沉淀剂对含有氨侧基的聚苯撑乙炔发光性能的影响

通过单体4-[(2,5-二溴苯)乙炔基]苯胺和1,4-二乙炔基-2,5-二戊氧基苯之间的Sonogashira偶合反应合成了带有p-氨基苯乙炔基共轭侧基的聚对苯撑乙炔（(PAnPE）). 该共轭聚合物的THF溶液（(2××10-－5 mol•·L-－1）)在473和519 nm处呈现两个比较强的荧光发射峰. 通过调节在聚合物PAnPE-THF溶液中所加入三种沉淀剂（(甲醇、乙酸、稀盐酸溶液）)的体积比例, 来改变PAnPE分子链的聚集态结构, 进而研究对其发光性能的影响规律. 实验结果表明: 由于沉淀剂与聚合物PAnPE分子链之间相互作用能力与方式的不同, PAnPE两个荧光峰的发射强度因聚合物分子链聚集结构不同而呈现不同的变化规律, 这有助于实现在化学传感器中的应用.     

蒽端基聚对苯亚乙炔的发光性能

报道了一种新的蒽端基聚对苯亚乙炔的合成与发光特性,分别考察了聚合物 P2的紫外吸收,荧光发射和电致发光光谱。结果表明,在聚对苯亚乙炔主链末端引 入蒽基团可改变其有效共轭长长及发光颜色,合成的模型小分子可证明这一点。电 致发光器件ITO/P2/Al在600 nm处发红光。     

含三嗪或查尔酮结构聚对亚苯基亚乙炔基的合成及其荧光特性

聚对亚苯基亚乙炔基(polyphenyleneethynylene,PPE)是主链由苯环与乙炔基交替相联的线型聚合物,其共轭主链的电子流动性好,在溶液中有较高的荧光量子效率,具有独特的光电性能,已在分子导线、分子传感器、液晶显示、发光二极管和能量传输材料等领域得到应用[1~4].在聚对亚苯基亚     

非共价键自组装制备聚对苯撑乙炔/聚丙烯酸水溶性荧光纳米粒子及其光物理行为研究

通过功能化聚对苯撑乙炔(含羟基与氨基)和聚丙烯酸之间的非共价键自组装制备了一系列含共轭聚合物的水溶性荧光纳米粒子, 并进行了相关结构和光学性质表征. 研究表明, 纳米粒子的大小和聚丙烯酸/聚对苯撑乙炔质量比直接相关. 光物理性质研究表明, 形成水溶性纳米粒子后, 疏水的聚苯撑乙炔链在纳米粒子中易于形成π-链间聚集, 其光物理性质与其在薄膜态时相似.     

含Gemini表面活性剂结构单元的新型两亲聚电解质的合成及聚集行为

分别将Gemini型单体1,3-双(二甲基十四烷基溴化铵)-2-丙烯酰氧基丙烷(14G)或1,3-双(二甲基十六烷基溴化铵)-2-丙烯酰氧基丙烷(16G)与丙烯酰氧乙基三甲基氯化铵(DAC, D)共聚合反应, 合成了新型含Gemini表面活性剂结构单元的两亲性阳离子聚电解质(D14G和D16G). 采用稳态荧光、电导、动态光散射及透射电镜等手段研究了这些聚电解质在水溶液中的聚集行为. 结果表明, 临界聚集浓度(CAC)随着Gemini型表面活性剂单元含量的增加而减小, 同时随着Gemini型表面活性剂单元中疏水碳链长度的增加而降低. 这些聚电解质在水溶液中同时存在分子内和分子间两种类型的聚集体, 而且碳链越长, 形成分子内聚集体的倾向越强. 随着Gemini表面活性剂单元含量的增加, D14G溶液中聚集体的流体动力学半径(Rh)也有所增大, 而D16G溶液中的聚集体的流体动力学半径(Rh) 却略有减小.     

