聚合及去掺杂反应,首次制备了能在N-甲基吡咯烷酮(NMP)中稳定溶解的本征态聚苯胺(EB)接枝MWNTs(EB-g-MWNTs)复合材料。复合材料中EB与p-MWNTs通过酰胺键连接,形成以p-MWNTs为核、EB为壳的纳米结构,并且EB的结构规整度提高;当该复合材料溶解在NMP中时,溶解度为33.72mg/mL,稳定性好,至少可保存1个月。     

聚苯胺接枝多壁碳纳米管/环氧树脂复合材料的结构与力学性能研究

将十二烷基苯磺酸(DBSA)掺杂聚苯胺(PANI)接枝多壁碳纳米管(PANI-g-MWNTs)与环氧树脂(Epoxy)溶液共混、固化,制备了DBSA掺杂PANI-g-MWNTs/Epoxy复合材料。当核(MWNTs)-壳(DBSA掺杂PANI)结构溶解分散于Epoxy溶液中时,MWNTs表面PANI的溶解和溶胀把MWNTs隔开,使MWNTs均匀分散在Epoxy基体中。复合材料固化后,断面呈韧性断裂特征,MWNTs均匀分布在基体中,MWNTs与Epoxy间存在较强的界面粘结。DBSA掺杂PANI-g-MWNTs的引入促进Epoxy的固化反应,固化起始温度、放热峰值温度和固化反应热较Epoxy降低。复合材料的拉伸强度、杨氏模量、弯曲强度、弯曲模量和冲击强度较Epoxy分别提高61%、43%、78%、49%和33%。     

复合磺酸体系原位聚合聚苯胺性能研究

采用不同比例的十二烷基苯磺酸(DBSA)与对甲基苯磺酸(TSA)复合磺酸体系替代盐酸体系,合成了具有一定溶解率的聚苯胺(PANI),研究了不同DBSA/TSA比例对掺杂态PANI的产率、掺杂程度、溶解率和电导率的影响.结果表明,DBSA/TSA摩尔比为7/3时所得PANI同时具有较好的电导率和溶解性.采用该体系合成的掺杂态PANI的电导率为1.1S/cm,在N-甲基吡咯烷酮(NMP)、丙酮、四氯化碳和二甲苯中的溶解率(质量分数)分别为70%,40%,26%和19%.     

聚苯胺功能化多壁碳纳米管/环氧树脂复合材料的热性能与电性能研究

采用可溶性导电聚苯胺功能化多壁碳纳米管(PANI-MWNTs)与环氧树脂(Epoxy)溶液共混制备了PANIMWNTs/Epoxy复合材料。当PANI-MWNTs溶解分散于Epoxy溶液中时,包覆在MWNTs表面的PANI分子链溶解和溶胀把MWNTs隔开,使MWNTs均匀分散在Epoxy中。MWNTs良好地分散及MWNTs与Epoxy间的界面粘结作用,阻碍Epoxy大分子链段的运动和热分解在复合材料中的传播,复合材料的玻璃化转变温度和热稳定性显著提高。PANI-MWNTs的引入使复合材料电导率上升,当其含量为1.25wt%时,复合材料的室温电导率为9.35×10-6 S·cm-1比Epoxy提高7个数量级。     

功能磺酸掺杂聚苯胺的电导率及其光谱特征研究

合成了十二烷基苯磺酸(DBSA)、磺基水杨酸(SSA)和对甲苯磺酸(TSA)掺杂的导电聚苯胺样品:PANI/DBSA,PANI/SSA,PANI/TSA.用四探针法测定其电导率,研究不同功能磺酸掺杂对聚苯胺电导率的影响,分析它们的FT-IR光谱、UV-VIS光谱吸收及NIR光谱反射现象及其变化.结果表明,功能磺酸掺杂剂的对阴离子尺寸大小影响其掺杂PANI的电导率和光谱特征,PANI/DBSA的对阴离子尺寸大于PANI/SSA,PANI/TSA,其电导率、FT-IR和UV-VIS图谱红移量都相对PANI/SSA,PANI/TSA大.同时不同功能磺酸掺杂聚苯胺的NIR光谱反射率为:PANI/DBSA＞PANI/SSA＞PANI/TSA.     

二次掺杂制备聚苯胺/石墨烯/碳纳米管复合材料及其防腐性能EI北大核心CSCD

在高氯酸体系中通过原位聚合将苯胺(ANI)单体分别与还原氧化石墨烯(RGO)、碳纳米管(CNTs)制备了一次掺杂态产物PANI/RGO和PANI/CNTs,产物分别经氨水解掺杂后,在高氯酸体系中经二次掺杂制备得到二次掺杂态聚苯胺/石墨烯/碳纳米管(Redoped PANI/RGO/CNTs)复合材料。通过扫描电镜、透射电镜、傅里叶变换红外光谱和紫外光谱对其不同产物形貌和结构进行表征,通过电化学工作站测试了不同产物在3.5%NaCl溶液的防腐蚀性能。结果表明,在RGO与ANI质量比为1:20、CNTs与ANI质量比为1:20时,二次掺杂态产物中聚苯胺纳米纤维可分别在RGO和CNTs上均匀生长并形成网状结构,纤维长度达到850 nm,形貌均一,其防腐蚀性能最优异,缓蚀效率可达81.79%。通过二次掺杂将PANI/RGO和PANI/CNTs复合制备Redoped PANI/RGO/CNTs材料,可有效避免石墨烯和碳纳米管在制备复合材料过程中的团聚,得到结构规整、防腐性能更优异的复合材料。     

