具有电活性苯胺四聚体接枝聚谷氨酸的合成与表征

以N-羟基琥珀酰亚胺(NHS)活化聚L-谷氨酸的羧基并与苯胺四聚体的氨基缩合,得到了以可生物降解的聚谷氨酸为主链,具有电活性的苯胺四聚体为侧链的新型接枝聚合物.用1H-NMR、质谱分析、光谱分析的方法确定了化合物的结构.侧链羧基的存在使聚合物可以溶解于碱性的缓冲溶液中.对聚合物的电化学性质进行了紫外及循环伏安的表征,研究结果表明,接枝后的聚合物具有与苯胺低聚体相似的可逆的氧化还原过程并可被质子酸掺杂,表现出良好的电化学活性.同时,以定量紫外吸收及元素分析的方法分别测定了聚合物的接枝率.实验中通过控制反应的投料比可以使苯胺四聚体的接枝率达到40%以上,并对聚合物的自掺杂现象进行了讨论.     

掺杂质子酸的类型对聚苯胺结构和电导率的影响

采用化学氧化聚合法以苯胺为单体，过硫酸铵为氧化剂，在不同质子酸的水溶液中合成聚苯胺，考察质子酸对聚苯胺电性能影响，并通过傅立叶红外吸收光谱（FTIR）和紫外可见光吸收光谱（UV－vis)研究聚苯胺掺杂前后结构的变化。结果表明，龙质子酸掺杂后聚 胺具有导电性是因为其分子链上电荷离城形成了共轭结构，具有不同质子酸中生成的聚苯胺氧化程度不同；分子链共轭程度与掺杂酸对阴离子大小有关，掺杂质子酸对阴离子越大，聚苯胺分子链共轭程度越大，电导率也就越高。     

聚间甲氧基苯胺的结构及其氧化还原活性研究

应用循环伏安法研究经HCl、TSA和HClO4等不同酸掺杂的聚间甲氧基苯胺(PmMAn)的电化学活性.结果表明,HClO4是合成PmMAn的最佳酸介质,在此介质中得到的聚合产物具有良好的氧化还原活性.FT IR,SEM和XRD测试分别说明,酸根离子作为抗衡阴离子嵌入PmMAn分子链,并对聚合物的氧化还原活性有较大影响;PmMAn表现出典型的高分子晶体性质,符合单斜晶系的特征.     

聚邻甲苯胺的质子酸掺杂

采用不同种类质子酸对聚邻甲苯进行进行掺杂, 发现质子酸的酸性, 分子尺寸和氧化性均不同程度地影响其掺杂率和电导率。大分子尺寸有机强酸掺杂可诱导掺杂态聚合物的溶解性。ESR测量结果表明, 中性聚邻甲苯胺的自旋电子主要定或 杂原子上; 质子酸掺杂导致氮原子上的电子产生重新组态, 并部分离域到邻近的芳环上, 显示出芳香π-电子的特性。电阻与压力依赖性研究揭示出质子酸掺杂聚邻甲苯胺的导电类型为电子型。     

氧化偶联聚合的方法合成新型电活性聚醚砜及其结构表征

通过氧化偶联聚合的方法我们制备了一种新型电活性聚芳醚砜,这种聚合物主链上含有苯基封端的苯胺四聚体齐聚物单元。我们通红外、核磁和XRD对其结构进行了表征。在1.0M的硫酸水溶液介质中我们对其电活性进行了研究,聚合物展现出两对氧化还原峰。此外,我们使用TGA测试手段对其热稳定性也做了研究。在室温质子酸掺杂的条件下聚合物的导电率为1.37 × 10-7 S·cm-1。     

聚N-甲基苯胺的质子酸掺杂

聚N-甲基苯胺(PMAn)可用酸碱进行可逆的掺杂及反掺杂。掺杂使电导增大。掺杂过程在本质上是链的质子化过程,与阴离子无关。用FTIR、UV-VIS、ESR表征了掺杂前后结构的变化。结果表明,掺杂后链上来偶电子增加,电子及电荷更加离域化,并与电导率增大相吻合。PMAn的导电载流子可能是离域化的阳离子自由基。     

