纳米银导电膜的制备及其光谱学分析

为了以温和的化学反应制备纳米银导电膜,在PET薄膜上涂布柠檬酸银乳液,并用抗坏血酸(Vc)还原,用红外光谱仪、紫外-可见光分光光度计、X射线衍射仪(XRD)、扫描电子显微镜、原子力显微镜等,研究柠檬酸银乳液及其还原涂层的微观形貌、晶体结构和导电性能。发现PVP保护的柠檬酸银乳液粒径分布在60～150 nm。银膜的UV-Vis吸收峰位于430 nm,表明其具有纳米结构。XRD分析表明,还原后的涂层形成了不完整的银晶体,水洗比乙醇处理更能促进柠檬酸银的彻底还原和银膜的晶型完善,降低银膜表面电阻。     

室温PVP还原银氨溶液法制备纳米银片及表征

以聚乙烯吡咯烷酮(PVP)为还原剂,在室温条件下还原银氨溶液制备纳米银片.用X射线粉末衍射(XRD)、透射电子显微镜(TEM)、紫外-可见(UV-Vis)吸收光谱对产物进行表征.结果表明,通过改变PVP用量及静置时间,可以调控纳米银片的形貌.     

半胱氨酸作为耦联剂制备的纳米银膜上的SERS研究

在直流10V电压下电解聚乙烯醇和硝酸银的混合液3h制备纳米银胶,将经过半胱氨酸修饰后的载玻片浸入银胶24h制得纳米银膜。用紫外可见分光光度计对银胶进行了观测,由于其吸收峰半高宽较窄可知银胶中纳米银颗粒粒径分布较为均匀。同时,使用扫描电镜对银膜进行了表征。通过对半胱氨酸分子SERS信号的分析得出了纳米银粒子在玻璃表面上可能的组装方式。以结晶紫(Crystal Violet)和孔雀石绿(Malachite Green)作为探测分子,采用便携式拉曼光谱仪测得两种分子不同浓度下的SERS谱。发现该方法所制得的纳米银膜有很好的表面增强效果。最后分析了半胱氨酸分子SERS信号对探针分子光谱的影响。     

质子酸功能化离子液体中银纳米颗粒的制备及其光学性能研究

以质子酸功能化离子液体1-丁基-3-甲基咪唑磷酸二氢盐([Bmim]H₂PO₄)为反应介质和表面活性剂,采用简单的化学还原法制备了具有形状各向异性的块状银纳米颗粒。通过X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见(UV-Vis)吸收光谱等一系列手段对其结构、形貌及光吸收特性进行了表征。结果表明,所制备的银纳米块具有立方结构,其平均横向尺寸约为30 nm,在硅片上自组装形成密堆积结构的多层膜。以1,2-二(4-吡啶基)乙烯(BPE)作为探针分子,研究所制备银纳米颗粒的表面增强拉曼散射(SERS)活性。结果表明所制的银纳米颗粒是较好的SERS基底,具有良好的增强效果,痕检能力及稳定性。对BPE分子的最低检测浓度可低至10-9mol·L-1,而且保存了90天后,其检测灵敏度没有显著的降低。     

微乳液法制备纳米银粒子的结构及其荧光现象研究

采用微乳液法合成了不同粒径的纳米银粒子,考察了环己烷和甲苯作为油相对制备纳米银的影响.对纳米银粒子的尺寸与结构进行了表征,观察到近球形多晶粒子,并有孪晶结构存在,对晶体结构的分析表明银粒子存在不同程度的点阵畸变,晶面间距增大.不同粒径的纳米银粒子氯仿体系可呈现荧光光谱,而纳米银甲苯体系则无荧光发射.结合紫外—可见吸收光谱和电子自旋共振谱对该体系的荧光发射机理进行了分析 关键词： 微乳液 纳米银粒子 纳米晶结构 荧光     

恒温法制备纳米银胶及其NIR-SERS活性研究

在恒温条件下(80℃)加热硝酸银和柠檬酸三钠混合液制得纳米银胶。将混合液66mL分别加热60,90,120,150,180和210分钟制得六个不同时间的纳米银胶样本。用紫外-可见(UV-Vis)分光光度计对上述6个样品进行检测,通过UV-Vis吸收光谱分析了纳米银胶中纳米银颗粒的粒径和粒径分布变化情况。同时使用激发光波长为785nm的便携式拉曼光谱仪,以结晶紫(1×10~(-6) mol/L)作为探针分子对加热不同时间的纳米银胶进行近红外表面增强拉曼散射(NIR-SERS)活性研究。最后分析了激光功率和银粒子浓度对结晶紫NIR-SERS光谱的影响。     

