不同铁盐氧化掺杂导电聚苯胺纳米结构的合成及性能研究

在没有外加掺杂剂的条件下,以FeCl3,Fe(NO3)3,Fe2(SO4)3,FePO4等多种铁盐为氧化剂,在水溶液中采用"无模板"的方法制备了具有较高电导率的聚苯胺纳米结构.铁盐是一种强酸弱碱盐,在水溶液中发生水解释放出质子,质子可以作为掺杂剂进入聚苯胺主链,因此,在苯胺的聚合过程中,铁盐同时起到氧化剂和掺杂剂的双重功能,进一步简化了导电聚苯胺纳米结构的合成条件,降低了反应成本.FTIR,UV-Vis,XRD等结构表征证实所得的纳米结构的聚苯胺均为掺杂态.试验发现,铁盐较低的氧化/还原电位使产物具有较小的直径和较高的电导率和结晶性.不同的对阴离子对聚苯胺产物的形貌有一定的影响,但对产物的结构和性能影响不大.铁盐与苯胺单体的比例对聚苯胺的形貌和电导率均有较大的影响.     

氧化剂对聚苯胺性质的影响

当过硫酸铵与苯胺的摩尔量之比为1∶1至2∶1时,化学合成的聚苯胺具有高的产率,电导率也较高,过多的过硫酸铵存在,使聚苯胺的电导率明显下降,这是由于它氧化了不同的中间体使产物不同,及聚苯胺被进一步氧化而造成的。各种强的氧化剂虽能提高电化学合成的聚苯胺的电极电位,但都使它的电导率和电化学活性显著降低,这仅是由于聚苯胺的进一步氧化所引起的。为了保持聚苯胺高的电化学活性,应避免它与强氧化剂共存。     

反应温度对衣康酸掺杂聚苯胺性能的影响

以衣康酸为掺杂剂,过硫酸铵为引发剂,采用化学氧化聚合法在不同的反应温度下合成聚苯胺(PANI)。计算其产率和电导率,并测定掺杂态聚苯胺的各项性能指标。通过电阻测试、傅立叶红外光谱测试(FT-IR)、紫外-可见光谱测试(UV-vis)、电子探针分别对产物的导电性、化学结构、紫外可见光谱和微观形貌进行了表征。结果表明,低温有利于减缓链终止的速度使得产物分子链较长,从而使载流子的传输更容易进行,产物电导率高;而温度高于10℃会使聚苯胺氧化断链,使产物电导率下降。以反应温度为10℃时电导率最高,为1.29×10-2(S·cm-1),且具有最高的产率为111.2%,微观形貌为纳米棒状结构。     

新型三维开放骨架磷酸铝化合物的合成及晶化过程中的共模板效应

以1,2-丙二胺(1,2-DAP)为结构导向剂,在180℃加热摩尔组成为n(Al_2O_3)∶n(P_2O_5)∶n(1,2-DAP)∶n(H_2O)=1∶6∶5.5∶139的初始混合物,合成了具有AlPO-CJ31骨架结构的新型三维开放骨架磷酸铝化合物(1);加热摩尔组成为n(Al_2O_3)∶n(P_2O_5)∶n(1,2-DAP)∶n(H_2O)=1∶6∶7.5∶139的初始混合物,合成了二维层状磷酸铝化合物APDAP_(12)-150.利用X射线粉末衍射分析(XRD)、元素分析、热重/差热分析等表征手段确认了化合物1的分子式为[Al_4P_5O_(20)·H_3O·H_2O]·[H_3NCH_2CHNH_3CH_3],质子化的水分子与双质子化的1,2-丙二胺共同起到了导向化合物1的作用.调变初始混合物中1,2-丙二胺的比例可显著影响其模板效应.1,2-丙二胺比例较低[n(1,2-DAP)=5.5]时,产物为三维开放骨架化合物,而当其比例较高[n(1,2-DAP)=7.5]时,产物为二维层状化合物.     

水溶液体系中氧化石墨烯的γ射线辐射还原

石墨烯是一种碳原子以二维蜂窝状晶格结构构成的单片层材料,由于其具有优异的电传导性、力学性能和热传导性近年来受到广泛关注.本文采用γ射线辐射技术分别处理水溶液和对苯二胺(PPD)水溶液中的氧化石墨烯(GO),得到辐照还原氧化石墨烯(RGO)和胺基化修饰的还原氧化石墨烯(RGON).通过傅里叶变换红外(FTIR)光谱、X射线光电子能谱(XPS)、拉曼(Raman)光谱、X射线衍射(XRD)和热失重分析(TGA)等表征分析产物的化学结构和元素组成;通过四探针测试仪和接触角测量仪研究产物的导电性能和亲水性.实验结果表明,在水溶液及PPD水溶液中γ射线辐射均可高效还原GO,还原后得到的RGO和RGON电导率均显著增大.PPD的胺基在辐射还原过程中还可以修饰到石墨烯的表面,因此RGON的亲水性比RGO好,但胺基的存在会干扰石墨烯表面π电子的传导,导致其电导率下降.     

