【作者】 兰阳；

【导师】 王恩波；

【作者基本信息】 东北师范大学 ， 无机化学， 2006， 博士

【摘要】 纳米结构材料嵌入聚合物基质中形成的纳米复合物由于其在催化,磁学,以及光子学中的潜在应用而倍受关注。本论文工作以多金属氧酸盐为核心通过交替沉积技术与原位化学反应相结合来制备此类复合膜。利用有效的在前体膜中成核、生长纳米粒子的方法,使用Keggin型钨系、钼系多酸,有目的地利用其酸性,强氧化性,在膜中发生反应,从合成出基于多酸的纳米粒子,通过增加多酸的反应循环数,我们可以实现了纳米粒子的可控合成,采用UV-vis光谱、FTIR光谱、X-射线光电子能谱、扫描电子显微镜、原子力显微镜、透射电子显微镜、循环伏安对所制备的纳米复合膜进行了组成、结构和性质表征。研究结果表明,多金属氧酸盐纳米粒子在复合膜中原位形成了,且保持原来的结构和性能。膜的特征吸光度随着反应循环的增加而线性增长,膜表面在反应前后也呈现不同的粗糙度。当我们利用多酸的酸性进行原位反应时,先将被聚电解质前体膜修饰后的基片放入多酸溶液中吸附,然后再吸附作为沉淀剂的季铵盐,使多酸在膜中被沉淀下来,不同种类的多酸或实验条件,可以得到不同的实验结果。以12-钼磷酸为原料,形成的纳米粒子不仅尺寸而且形貌均随反应循环而发生变化,其形貌由最初的球型粒子逐渐生长成为鹅卵石型结构;以12-钨硅酸为原料,则形成了分散均匀的纳米棒,纳米棒的长度可以通过季铵盐的烷基链来调节;当选择硝酸银为沉淀剂时,我们改变了反应顺序,先将前体膜浸入硝酸银溶液中,然后再浸入钨硅酸溶液中,从而得到了构型好的球状纳米粒子,并且一直保持球状形貌。当利用多酸的强氧化性进行原位反应时,先将前体膜浸入pH=4的吡咯单体溶液中,在此状态下,吡咯单体带正电荷,可以被吸附到膜内,然后再浸入12-钼磷酸的溶液中,使吡咯单体在膜中发生氧化聚合,形成多酸杂化的聚吡咯纳米粒子,随着反应循环的增加,纳米粒子的尺寸增大了,而且当反应到一定程度后,纳米粒子清晰可见,并且有些连接成链。聚电解质前体膜不仅可以用作纳米反应器,而且它还可以修饰基片,从而组装一些对基片有特殊要求的材料。选择含有氨基的聚阳离子和PSS交替沉积来构筑前体膜,将截短的多臂碳纳米管垂直组装到了膜上,共价键的引入大大提高了形成的单层膜的稳定性,而且交替沉积技术的使用也克服了以往自组装碳纳米管阵列要求金或银基片的局限。更多还原

【Abstract】 Nanocomposites of nanometer-sized materials embedded within a polymer matrix have attracted much attention, for their potential applications in catalysis, magnetics, and photonics. This thesis focuses on the preparation of such nanocomposite films based on polyoxometalates by combination of layer-by-layer self-assembly technology with in situ chemical reaction.The effective method of nucleation and growth of nanoparticles as applied to synthesize W- and Mo- containing polyoxometalates nanoparticles in precursor films by making use of their acidity or oxidative property. The controllable synthesis of nanoparticles can be achieved by increasing synthetic cycle of polyoxometalates. The composition, structure, and properties of the as prepared composite films have been characterized in detail by UV-vis, FTIR, X-ray photoelectron spectra, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and cycle voltammograms. The results indicate that the polyoxometalates nanoparticles in-situ formed in the films and their identities were preserved. The characteristic absorbance increased nearly in line with the number of synthetic cycle. The nanocomposite films showed different roughness before and after synthesis.By using the acidity of polyoxometalates, the substrate modified by polyelectrolyte precursor film was alternately dipping into polyoxometalates solution and solution of tetraalkylammonium salts as precipitator. The experiments show that different polyoxometalates as starting materials or reaction condition can lead to different results. Both the size and morphology of the nanoparticles changed with synthetic cycle when H3PMo12O40 was as raw material. Moreover, the morphology of them changed from global to egg-shaped. While, well dispersed nanorods were achieved when H4SiW12O40 was as raw material and the size of them increased with the reaction cycle. The length of nanorods can be tailored by choosing tetraalkylammonium with different alkyl chain. However, the manipulative sequence was exchanged when AgNO3 was as precipitator. The substrate was dipping into AgNO3 solution first and then H4SiW12O40 solution. The well defined global nanoparticles can be obtained and the size of them also increased with synthetic cycle, whereas, the morphology of them didn’t change.By using the strong oxidative property of polyoxometalates, the precursor films were immersed in pyrrole monomer solution with pH=4 and then in H3PMo12O40 solution. The positive charged pyrrole monomer was adsorbed and then polymerized in the films. Repeating above steps, the polypyrrole nanoparticles doped with polyoxometalates were formed and the size of them increased with the increasing of synthetic. Moreover, the更多还原