不同表面修饰制备高性能柔性薄膜晶体管

分别采用六甲基二硅胺(HMDS,Hexamethyldisilazane)和聚苯乙烯/氯硅烷复合材料修饰聚乙烯基苯酚(PVP)绝缘层制备了底接触的有机薄膜晶体管并研究了其半导体层的表面形貌和器件的电学性能。原子力显微镜观察发现,并五苯半导体薄膜在不同的界面修饰上的生长形貌产生了很大变化。在PVP上沉积的并五苯晶粒尺寸都小于150 nm,经过聚苯乙烯/氯硅烷复合材料和HMDS处理后的PVP表面生长的并五苯晶粒尺寸则分别在200~400 nm和400~600 nm。大尺寸的晶粒能够减小器件沟道内的陷阱浓度,从而有效地提高电学性能。PVP绝缘层采用聚苯乙烯/氯硅烷和HMDS修饰后,与未修饰的器件相比迁移率分别提高了58倍和82倍。采用HMDS作为表面修饰层制备柔性OTFT,并五苯场效应晶体管的关态电流约为10-9A,电流的开关比超过104,最大场效应迁移率约可达0.338 cm2·V-1·s-1.     

纳米银粒子复合膜的制备及光学性质测量

本文介绍了一种制备纳米复合薄膜的简易方法.以银胶为纳米粒子的来源,将银粒子渗入明胶基质中,成功地制备出纳米银粒子明胶复合膜及染料(FS,Rh6G)包覆纳米银粒子的复合膜.并报道了所制备的复合膜的电镜(TEM)、吸收谱和荧光光谱测量结果.     

不同方法制备Y_3Al_5O_(12)∶Ce~(3+)黄色荧光粉的对比研究（英文）

分别以高温固相法、溶胶-凝胶法和水热-热解法制备了Ce~(3+)掺杂的YAG黄色荧光粉,通过X-射线衍射(XRD)、场发射扫描电镜(FESEM)及荧光光谱(PL)进行表征,考察YAG∶Ce~(3+)黄色荧光粉的晶相、形貌及发光性能对制备方法的依赖性。实验表明,三种方法都实现了Ce~(3+)取代Y~(3+)的位置进入晶格,Ce~(3+)掺杂的YAG荧光粉在晶体结构上都保持立方晶体结构。高温固相法所得样品为不规则球形,粒径尺寸较大;溶胶-凝胶法所得样品为纳米尺度范围,细小颗粒团聚严重,水热-热解法所得样品形貌为球形结构且分散性较好,粒度在10μm左右。荧光光谱显示,三种样品都可被460 nm蓝光有效激发,在550 nm处产生宽带发射,但样品发光强度及量子效率差异较大,该现象主要是由样品形貌及粒径尺寸的差异引起的。     

纳米银/丝素复合材料的制备及其光谱性质研究

开发可靠、生态友好的纳米材料合成方法是当今纳米技术发展的一个重要方面,基于天然生物材料如丝素蛋白原位合成来制备纳米贵金属溶胶是一种具有极大发展潜力的方法之一。文章在室温下以丝素原位还原硝酸银制得了纳米银/丝素复合溶胶,通过紫外-可见光谱、原子力显微镜、荧光光谱和共振光散射对其制备过程和光谱性质进行了表征。实验表明丝素链中的酪氨酸残基对AgNO₃还原生成纳米银颗粒起了主要作用,制得的纳米银粒子均匀地包埋在丝素胶体中,具有很好的分散性和稳定性,可长期保存。丝素蛋白与纳米银复合后,荧光强度明显增加,证明了丝素蛋白与纳米银表面之间形成了较强的化学吸附,在银表面形成了一个相对稳定的络合物致密层。同时利用共振散射光谱分析实验进一步证实了纳米银粒子的形成。     

PS/Ag核壳结构复合微球的制备与性能

以乳液聚合法制备的平均粒径1.2~1.5μm单分散聚苯乙烯(PS)微球为核,经过超声敏化、化学镀、还原等过程制备了PS/Ag核壳结构复合微球。采用透射电镜、X射线衍射、红外光谱、紫外可见光谱对其形貌、物相、结构与光学性质进行了表征与分析。结果表明:PS/Ag复合微球粒径相对均一;通过多次敏化、控制二次银氨溶液浓度(0.002~0.006 mol/L),可实现对纳米银壳层厚度的调控;纳米银壳层沉积生长过程中,随着PS微球表面银粒子的增多、增大,复合微球的光学等离子体共振吸收峰产生显著的展宽与红移。     

