紫外光引发Pickering乳液聚合制备中空复合微球的研究

用光引发剂2-羟基-4-(2-羟乙氧基)-2-甲基苯丙酮(IHT-PI 659)对纳米SiO₂表面进行接枝使之兼具两亲性及光引发特性|以该功能性纳米SiO₂为稳定剂构筑O/W(水包油)型Pickering乳液|用紫外光引发处于内油相的甲基丙烯酸甲酯单体聚合, 制备出具有中空结构的SiO₂/PMMA复合微球, 采用傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)、透射电镜(TEM)及扫描电子显微镜(SEM)对复合微球进行了表征, 并提出了紫外光引发Pickering乳液聚合制备中空复合微球的机理.     

碳纳米管/壳聚糖复合微球的原位仿生矿化及表征

对碳纳米管(CNTs)进行酸化处理, 采用乳化交联法制备CNTs/壳聚糖(CS)复合微球, 在其表面诱导羟基磷灰石仿生合成, 研究了CNTs对复合微球仿生矿化的影响, 并与纯CS微球的仿生矿化进行了对比. 利用扫描电子显微镜(SEM)、 X射线衍射仪(XRD)、 溶胀率和含水率测试等考察了复合微球矿化前后的形貌特征、 物相结构及稳定性. 结果表明, 在相同时间下, CNTs/CS复合微球表面纳米羟基磷灰石的形成能力明显优于纯CS微球, 且形态稳定性更高. 细胞实验结果表明, 与MG63细胞共培养7 d时, 矿化复合微球细胞增殖明显.     

常温制备形貌可控中空羟基磷灰石的研究

利用锂钙硼玻璃(LCB)微球在磷酸盐溶液中的原位转化反应,在常温下制备中空的羟基磷灰石(HA)微球,研究了玻璃微球的组分、磷酸盐浸泡液的浓度及热处理等工艺参数对微球的形貌影响。研究结果表明,常温下反应得到的产物微球为晶型较好具有中空结构的羟基磷灰石,随着玻璃微球组分中CaO含量的升高,中空微球的球壁逐渐变厚,当CaO含量达到30%时,微球变为实心结构。磷酸盐溶液浓度较低时,中空微球的球壁容易形成层状结构。     

肾上腺髓质素微球复合PLGA/纳米轻基磷灰石支架材料的制备及生物活性评价

利用离子乳化交联法制备了负载肾上腺髓质素的壳聚糖微球,应用热致相分离法制备了乳酸和乙醇酸共聚物/纳米羟基磷灰石(PLGA/nHA)支架材料并在其中包覆载药微球.通过扫描电子显微镜、体外释放行为、材料溶血行为、碱性磷酸酶(ALP)活性的测定、支架材料表面细胞荧光染色和MTT[3-(4,5-二甲基噻唑-2)-2,5-二苯基...     

明胶/羟基磷灰石复合物微球中明胶对无机相影响的研究

在油包水的乳液体系中,通过原位合成的方法使羟基磷灰石(HAP)在明胶链上化学沉积,改变明胶溶液的浓度,制得了一系列的明胶/HAP复合物微球.采用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和热失重分析仪(TGA)等对产物的组成、形貌以及热失重情况进行了表征.结果表明,明胶用量对复合物微球中HAP的形成具有重要影响.在明胶溶液浓度为0.025 g/mL时,明胶分子链提供的结合位点恰好与溶液中游离的Ca²⁺、PO₄^3-等离子达到平衡状态,复合物微球中无机相含量达40%,这是明胶与HAP以化学键合的形式结合所能得到的最大值.     

生物功能化纳米SiO2 微球的构建及对谷胱甘肽S-转移酶的捕获分离

采用巯基丙基三甲氧基硅烷(MPS)一步水解法制备了表面带有巯基(-SH)的纳米SiO2微球(nSiO2-SH), 探讨了水/醇体积比、 反应温度、 MPS初始浓度及反应时间对nSiO2-SH微球形貌的影响, 并分析了反应机理. 制备的nSiO2-SH微球进一步与还原型谷胱甘肽(GSH)中的-SH反应生成双硫键(-S-S-), 在微球表面键合上GSH分子, 得到了生物功能化的纳米nSiO2-GSH微球. 通过扫描电子显微(SEM)、 透射电子显微镜(TEM)、 傅里叶变换红外光谱(FTIR)和热重分析仪(TG)对样品的表面形貌、 尺寸和组成等进行了表征. 利用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳法(SDS-PAGE)检测样品对谷胱甘肽S-转移酶(GST)的分离效果, 结果表明, nSiO2-GSH微球能从混合蛋白中特异性吸附GST, 达到了分离GST的目的.     

