核壳结构TiO2/Ag反蛋白石的制备与形貌观察

用化学还原法制备了银包覆聚苯乙烯(PS)微球结构,通过垂直沉积法排列出具有密堆积结构的PS-Ag蛋白石模板,然后采用溶胶-凝胶法渗透TiO2,最后焙烧处理除去PS,制备出了规整的核壳结构TiO2/Ag反蛋白石。采用扫描电镜、透射电镜和X射线衍射对该样品进行了分析。结果表明,PS球表面包覆的为纳米尺度的金属Ag;所制备的PS/Ag核壳微球蛋白石经过480℃、12h焙烧处理后获得的核壳TiO2/Ag反蛋白石结构的单胞参数可以通过调节包覆银层的厚度来调变,即改变AgNO3与PS球的质量比获得具有不同银包覆层厚度、不同单胞参数的三维蛋白石和反蛋白石结构。     

核壳结构TiO2/Ag反蛋白石的制备与形貌观察

用化学还原法制备了银包覆聚苯乙烯(PS)微球结构,通过垂直沉积法排列出具有密堆积结构的PS-Ag蛋白石模板,然后采用溶胶-凝胶法渗透TiO2,最后焙 烧 处 理 除 去PS,制 备 出 了 规 整 的 核 壳 结 构TiO2/Ag反蛋白石。采用扫描电镜、透射电镜和X射线衍射对该样品进行了分析。结果表明,PS球表面包覆的为纳米尺度的金属银;所制备的PS/Ag核壳微球蛋白石经过480℃、12h焙烧处理后获得的核壳TiO2/Ag反蛋白石结构的单胞参数可以通过调节包覆银层的厚度来调变,即改变AgNO3与PS球的质量比获得具有不同银包覆层厚度、不同单胞参数的三维蛋白石和反蛋白石结构。     

Ag纳米粒子表面BSA隔离层对聚苯乙烯荧光的增强效应

通过氧化还原法制备了粒径处于50~65nm的球形银(Ag)纳米粒子,采用扫描电子显微镜(SEM)分析其形貌及单分散性。在Ag纳米粒子基础上采用沉积自组装法合成了有效粒径为80.8nm的Ag/牛血清白蛋白(BSA)核壳结构纳米粒子。结合SEM、透射电子显微镜(TEM)、X射线衍射(XRD)和荧光发射光谱(FL)分析发现,BSA有效地包覆在Ag纳米粒子的外层,Ag/BSA核壳结构纳米粒子单分散性良好,加入Ag/BSA核壳结构纳米粒子的聚苯乙烯(PS)的荧光强度从100增强到6 000。研究结果表明,BSA隔离层对位于Ag表面附近的PS分子的荧光强度有显著的增强效应。     

SiO_2@Ag核壳粒子表面形貌及壳层厚度影响因素的研究

用溶胶-凝胶法制备单分散的亚微米二氧化硅,经表面巯基化改性后,采用自组装化学镀法在其表面包Ag,得到SiO2@Ag核壳复合粒子,研究还原剂的种类、浓度和反应温度对核壳结构SiO2@Ag亚微米颗粒形貌及表面Ag壳层厚度的影响规律。结果表明:还原剂的种类对SiO2@Ag核壳复合粒子表面形貌影响较大,还原性太弱很难在二氧化硅表面形成致密均匀的银层,还原性太强则容易形成散银;还原剂浓度增加使二氧化硅表面银颗粒的粒径增大,银壳层厚度增大,但是当还原剂浓度到达一定的值后,浓度对银粒径大小和银壳厚度的影响变弱;反应温度对SiO2@Ag核壳复合粒子表面形貌也有较大影响,0~30℃时,银粒子随温度升高尺寸变大,银壳厚度也相应增大,若温度继续增加到50℃后则开始出现散银,包覆效果变差。     