乳液聚合DBSA/TSA掺杂聚苯胺的XPS表征

以乳液聚合法制备DBSA/TSA复合磺酸掺杂态聚苯胺,主要采用XPS手段对其性能进行了表征.结果表明:当DBSA/TSA的摩尔比为3/2时,合成的掺杂态PANI具有较高导电率,可达6.32×10-2S/cm;乳化剂以两种方式存在:提高PANI导电率的掺杂剂和独立存在的稳定剂.     

循环伏安法制备十二烷基苯磺酸掺杂聚苯胺纳米纤维的聚合过程

采用循环伏安法在镀金聚对苯二甲酸乙二酯(PET)膜上聚合了十二烷基苯磺酸(DBSA)掺杂的聚苯胺(PANI)膜,对比研究了PANI聚合过程中不同时刻的循环伏安特性、微观形貌和交流阻抗特性。结果表明,在DBSA溶液中,PANI循环伏安法聚合过程可以分为工作电极表面异相成核、晶核径向生长和纤维横向生长3个阶段。在聚合初期,异相成核需要在一个较高的电位下进行,一旦成核,聚合可以通过晶核引发自催化成膜反应在较低的电位下迅速进行。为了获得性能较好的PANI膜,循环伏安法电位上限应大于0.8V。     

聚十二烷基苯磺酸对聚苯胺电化学性能的影响

考察了多扫循环伏安法制备出的聚十二烷基苯磺酸/聚苯胺(PDBSA/PANI)复合材料的电化学性能。结果表明，与自吸附十二烷基苯磺酸/聚苯胺(DBSA/PANI)、纯PANI相比，PDBSA/PANI复合材料的荷电量最大，电化学阻抗最小，说明PDBSA更能显著地增强PANI的导电性；PDBSA/PANI复合材料的比电容为407.692F/g,比DBSA/PANI复合材料(339.307F/g)和纯PANI(235.088F/g)均高，表明PDBSA可以较大程度地改善PANI的电荷贮存性；pH和扫速试验显示PDBSA没有改变PANI的单电子单质子的氧化还原反应，说明PDBSA没有参与到聚苯胺的氧化还原反应中。     

Preparation and characterization of soluble and DBSA doped polyaniline grafted multi-walled carbon nanotubes nano-composite

Soluble and highly doped polyaniline (PANI) grafted multi-walled carbon nanotubes (MWNTs) nano-composite was synthesized by in situ oxidation polymerization, de-doping with ammonium hydroxide and doping the PANI-Emeraldine base (PANI-EB) grafted MWNTs nano-composite in N-methyl-2-pyrrolidinone (NMP) with Dodecyl benzene sulfonic acid (DBSA). Transmission electron microscope (TEM), Raman spectra, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and standard four-probe methods were employed to characterize morphology, chemical structure and electronic conductivity of the nano-composite. The results show that oxidized phenylamine groups of phenylamine groups contained MWNTs (p-MWNTs) initiate PANI polymerization on the surface of p-MWNTs. PANI coatings graft on the surface of p-MWNTs via amide bond forming homogeneous core (p-MWNTs)–shell (PANI) nano-structures. After doping PANI-EB grafted MWNTs nano-composite with DBSA, the attachment of soluble DBSA doped PANI chains on the surface of p-MWNTs via covalent bonding renders p-MWNTs compatible with polymer matrix and lead to DBSA doped PANI grafted MWNTs nano-composite soluble and stable in NMP. Owing to incorporation of p-MWNTs and chemical bridges between p-MWNTs and PANI chains, conductivity of DBSA doped PANI grafted MWNTs nano-composite at room temperature is increased by about two orders of magnitude over neat DBSA doped PANI.     

MWNTs/PANI composite materials prepared by in-situ chemical oxidative polymerization for supercapacitor electrode

Multi-walled carbon nanotubes (MWNTs)/polyaniline (PANI) composite materials were prepared by in-situ chemical oxidative polymerization of an aniline solution containing well-dispersed MWNTs. The supercapacitive behaviors of these composite materials were investigated with cyclic voltammetry (CV), charge–discharge tests, and ac impedance spectroscopy, respectively. The composites based on the charge-transfer complex between well-dispersed MWNTs and PANI matrixes show much higher specific capacitance, better thermal stability, lower resistance, and were more promising for applications in supercapacitors than a pure PANI electrode. The highest specific capacitance value of 224 Fg⁻¹ was obtained for the MWNTs/PANI composite materials containing MWNTs of 0.8 wt%. The improvement mechanisms of the capacitance of the composite materials were also discussed in detail.     