纳米TiO_2微球对聚氨酯的改性

采用十六胺作为表面修饰剂,通过一种简单易行的方法成功制备了纳米TiO_2微球.分别利用傅立叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等表征手段对纳米TiO_2微球进行了结构和形貌表征.将制备的纳米TiO_2微球添加到水性聚氨酯基体(WPU)中,测试了其性能.结果表明,纳米TiO_2微球的添加显著提高了WPU的抗紫外线性能、耐水性和热稳定性等.     

Pd/PdO纳米复合微球的合成及催化性能

采用甲基丙烯酸锌加速还原氯化钯(PdCl₂) 溶液中的钯离子(Pd ²⁺)为钯(Pd) 纳米微球, 进而用得到的钯纳米微球直接制备钯/氧化钯(Pd/PdO) 纳米复合微球. 通过扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 粉末X射线衍射分析(XRD)及X射线光电子能谱分析(XPS) 等方法对 Pd/PdO 纳米复合微球进行表征, 结果表明, 制备的纳米复合微球为表面粗糙、 大小均一的纳米微球. 采用紫外-可见吸收光谱(UV-Vis) 等方法考察了 Pd/PdO 纳米复合微球在对硝基苯酚(4-NTP) 还原反应中的催化性能, 发现其具有良好的催化活性和循环稳定性.     

聚合物模板微球表面电性对中空二氧化硅微球形貌的影响

分别以过硫酸钾和偶氮二异丁基脒盐酸盐为引发剂,以聚乙烯吡咯烷酮(PVP)为分散剂,在水中引发苯乙烯聚合制备了2种表面分别带负电性和正电性基团的聚苯乙烯(PS)模板微球.在氨水催化下,利用正硅酸乙酯的水解缩合,形成PS/SiO_2复合微球,去除模板后得到中空SiO_2微球,并对其进行FTIR、电子显微镜、TGA以及氮气吸附等分析表征.结果表明,PS模板微球表面的电性决定了OH-的分布,从而导致PS模板微球表面SiO_2壳层不同的形成机制.当以表面带负电的PS微球为模板时,可得到树莓状的中空SiO_2微球;而以表面带正电的PS微球为模板时,得到是表面光滑的,具有介孔结构的中空SiO_2微球.     

肾上腺髓质素微球复合PLGA/纳米羟基磷灰石支架材料的制备及生物活性评价

利用离子乳化交联法制备了负载肾上腺髓质素的壳聚糖微球,应用热致相分离法制备了乳酸和乙醇酸共聚物/纳米羟基磷灰石(PLGA/nHA)支架材料并在其中包覆载药微球.通过扫描电子显微镜、体外释放行为、材料溶血行为、碱性磷酸酶(ALP)活性的测定、支架材料表面细胞荧光染色和MTT[3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐]比色法等手段综合评价载药支架材料的性能及生物活性.结果表明,微球直径均匀,载药支架孔径大小合适并相互穿通.支架材料的溶血率小于5%,符合医用材料的溶血实验要求.载药支架及支架材料本身对成骨细胞及血管内皮细胞的增殖以及成骨细胞的分化均有一定的促进作用.     

