【作者】 姜立忠；

【导师】 武德珍；

【作者基本信息】 北京化工大学 ， 材料学， 2007， 博士

【摘要】 有机/无机复合纳米粒子以其同时具有无机材料优越的光、电、磁等性质,有机材料的优良加工性能、生物相容性能等特性受到了人们的极大关注。近年来,设计具有特殊功能特性的有机/无机复合纳米粒子成为纳米科学技术的研究热点。本文通过有机/无机复合纳米粒子的制备,对自由基共聚法合成环境响应性纳米二氧化硅粒子、无皂乳液法合成二氧化硅/聚（甲基丙烯酸甲酯-丙烯酰胺）（PMMA-AM）核/壳纳米粒子、离子交换-软模板法合成二氧化硅-聚丙烯酸（PAAc）-Ag复合纳米粒子、自由基共聚法合成PAAc接枝磁性四氧化三铁纳米粒子和界面引发聚合合成四氧化三铁/聚（异丙基丙烯酰胺）（PNIPAM）中空纳米复合微球进行了研究,其中主要工作如下:本文首先以正硅酸四乙酯（TEOS）为硅源、无水乙醇为溶剂、氨水为催化剂、γ-甲基丙烯酰氧基丙基三甲氧基硅烷（MPS）为偶联剂,采用原位一步法合成了表面乙烯基双键功能化的纳米二氧化硅粒子,并对St（o|¨）ber法和原位一步法两种合成方法进行比较,结果表明原位一步法更为简单、有效。本文以AAc为单体、过硫酸钾（KPS）为引发剂、去离子水为溶剂,采用自由基共聚法合成了核/壳或“发”形结构的PAAc接枝纳米二氧化硅粒子;并对不同反应条件下合成的复合粒子PAAc接枝率进行热失重（TGA）表征,发现PAAc接枝率随着聚合反应时间和共聚单体AAc浓度的增大而增大,随着纳米二氧化硅粒子和引发剂浓度的增加而降低。通过动态光散射（DLS）研究表明,PAAc接枝纳米二氧化硅粒子具有环境响应特性,粒子粒径随着pH值的增大呈现先增大后降低的趋势,在pH值为10时达到最大值;随离子强度的增大而降低;并且复合粒子对高价态离子比低价态离子更为敏感。本文以双键功能化二氧化硅纳米粒子为大分子单体,甲基丙烯酸甲酯（MMA）、丙烯酰胺（AM）为共聚单体,对合成二氧化硅/PMMA-AM核/壳纳米粒子进行研究,发现这种新型复合粒子形成以二氧化硅纳米粒子为核、PMMA-AM的共聚物为壳的核-壳结构,并且具有良好的亲水性。TGA研究表明:各种反应条件均会对聚合物接枝率产生一定的影响。其中,PMMA-AM接枝率随MMA单体浓度的增加而增加,并逐渐趋于不变;AM的用量在高于1 wt%时对PMMA-AM接枝率影响不大;随引发剂KPS的浓度的增加,PMMA-AM接枝率先增加后降低,当KPS过硫酸钾用量为单体质量的1.2%时接枝率最大;聚合反应温度也使PMMA-AM接枝率呈现先增大后降低的趋势,并于75℃时达到最大,但总体影响不大。本文以硝酸银为银盐,硼氢化钠为还原剂,通过离子交换过程,以PAAc为软模板成功制备出银纳米粒子负载的水溶性二氧化硅纳米微球,即S-P-Ag纳米微球。并采用透射电镜（TEM）和紫外-可见（UV-vis）吸收光谱对S-P-Ag纳米微球表面Ag纳米粒子的形态和浓度进行了研究,发现随着银盐浓度和pH的增大,Ag纳米粒子的粒径逐渐增大,其SPR吸收谱图呈现红移现象。以S-P-Ag-7-0.1复合纳米微球为例、大肠杆菌为菌种,研究了复合纳米微球的杀菌活性,结果表明:复合纳米微球具有极高的杀菌活性;并且随着二氧化硅纳米微球固含量的增加,复合纳米微球的杀菌率随之升高;当二氧化硅纳米微球固含量为1000ppm时（此时银纳米粒子含量约为50ppm）,复合纳米微球的杀菌率达到了99.99%。本文以Fe²⁺和Fe₃₊为铁离子源、氨水为沉淀剂采用共沉淀法合成了四氧化三铁纳米粒子,并以TEM对沉淀剂氨水的用量对共沉淀法制备的四氧化三铁纳米粒子的粒径和分散性进行研究,结果发现只要反应体系保持碱性均可获得尺寸均一的四氧化三铁纳米粒子。本文以AAc为单体、KPS为引发剂、去离子水为溶剂和乙烯基双键改性的四氧化三铁（Fe₃O₄）粒子为大分子单体,对自由基共聚法制备PAAc接枝纳米Fe₃O₄粒子的合成过程进行了研究,结果发现,接枝后的粒子呈核/壳结构,并且经PAAc接枝改性后的纳米Fe₃O₄粒子团聚现象进一步减弱,分散性得到较好的改善。采用TGA对不同反应条件下制备的PAAc接枝纳米粒子的PAAc接枝率进行了研究,发现PAAc接枝率随着聚合反应时间和共聚单体AAc浓度的增大而增大,随着引发剂浓度和聚合反应温度的增加而先升高后降低。最后本文采用两亲性纳米四氧化三铁粒子和氧化-还原反相乳液界面引发过程成功制备出粒径约1～1.5μm,壁厚100 nm左右的Fe₃O₄/PNIPAM中空纳米复合微球,并且微球的矫顽力为零,即为超顺磁性。更多还原