恒电压法制备掺杂聚苯胺薄膜

在不同的酸溶液中加入定量苯胺单体,利用电化学恒压法制备了导电性能优良的聚苯胺薄膜,研究了以不同浓度(0.5、1、1.5、2mol/L)的盐酸、高氯酸和对甲苯磺酸为电解质溶液,苯胺在ITO导电玻璃上的聚合电压和颜色变化,并用FT IR、循环伏安和SEM研究了聚合物的结构及性能。研究表明,在不同酸掺杂下薄膜的颜色依次为黄绿色、绿色、深绿色、天蓝色和深蓝色,这是由于不同掺杂酸对阴离子大小的不同导致其分子链上电荷离域不同,从而使得聚合物的掺杂程度不同而发生不同的红移;随着使用电压的增大,溶液中导电能力增强,聚苯胺薄膜的颜色加深;随着同种酸浓度的增加,质子酸的酸性越强,苯胺的聚合电位就越低。     

取代聚苯胺的聚集态结构

环取代基及掺杂对聚苯胺分子链结构产生影响的同时也对大分子聚集态结构产生影响.通过对聚合物膜的XRD、SEM研究，表明在所合成的环取代聚苯胺衍生物中，聚合物的结晶性依POT（聚邻甲苯胺）、PDMAn（聚 2，5 二甲氧基苯胺）、PmClAn（聚间氯苯胺）顺序增加；与本征态的比较，质子酸掺杂后聚合物的结晶性有所提高.POT基本上表现出了非晶聚合物的性质； PDMAn具有同质多晶的结构特征，但结晶度较低； PmClAn表现出了典型高分子晶体性质，符合单斜晶系的特征（晶胞参数为a=0.679 nm， b=2.304 nm， c=0.5734 nm， α=90°， β=100.9°， γ=90°）.采用HyperChem程序包中的MM＋分子力学方法对1H NMR和XRD实验结果进行结构优化，确定了苯式结构/醌式结构为3/2的PmClAn大分子链的构象.     

不同酸溶液中恒电压法制备聚苯胺薄膜

在不同的酸溶液中加入定量苯胺单体,利用电化学恒压法制备了导电性能优良的聚苯胺薄膜,研究了以不同浓度(0.5、1、1.5、2mol/L)的盐酸、高氯酸和对甲苯磺酸为电解质溶液,苯胺在ITO导电玻璃上的聚合电压和颜色变化,并用FT IR、循环伏安和SEM研究了聚合物的结构及性能。研究表明,在不同酸掺杂下薄膜的颜色依次为黄绿色、绿色、深绿色、天蓝色和深蓝色,这是由于不同掺杂酸对阴离子大小的不同导致其分子链上电荷离域不同,从而使得聚合物的掺杂程度不同而发生不同的红移;随着使用电压的增大,溶液中导电能力增强,聚苯胺薄膜的颜色加深;随着同种酸浓度的增加,质子酸的酸性越强,苯胺的聚合电位就越低。     

沸石分子筛孔道中聚苯胺的选择性掺杂研究

用电化学方法聚合分子筛孔道内的苯胺, 根据聚苯胺在无机质子酸中的掺杂反应研究了ZSM-5,Y型分子筛对磷钼杂多酸的形状选择作用     

Amphiphilic copolymers with poly(meth)acrylic acid chains “grafted from” caprolactone 2‐(methacryloyloxy)ethyl ester‐based backbone

Well‐defined amphiphilic graft copolymers containing hydrophilic poly((meth)acrylic acid) (PMAA) or poly(acrylic acid) (PAA) side chains with gradient and statistical distributions were synthesized. For this purpose, the hydroxy‐functionalized copolymers with various gradient degrees, in which 2‐(6‐hydroxyhexanoyloxy)ethyl (meth)acrylate units (caprolactone 2‐[methacryloyloxy]ethyl ester, CLMA) formed strong gradient with tert‐butyl acrylate (tBA), slight gradient copolymers with tert‐butyl (meth)acrylate (tBMA), and statistical copolymers with methyl (meth)acrylate (MMA) were modified to bromoester multifunctional macroinitiators, P(tBMA‐grad‐BrCLMA), P(BrCLMA‐grad‐tBA), and P(BrCLMA‐co‐MMA). In the next step, they were applied in controlled radical polymerization of tBMA and tBA yielding graft copolymers with various lengths of side chains as well as graft densities. Further, the tert‐butyl groups in copolymers were successfully removed via acidolysis in the presence of trifluoracetic acid, which caused transformation of the hydrophobic graft copolymers into amphiphilic ones with ability of self‐assembly for the future biomedical applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Conducting polymer films fabricated by oxidative graft copolymerization of aniline on poly(acrylic acid) grafted poly(ethylene terephthalate) surfaces