氯化铁氧化掺杂的聚苯胺纳米纤维团簇

没有外加质子酸的条件下,以氯化铁为氧化剂和掺杂剂,在界面体系中由苯胺(An)采用“无模板”的方法成功地制备了电导率为10-2～10-1S/cm的聚苯胺纳米纤维(d=20～30nm).实验证明FeCl3同时起到氧化剂和掺杂剂的双重作用,从而进一步简化了导电聚苯胺纳米纤维的合成条件.与使用过硫酸铵为氧化剂的传统聚合方法相比,FeCl3较小的氧化/还原电位使产物具有较小的直径和较高的结晶性.同时发现聚苯胺的形貌和电导率均与[FeCl3]/[An]的比例有关.FTIR,UV-Vis,XRD结构表征证实所得的聚苯胺纳米纤维为掺杂态.     

钯三角双锥单孪晶的合成

采用液相还原法,以Na_2PdCl_4为钯源,PVP为还原剂和分散剂,碘离子作为晶面选择吸附剂和配位剂,硝酸根离子作为氧化蚀刻剂,水为溶剂,在n(Na_2PdCl_4)∶n(PVP)∶n(KI)∶n(NaNO_3)=1∶35∶10∶9和pH=11条件下,合成了形貌规整的纯度大于99%的钯三角双锥单孪晶.碘离子在合成体系中主要通过改变钯前驱体还原速率来影响钯晶种的生长转化和产物的形貌,对氧化蚀刻作用的影响在较高pH值下并不明显.钾离子和钠离子比例的变化显著影响了产物的形貌组成,此阳离子效应可归因于反应体系在钠离子存在时较钾离子存在时表现出更快的钯前驱体还原速率.     

氧化石墨烯/聚苯胺复合材料的制备及电化学电容性能的研究

以对苯二胺为引发剂,用苯胺和氧化石墨烯(GO)为原料,采用化学原位聚合法制备了氧化石墨烯/聚苯胺(GP)复合材料,不添加任何表面活性剂和模板剂。采用傅里叶变换红外(FTIR)光谱、X射线粉末衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)对复合材料进行了物性表征,并对其电化学性能进行了测试。结果显示,复合材料保持了氧化石墨烯的基本形貌,聚苯胺纤维分布在氧化石墨烯层间及所形成的褶皱上。二者形成的二元纳米复合材料,发挥良好的协同作用,电化学性能得到了改善。当电流密度为0.5A·g-1时,复合材料的比电容可以达到623F·g-1,远大于石墨烯和聚苯胺单体的比电容。     

硅钨酸掺杂的聚苯胺：实物模板法制备及催化性能

以不同形态的实物为模板,硅钨酸为掺杂剂,过硫酸铵为氧化剂合成了不同微观形貌掺杂态聚苯胺,并用红外光谱、气相色-质联用仪及扫描电镜对其进行了表征。考察了所制备的聚苯胺催化合成环己酮1,2-丙二醇缩酮的性能,探讨了不同微观形貌掺杂态聚苯胺催化剂对缩酮反应的催化活性,研究了催化剂用量、反应时间等因素对产品收率的影响,以及不同沸程的产物。结果表明:硅钨酸掺杂聚苯胺是合成环己酮1,2-丙二醇缩酮的良好催化剂,其中微观结构为球状的聚苯胺催化性能最佳。在n环己酮∶n1,2-丙二醇=1∶1.4,催化剂用量为反应物总质量的1.6%,反应时间为40 min的最佳条件下,环己酮1,2-丙二醇缩酮的收率为89.2%。     

分子筛合成中六亚甲基亚胺与环己胺二元胺的模板作用

 以固体硅胶为硅源考察了六亚甲基亚胺(HMI)和环己胺(CHA)二元胺模板剂对分子筛合成产物的影响. XRD测试结果表明,当晶化温度为160 ℃,晶化时间为84 h, SiO2/Al2O3摩尔比为30, Na2O∶H2O∶(HMI+CHA)∶SiO2摩尔比为0.11∶45∶0.35∶1时,即使HMI仅占二元胺模板剂的25%(摩尔分数),所得分子筛仍为MCM-22; 其它条件相同时,以单纯CHA为模板剂得到的是ZSM-35分子筛. 用13C MAS NMR研究了HMI和CHA的状态,结果表明在单一HMI合成体系中,HMI既起MCM-22结构导向作用,又经质子化后起稳定骨架的作用; 而在HMI和CHA二元胺体系中,HMI主要起结构导向作用,CHA则填充在MCM-22层间十元环中稳定骨架.     