芴酮对聚醚侧链聚芴体系的影响: 合成, 表征及光物理性质的研究

利用Yamamoto聚合反应, 通过调节单体2,7-二溴9,9'-二-(三乙氧基甲基)芴和2,7-二溴芴酮的比例, 合成了侧链为极性聚醚链, 芴酮含量逐渐增加的聚芴系列. 通过聚合物溶液及固态薄膜的紫外荧光谱图, 深入研究芴酮作为能量受体的能量转移过程及其对聚合物光物理性质的影响. 结果表明: 稀溶液中体系呈现聚芴本征态的荧光发射, 能量转移对溶液浓度具有依赖性; 固态薄膜中能量转移效率随芴酮含量的增加而快速增长, 退火后这种现象更加明显.     

含二乙炔类共轭聚合物的合成及性能研究

在以CuCl和四甲基乙二胺(TMEDA)作为催化剂和邻二氯苯作溶剂条件下,以二-(4-乙炔苯基)-4-辛氧基苯胺(M1)和3, 6-双(乙炔基)-N-辛基咔唑(M2)作为单体,通过Glaser-Hay氧化偶联反应合成了含有咔唑和三苯胺结构单元的聚芳烃二乙炔共轭聚合物.采用红外光谱、核磁共振谱、热失重分析、紫外吸收光谱和荧光光谱等方法对聚合物进行结构表征与性能测试.所得到的聚合物都溶于普通的有机溶剂(如四氢呋喃、二氯甲烷、氯仿、甲苯等).结果表明,聚合物具有优异的热稳定性,热失重5 %时,分解温度在400℃以上;在光激发的条件下,聚合物在二氯甲烷溶液中发射蓝光.     

聚乙烯醇调控水溶性共轭聚噻吩的光学性质

针对发光共轭聚合物稀溶液在干燥形成固体时的荧光淬灭问题, 通过高分子聚乙烯醇(PVA)的氢键网络调控水溶性共轭聚噻吩在溶液中的聚集行为和构象, 并采用不同的干燥方式实现了调控其固体光学性质的目的. 紫外-可见光吸收、荧光发射光谱测试表明, 在水溶液中PVA可以分散共轭聚合物链, 并增强其共平面性; 高温干燥后, 聚噻吩薄膜与无PVA添加的聚噻吩溶液的荧光性质相似; 而采用冷冻干燥法, 薄膜则保留了添加PVA后混合溶液的发光特性. 该结果表明, PVA对聚噻吩在溶液状态下的聚集/分子构象的调控行为随干燥方式的不同得到了不同程度的保留——高温加热干燥仅维持了PVA对聚噻吩的分散作用; 而冷冻干燥则完整保留了PVA与聚噻吩的分子间相互作用, 将溶液中分子的分散状态和构象同时固定. 本研究从干燥方式的角度为固态共轭聚合物聚集行为及发光性质的调控提供了新的策略.     

两亲聚电解质水溶液

本文着重讨论了影响两亲聚电解质在水中形态及其水溶液性质的主要因素，包括：１）疏水基含量；２）疏水基分布；３）溶液中微环境；４）增溶作用。并举例说明两亲聚电解质水溶液的应用，包括：１）配制无皂水溶胶涂料；２）用作净化含活性染料废水的絮凝剂；３）用作水溶液的粘度调节剂；４）用作水介质中聚合物胶乳的表面活性剂。     