【Abstract】 Organic/inorganic nanocomposite particles have been of great interest based on the fact that the inorganic enhance the optical,electrical,and magnetic properties while the organic offers the processing and biocompatibility.More recently,the synthesis of organic/inorganic nanoparticles with stimuli-responsive,antibacterial,and biocompatible properties has attracted special interest.In this dissertation,several different organic/inorganic nanoparticles including the poly(acrylic acid) (PAAc)-grafted silica nanoparticles,the silica/poly(methyl methacrylate-acryl amide)(PMMA-AM)core-shell nanoparticles,the silver nanoparticles embedded silica nanospheres,the PAAc-grafted magnetite nanoparticles,and the magnetite/poly(N-isopropylacryl amide) (PNIPAM)hollow nanocomposite microspheres have been successfully synthesized.In the first,vinyl bond modified silica nanoparticles were synthesized by modified stober method from tetraethoxysilane(TEOS),γ-methacryloxypropyltrimethoxysilane(MPS)in ethanol solution under base condition.Comparing with stober method,this process can easily obtain the vinyl bond modified silica nanoparticles.Silica-PAAc core-shell nanoparticles were successfully prepared via graft copolymerization of acrylic acid(AAc)onto vinyl bond modified silica NPs.Transmission electron microscopy(TEM)results indicated that the obtained micropheres have core-shell morphology.Fourier Transform Infrared(FTIR)analysis and X-ray photoelectron spectroscopy(XPS)measurements confirmed that the surface of the nanoparticles was polymer-rich,which was consistent with the core-shell morphology.The influence of the synthetic conditions,such as reaction time and AAc concentration on the graft yield of PAAc grafted silica NPs was investigated.Dynamic light scattering(DLS)analysis showed that the silica-PAAc core-shell nanoparticles possessed excellent stimuli response to pH and ion strengthen.Because of their pH-responsive behavior and small feature size,nanostructure devices designed from the smart silica nanoparticles have potential applications including sensors and membranes.Polymer/silica inorganic/organic composite core/shell nanoparticles bearing amino groups on the surface were prepared via emulsifier-free emulsion copolymerization of methyl methacrylate(MMA)and acrylamide(AM).The prepared composite nanoparticles were characterized using FTIR analysis,TEM,and thermogravimetric analysis (TGA).The results showed that the obtained composite nanoparticles have a core/shell structure,and the surface of the nanopartilces was polymer-rich which were consistent with the core/shell morphology.The influence of the synthetic conditions,such as MMA concentration and potassium persulfate(KPS)concentration on the graft yield of composite nanoparticles was investigated.Because of their surface bearing amino groups,the novel composite nanoparticles have potential application in cohesive material,coating material,and so on.Silver nanoparticles embedded on silica nanospheres were prepared by using ion-exchangeable PAAc grafted on the silica surface as soft template followed by chemical reduction.The prepared hybrid nanospheres were characterized using XPS,X-ray diffraction(XRD), TEM,ultraviolet visible absorption spectroscopy(UV-vis),and bactericidal activity measurement.The results suggest that mono-dispersed Ag nanoparticles with controllable diameters can be obtained on the surface of silica nanospheres by varying the Concentration of silver nitrate and the suspension pH value,and the hybrid nanospheres have excellent bactericidal activity and potential application as a bactericidal agent in biomedical fields.In addition,novel PAAc grafted magnetic magnetite nanoparticles have been prepared by grafting copolymerization of acrylic acid onto the MPS modified magnetite nanoparticles and characterized with FTIR,TEM and TGA.The results shows that the PAAc grafted magnetite nanoparticles have a core-shell structure and good dispersibility.The influence of synthetic conditions,such as reaction time,AAc concentration,KPS concentration and reaction temperature on the graft yield of PAAc grafted magnetite nanoparticles was investigated.The graft yield increased with the increasing reaction time and AAc concentration,however,had a maximum with the increasing initiator concentration and reaction temperature.Finally,stimuli-responsive hollow magnetite/poly(N-isopropylacryl amide)(PNIPAM)nanocomposite microsphere were synthesized via an interfacial polymerization approach at the interfaces of an inverse water/oil emulsion.TEM and magnetic properties results shown that the hollow microspheres with a wall thickness of about 100 nm and a size of about 1.2μm and they are superparamagnetic.更多还原