【作者】 赵雪霞；

【导师】 刘旭光；

【作者基本信息】 太原理工大学 ， 化学工程与技术， 2013， 博士

【摘要】 近年来,尺寸大小(从纳米级到微米级)和结构不同的球形碳材料已经通过不同的方法制备出来,丰富了碳材料的研究领域。碳微球(Carbon microspheres, CMSs)直径在100nm～1μm之间,且有独特的结构和优异的物化性能,如化学稳定性、热稳定性、优良的导电和导热性等；功能化的CMSs还具有某些特殊的催化、磁学、电学和光学性能,主要应用于增强复合材料、锂离子电池电极材料、催化剂载体、吸附材料、光伏材料、响应性材料、生物医疗材料等方面,是一种具有开发潜力和应用前景的碳材料。本论文主要在CMSs表面修饰的基础上,通过接枝不同的聚合物,制备自组装碳膜、表面二苯并噻吩(DBT)分子印迹吸附材料和聚合物太阳能电池本体异质结薄膜材料,通过形貌、结构和性能的表征与分析,发现针对不同的聚合物,不同工艺条件下合成的CMSs/聚合物复合材料可应用于光子晶体、油品的深度脱硫和太阳能电池领域。主要的研究结果如下：1.酸化CMSs自组装碳膜。通过对酸化CMSs溶液体系进行pH值调节以及成膜自组装,发现碱性溶液中CMSs的分散性较好,并且在pH=13的悬浮液中通过垂直沉积法在载玻片上自组装制得了排列致密的薄膜,样品在自然光的照射下,呈现出了一定强度的反射光,颜色较为均匀,表明所得自组装膜具有较好的均匀性,可用于光子晶体。2. CMSs表面分子印迹聚合物(MIP/CMSs)的合成和吸附性能。通过对CMSs表面进行硅烷化修饰、接枝和聚合,以2-乙烯基吡啶(2-VP)为单体,合成了针对DBT专一吸附的MIP/CMSs。(1)讨论了硅烷偶联剂KH-570对CMSs的修饰效果,发现65℃下,0.3g酸化CMSs中加入1mL的KH-570,反应溶剂60mL(乙醇：水=3:1),硅烷化反应时间为2h时,CMSs表面接枝上KH-570,且CMSs表面包覆层均匀,颗粒之间分散性良好,KH-570接枝率为11%；以2-VP为单体合成了MIP/CMSs并评价其吸附效果。(2)以DBT为模板分子、2-乙烯基吡啶(2-VP)为单体、偶氮二异丁腈(AIBN)为引发剂、乙二醇二甲基丙烯酸酯(EDMA)为交联剂,在CMSs表面制得了表面分子印迹材料(MIP/CMSs)。吸附动力学曲线表明MIP/CMSs对DBT的吸附量达到24.6mg/g。尽管以单体2-VP合成的MIP/CMSs对DBT吸附量偏低,但竞争吸附实验表明,本实验合成的MIP/CMSs对DBT的吸附性能明显优于与其结构相似的苯并噻吩。3.多孔CMSs (PCMSs)表面分子印迹聚合物的合成和吸附性能。PCMSs与光滑CMSs相比,比表面积大,反应活性强,改用PCMSs作为基质,提高了接枝的反应活性,增强了表面印迹材料的脱硫能力,并省去表面酸化的步骤,简化了制备工艺。所以,利用水热合成法制备PCMSs,并在其表面接枝α-甲基丙烯酸(MAA)得到针对DBT专一吸附的分子印迹聚合物(MIP/PCMSs)。(1)水热合成PCMSs,当反应时间为28h,葡萄糖浓度为0.25mol/L时得到的PCMSs形貌均一,粒径约为160nm左右,其生长过程表面已经富含活性官能团,比表面积达到468.3m2/g以上,可作为分子印迹材料的良好基质。(2)分别探讨了MIP/PCMSs制备过程中KH-570及MAA的影响,并在最优参数基础上以DBT为模板分子、MAA为单体、AIBN为引发剂、EDMA为交联剂,在PCMSs表面制得了DBT表面分子印迹材料。吸附结果表明MIP/PCMSs对DBT的饱和吸附量达到376mg/g,是课题组前期合成的MIP/CMSs最大吸附量(109.5mg/g)的3.4倍,非印迹材料(NIP/PCMSs)对DBT的饱和吸附量为240mg/g, MIP/PCMSs对DBT具有良好的识别能力,且吸附过程符合准二级反应动力学方程；在选择性实验中,MIP/PCMSs对于BT的饱和吸附量为244mg/g,表明印迹聚合物对DBT具有良好的选择性。4.聚3-己基噻吩:CMSs (P3HT:CMSs)复合膜的合成及其光伏性能。首先考察CMSs能级结构和光电性能的关系,然后以P3HT:CMSs本体异质结复合膜的制备为目的,在对CMSs表面酸化修饰(A-CMSs)的基础上,进一步用1,6-己二胺和十二胺进行胺化优化参数分别得到(H-CMSs和D-CMSs),提高其分散性和能级匹配性；最后制得三种P3HT:CMSs复合膜,考察共混体积比、旋涂条件和退火处理的影响。通过结构表征和光电性能测试,得出如下结果：(1)对三种修饰的CMSs (A-CMSs, H-CMSs和D-CMSs)进行电化学循环伏安(CV)分析,得出它们与P3HT的能级差大于激子结合能(0.3eV),可作为电池受体材料；对于LUMO能级,D-CMSs> H-CMSs> A-CMSs。(2)薄膜材料经退火后,在可见光区吸收区域变宽且发生红移,结晶性能提高,开路电压(Vo。)、短路电流和能量转换效率(PCE)明显提高。(3)相对而言,所制备的P3HT:D-CMSs本体异质结复合膜形貌良好,可见光区吸收性好,激子分离率高；基于薄膜退火后的光伏器件,测得电池的性能：P3HT:D-CMSs>P3HT:H-CMSs>P3HT:A-CMSs聚合物电池,P3HT:H-CMSs复合膜的光伏器件与P3HT:A-CMSs相比,Voc由0.690V提高到0.730V, PCE提高约25%,P3HT:D-CMSs与P3HT:H-CMSs复合膜电池相比,Voc进一步提高,PCE提高约100%。总之,对CMSs进行胺化修饰不仅能提高其分散性,改变复合膜的形貌,同时能改善电池的能级结构从而提高开路电压。胺化和退火均有利于提高器件的能量转换效率。更多还原

【Abstract】 Recently, spherical carbon materials with specific size (from nanoscale to micron level) and unique structure have been synthesized by various methods, enriching the research fields of carbon materials. Carbon microspheres (CMSs), with diameters between100nm-1μm, have unusual structures and excellent physical/chemical properties, such as chemical durability, thermal stability and extraordinary thermal conductivity, which are valuable for enhancing