【作者】 吴俊；

【导师】 路庆华；

【作者基本信息】 上海交通大学 ， 高分子化学与物理， 2014， 博士

【摘要】 超分子化学是“超越分子概念的化学”，是研究多个分子之间通过非共价键的弱相互作用力（次级键）经过高层次组装成有序聚集体的一门科学。将功能小分子以非共价键方式构筑到聚合物体系中是一种开发新型功能超分子材料的重要方法。这类超分子材料的制备方法简单，结构易于控制。更重要的是非共价键是弱相互作用力，具有可逆性，可以通过选择不同的功能单元来调控超分子材料的性能。本论文主要内容包含两个方面：一是通过离子组装制备含有偶氮苯光敏超分子材料，研究偶氮苯组装单元结构和材料光学性能之间的关系，利用偶氮苯的光取向驱动荧光分子取向，从而制备各向异性荧光发射材料；二是通过静电纺丝技术制备氢键超分子纤维材料，研究氢键超分子纤维的荧光性能及其作为化学传感器的应用。具体内容如下：（1）离子组装制备含不同末端取代基偶氮光敏基团离子复合物及其光致各向异性研究，考察偶氮苯单元结构与复合物光学性能的关系。首先合成了一系列末端含有不同取代基的偶氮苯组装单元，末端取代基的类型有-CN、-CF3、-OCH3和-N(CH3)2。分别将它们与聚丙烯酸钠（PANa）按照电荷比1:1离子组装得到离子复合物PACNAZO、PACFAZO、PAMAZO和PANDAZO。1HNMR、FT-IR和EDS分析结果表明离子复合物按照化学计量比进行离子复合。离子复合物具有长程有序的层状微纳米结构，层间距与末端取代基的类型有关。当末端取代基的Hammett取代常数为正数（σp-R>0，R=-CN、-CF3）时，层间距较大，复合物形成的是侧链部分重叠的堆积结构。当末端取代基的Hammett取代常数为负数（σp-R <0，R=-N(CH3)2、-OCH3）时，复合物形成的是侧链完全重叠的堆积结构。在355nm脉冲激光辐照下，复合物薄膜表现出优异的光取向性能，取向方向垂直激光的偏振方向。PACNAZO、PAMAZO和PANDAZO的面内取向度S值分别高达0.54、0.58和0.59。PACFAZO的面内取向度S只有0.012，这是由PACFAZO薄膜在355nm处的弱吸收和-CF3的低表面能导致。最后探讨了复合物薄膜的光致双折射性能：当使用488nm的连续激光作为泵浦光源时，PANDAZO表现出优异的光致双折射性能，在辐照40min后，双折射（Δn）达到饱和值0.354，关闭泵浦光后，Δn值继续上升至0.365，不再变化，其他三种离子复合物薄膜没有检测到明显的双折射信号；当使用405nm的连续激光作为泵浦光源时，PANDAZO仍表现高的光致双折射特性，并且响应速度增加，Δn值达到饱和值的时间从原来的40min缩短到7min，PACNAZO和PAMAZO也产生了一定的双折射，双折射值分别为0.039和0.054。研究结果表明激光波长越接近偶氮离子复合物的最大紫外吸收波长，光致各向异性越明显，响应速度越快，这为今后设计新型光响应性材料提供了理论指导。（2）离子共组装制备含偶氮苯和二苯乙烯双功能离子复合物及其各向异性荧光发射性能的研究。基于利用取向单元的光取向驱动荧光单元取向来制备各向异性荧光发射材料的理念，我们通过离子组装制备了一类既含有偶氮苯光取向单元又含有二苯乙烯荧光单元的液晶离子复合物。首先合成了偶氮苯单元MAZO和二苯乙烯单元Nstil，然后以不同摩尔比（m: n）离子共组装在聚丙烯酸钠（PANa）主链上得到离子复合物PMmNn。通过1H NMR、FT-IR和UV-vis等表征手段，确认了离子复合物由两个组装单元共组装得到，离子复合物中MAZO单元和Nstil单元以起始投料比与PANa按正负电荷比1:1进行组装。采用了TGA、DSC、POM、SAXS和WXRD等测试手段研究离子液晶复合物的热稳定性、相态和微观结构。PMmNn的热稳定性高达165°C，在一定的温度范围内呈现近晶相液晶性质。PMmNn具有长程有序的层状微结构，层间距d值随荧光分子含量的增加而增加。离子复合物中二苯乙烯单元的荧光未被偶氮苯淬灭。在线性偏振激光（355nm）辐照下，复合物薄膜中偶氮苯单元发生取向，同时驱动二苯乙烯单元取向，取向方向都垂直激光的偏振方向。PMmNn取向薄膜具有各向异性荧光发射性质，荧光二向色性Rex高达4.6。离子复合物薄膜的面内取向度S，荧光强度I和荧光二向色性Rex都随二苯乙烯单元含量的降低而增加。（3）静电纺丝制备含有二苯乙烯的氢键复合物荧光纳米纤维。首先合成了一端是硝基，一端是羟基的二苯乙烯（ST）作为氢键给体，氢键受体为聚苯乙烯共聚4-乙烯基吡啶（PS-co-P4VP）。将它们的DMF溶液进行静电纺丝制备了超分子荧光纳米纤维PSVP(ST)x。从工作电压、工作距离、PS-co-P4VP的浓度和ST的浓度对PSVP(ST)x静电纺丝条件进行优化，确定最优静电纺丝条件：工作电压为15kV，工作距离为20cm，环境温度为40°C，PS-co-P4VP的浓度为120mg mL-1。通过反射红外光谱确认PS-co-P4VP的吡啶基团与ST单元的羟基之间氢键的形成，氢键促进ST单元在溶液中的荧光。超分子纤维具有强的荧光发射性质，最大荧光发射峰位于629nm，相对于在溶液中的荧光，荧光发射峰发生红移。超分子纤维的荧光强度随着ST分子含量的降低而升高。采用荧光显微镜直接观察单根超分子纤维的荧光，并获取了荧光照片，用绿光激发时，纤维发出强的橙红色光。最后用带有平行电极的凹槽收集装置制备了单轴取向性良好的荧光纳米纤维。（4）静电纺丝制备聚联二炔的超分子纤维及其化学传感的应用。首先制备包含不同含量聚联二炔（PDA）单体的静电纺丝超分子纤维，再通过光引发聚合得到包含PDA的超分子纤维PSVP(PDA)x。PDA单体在静电纺丝过程中自组装成分子级别的有序结构，在紫外光辐照下可发生聚合，超分子纤维的颜色从原来的白色转变成蓝色。PDA含量越高，超分子纤维的颜色越深，当纤维中PDA单体与聚合物基质中吡啶基团的摩尔比达到0.12时，这种颜色变化十分显著。聚合过程中，PDA中羧基与聚合物基质中吡啶基团间的氢键未受影响，纤维形貌未发生变化。蓝相超分子纤维可用作温度传感器，当温度升高，超分子纤维颜色从蓝色逐渐转变为红色，温度不同，颜色不同。使用反射UV-vis光谱分析了颜色响应（CR）值与温度之间的关系，CR值在80°C时达到饱和。最后考察了超分子纤维作为有机胺液体特别是有机胺蒸汽传感器的应用，超分子纤维可作为高灵敏性，高选择性的有机胺蒸汽颜色传感器，对有机胺蒸汽的检测限低至100ppb。传感器对有机溶剂蒸汽，酸性气体和环境湿度都不具有颜色响应性。传感器蓝色到红色的颜色响应性质可直接通过裸眼观测，不需要借助实验仪器。因此这类颜色传感器具有良好的应用前景，尤其在缺乏大型检测设备的偏远地区。更多还原