Preparation of monodisperse polystyrene/silica core-shell nano-composite abrasive with controllable size and its chemical mechanical polishing performance on copper

Monodisperse silica-coated polystyrene (PS) nano-composite abrasives with controllable size were prepared via a two-step process. Monodisperse positively charged PS colloids were synthesized via polymerization of styrene by using a cationic initiator. In the subsequent coating process, silica formed shell on the surfaces of core PS particles via the ammonia-catalyzed hydrolysis and condensation of tetraethoxysilane. Neither centrifugation/water wash/redispersion cycle process nor surface modification or addition surfactant was needed in the whole process. The morphology of the abrasives was characterized by scanning electron microscope. Transmission electron microscope and energy dispersive X-ray analysis results indicated that silica layer was successfully coated onto the surfaces of PS particles. Composite abrasive has a core-shell structure and smooth surface. The chemical mechanical polishing performances of the composite abrasive and conventional colloidal silica abrasive on blanket copper wafers were investigated. The root mean square roughness decreases from 4.27 nm to 0.56 nm using composite abrasive. The PS/SiO₂ core-shell composite abrasives exhibited little higher material removal rate than silica abrasives.     

Polystyrene/Fe3O4 magnetic emulsion and nanocomposite prepared by ultrasonically initiated miniemulsion polymerization

Ultrasonically initiated miniemulsion polymerization of styrene in the presence of Fe3O4 nanoparticles was successfully employed to prepare polystyrene (PS)/Fe3O4 magnetic emulsion and nanocomposite. The effects of Fe3O4 nanoparticles on miniemulsion polymerization process, the structure, morphology and properties of PS/Fe3O4 nanocomposite were investigated. The increase in the amount of Fe3O4 nanoparticles drastically increases the polymerization rate due to that Fe3O4 nanoparticles increase the number of radicals and the cavitation bubbles. Polymerization kinetics of ultrasonically initiated miniemulsion polymerization is similar to that of conventional miniemulsion polymerization. PS/Fe3O4 magnetic emulsion consists of two types of particles: latex particles with Fe3O4 nanoparticles and latex particles with no encapsulated Fe3O4 nanoparticles. Fe3O4 nanoparticles lower the molecular weight of PS and broaden the molecular weight and particle size distribution. Thermal stability of PS/Fe3O4 nanocomposite increases with the increase in Fe3O4 content. PS/Fe3O4 emulsion and nanocomposite exhibit magnetic properties. PS/Fe3O4 magnetic particles can be separated from the magnetic emulsion by an external magnetic field and redispersed into the emulsion with agitation.     

Core–corona PSt/P(BA–AA) composite particles by two-stage emulsion polymerization

Raspberry-shaped composite particles with polystyrene (PSt) as core and poly(n-butyl acrylate-co-acrylic acid) (P(BA–AA)) as corona were synthesized via emulsion polymerization. The random copolymer, P(BA–AA), was pre-prepared and used as a polymeric surfactant, its emulsifying properties adjusted by changing the mass ratio of BA and AA. The morphology of the resulting core–corona composite particles, P(St/P(BA–AA)), could be regulated and controlled by varying the concentrations of P(BA–AA) or the mass ratio of BA:AA in P(BA–AA). The experimental results indicate that 3.0–6.0 wt% of P(BA–AA) is required to obtain stable composite emulsions, and P(BA–AA) with a mass ratio of BA:AA = 1:2 is able to generate distinct core–corona structures. A mechanism of composite particle formation is proposed based on the high affinity between the PSt core and the hydrophobic segments of P(BA–A). The regular morphology of the colloidal film is expected to facilitate potential application of core–corona particles in the field of light scattering. Furthermore, the diversity of core–corona particles can be expanded by replacing P(BA–AA) corona particles with other amphiphilic particles.     

Synthesis of carbon black/polystyrene conductive nanocomposite. Pickering emulsion effect characterized by TEM

In this study, carbon black/polystyrene electrically conductive composites were obtained by suspension polymerization technique. The composite was characterized using transmission electron microscopy, which indicated two outstanding features concerning to the carbon black; first, that the carbon particles were adsorbed onto the surface of the polystyrene particles, similarly as in the Pickering emulsion phenomenon and second, that the primary aggregate structure of the carbon black was significantly affected by the dispersion process. On the other hand, the composite resistivity was in the order of 200 Ωcm, which was attributed to the direct contact of primary carbon black particles (percolation) and not to the tunneling effect. The obtained composite was evaluated as the electrically conductive element in SBR matrix.     