composite materials, electrode material for lithium ion battery, catalyst supports, photovoltaic materials, responsive materials and biomedical materials.This dissertation mainly investigated the surface modification of CMSs and their applications. Self-assembled carbon films, molecularly imprinted adsorbents and bulk-heterojunction films for polymer solar cells were fabricated by grafting various polymers. These as-synthesized materials were applied in photonic crystal, solar cells and deep desulfurization from oils.The main results are as follows:1. Self-assembly of carbon films from acidified CMSs. The effects of pH values on the CMSs dispersion and self-assembled films with were discussed. The CMSs film with more ordered and denser structure was obtained using NaOH as solvent under pH=13at deposition temperature of50℃. The sample showed a good reflection to light with uniform color, which indicated the formation of uniform CMSs film and laid a foundation for photonic crystal. 2. The synthesis of molecularly imprinted polymers on the CMSs (MIP/CMSs) and their adsorption property. The MIP/CMSs were prepared using2-vinyl pyridine (2-VP) as monomer and dibenzothiophene (DBT) as template through modifying CMSs surfaces by silanization, grafting and polymeration. Their adsorption to DBT was also investigated.(1) The discussion of silanization process by KH-570. The optimum parameters were:1.0mL of KH-570to0.3g of oxidized CMSs, reaction time of2h at65℃, pH≈5, ethanol=45mL, water=15mL. The dispersion of the silanized CMSs in ethanol was improved and grafting ratio of KH-570reached11%, contributing to the enhanced compatibility of CMSs with various monomers.(2) MIP/CMSs were prepared on the surface of CMSs using DBT as template,2-VP as the functional monomer, chloroform as solvent, azobisisobutyronitrile (AIBN) as initiator and ethylene glycol dimethacrylate (EDMA) as crosslinking agent. The adsorption capacity of DBT on MIP/CMSs was24.6mg/g, higher than that of non-imprinted polymers. Though the adsorption ability was a little lower, the MIP/CMSs using2-VP as monomer exhibited better selectivity towards DBT than similarly structured benzothiophene, as proved by competitive experiment.3. The preparation of porous carbon microspheres (PCMSs) surface molecularly imprinted material (MIP/PCMSs) using methacrylic acid (MAA) as monomer and their adsorption property. PCMSs were synthesized by hydrothermal synthesis method and they showed larger surface area and higher reactivity than the CMSs synthesized by CVD method, which would enhance the desulfurization capability of the MIP/PCMSs.(1) PCMSs with the diameter of160nm and a specific surface area of468.3m2/g were synthesized by hydrothermal method at180℃combined with an annealing process using aqueous glucose solution as raw materials. The optimum parameters were:0.250mol/L glucose solution with reaction time of28h at180℃. The as-obtained PCMSs were abundant in oxygen-containing functional groups on the surfaces, which promoted the surface activation, improved the grafting reactivity and overcame the difficulty of surface modification in the process of MIP/PCMSs preparation.