【Abstract】 Supramolecular chemistry, defined as “chemistry beyond the molecule”, was studied on theassembled entities of higher complexity that resulted from the association of two or more moleculesheld together through the non-covalent-bond (secondary bond). It is an important method to explorenovel functional supramolecular complexes by constructing functional small molecules to the polymersby non-covalent-bond interactions. This method is simple and the structure of supramolecular complexis easy to control. More importantly, the weak interactions and reversibility of non-covalent bondsendow the supramolecular materials with some special properties. This dissertation mainly consists oftwo parts: The first part focuses on the photosensitive ionic complexes including azobenzene by theionic self-assembly technique. The relationship between the azobenzene structure and materialproperties was discussed. Anisotropic fluorescence emission materials were prepared by thecooperative orientation of fluorescent molecules during the orientation process of azobenzene. Thesecond part researches on the hydrogen-bond supramolecular electrospun fibers, including fluorescentelectrospun fibers and colorimetric response electrospun fibers. The detailed contents are shown asfollows:(1) A series of photoresponding ionic complexes was prepared by the ionic self-assembly (ISA) ofsodium polyacrylate (PANa) and azobenzene chromophores (RAZO) bearing different terminal groups(-CN,-OMe,-N(CH3)2, and-CF3), which are designated as PACNAZO, PAMAZO, PANDAZO, andPACFAZO, respectively.1H NMR, IR and EDS show that the ionic self-assembly of PANa and RAZOis according to the stoichiometric1:1charge ratio. The ionic complexes are stable up to165°C。 Thelamellar microstructures of the complexes are confirmed by X-ray diffraction. By comparing the Braggspacing “d” of the complexes with the calculated lengths of the side chains, two kinds of layeredarchitectures are proposed. The ionic complexes with an electron-donating terminal substituent (σp-R <0) form an interdigitated lamellar structure with full overlap of the side chains, while the complexeswith an electron-withdrawing terminal substituent (σp-R>0) form an interdigitated packing structurewith partial overlap of the side chains. The PARAZO films can be oriented under the irradiation with 355nm linear pulsed laser. The orientation direction is perpendicular to the laser polarization. Thein-plane orientation order parameter (S) of PANDAZO film is up to0.59. For the weak absorption at355nm, the photoinduced orientation of PACFAZO film is not obvious. Finally, the photoinducedbirefringence properties of the complex films are investigated. The PANDAZO film shows extremelyhigh birefringence (n=0.365) by using488nm continuous laser as the pump light. The other ioniccomplexes have no obvious photoinduced birefringence for the weak absorption at488nm. Therefore,a continuous laser with short wavelength (405nm) is used as the pump light. The complex films ofPACNAZO and PAMAZO produce certain birefringence. The results show that the wavelength of thepump light is closely related to the orientation behavior of the ionic complexes containing azobenzene.This provides a theoretical guidance to design novel photosensitive materials.