端基为橙光基团的聚芴合成和发光性质

含溴橙光化合物与双(三环己基膦)钯(0)进行氧化加成反应,合成了相应的芳基钯(Ⅱ)配合物.在加热条件下,该配合物可以引发AB型芴单体聚合,得到端基为橙光芳基基团的聚芴共轭聚合物.含溴橙光化合物与不同配体钯(0)配合物组成催化体系,原位引发聚合,同样可以制备上述端基结构明确的共轭聚合物.其中,以三(邻甲基苯基)膦或卡宾化合物为辅助配体时,室温下即可引发AB型芴单体进行催化剂转移聚合.卡宾化合物为辅助配体时,可以获得Mn为7.48×10~4的高分子量聚芴.MALDI-TOF分析证实,聚合物的一个端基是来自催化剂钯配合物中的橙光芳基基团,另一端基为Br/H原子.聚合物光致发光(PL)光谱主要表现为聚芴单元的蓝色荧光发射.电致发光(EL)光谱表明,聚合物在低分子量时表现为橙红光发射,而在高分子量时,能够得到白光发射.在数均分子量Mn为7.48×10~4时,聚合物可实现纯白光发射,国际色坐标CIE为(0.31,0.32).     

Solvation and aggregation of polyphenylethynylene based anionic polyelectrolytes in dilute solutions

The absorption and fluorescence properties of a polyphenylethynylene based conjugated polyelectrolyte with sulfonate solubilizing groups (PP2) are shown to change dramatically with solution conditions because of the equilibrium between unaggregated and aggregated forms of the polymer. The fluorescence of PP2 is strongly quenched on addition of counterions such as Na+, K+, Li+, and TBA+, an effect which arises from the creation of salt stabilized aggregates. The formation of aggregates has been further corroborated by concentration and temperature studies in water and comparisons to dimethylsulfoxide solvent, in which the polymer does not aggregate. In aqueous solutions, the addition of the cationic surfactant, octadecyltrimethyl ammonium, causes the polymer aggregates to dissociate and creates polymer/surfactant aggregates that have spectral properties like that of the unaggregated polymer.     

Fluorescence study of chromophore labeled strong polyelectrolyte bound with oppositely charged surfactant

Four strong polyelectrolyte samples of 2-(acrylamido)-2-methylpropanesulfonic acid (AMPS) and N,N-dimethylacrylamide (DMAA) were radically copolymerized with a single label of naphthalene or pyrene, with both labels and without label, containing about 40 mol % AMPS. Fluorescence nonradiative energy transfer (NRET) I_Py/I_Np, anisotropy r, I₁/I₃ and excimer emission I_E/I_M of pyrene labels were observed in dilute aqueous solutions with and without cationic surfactant of cetyltrimethylammonium bromide (CTAB). The overlap concentration was determined as 3 g/L from the appearance of intermolecular excimer. The variation of intra- and intermolecular NRET with total polyelectrolyte concentration showed that the charged chains preferentially interpenetrated each other rather than reduce their coil volume as their concentration beyond the overlap threshold. By binding with CTAB, the polyelectrolyte chain became more coiled as known from the reduced viscosity. The intramolecular NRET was dominant when [CTAB]Д᎒^-5 M and then the intermolecular NRET occurred at higher CTAB concentrations with hydrophobic aggregation between CTAB tails bound on different polyelectrolyte chains. The CTAB concentration corresponding to the maxima of I_Py/I_Np just is equal to the AMPS monomer concentration, indicating the formation of 1:1 binding between surfactant and polyelectrolyte in very dilute solutions. Added salt of NaCl up to 0.1 M hardly affected the intramolecular NRET but affected the I_Py/I_Np value for the intermolecular NRET.     

Interaction between the conjugated polyelectrolyte poly{1,4-phenylene[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl} copolymer and the lecithin mimic 1-O-(l-Arginyl)-2,3-O-dilauroyl-sn-glycerol in aqueous solution

In this paper, the interaction between the water-soluble conjugated polyelectrolyte poly{1,4-phenylene[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl} copolymer and the amino acid glyceride conjugate 1-O-(L-arginyl)-2,3-O-dilauroyl-sn-glycerol dichlorohydrate (a mimic for the phospholipid lecithin) has been studied in aqueous solution by electronic spectroscopy (absorption and fluorescence) and small-angle neutron scattering (SANS). A significant increase in the polymer fluorescence and blue shift in its emission are observed on association with the surfactant. This is suggested to be due to breakup of polymer aggregates. In addition, the spectroscopic and photophysical data suggest this is followed by the vesicle to ribbon transition characteristic of this surfactant, leading to incorporation of single chains of the polymer within mixed polymer-surfactant aggregates. Support for this comes from preliminary SANS measurements, from which evidence for polymer dissolution and formation of two-dimensional structures has been obtained.     