聚苯乙烯/纳米SiO2复合颗粒制备与表征

为改善二氧化硅(SiO2)纳米粒子与聚合物基体间的亲和性,使SiO2表面功能化,将硅烷偶联剂KH-570引入C=C基团,采用乳液聚合方法在纳米SiO2粒子表面接枝苯乙烯(St)单体,实现了纳米二氧化硅表面的聚苯乙烯(PS)高分子包覆改性,制备了具有核/壳结构的SiO2-PS复合纳米粒子,产物的单体转化率和接枝效率在80%以上.研究了二氧化硅含量和偶联剂用量对聚合反应的单体转化率和接枝效率的影响,探讨了偶联剂的作用机理,利用FT-IR、TEM、TG对SiO2-PS复合粒子的表面结构进行了表征.结果表明,复合粒子具有明显的核壳结构,壳层厚度在20nm左右,乳液聚合过程可有效使二氧化硅的团聚体剥离呈纳米级颗粒.     

聚苯乙烯/银核壳结构纳米微球的制备与表征

采用两步法的简单路线制备出银纳米粒子包覆的聚苯乙烯(PS)微球,首先通过乳液聚合法合成出聚苯乙烯微球;然后对苯乙烯进行敏化和活化,搅拌下加入银的还原液,从而制备出Ag-PS核壳结构的纳米微球.同时借助于TEM、UV-vis、 FE-SEM进行表征,分析其微观结构.结果表明,所得的聚苯乙烯微球粒径约为40nm;聚苯乙烯/银核壳结构纳米微球粒径为45～350nm,银层厚度可随意调控.     

SiO_2空心纳米微球的合成

为了改善聚合物粒子与SiO2粒子之间的亲和力及SiO2粒子在聚合物粒子表面的吸附,首先使用共单体4-乙烯基吡啶(4VP)功能化苯乙烯(PS)粒子,合成了聚(苯乙烯-共-4-乙烯基吡啶)(P(St-4VP))粒子。然后在NH4OH/乙醇介质中,将溶胶-凝胶法生成的SiO2粒子包覆在P(St-4VP)粒子表面,聚合物核被溶解得到SiO2空心纳米微球。随着P(St-4VP)粒子中共单体4VP含量以及正硅酸乙酯(TEOS)用量增加,SiO2空心纳米微球的壳层厚度增加,且壳层表面变得粗糙。随着PVP用量增加,SiO2空心纳米微球的平均尺寸下降,其壳层从松散粗糙变得致密光滑。NH4OH用量增加对SiO2空心纳米微球尺寸和形态的影响不大。     

无皂乳液聚合法制备PS/TiO2核-壳复合微球

采用无皂乳液聚合法制备聚苯乙烯(PS)微球,将所制备的PS微球经磺化吸水后,利用钛酸丁酯作前驱体在乙醇中反应,使TiO2包覆在磺化苯乙烯微球表面,得到有机-无机PS/TiO2复合微球。在所得的杂化微球表面接枝上可聚官能团,利用无皂乳液聚合将聚甲基丙烯酸甲酯聚合到微球表面,得到核-壳-壳杂化微球。用FT-IR、SEM和TGA等方法对所制得的复合微球进行表征。结果表明PS、PS/TiO2及PS/TiO2/PMMA微球表面光滑,球形度好,单分散性良好;通过改变TBOT的加入量可以控制TiO2对PS微球的包覆厚度。     

银/聚苯胺纳米复合材料的制备及形成机理

采用反胶束原位复合法制备了银/聚苯胺(Ag/PANI)纳米复合材料,并且探讨了Ag/PANI纳米复合材料的形成机理。通过红外光谱、紫外吸收光谱、X射线衍射、扫描电镜和透射电镜对复合物进行了表征。研究结果表明,Ag/PANI复合材料中Ag为纳米粒子,粒径为50 nm,苯胺自吸附在银纳米粒子表面聚合,形成PANI包覆Ag纳米粒子壳-核结构。Ag纳米粒子在PANI中均匀分散,Ag/PANI复合粒子大部分呈现类球形状的表面形貌,复合粒子粒径较PANI有了明显减小。并提出了Ag/PANI复合材料的形成机制。     