A composite of polyelectrolyte-grafted multi-walled carbon nanotubes and in situ polymerized polyaniline for the detection of low concentration triethylamine vapor

Multi-walled carbon nanotubes (MWNTs) grafted with sodium polystyrenesulfonate (NaPSS) were deposited on an interdigitated gold electrode decorated with a layer of positively charged poly(diallyldimethylammonium chloride) by a self-assembly method. Then polyaniline (PANI) was in?situ polymerized on the surface of the MWNTs to prepare a composite. The structure and morphology of the composite were investigated by Raman spectroscopy and scanning electron microscopy. The electrical responses of the composite to triethylamine vapor of low concentrations were measured at room temperature. It was found that the composite exhibited a linear response to the vapor in the range of 0.5-8?ppm with the highest sensitivity of ～80%, which is much higher than that of MWNTs and PANI separately, and an obvious synergetic effect was observed. In addition, the detection limit was as low as the ppb level, and reversible and relatively fast responses (t(90%)～200?s and ～10?min for sensing and recovery, respectively) were observed. The sensing characteristics are highly related to the gas responses of PANI, and a sensing mechanism considering the interaction of MWNTs and PANI was proposed.     

Electrochemical fabrication of polyaniline/multi-walled carbon nanotube composite films for electrooxidation of methanol

Polyaniline (PANI)/multi-walled carbon nanotubes (MWNTs) composite films were fabricated by electropolymerization of aniline containing well-dissolved MWNTs. The films can be used as catalyst supports for electro-oxidation of methanol. Cyclic voltammogram and Chronoamperogram results show that platinum particles deposited on PANI/MWNT composite films exhibit higher electrocatalytic activity towards methanol oxidation than that deposited on pure PANI films. The porous structure and electrical conductivity of PANI films has been significantly changed by introduction of MWNTs, higher surface areas of PANI/MWNT composites has been achieved therefore. It favors for platinum particles to be highly dispersed on the PANI/MWNT composite films and the better electrocatalytic activity of Pt/PANI/MWNT electrode is induced consequently.     

Synthesis and characterization of HCl doped polyaniline grafted multi-walled carbon nanotubes core-shell nano-composite

Multi-walled carbon nanotubes (MWNTs) was modified with p-phenylenediamine (p-PDA) and hydrochloric acid (HCl) doped polyaniline (PANI) grafted MWNTs nano-composite was synthesized by in situ oxidation polymerization. Raman spectra, XPS, TEM and XRD reveal that modification does not decrease the integrity of outer graphite sheets in p-PDA modified MWNTs (p-MWNTs) excessively and results in phenylamine groups with concentration of 3.7% covalently grafted on the surface of p-MWNTs via amide bond. Oxidized phenylamine groups initiate polymerization and contribute to the formation of inner layer of PANI coatings. As self-assembly templates, p-MWNTs are encapsulated by PANI forming a homogeneous core (p-MWNTs)-shell (HCl doped PANI) nano-structure with controlled organization. In earlier reaction period, polymer chains are highly ordered and microcrystalline domains are enriched in the inner PANI layers. When deposition of PANI chains under less restriction, more amorphous parts are distributed in the outer layers of PANI coatings. TGA and conductivity data reveal that although chemical modification affects the performance of p-MWNTs, thermal stability and electronic conductivity at room temperature of HCl doped PANI grafted MWNTs nano-composite are highly improved owing to incorporation of p-MWNTs and covalent bindings between PANI and carbon nanotubes.     

All-organic PANI–DBSA/PVDF dielectric composites with unique electrical properties

Novel all-organic polymer high-dielectric permittivity composites of polyaniline (PANI)/poly (vinylidene fluoride) (PVDF) were prepared by solution method and their dielectric and electric properties were studied over the wide ranges of temperatures and frequencies. To improve the interface bonding between two polymers, dodecylbenzenesulfonic acid (DBSA), a bulky molecule containing a polar head and a long non-polar chain was used both as a surfactant and as dopant in polyaniline (PANI) synthesis. Synthesized conducting PANI–DBSA particles were dispersed in poly(vinylidene fluoride) (PVDF) matrix to form an all-organic composite with different PANI–DBSA concentrations. Near the percolation threshold, the dielectric permittivity of the composites at 100 Hz frequency and room temperature was as high as 170, while the dielectric loss tangent value was as low as 0.9. Like typical percolation system, composites experienced high dielectric permittivity at low filler concentrations. However, their dielectric loss tangent was low enough to match with non-percolative ceramic filler-based polymer composites. Maximum electrical conductivity at 24 wt% of PANI–DBSA was mere 10^?6 S/cm, a remarkably low value for percolative-type composites. Increase in the dielectric permittivity of the composites with increase in temperature from 25 to 115 °C for different PANI–DBSA concentrations was always in the same range of 50–60 %. However, the degree of increase in the electrical conductivity with the temperature was more prominent at low filler concentrations compared with high filler concentrations. Distinct electrical and their unique thermal dependence were attributed to an improved interface between the filler and the polymer matrix.