锂离子电池负极材料ZnMn2O4微米空心球的制备和电化学性能

通过溶剂热方法合成了ZnMn2O4微米空心球,并探讨了其形成机理。采用XRD,SEM,TEM等测试手段对产物的结构、形貌和组成进行了表征。实验结果表明,溶剂热反应条件如反应温度、反应介质对于产物的结构和形貌起着关键作用。在140℃,采用乙醇和水作为反应介质,反应6 h可以制备出直径约3μm的ZnMn2O4微米空心球;当以乙醇为溶剂,反应6 h可以得到团聚的尺寸约250 nm的ZnMn2O4纳米颗粒。将所制备的ZnMn2O4微米空心球/纳米颗粒组装成锂扣式模拟电池,考察其电化学脱嵌锂性能。电化学测试结果显示,与ZnMn2O4纳米颗粒相比,空心结构的ZnMn2O4微米球具有较高的初始放电容量(1335 mAh·g-1)和较好的倍率性能,有望作为锂离子电池的新型负极材料。     

Room temperature synthesis of hollow CdMoO(4) microspheres by a surfactant-free aqueous solution route

Hollow cadmium molybdate microspheres have been successfully prepared via a template-free aqueous solution method with the assistance of NaCl at room temperature. The structure and morphology of the CdMoO(4) hollow microspheres were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The microspheres have diameters of 3-6 microm and hollow interiors of 2-3 microm. The shell is composed of numerous single-crystalline nanorods with diameters of 30-120 nm and lengths of 1-2 microm which are radially oriented to the center. A certain concentration of NaCl plays a key important role in the formation process of hollow microspheres, which might provide a suitable chemical environment to favor the formation of hollow CdMoO(4) microspheres. A possible NaCl-induced Ostwald ripening process is proposed for the formation of hollow CdMoO(4) microspheres on the basis of scanning electron microscopy observation of intermediate products at different precipitation stages.     

α-Fe_2O_3空心球的水热法制备及其对苯酚的吸附性能

以铁氰化钾、磷酸二氢铵等为反应物,采用水热法合成了α-Fe2O3空心球,并用XRD,TEM,FESEM(场发射扫描电镜)、UV-Vis和低温氮吸附脱附对其进行了表征。结果表明,α-Fe2O3空心球直径在200～560nm之间,其BET比表面积为80m2·g-1,平均孔径为8.5nm。考察了反应时间、反应物用量和反应温度等对α-Fe2O3空心球形貌和大小的影响,提出了其可能的形成机理。研究了室温下α-Fe2O3空心球吸附苯酚的性能,吸附达平衡时,其吸附苯酚的量达97mg·g-1。     

Preparation of Hollow Silica Microspheres via Poly(N-isopropylacrylamide)

Core-shell structured SiO₂/poly(N-isopropylacrylamide) (SiO₂/PNIPAM) microspheres were successfully fabricated through hydrolysis and condensation reaction of tertraethyl or-thosilicate (TEOS) on the surface of PNIPAM template at 50 oC. The PNIPAM template can be easily removed by water at room temperature so that SiO₂ hollow microspheres were finally obtained. The transmission electron microscope and scanning electron microscope observations indicated that SiO₂ hollow microspheres with an average diameter of 150 nm can be formed only if there are enough concentration of PNIPAM and TEOS, and the hy-drolysis time of TEOS. FTIR analysis showed that part of PNIPAM remained on the wall of SiO₂ because of the strong interaction between PNIPAM and silica. This work provides a clean and efficient way to prepare hollow microspheres.     

五氧化二钒空心球制备及其作为镁二次电池正极材料

利用碳球作为模板,通过与异丙醇氧钒的溶剂热反应制备了五氧化二钒(V₂O₅)空心球。 采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)等技术手段对V₂O₅空心球进行了表征。 实验结果表明,V₂O₅空心球的直径约为1.5 μm,壁厚约100 nm。 将V₂O₅空心球作为镁二次电池的正极,在0.2 C充放电条件下,材料的首次放电比容量达140 mA·h/g,经20次循环后容量为110 mA·h/g。     

Time-dependent control of hole-opening degree of porous ZnO hollow microspheres

Well-designed, monodispersed porous ZnO hollow microspheres with controlled hole-opening were successfully synthesized by a facile two-step solution route at low temperature. The hollow microspheres having average diameter of 3-4 μm showed time-dependent hole-opening, i.e. 4-100% for 15-75 min. The hole-opening percentage increases linearly with time until complete opening. The ZnO hollow microspheres also exhibited a high surface area (34 m(2) g(-1)), a large pore volume (0.19 cm(3) g(-1)) and an average pore diameter of 3.8 nm. A plausible growth mechanism for the formation of ZnO hollow microspheres was also proposed.     