双重磁响应温敏复合微球的制备及表征

在Fe3O4纳米粒子表面聚合包覆温敏性聚N-异丙基丙烯酰胺(PNIPAM)及其与聚苯乙烯(PS)、聚α-甲基丙烯酸(PMAA)的共聚物,制备表面不同亲水/疏水性质的双重磁响应温敏复合微球。利用透射电镜(TEM)、红外光谱(FT-IR)及Zeta粒度仪(DLS)等对复合微球进行了表征。结果表明,复合微球呈现核壳结构,粒径约为150nm~300nm;在复合微球温敏聚合物中引入亲水/疏水链段可以有效调节其最低临界溶解温度(LSCT),随着温敏聚合物亲水性的提高,微球LSCT向高温移动,且该微球具有良好的双重磁响应特性(磁靶向响应性和磁热响应性)。     

轻质高导电镀银复合粒子的制备研究

采用分散聚合工艺,以聚乙烯吡咯烷酮为分散剂,偶氟二异丁腈为引发剂,无水乙醇为分散介质,制备出粒径2.0μm、表面光滑、分散均匀的聚苯乙烯微球.将其进行表面磺化处理后运用化学镀工艺制备出了具有轻质高导电特性的聚苯乙烯/银复合粒子.对所制备的复合粒子进行了扫描电镜、红外光谱以及体积电阻率的测试.结果表明:所制备的复合粒子包覆均匀、导电性能良好;表面修饰提高了PS微球表面的电负性和亲水性并引入了磺酸基团,对PS微球表面镀银起到了重要作用;另外,随着PdCl2浓度和AgNO3/PS质量比的增加,复合粒子包覆完整性和导电性能都随之增加,最佳体积电阻率为1.61×10 -4Ω·cm.     

核壳式纳米Al2O3/PS复合粒子的表征及增韧选区激光烧结聚苯乙烯的研究

运用TEM,FTIR对乳液聚合方法制备纳米Al2O3/PS复合粒子结构进行了表征,结果表明,制备出的复合粒子具备以纳米氧化铝为核、以聚苯乙烯为壳的核壳式结构;并将核壳式复合粒子用来增韧选区激光烧结聚苯乙烯,结果发现,其缺口冲击强度达到12.1kJ/m2,较纯聚苯乙烯提高了50%左右,比添加未经任何改性处理纳米氧化铝粒子的复合材料提高了30%;利用FE-SEM对试件的冲击断面进行了微观结构分析,结果表明:核壳式纳米Al2O3/PS复合粒子改善了纳米粒子与基体表面极性的差异,增强了其与聚合物基体之间的界面相容性,从而改性了选区激光烧结制备聚苯乙烯基复合材料,并很好地起到增韧的效果.     

Facile synthesis and characterization of CdTe quantum dots–polystyrene fluorescent composite nanospheres

A novel method for the synthesis of CdTe quantum dots–polystyrene (CdTe/PS) composite nanospheres was developed by a two-step route. The as-prepared composite nanospheres were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD), fluorescent microscope imaging and fluorescence spectrometer. The results showed that the composite nanospheres were spherical and relatively uniform with a diameter of 120 nm. Compared with previous methods, the proposed method was simple, efficient and inexpensive, moreover the composite nanospheres exhibited favorable water-dispersible, stable, size-tunable and fluorescent properties.     

Surface-enhanced Raman detection of melamine on silver-nanoparticle-decorated silver/carbon nanospheres: effect of metal ions

Silver/carbon (Ag/C) core-shell nanospheres synthesized by a hydrothermal method were used as templates for fabricating silver nanoparticle-decorated Ag/C (Ag/C/AgNps) nanospheres. The particle size of Ag nanoparticles can be tuned by varying the concentration of Ag precursor. Detection of melamine molecules at concentrations as low as 5.0×10(-8) M shows that the Ag/C/AgNps nanosphere is a good SERS-active substrate. The effect of heavy metal ions on the detection of melamine is also investigated. It was found that the SERS spectrum profile of melamine is very sensitive to the presence of heavy metal ions: the peak positions of the SERS bands exhibit some apparent change with the kind of metal ion, showing a blue or red shift compared with those in the SERS spectrum of melamine; the SERS signal intensity decrease with increasing the concentration of metal ion.     