A conductive polyaniline/poly(ethylene terephthalate) (PANI/PET) composite film was fabricated via the oxidative graft copolymerization of aniline (ANI) onto the plasma-induced poly(acrylic acid) (PAAc) grafted PET surface. The attenuated total reflectance Fourier transform infrared spectroscopy spectra (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that PANI was successfully grafted onto the surface of the PAAc-g-PET films. The effects of the experimental conditions on the percentage of PANI grafted onto the PAAc-g-PET films were extensively investigated. A very high grafting percentage of ANI can be obtained through the acid-base reaction between the aniline monomer and PAAc on the PAAc-g-PET surface at high temperature. As a result, the grafting percentage of PANI can be increased to as high as 12.18 wt %, which causes the surface resistance of the PANI-g-PAAc-g-PET film to be reduced to about 1000 Omega/sq. We predicted that this is because of the high flexibility of the PAAc molecular chains and high solubility of aniline, both of which facilitate the binding of aniline to PAAc during this high temperature acid-base reaction. It was observed by atomic force microscopy (AFM) that the PANI-modified PET surface exhibits higher size irregularity and surface roughness, which further indicated that a much greater number of aniline molecules can be reactively bonded to and distributed along the grafted AAc chains and that the PANI-g-PAAc-g-PET surface resulting from the sequential oxidative graft copolymerization can possess higher electrical conductivity.     

Greffage de l'acide methacrylique sur des films de poly(chlorure de vinyle) par la methode radiochimique directe

Since PVC films do not swell in pure methacrylic acid (MAA) the films were subjected to gamma-rays while dipped in various mixtures MAACHCl₂. Under such conditions, the grafting proceeds smoothly and its rate exhibits a flat maximum for the mixture containing ca. 50% (molar) monomer. The rate satisfies the relationship Rate = KI^0.6 and the over-all activation energy of the process is 4 kcal/mole. MAA grafted PVC films do not swell in solvents for PMAA (such as water or methanol) even for high grafting ratios. This result is unexpected since PTFE films grafted with either acrylic or methacrylic acid swell to a large extent in water and are excellent membranes. The swelling of the grafted PVC films was investigated in mixtures 1,2-dichloroethylene -methanol. It was found that the extent of swelling was highest in the mixture containing 35% methanol. The unusual swelling properties of these grafted films are attributed to strong polar interactions between PVC and PMAA chains.     

Synthesis,structure characterization,and gas sensitive properties of a copolymer of aniline with phenol

A new kind of conductive copolymers of aniline with phenol was designed and synthesized by using oxidation polymerization and the results showed that the apparent inherent conductivities of the copolymers are in the range of 10^?2 to 10^?10 S/cm which covers from conductors to insulators. The results showed that the conductivity of the copolymers strongly depends on synthesis conditions, such as reaction time, molar ratios of oxidizer to monomers and aniline to phenol, concentrations of reactants, and reaction temperature. Compared to the conventional (co)polymers of aniline and its derivatives, the magnitudes of the reversible conductivity changes are very significant, about two orders, and get to the maximum readings in about 5 min when they are exposed to ammonia gas, hydrochloric acid gas, and a various vapors of organic compounds, such as methanol, alcohol, acetone, benzene, toluene, chloroform, carbon tetrachloride, etc. It should be noted that with the introduction of the weak acidic structural units into the polyaniline chains, the copolymers are reversibly responded to both acidic and basic gases promptly. Copyright © 2009 John Wiley & Sons, Ltd.     

N-乙烯基咔唑标记甲基丙烯酸-苊烯共聚物的荧光特性

合成了苊烯(ACE)含量依次为4.3、7.5、15.1及20.8 mol％的N 乙烯基咔唑(NVCz)标记甲基丙烯酸(MAA) 苊烯共聚物(PMAA ACE/NVCz）和ACE含量仅为0.5 mol％的ACE MAA共聚物（PMAA ACE）,研究了各共聚物在稀水溶液中的荧光行为和pH、表面活性剂等对共聚物荧光特性的影响.实验发现:在酸性介质中共聚物的压缩线团构象使激发态缔合物荧光相对增强,ACE到NVCz能量转移效率增加;碱性介质中共聚物构象相对松散,ACE到NVCz能量转移效率降低,因此荧光光谱中NVCz特征几乎消失.阴离子表面活性剂十二烷基磺酸钠(SDS),阳离子表面活性剂十六烷基三甲基溴化铵(AHTB)以及中性表面活性剂吐温80的引入使共聚物在酸性介质中的单体荧光特征增强,ACE到NVCz的能量转移效率下降;在碱性介质中引入AHTB部分中和了共聚物链上的负电荷,使共聚物构象重新卷曲,ACE到NVCz的能量转移效率提高,荧光光谱中NVCz特征重新出现,ACE单体荧光特征相应减少;在碱性介质中引入SDS以及吐温80对共聚物荧光光谱影响不大.     

