静电层层自组装制备聚苯乙烯微球(核)/MCM-41纳米粒子(壳)阶层结构复合微粒

采用聚苯乙烯磺酸钠(PSS)和聚二烯丙基二甲基氯化铵(PDDA)两种聚电解质, 通过静电层层自组装成功地将MCM-41介孔二氧化硅纳米粒子包覆到聚苯乙烯(PS)微球表面. 实验结果表明, 当以尺寸为1.4 μm的PS微球为核时, 包覆了两个聚电解质双层(PDDA/PSS)2的PS(PDDA/PSS)2(PDDA/MCM-41)复合结构微粒与包覆了一个聚电解质双层(PDDA/PSS)的PS(PDDA/PSS)(PDDA/MCM-41)复合结构微粒相比, 复合结构微粒之间的交联程度降低, 但是MCM-41纳米粒子在聚苯乙烯微球表面的包覆都比较松散, 且产物中存在大量杂质. 而当以尺寸为5 μm的聚苯乙烯微球为核时, MCM-41纳米粒子紧密地包覆在聚苯乙烯微球表面, 复合结构微粒之间只有少量桥连物, 且产物中杂质很少.     

PDDA/SnTsPc静电自组装膜的制备及其形态研究

采用静电层-层自组装技术制备出了含有阴离子磺化酞菁锡(SnTsPc)和阳离子聚二烯丙基二甲基胺盐酸盐(PDDA)交替复合超薄膜.利用紫外-可见光谱表征了PDDA/SnTsPc多层膜的组装过程,表明薄膜的吸收是连续的、有规律的.原子力结果表明,膜表面是光滑的、均匀的;在膜表面紧密堆积的纳米粒子的平均粒径为53.1 nm,平均表面粗糙度是4.021 nm.     

仿贝壳结构的自组装有机-无机纳米复合薄膜的制备及结构表征

利用超分子自组装法在玻璃表面制备了聚合前后DMTB/SiO2和DMCB/SiO2复合薄膜.在所制备的复合薄膜中,表面活性剂DMTB和DMCB既作结构导向剂,又作聚合单体.用FTIR,XRD和TEM等表征了薄膜的结构.结果表明,所制备的薄膜具有有机-无机有序交替的层状结构.DMCB/SiO2和DMTB/SiO2复合薄膜有机层与无机层间的距离分别为聚合前3.48和3.44nm,聚合后2.84和2.92nm.     

富勒醇与阳离子聚电解质复合薄膜的制备与表征

采用静电自组装技术制备了富勒醇与聚对亚苯亚乙烯基 (PPV)的前驱体、聚二烯丙基二甲基氯化铵(PDDA)的复合薄膜 ,利用紫外 可见光吸收光谱 (UV Vis)、原子力显微镜 (AFM )、透射电镜 (TEM)和X射线光电子能谱 (XPS)对薄膜进行了表征 .UV Vis吸收光谱显示 ,在特定波长下自组装薄膜的吸光度与薄膜的双层数成线性关系 ,组装过程具有一致性与重复性 .AFM图象显示富勒醇组装到基片表面后形成直径为几十到10 0多nm的团簇 .富勒醇溶液过滤后组装薄膜 ,薄膜具有较好的均匀性 ;富勒醇溶液不经过滤 ,直接组装薄膜 ,将在薄膜中引入C6 0 晶粒 .XPS分析结果提示C6 0 被羟基修饰并通过静电吸引机制与阳离子聚电解质组装成膜 .富勒醇与PPV的前驱体、PDDA具有很好的自组装性能 ,膜层间的结合力较强 ,所组装的薄膜具有较高的牢固度 .     

静电自组装铁电超薄膜及其性能研究

利用静电自组装方法在石英玻璃表面交替沉积聚二烯丙基二甲基氯化铵(PDDA)和聚偏氟乙烯(PVDF)超薄膜,制得PDDA/PVDF铁电复合超薄膜.通过石英晶体微天平实时监测超薄膜的沉积,研究了超薄膜的表面形貌、结构及电性能.结果表明,自组装每层PVDF超薄膜的厚度为7.5 nm;PDDA/PVDF铁电复合超薄膜的表面平整、均匀,其中C1s的光电子能谱与极化处理后充负电荷的PVDF铁电聚合物一致,但F1s由于溶解再组装过程而降低了0.3 eV;静电自组装材料纳米级的薄膜厚度和聚合物的络合作用导致了铁电复合超薄膜的非晶结构和高的表面电阻率.     

Pickering乳液聚合制备核-壳结构PS-SiO2复合微球

用二氯二甲基硅烷对纳米SiO2粒子进行疏水改性,当其表面Zeta电位由-54.8 mV变成-25.8 mV时,SiO2粒子就能在苯乙烯-水界面自组装,形成稳定的Pickering乳液,即以胶体粒子为乳化剂的乳液.利用Pickering乳液聚合制备了以聚苯乙烯(PS)为核、纳米SiO2为壳的PS-SiO2复合微球.用FT-IR、XPS、SEM、偏光显微镜等对复合微球进行了表征.结果表明:复合微球由聚苯乙烯和纳米二氧化硅粒子组成,二氧化硅粒子以单层、六方密排的方式分布在聚苯乙烯微球表面.     