Preparation of Fe3O4/polystyrene composite particles from monolayer oleic acid modified Fe3O4 nanoparticles via miniemulsion polymerization

Fe₃O₄/polystyrene composite particles were prepared from oleic acid (OA) modified Fe₃O₄ nanoparticles via miniemulsion polymerization. It was concluded that the surface properties of OA modified magnetite nanoparticles have a great effect on preparation of the composite particles. When Fe₃O₄ nanoparticles coated by multilayer of OA was employed, there were large amounts of free polystyrene particles in the product. Fe₃O₄/polystyrene composite particles with defined structure and different magnetite content can be readily prepared from monolayer OA modified Fe₃O₄ nanoparticles. It was concluded that surface of the monolayer OA modified Fe₃O₄ nanoparticles is more hydrophobic than that of the multilayer coated ones, thus improving the dispersibility of the Fe₃O₄ nanoparticles in styrene monomer and allowing preparation of the Fe₃O₄/polystyrene composite particles with defined structure and controllable magnetite content.     

Effect of surface treatment of magnetic particles on the preparation of magnetic polymer microspheres by miniemulsion polymerization

Surface treated magnetic particles were used to prepare well encapsulated submicron polystyrene/magnetic (PS/Fe₃O₄) composite microspheres via miniemulsion polymerization. The effects of the different surface treatment agents Disperbyk-106, Disperbyk-111, KH550, sodium dodecyl sulfate (SDS) and oleic acid were investigated on the encapsulation of polymer via miniemulsion polymerization. The interface interactions between magnetic particles, dispersants and coupling agents were analyzed from their IR spectra. It was found that Disperbyk-106 was the best dispersant in terms of preparing magnetic polymer microspheres with high encapsulation efficiency. The effect of wet or dry magnetic particles on encapsulation was also discussed.     

纳米铝粉/聚苯乙烯包覆粒子的制备及表征

利用超声波的分散和粉碎作用,对纳米Al粒子进行了表面疏水处理。然后,以无水乙醇为反应介质,苯乙烯为单体,偶氮二异丁腈为引发剂,聚乙烯吡咯烷酮为分散剂,在氮气保护环境下,利用超声波的活化和引发作用,引发苯乙烯单体在纳米Al粒子表面进行分散聚合反应,制备出了纳米铝粉/聚苯乙烯包覆粒子。最后,运用多种测试手段对纳米Al/PS包覆粒子形貌、粒径大小及分布、表面特性、化学组成及结构等进行了表征。测试结果表明,所制备的纳米Al/PS包覆粒子已经形成了完整的球型核壳包覆结构,表面完整无缺陷,粒径大小约为2.0 m。     

Nano-sized polystyrene prepared using bifunctional vinyl urethane macromonomer in emulsion polymerization

The linear-type bifunctional vinyl urethane macromonomer (L-VUM: Mw; 40,453) was synthesized and applied to emulsion polymerization of styrene in DDI water. The structure of L-VUM was confirmed using ¹H NMR and FT-IR. The macromonomer served as a good nonionic surfactant resulted in stable polystyrene nanospheres. Polystyrene particles were prepared with various concentrations of macromonomoer (1–30 wt% refer to monomer), initiator (0.5–2 wt%) and different temperatures (60–80 °C). Monodisperse PS nanospheres with 30 wt% L-VUM have a number-average diameter (D_n) of 200 nm with good uniformity (1.011) and molecular weight (M_w) 231,180 g/mol. The particle morphology, molecular weight and distribution, uniformity and the stability of the nanospheres upon the reaction temperature and concentration of L-VUM will be thoroughly discussed.     

用分散聚合反应制备SiO2/PS包覆粒子（英）

采用分散聚合反应制备了纳米SiO2/PS包覆粒子,并对其结构进行了表征。首先在超声波场中用表面活性剂对纳米SiO2粒子进行亲油化处理,然后在氮气保护下利用超声波的分散、粉碎、活化、引发等多重作用,在实现纳米SiO2粒子在反应介质中纳米分散的同时,引发苯乙烯单体在纳米SiO2粒子表面发生分散聚合反应,制备出纳米SiO2/PS包覆粒子。最后,采用SEM,TEM,FTIR,XPS等测试手段对纳米SiO2/PS包覆粒子进行了表征,测试结果表明,PS实现了对纳米SiO2的包覆,形成了核壳包覆结构。