(2) Based on the design of the materials which contain a photoinduced orientation unit and thefluorescent unit, a series of fluorescent ionic complexes (PMmNn) are prepared based on ionicself-assembly of azobenzene unit (MAZO) and stilbene unit (Nstil) with sodium polyacrylate (PANa)according to the1:1charge ratio, in which the ratio of Nstil unit to MAZO unit is m: n.1H NMR, IRand UV-vis spectra confirm that the ionic complexes are composed of MAZO unit, Nstil unit andPANa main chain, which also confirm that the MAZO unit and Nstil unit attached to PANa backboneaccording to the initial calculated proportion. The ionic complexes exhibit high thermal stability andsmectic liquid crystalline behavior. The long-range lamellar microstructures are also confirmed bysmall angle X-ray scattering (SAXS). And layer spacing (d) of the complexes increases with theincrease of the content of the fluorescent unit. Both the MAZO unit and Nstil unit are oriented underthe irradiation with linear polarization pulsed laser. And the orientation direction is perpendicular to thelaser polarization. Polarized UV-vis spectra of the oriented PMmNn films indicate that the orientationof fluorescent unit is driven by azobenzene unit. The oriented PMmNn films exhibit anisotropicfluorescence emission. The fluorescent dichroic Rexis up to4.6. Moreover, the in-plane orderparameter S, fluorescent intensity I and dichroic Rexof the PMmNn films increase with the decreasingthe content of Nstil unit in the films.(3) The fluorescent supramolecular electrospun fibers PSVP(ST)xcontaining stilbene are prepared by electrospinning from the DMF solution of stilbene unit (ST) and polystyrene-co-poly(4-vinylpyridine)(PS-co-P4VP), where stilbene unit with hydroxy group is the hydrogen-bond donor while thehydrogen-bond acceptor is PS-co-P4VP. The electrospun conditions are optimized from workingvoltage, working distance, the concentration of PS-co-P4VP and ST. Working voltage is15kV.Working distance is20cm. The electrospun temperature is40°C. The concentration of PS-co-P4VP is120mg mL-1. The hydrogen bond between the ST unit and PS-co-P4VP is confirmed by attenuatedtotal reflectance (ATR) FT-IR spectra. The supramolecular complexes show strong fluorescenceemission in DMF solution or their electrospun fibers. The hydrogen bond between the ST unit andPS-co-P4VP accelerate fluorescence emission of ST molecule in DMF solution. The fluorescence ofthe electrospun fibers is also investigated. The red shift is observed in the fiber with respect to that inDMF solution due to the dimer emission in the electrospun fibers. Furthermore, the fluorescenceintensity of the electrospun fibers increases with decreasing the content of ST in the fibers. At last, theuniaxially oriented PSVP (ST)0.04fluorescent fiber is prepared by using an aluminium U-shaped groovewith gap of1cm as receptor.