(2) The influence of KH-570and MAA in the coupling and grafting processes were discussed. Based on the optimized parameters, MIP/PCMSs were prepared using DBT as template, chloroform as solvent, AIBN as initiator and EDMA as crosslinking agent. The adsorption results show that the adsorption capacity of DBT on MIP/PCMSs was376mg/g,3.4times that our previous results (109.5mg/g), also higher than that of non-imprinted polymers (240mg/g); the recognition factor was1.57and the adsorption equilibrium time was3h at25℃. The pseudo second order kinetic model provided better correlation for the kinetic adsorption of DBT onto MIP/PCMSs. Selective adsorption experiments suggest that MIP/PCMSs had better selective recognition for DBT and selectivity factor was1.55.4. The synthesis of poly (3-hexylthiophene):CMSs (P3HT:CMSs) composite films as the electron acceptor for polymer solar cells. The relation between energy level structure and photoelectric performance of CMSs was investigated. To prepare P3HT:CMSs bulk heterojunction, acidified and two kinds of aminated CMSs were obtained and three kinds of P3HT:CMSs composite films were prepared by blending and spin-coating using P3HT:A-CMSs (acidified CMSs), P3HT:H-CMSs (1,6-hexanediamine as aminating reagent) and P3HT:D-CMSs (dodecylamine as aminating reagent). The blending volume and conditions of spin-coating and annealing treatment were also investigated.(1) For the three modified CMSs (A-CMSs, H-CMSs and D-CMSs), cyclic voltammetry measurements proved the energy level difference of donor and acceptor was greater than binding energy of exciton (0.3eV), thus it is probable to use the CMSs as acceptor. The sequence of LUMO energy level was D-CMSs>H-CMSs>A-CMSs.(2) Visible region absorption of the P3HT:CMSs composite films was broadened and a red-shift was observed after annealing. Meanwhile, the improved crystallization degree of film led to significant improvement of charge mobility, the open circuit voltage (Voc), short circuit current density (Jsc) and power conversion efficiency (PCE).(3) P3HT:D-CMSs composite films had optimum morphology and optical performance. After annealing, the sequence of performance of cells was P3HT:D-CMSs> P3HT:H-CMSs> P3HT:A-CMSs. Compared with P3HT:A-CMSs, the Voc of P3HT:H-CMSs heterojunction increased from0.690V to0.730V, and the PCE increased by25%. P3HT:D-CMSs composite films showed higher Voc and PCE than P3HT:H-CMSs. In conclusion, amination process not only improved the dispersion of CMSs, but also enhanced the Voc of the solar cells. Amination process and annealing contributed to the improvement of the PCE of the devices.更多还原