Preparation of hybrid film of polyaniline and organically pillared zirconium phosphate nanosheet by electrodeposition

α-Zirconium phosphate was chemically modified with 1,2-bis(dimethylchlorosilyl)ethane to graft organic chain, and then it was used as host material for inorganic nanosheet-polyaniline hybrid. The grafted α-zirconium phosphate was exfoliated in an acetonitrile solution with tetrabutylammonium salt and aniline. The electrodeposition in the presence of aniline was performed, and then it resulted in a formation of higher-order structure in which phosphate nanosheet was propped up by 1,2-bis(dimethylchlorosilyl)ethane with intrusion of polyaniline into the nanospace. The gravimetric capacitance of the α-zirconium phosphate without grafts and polyaniline hybrid film was around 194 F/g with the base on the amount of polyaniline mass. On the other hand, the α-zirconium phosphate nanosheet with grafts and polyaniline hybrid film provided larger capacitance of around 350 F/g in maximum. The nanospace formed by grafted phosphate nanosheet with 1,2-bis(dimethylchlorosilyl)ethane molecules gives increased amounts of polyaniline included and diffusion paths for ions.     

温度/pH敏感性P(MAA-g-DEAM)共聚物水溶液的相行为

利用大分子单体技术通过自由基共聚法合成了由甲基丙烯酸(MAA)和N, N-二乙基丙烯酰胺(DEAM)组成的几种不同组成的P(MAA-g-DEAM)接枝共聚物.通过UV-Vis 透光率的测定和荧光探针技术, 对共聚物水溶液的相行为进行了研究. 研究表明, 此接枝共聚物具有相互独立的温度和pH 敏感性；几种组成不同的P(MAA-g-DEAM)接枝共聚物具有基本相同的低临界溶解温度(LCST)；它们的临界相变pH与接枝共聚物的组成有关, 温敏性PDEAM 枝链的接枝率越高, 其临界相变pH 越高. pH > 5.5 时, 接枝共聚物的主链是一种较为松散的线团构象；pH < 5.5 时, 接枝共聚物的主链是一种较为压缩的线团构象. 这种接枝共聚物高分子聚集体在新的纳米复合材料的合成方面有可能获得应用.     

Collapsed conformation of poly(methacrylic acid) chain containing nonionic hydrophilic units

Copolymers of methacrylic acid (MAA) and a nonionic hydrophilic monomer N-vinylpyrrolidone (NVP) were synthesized by polymerization in aqueous solution in the absence of metal ions. The NVP content of the copolymers ranged from 2 to 36 mole % with sequences of MAA interrupted at random by a single unit of NVP at all compositions. The pH-induced conformational transition of these copolymers was followed by potentiometric titration and viscosity studies and the results were compared with those of pure poly(methacrylic acid) (PMAA). The negative free energy of transition from the un-ionized compact from to expanded structure showed a gradual decrease with increasing NVP content, and the collapsed conformation observable for PMAA at low degrees of ionization (0 < α < 0.3) disappeared at NVP contents greater than 15 mole%. These findings are supported by viscosity data. The results suggest that long-range methyl–methyl hydrophobic contacts still possible in higher NVP content copolymers are not sufficient to bring about the collapse of the molecule and a minimum average sequence length of about 20 MAA units is required to compact the molecule. Hydrophilic “shielding” of MAA chains by NVP segments could also partly destabilize the collapsed structure.     

P(DEAM-co-MAA)在稀水溶液中构象行为的荧光探针研究

利用UV透光率测定,荧光探针技术等研究了N,N-二乙基丙烯酰胺(DEAM)与甲基丙烯酸(MAA)的共聚物P(DEAM-co-MAA) 在稀水溶液中的构象行为.结果表明，当共聚物中DEAM含量小于8.00％(molar fraction),溶液的pH < 6时,P(DEAM-co-MAA)在稀水溶液中的构象行为与聚甲基丙烯酸(PMAA)相似,共聚物可形成疏水微区,表现为一种较为高度压缩的线团构象;当共聚物中DEAM含量大于8.00％(molar fraction)时,由于高分子的稀释效应,P(DEAM-co-MAA)在pH 2～10范围内表现为较为松散的伸展构象.P(DEAM-co-MAA)构象随其组成和pH变化的这种性质有可能在新型敏感性凝胶的合成设计上获得应用.