模板合成H_4PMo_(11)VO_(40)/聚苯胺纳米线列阵及其聚合机理探讨

在氧化铝模板中制备了HPA/PANI纳米线列阵,SEM、TEM表明列阵中纳米线直径约为80 nm;XRD与FT-IR证明形成了有效掺杂;单根纳米线的导电率为16.2 S.cm-1;材料的TG-DTA表明PANI纳米线材料有三步失重过程,失去吸附水过程,多酸失去结晶水和PANI结构持续分解过程,多酸结构分解过程;在氧化聚合过程中H4PMo11VO40即为质子酸又为氧化剂和掺杂剂;聚合反应采用自由基机理进行,掺杂反应发生在形成醌二亚胺式自由基正离子和双苯胺式自由基正离子和醌二亚胺式自由基正离子偶联聚合成链结构时.     

二磺酸掺杂高热稳定性导电聚苯胺的合成及性能

以有机二磺酸作为掺杂剂合成了具有高热稳定性的二磺酸掺杂导电聚苯胺。研究了反应时间、温度、酸/苯胺摩尔比等因素对产率、产物的导电率与分子量的影响。利用微波加热的方法测试有机二磺酸掺杂聚苯胺的热稳定性能，结果表明：有机二磺酸掺杂的导电聚苯胺在微波场中升温速率快，并且具有良好的反复升温性能。     

一步乳液聚合法制备高溶解性导电聚苯胺

报道了一种高溶解性导电聚苯胺(PANI)的制备方法,以聚2-丙烯酰胺-2-甲基丙磺酸(PAMPS)作为掺杂酸和乳化剂,利用其特有的长链、亲水性及强酸性基团效应,通过乳液聚合法一步合成出具有较高溶解性的导电聚苯胺。利用核磁共振光谱仪(NMR)、傅里叶红外光谱仪(FT-IR)和扫描电子显微镜(SEM)等技术手段对产物结构和性能进行了表征分析。结果表明,在m(苯胺)∶m(AMPS)∶m(APS)=1∶2∶1.5;AMPS质量分数为20%;APS质量分数为30%;反应时间为5 h;反应温度为5℃的条件下,聚苯胺的产率高达86%,在有机溶剂二甲基甲酰胺(DMF)中的溶解度可达0.3814 g/g,在水中的溶解度可达0.2123 g/g,电导率达5.9 S/cm。     

Thermal stability study of conductive polyaniline/polyimide blend films on their conductivity and ESR measurement

Conductivity stability at thermal environment of conductive polyaniline‐complexes/polyimide (PANI‐complexes/PI) blends, which were doped by camphorsulfonic acid (CSA) and dodecylbenzenesulfonic acid (DBSA), respectively, were investigated by conductivity measurements, electron spin resonance (ESR) spectra, differential and scanning thermometer (DSC). In the conversion process of PANI/Polyamic acid (PAA) to PANI/PI, the blend endeavored some kinds of alteration such as decomplexation of moisture and solvent, dissociation of dopant, crosslinking of PANI chain, and the imidization of PAA chain. PANI‐DBSA/PI showed higher thermal stability of conductivity than PANI‐CSA/PI, and both samples showed nearly linear decay of conductivity with increasing temperature showing greatly enhancement of conductivity stability. When they were exposed at near or over glass transition temperature, the conductivity decay became faster. The conductivity stability at base environment was also higher for PANI‐DBSA/PI due to difficulty in accessing of hydroxyl ion to PANI, which were resulted from dopant. DBSA‐doped blends showed increased polaron mobility and concentration at relatively high temperature, which led to extremely higher conductivity and its stability at high temperature. Copyright © 2002 John Wiley & Sons, Ltd.     

聚苯胺/离子液体/蒙脱土纳米复合材料的制备及其导电性能研究

采用1-羧甲基-3-甲基咪唑氯化盐离子液体对钠化蒙脱土进行插层改性,然后用苯胺的盐酸溶液进行二次插层,以过硫酸铵为氧化剂,盐酸溶液为掺杂剂,使进入离子液体/蒙脱土(CMMIm/MMT)层间的苯胺(An)发生氧化聚合反应,制备了一种具有良好导电性的聚苯胺/离子液体/蒙脱土复合材料(PANI/CMMIm/MMT).用红外光谱、X-射线衍射,热重分析和DSC对样品进行了表征.结果表明当离子液体/蒙脱土用量为7.5%、盐酸浓度为1mol/L、过硫酸铵与苯胺的摩尔比为1∶1、0℃下反应6h时制备的PANI/CMMIm/MMT纳米复合材料电导率最高,达到了0.3S/cm,是相同条件下聚苯胺/钠化蒙脱土纳米复合材料电导率的2.5倍,聚苯胺的7.5倍.     