(4) A series of polydiacetylene acid (PDA)-embedded supramolecular electrospun fibers areprepared and applied as colorimetric sensor of detection of temperature, organic amines and theirvapors. The PSVP(DA)xsupramolecular electrospun fiber is first prepared by electrospinning the DMFsolution of10,12-pentacosadiynoic acid (DA) and polystyrene-co-poly(4-vinylprydine)(PS-co-P4VP)(“x” in the abbreviation represented the molar ratio of DA molecular to the pyridyl group inPS-co-P4VP). The uniform-dimeter and continuous fibers are obtained when the concentration ofPS-co-P4VP is100mg mL-1. The hydrogen bond between the carboxyl groups of DA monomers andthe pyridyl groups in PS-co-P4VP is confirmed by ATR FT-IR spectra. The self-assembly of DAmonomers occurs during the evaporation of solvent in the process of electrospinning for the attractiveforce between the DA monomers (i.e. hydrophobic interaction and π-π stacking interaction). Theassembled DA monomers in fibres are further polymerized to form PDA with alternating ene-yne mainchain under the254nm UV light irradiation. The color of the fiber mats charges from white to blue.The blue color of the fibre mat becomes deeper gradually with the content of DA monomer increasing. After UV-irradiation and following annealing at90°C, no change in the morphology of the electrospunfibres is found though the color of fibre mats presented white-blue-red transition. The hydrogen bondsbetween PDA and PS-co-P4VP are not destroyed after these treatments. The colorimetric response ofthe electrospun fibers to temperature is first investigated. Take PSVP(PDA)0.12as an example, the colorchange from blue-purple-red is observed while heating the fiber mats from room temperature to90°C.Colorimetric response (CR) value is used to evaluate the degree of converting from the blue phase intored phase, which can be calculated by UV-vis spectra. The relationship between CR value and thetemperature is discussed. The colorimetric response of the supramolecular fiber mats to organic amineor their vapors is also investigated. The color change from blue to red is observed when the fiber matsexposed to100ppb concentration organic amine vapors. The selectivity of the colorimetric sensor isinvestigated. No color change is observed while exposure to common organic solvents and acidic gases.These results indicate that the PDA-embedded supramolecular fiber mats are high sensitive andselective sensors for the detection of temperature, organic amine and their vapors by simple colortransition.更多还原