Surfactant--polymer aggregates formed by sodium dodecyl sulfate, poly(N-vinyl-2-pyrrolidone), and poly(ethylene glycol)

The interaction of sodium dodecyl sulfate (SDS) in aqueous solution with poly(N-vinyl-2-pyrrolidone) (M(w) = 55,000 g/mol) in the presence of poly(ethylene glycol) (M(w) = 8000 g/mol) is investigated by electrical conductivity, zeta potential measurements, viscosity measurements, fluorescence spectroscopy, and small-angle X-ray scattering (SAXS). The results indicate that SDS-polymer interaction occurs at low surfactant concentration, and its critical aggregation concentration is fairly dependent on polymer composition. The polymer-supported micelles have average aggregation numbers dependent on surfactant concentration, are highly dissociated when compared with aqueous SDS micelles, and have zeta potentials that increase linearly with the fraction of PVP at constant SDS concentration. The analysis of the SAXS measurements indicated that the PVP/PEG/SDS system forms surface-charged aggregates of a cylindrical shape with an anisometry (length to cross-section dimension ratio) of about 3.0.     

Synthesis and surfactochromicity of 1,4‐diketopyrrolo[3,4‐c]pyrrole(DPP)‐based anionic conjugated polyelectrolytes

Two novel anionic conjugated copolyelectrolytes PSDPPPV and PSDPPPE were synthesized via Heck/Sonogashira coupling reactions and characterized by FT‐IR, ¹H NMR, UV‐vis, and PL spectroscopy. The two polymers are respectively constituted of 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPV) and 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPE) with 1,4‐diketo‐2,5‐bis(4‐sulfonylbutyl)‐3,6‐diphenylpyrrolo[3,4‐c]pyrrole (SDPP) which is a novel water soluble diketopyrrolopyrrole derivative. PSDPPPV and PSDPPPE show broad absorption band in visible region and they exhibit strong fluorescence quenching in aqueous solution. The fluorescence of their aqueous solutions can be enhanced in the presence of cationic surfactant or polymer nonionic surfactant. Fluorescence enhancement by introduction of polyvinylpyrrolidone (PVP) shows linear response. This result provides a controllable method to increase fluorescence intensity of dipyrrolopyrrole‐based conjugate polyelectrolytes in aqueous phase. The optical properties suggested that PSDPPPV and PSDPPPE which are negatively charged conjugated polymers can assemble with positively charged photovoltaic materials to form ionic photoactive layer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 739–751     

Bulk Properties of Carboxymethylchitosan and Cationic Surfactant Mixtures: Fluorescence and Surface Tension Studies

The interactions between carboxymethylchitosan and alkyltrimethylammoniumbromides were studied in aqueous solution. The dependences of aggregation behavior on surfactant concentration, polyelectrolyte concentration, as well as surfactant chain length were investigated mainly using fluorescence spectroscopy method. The variation of I ₁/I ₃ of pyrene fully characterized the aggregation behavior of the polymer-surfactant complex. Meanwhile, based on that Nile red has the sensitivity to the environmental polarity different to pyrene, the changes of aggregates size and number can be reflected by the fluorescence spectroscopy of Nile red.     