Preparation of nanoparticles and hollow spheres of ��-Fe2O3 and their properties

Uniform nanoparticles and hollow microspheres of hematite (??-Fe₂O₃) were obtained via a hydrothermal method by using iron (III) chloride as a precursor. The effects of reactant concentration, reaction time and temperature on the morphology of the samples were studied. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and superconducting quantum interference device magnetometer (SQUID) measurement. ??-Fe₂O₃ nanoparticles show a superparamagnetic behavior and the average size of the spherical particles was around 60 nm. However, hollow microspheres show a normal ferromagnetic behavior at room temperature with remanent magnetization and coercivity of 0.2482 emu/g and 2,516 Oe, respectively, and their average diameter was around 2 ??m. The effects of reactant concentration and reaction temperature on the formation of the products were investigated. The experimental results reveal that the magnetic properties of hematite can be tuned by controlling the morphology.     

Characterization of hydroxyapatite by electron microscopy.

The obtention of hydroxyapatite (HAp) is reported using brushite (CaHPO4.2H2O) and the skeleton of a starfish (Mellita eduardobarrosoi sp. nov.), primarily composed of magnesian calcite ((Ca,Mg)CO3) as precursors. Stoichiometric amounts of both were reacted under hydrothermal conditions: a pressure of 5.8 MPa and a temperature of 200 degrees C for 2, 4, 6, 8, 10, and 20 h of reaction times. The samples obtained were characterized by means of scanning electron microscopy, X-ray diffraction, infrared spectroscopy, and transmission electron microscopy. Two defined populations of HAp fibers were found: A bundle of fibers 75 mum in length and 1-13 mum in diameter, and a second bundle of fibers 5 mum in length and less than 0.5 mum in diameter. Furthermore, an increase in HAp formation and a Ca/P ratio as a function of reaction time were observed. The growth mechanism of HAp is also discussed.     

dl‐Aspartic Acid‐Mediated Hydrothermal Synthesis of β‐ZnS Microspheres and Their Optical Properties

ZnS hollow microspheres were synthesized by a dl ‐aspartic acid mediated hydrothermal route. dl ‐aspartic acid plays an important role as crystal growth soft template, which regulates the release of Zn²⁺ ions for the formation of ZnS hollow spheres. The formation of these hollow spheres was mainly attributed to an Ostwald ripening process. The products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), electron diffraction (ED), UV/Vis spectroscopy (UV), and photoluminescence (PL). The shells of the microspheres were composed of ZnS quantum dots (QDs) with the average size of 2.31 nm. The average microspheres diameter is 0.5–3.5 μm. The shell thickness of the hollow sphere is ≈?300 nm. The optical bandgap energy increased significantly compared to the bulk ZnS material due to the strong quantum confinement effect. Two strong emissions at ≈?425 nm and ≈?472 nm in the photoluminescence (PL) spectrum of ZnS hollow microspheres indicate strong quantum confinement because of the presence of QDs.     

离子液体辅助CaMoO4中空微米球的制备及光学性质研究

以1-正丁基-3-甲基咪唑溴盐离子液体([BMIM]Br)/水体系为反应介质，利用简便的液相沉淀法在室温下合成了钼酸钙(CaMoO₄)中空微球体材料。分别利用X-射线粉末衍射(XRD)、场发射扫描电子显微镜(SEM)以及透射电子显微镜(TEM)对产品的相结构及形貌进行表征，发现产品为空心结构的白钨矿型微米级球体,并且该CaMoO₄微球体是由粒径为10～20 nm的纳米粒子聚集而成。利用紫外可见(UV-Vis)漫反射谱及室温光致发光(PL)谱测试了产品的光学性质。通过与纯水相、1-乙基-3-甲基咪唑溴盐离子液体([EMIM]Br)/水及1-正己基-3-甲基咪唑溴盐离子液体([HMIM]Br)/水等体系中所得产品的对比，证明了[BMIM]Br对产品的形貌及光学性能等具有重要影响，并对中空微球体形成的机理进行了讨论。