One‐step preparation of solution processable conducting polyaniline by inverted emulsion polymerization using didecyl ester of 4‐sulfophthalic acid as multifunctional dopant

A new one‐step method of preparation of solution processable conductive polyaniline (PANI) is reported using didecyl ester of 4‐sulfophthalic acid (DESPA) as multifunctional material. It consists of inversed emulsion polymerization of aniline in water/chloroform mixture with benzoyl peroxide initiator, maleic acid (MA) as a codopant and DESPA as protonating agent, surfactant, and plasticizer. The resulting product combines reasonable conductivity (ca.0.03 S/cm) with solubility in common solvents such as tetrahydrofuran and chloroform. Elemental analysis together with spectroscopic studies show that the protonation level of emulsion polymerized PANI (0.47 per mer involving one ring and one nitrogen) is very close to that predicted for PANI in the oxidation state of emeraldine (0.5). MA is incorporated into the polymer matrix as a co‐dopant in the ratio 1:4 with respect to the DESPA dopant. PANI‐DESPA‐MA three components system shows a highly ordered, layer‐type supramolecular structure, in which planes of regularly π‐stacked PANI chains are separated by a double layer of dopants. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1051–1057, 2008     

APS/NaClO 复合氧化剂对乳液法合成聚苯胺的微观形貌及其电化学性能的影响

采用乳液法, 以过硫酸铵(APS)和次氯酸钠(NaClO)为复合氧化剂合成导电聚苯胺(PANI). 考察了NaClO 的加入与否对PANI 微观形貌与电化学性能(循环伏安和电导率)的影响, 以及APS、乳化剂十二烷基苯磺酸钠(SDBS)和NaClO的用量对PANI 电化学性能的影响. 结果表明: NaClO 的加入对PANI 的微观取向结构具有重要的影响. 与采用单一APS 合成的PANI 相比, 复合氧化剂合成的PANI 具有较高的循环伏安峰电流以及更加优异的电导率(约为前者的2.6倍). 当苯胺(An)与APS 的物质的量比(n_An:n_APS )为8:7, An 与SDBS 的物质的量比(n_An:n_SDBS )为10:4, NaClO 用量为5%(质量分数)时, PANI 的各项性能指标达到最好; 紫外可见光谱和红外光谱的表征结果表明, 采用复合氧化剂并未对PANI 的分子结构产生明显的影响.     

Electromagnetic functionalized cage-like polyaniline composite nanostructures

Novel cage-like and electromagnetic functional polyaniline (PANI)/CoFe2O4 composite nanostructures, in which the self-assembled PANI nanofibers (approximately 15 nm in diameter) entwined around the octahedral CoFe2O4 magnet acting as the nucleation site or template, were successfully prepared by FeCl3 as either oxidant and dopant via a self-assembly process. The coordination effect of the magnet as a nucleation site or template and the magnetic interaction between the PANI nanofibers and CoFe2O4 as a driving force results in such cage-like nanostructures. The cage-like composite nanostructures not only have high conductivity (sigmamax approximately 5.2 S/cm), but also show a typical ferromagnetic behavior.     

Micelle-assisted synthesis of PANI nanoparticles and application as particulate emulsifier

Well-defined water-dispersible polyaniline (PANI) nanoparticles were synthesized by in situ chemical oxidative polymerization of aniline in the presence of an amphiphilic P(AMPS-co-VM) copolymer micelle. P(AMPS-co-VM) copolymer was prepared by the free radical polymerization of 7-(4-vinylbenzyloxyl)-4-methyl-coumarin (VM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) which can self-assemble into micelles in aqueous solution. Here, P(AMPS-co-VM) copolymer micelle is used not only as soft template but also as acid dopant in our reaction system. The structure, size, and morphology of PANI nanoparticles were characterized by various experimental techniques. It is found that the morphology and the size of the PANI nanoparticles strongly depend on the molecular characteristics of the P(AMPS-co-VM) copolymer. The synthesized PANI nanoparticles behaved as particulate emulsifier for the stabilization of oil-in-water emulsions.     

Microtubules of polyaniline doped with HCl and HBF4

Microtubules of polyaniline (PANI) doped with HCl, HBF₄, and β-naphthalene sulfonic acid (NSA) were synthesized by an improved in situ doping polymerization method. Ultraviolet-visible spectra, scanning electron microscopy, ESR, and X-ray diffraction characterized the molecular structure of the resulting PANI microtubules. These microtubules had a diameter of 1 ∼ 10 μm and a conductivity at room temperature of 0.2 ∼ 3.5 S/cm, depending on the molecular structure and concentration of the dopant. The degree of crystallinity of the PANI microtubules was enhanced by increasing the molecular size of the dopant; that is, the order PANI-NSA > PANI-HBF₄ > PANI-HCl was observed in the crystallinity of the microtubules. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4605–4609, 1999