乳液聚合合成单分散纳米级PMMA微球

采用乳液聚合法制备了单分散性聚甲基丙烯酸甲酯（PMMA）纳米微球,分析了聚合过程中不同单体滴加时间、不同表面活性剂用量、不同引发剂用量以及不同引发剂种类等因素对聚合体系中微球的粒径以及粒径分布的影响,研究表明,PMMA微球的粒径随单体滴加时间、表面活性剂用量、引发剂用量的增加而减小;采用AIBN引发剂制备的微球的粒径较采用KPS引发剂大。     

Controllable preparation of magnetic polymer nanospheres with high saturation magnetization by miniemulsion polymerization

Magnetic Fe₃O₄/poly(styrene-co-acrylamide) core/shell nanospheres were prepared by one-step miniemulsion polymerization in the presence of Fe₃O₄ ferrofluids. The functional monomer of acrylamide was used not only to modify the surface of the nanospheres with functional groups, but also to form modified bilayer with SDBS to control the encapsulation and particle size of nanospheres. The properties of magnetic nanospheres were characterized by IR, TEM, TG and VSM. The results indicated that the superparamagnetic nanopsheres had small particle size of 60 nm, high saturation magnetization of 27.1 emu/g, high magnetic content and abundant functional groups. The possible formation mechanism of magnetic nanospheres was discussed in detail.     

One-pot synthesis of ZnO/Ag nanospheres with enhanced photocatalytic activity

ZnO/Ag composite nanospheres with an average diameter of about 440 nm, were synthesized through a facile one-pot solvothermal reaction, using a kind of biomolecular sodium alginate as template, H₂O and diethanolamine as solvents, followed by the assembly of ZnO and Ag nanoparticles in-situly produced. The composite spheres were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy disperse X-ray spectrum. Moreover, the results showed that the as-made ZnO/Ag assembled nanospheres exhibited better photocatalytic performance than the pure ZnO nanoparticles and this one-pot synthesis method has great potential to be extended for the synthesis of other metallic oxide/metal spheres.     

Facile method to synthesise polystyrene/silver composite nanoparticles with core–shell structures

We report a facile method for the fabrication of polystyrene/silver composite nanoparticles with core–shell nanostructures. First, polystyrene (PS) nanoparticles with carboxyl acid groups on their surfaces were prepared via the dispersion polymerisation of styrene in water with the assistance of acrylic acid. Second, with the addition of [Ag(NH₃)₂]⁺ to the PS dispersion, [Ag(NH₃)₂]⁺ was absorbed onto the surfaces of the modified PS nanoparticles. Finally, the [Ag(NH₃)₂]⁺ complex ions were reduced to Ag to form the PS/Ag nanocomposites upon heating. The resulting PS/Ag composite nanoparticles were characterized via scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and dynamic light scattering.     

Possibility for the development of cosmetics with PLGA nanospheres

The optimized preparation of Poly–(lactide-co-glycolic acid) (PLGA) nanospheres containing ubiquinone (UQ) for cosmetic products was pursued. By investigating various conditions for the preparation of UQ/PLGA nanospheres such as the molecular weight of PLGA, PLGA concentration, and UQ concentration, UQ/PLGA nanospheres with increased stability and slower drug release at a higher drug loading efficiency were prepared. Permeation tests on the prepared nanospheres using iontophoresis via electric dermal administration on membrane filters (200?nm pore size) and hairless mouse skin samples were also carried out. After iontophoresis, the nanospheres choked the membrane filter and remained on the horny layer of the hairless mouse skin, even after washing. Therefore, the prepared UQ/PLGA nanospheres and the established iontophoresis technique with the PLGA nanospheres in the present study can be applied to the future development of cosmetics.