Fluorescence Probe Study of the Interaction Between Acrylic Acid-co-Ethyl Methacrylate Copolymers and Sodium Dodecylsulfate

The interaction between sodium dodecylsulfate (SDS) and acrylic acid (AA)–ethyl methacrylate (EMA) copolymers has been investigated using steady state fluorescence and conductimetric measurements to assess the effect of the polymer composition on the aggregation process. Micropolarity studies using the ratio between the emission intensities of the vibronic bands of pyrene (I₁/I₃) and the shift of the fluorescence emission of pyrene-3-carboxaldehyde show that the interaction of SDS with AA-EMA copolymers occurs at surfactant concentrations smaller than that observed for the pure surfactant in water and depends on the copolymer composition. The increase of ethyl methacrylate in the copolymers lowers the critical aggregation concentration (CAC) due to the larger hydrophobic character of the polymer backbone. The formation of aggregates on the macromolecule is induced mainly by hydrophobic interactions, but the process is also influenced by the ionic strength due to the counter-ions of the polyelectrolyte.     

The effect of poly(N,N-dimethylacrylamide) on the lamellar phase of Aerosol OT/water

The effect of a water-soluble uncharged polymer on the stability of the lamellar phase of the Aerosol OT (AOT)/water system is studied. The lamellar phase still exists when water is replaced by an aqueous solution of poly(N,N- dimethylacrylamide) (R_gƼ᎒² Å). Since the coil dimensions are (much) larger than the thickness of the water layers (d_wᅣ Å), the polymer molecules do not enter the lamellar phase. Instead segregation in small domains occurs, and in equilibrium with the AOT-rich phase another separate phase containing the polymer is formed. The polymer-rich phase exerts an osmotic pressure that reduces the water content in the AOT-rich phase, and by compression the repeat distance is reduced.     

Evolution in the supramolecular complexes between poly(phenylene ethynylene)-based polyelectrolytes and octadecyltrimethylammonium bromide as revealed by fluorescence correlation spectroscopy

Poly(phenyleneethynylene)-based conjugated polyelectrolytes (PPE-SO(3)(-)) are a class of polyions with rigid backbones. This work uses fluorescence correlation spectroscopy to study how the diffusion of complexes, formed between a PPE-SO(3)(-) polyelectrolyte and octadecyltrimethylammonium bromide (OTAB) surfactant molecules, changes with OTAB concentration below its critical micelle concentration. The dependence of the hydrodynamic radius of the complexes on the OTAB concentration has three regimes. In the low concentration regime ( C(OTAB)/ C(monomer) < 6), the complex has a size comparable to that of the polymer in deionized water. In the intermediate concentration regime (6 < C(OTAB)/ C(monomer) < 400), the complexes have the largest size and substantial heterogeneity. In the high concentration regime (400 < C(OTAB)/ C(monomer) < 1800), the complexes have a size that is about three times larger than that in the low concentration regime. These results elucidate features of the self-assembly of a polyelectrolyte and an ionic surfactant and show that the C(OTAB)/ C(monomer) concentration ratio controls the composition of polyelectrolyte/surfactant complexes.     

New three-arm amphiphilic and biodegradable block copolymers composed of poly(epsilon-caprolactone) and poly(N-vinyl-2-pyrrolidone). Synthesis, characterization and self-assembly in aqueous solution

The synthesis, characterization and the self-assembly process of a novel biodegradable block copolymer containing a poly(epsilon-caprolactone), PCL, central block and three poly(N-vinyl-2-pyrrolidone), PVP, arms are reported. Three samples with different amounts of PVP were investigated. The copolymers were characterized by FTIR spectroscopy, (1)H NMR and viscosity measurements. The composition and the molecular weights of the block copolymers were established using size exclusion chromatography SEC and (1)H NMR. Micelle formation by these copolymers was monitored by using the vibrational fine structure of pyrene monomer fluorescence and the critical aggregation concentrations, cac, of the copolymers in aqueous solution were determined using sigmoid Boltzmann-type fitting of the fluorescence data. Dynamic light scattering measurements showed a bimodal size distribution for the copolymers in solution, indicating that the micellization is an intermolecular process. Partitioning coefficients of pyrene between copolymer micelles and water were also determined and increase in magnitude with increasing epsilon-caprolactone content of the copolymer.