【作者】 李伟；

【导师】 张志焜；

【作者基本信息】 青岛科技大学 ， 无机化学， 2010， 硕士

【摘要】 纳米复合材料是指至少有一维方向的尺寸在纳米尺度范围内。具有量子尺寸效应,小尺寸效应以及表面效应等纳米材料所特有的性质,性能优于一般块体材料。壳聚糖作为一种天然的高分子,展现了良好的生物适应性、生物可降解性和水性吸附能力,可以广泛应用在生物医学领域和水污染处理方面。壳聚糖纤维在特殊织物方面具有潜在的应用价值。此外,由于高聚物空心纳米球结构在包覆性能、可控渗透性和表面功能性上的优势,使得其在化学、生物和材料科学方面的应用受到了相当大的关注。因此,壳聚糖纳米复合材料的制备和性能研究将具有非常广阔的应用前景。本文主要研究了壳聚糖/TiO₂一维复合纤维和壳聚糖/聚丙烯酸包覆SiO₂的纳米微球以及Eu³⁺掺杂的壳聚糖/聚丙烯酸纳米球,并对它们的光学性质进行了初步研究。一、实验中所得壳聚糖/TiO₂一维复合材料表现出比较好的荧光性能。壳聚糖和TiO₂均分散于NaOH溶液中,表面活性剂在产物的生长过程中起到了关键作用,且阴离子表面活性剂十二烷基硫酸钠（SDS）效果最好。实验中还研究了各个反应条件对产物最终形貌的影响,比如:表面活性剂、反应温度和反应时间。对产物的生长机理作出了初步推测。荧光测试分析表明,当激发光为紫外光时,壳聚糖/TiO₂一维复合材料表现出比较好的光致发光性能,这将使得这种无毒的一维纳米复合材料可能应用在将来的荧光织物中。二、壳聚糖与丙烯酸可以自组装为球形结构,高聚物纳米球的空心结构通过内部丙烯酸单体的聚合而形成。采用这种方法成功制备了壳聚糖与聚丙烯酸的（CS/PAA）纳米微球。将壳聚糖直接溶解于丙烯酸溶液中,在N₂保护下,加入引发剂引发聚合。在反应后期再加入戊二醛引发壳聚糖表面交联致密,即得所需要的纳米微球。在此基础上,制备了CS/PAA包覆SiO₂纳米微球,运用扫描电子显微镜、透射电子显微镜、X射线衍射仪、傅立叶转变红外光谱仪和光致发光光谱等技术对所得产物的形貌、分散性及荧光性能进行表征,并简单探讨其形成机理。三、CS/PAA的纳米球通过丙烯酸单体聚合后交联壳聚糖高分子链制得,在壳聚糖未交联之前将Eu³⁺加入到反应液中,然后加入交联剂戊二醛,得到Eu³⁺掺杂的CS/PAA纳米球,并对具体的实验过程进行了详细描述。荧光性能研究表明,产物中含有Eu³⁺的特征峰,明显改善了CS/PAA纳米球的荧光性能。鉴于壳聚糖优良的生物相容性,本文所制备的Eu³⁺掺杂CS/PAA纳米球在生物标识方面将具有良好的应用前景。更多还原

【Abstract】 The nanocomposites have at least one characteristic length scale that is of the order of nanometers. Due to the special properties, such as quantum size effects, small size effect and surface effect, nanocomposites show excellent properties compared with the bulk materials. As a natural polymer, chitosan intrinsically exhibits enticing properties such as biocompatibility, biodegradability, and aqueous adsorption capabilities. These properties make chitosan an ideal polymer for a wide variety of fields and industrial applications such as biomedical applications and the treatment of water pollution. Chitosan nanofibers have potential applications in specific textile. Furthermore, polymeric hollow nanospheres have attracted considerable research attention due to their large variety of applications in chemistry, biotechnology, and materials science. The advantages of polymeric hollow nanosphere include its encapsulation property, controllable permeability, and surface functionality. Therefore, the synthesis and property of nanocomposites based on chitosan will exhibit an attractive application prospect.In this paper, the synthesis and optical properties of one-dimensional （1-D） hybrid materials based on chitosan/titania （TiO₂） have been reported, and the chitosan/polyacrylic acid （CS/PAA） nanospheres containing silicon dioxide （SiO₂） cores and Eu-doped CS/PAA nanospheres have been also investigated.1-D hybrid materials based on chitosan/titania featuring fascinating fluorescence are reported in this paper. Chitosan and TiO₂ were dispersed using a single chemical species of NaOH solution. Surfactants have a key contribution to the growth of production. The anionic surfactant sodium dodecyl sulfate （SDS） is the best guide. The effects of reaction parameters, such as surfactant, reaction temperature and reaction time, on the morphology of the products were investigated. The growth mechanism of the 1-D hybrid materials was proposed. Photoluminescence （PL） investigation shows that the 1-D hybrid materials exhibit inspiring emissions under UV excitation, indicating that these nontoxic emissive 1-D nanomaterials may find use as fluorescent fabrics in the future.The hollow structure of polymeric nanospheres is spontaneously formed by polymerization of acrylic acid monomers inside the chitosan-acrylic acid assemblies. CS/PAA nanospheres were successfully prepared with acrylic acid and chitosan via this method. Firstly, chitosan was directly dissolved in acid solution, then initiator was added to initiate polymerization in N2 atomosphere. Finally, the surface of CS/PAA nanospheres was cross-linked by glutaraldehyde. Based on this, SiO₂ nanospheres were in-situ coating by CS/PAA. The morphology, dispersity and fluoresent properties of the products were characterized by scanning electron microscope （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, fourier transform infrared （FT-IR） spectrometry, and PL. The formation mechanism of the products was simply discussed.Eu-doped CS/PAA nanospheres were successfully prepared. The CS/PAA nanospheres were formed by polymerization of acrylic acid and cross-linking of chitosan at the end of polymerization. Eu³⁺ was added in the reaction solution before the cross-linking of chitosan, and then the products were synthesized by adding glutaraldehyde as the crosslinking agent. The whole reaction process was described in detail. Fluorescence studies suggested that the characteristic peaks of Eu³⁺ was detected in the product, which greatly improved the fluorescence properties of CS/PAA nanospheres. Combine with the excellent biocompatibility of CS, Eu-doped CS/PAA nanosphere may have potential applications in biolabelling.更多还原