对称性降低的SiO2/Ag核壳结构纳米粒子的制备及表面增强拉曼活性研究

采用湿化学还原法在自组装的单层阵列二氧化硅纳米粒子表面沉积银膜制备了SiO2核/Ag帽复合纳米结构。通过透射电镜(TEM)、扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见分光光度计(UV/Vis)研究和表征了该复合纳米结构的表面形貌、结构及光学性质。所制备的复合纳米粒子表面粗糙,其表面呈现无数纳米级谷粒状结构,SiO2内核粒径为350nm的银纳米帽的表面等离子共振吸收的2个共振峰分别位于382和689nm处。以亚甲基蓝作为探测分子研究了SiO2粒径为350和450nm的SiO2/Ag帽状复合纳米粒子的表面增强拉曼散射(SERS)活性,增强因子分别为3.6×109和3.9×109。结果表明,湿化学还原法制备的SiO2核/Ag帽复合纳米结构是很好的拉曼活性基底。     

层层自组装结合后处理制备耐磨超亲水增透纳米粒子涂层

通过层层自组装方法制备的二氧化硅纳米粒子涂层由于具有增透、超亲水的良好性质, 引起了广泛关注. 然而, 这种涂层的耐磨性往往达不到实际应用的要求. 本工作尝试通过后处理来增强涂层耐磨性. 首先采用自制二氧化硅纳米颗粒, 聚二烯丙基二甲基氯化铵(PDDA)和聚苯乙烯磺酸钠(PSS), 通过层层自组装制备了PDDA/SiO₂纳米粒子涂层, 其中(PDDA/SiO₂)₆涂层透过率最高. 随后将(PDDA/SiO₂)₆涂层依次经过124 ℃水热处理1 h和700 ℃快速淬火200 s处理, 得到同时具有超亲水性和增透性的涂层, 其中(PDDA/SiO₂)₆涂层在可见光范围内最大透过率高达99.0%. 实验表明, 这种后处理也极大地提高了涂层的耐磨性.     

氨基功能化有序介孔Si02薄膜组装Au纳米粒子复合材料的可调色散性质

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷(P123)为模板剂,采用共溶胶的蒸发诱导自组装方法制备了氨基功能化介孔SO2薄膜,然后利用氯金酸(HAUCl4)与介孔SiO2薄膜孔道内壁的氨基之间的中和反应组装Au纳米粒子,制备得到Au/SiO2纳米复合材料.用TEM,XRD和UV-Vis光谱对材料进行了测试.结果表明,无水乙醇...     

石墨烯/银复合薄膜的制备及表征

采用静电自组装技术,通过交替沉积聚(二烯丙基二甲基氯化铵)(PDDA)(或硝酸银)和氧化石墨烯,制备氧化石墨烯/PDDA薄膜和氧化石墨烯/硝酸银复合薄膜。然后在600℃下通入氩气和氢气进行气氛还原得到石墨烯薄膜和石墨烯/银复合薄膜。采用AFM、SEM、XPS、UV-Vis以及四探针电阻仪等对薄膜结构及性质进行表征。结果表明,通过静电自组装法可以获得生长均匀的薄膜。对比于相同自组装次数的石墨烯薄膜,石墨烯/银复合薄膜具有更好的透光性和更低的薄膜方块电阻。在λ=500 nm时,四层石墨烯/银复合薄膜的透过率为85%左右,而石墨烯薄膜的透过率为72%左右;石墨烯薄膜的方阻为161.39 kΩ.□-1,而石墨烯/银复合薄膜的方阻为99.11 kΩ.□-1。     

Double-layered TiO2-SiO2 nanostructured films with self-cleaning and antireflective properties

Dual function of self-cleaning and antireflection can be created in double-layered TiO2-SiO2 nanostructured films. The film were prepared by (1) layer-by-layer deposition of multilayered SiO2 nanoparticles with polydiallyldimethylammonium (PDDA) cations, (2) layer-by-layer deposition of multilayered titanate nanosheets with polications on PDDA/SiO2 multilayer films, and (3) burning out the polymer and converting titanate nanosheets into TiO2 by hearing at 500 degrees C. The as-prepared films, consisting of a porous SiO2 bottom layer and a dense TiO2 top layer, improved the transmittance of glass or quartz substrates, as demonstrated by transmission spectra collected at normal incidence. The photocatalytic properties of the films were studied by the change of the water contact angle together with the decay of the IR absorption of the hydrocarbon chain of octadecylphosphonic-acid-modified films under 2.6 mW cm-2 UV illumination. Both the antireflective and the photocatalytic properties of the films were dependent on the number of PDDA/nanosheet bilayers deposited. however, excellent surface wettability of the films for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the double-layered nanostructured film.     

Layer-by-layer fabrication of broad-band superhydrophobic antireflection coatings in near-infrared region

Broad-band superhydrophobic antireflective (AR) coatings in near infrared (NIR) region were readily fabricated on silicon or quartz substrates by a layer-by-layer (LbL) assembly technique. First, a porous poly(diallyldimethylammonium chloride) (PDDA)/SiO2 nanoparticle multilayer coating with AR property was prepared by LbL deposition of PDDA and 200 nm SiO2 nanoparticles. PDDA was then alternately assembled with sodium silicate on the PDDA/SiO2 nanoparticle coating to prepare a two-level hierarchical surface. Superhydrophobic AR coating with a water contact angle of 154 degrees was finally obtained after chemical vapor deposition of a layer of fluoroalkylsilane on the hierarchical surface. Quartz substrate with the as-fabricated superhydrophobic AR coating has a maximal transmittance above 98% of incidence light in the NIR region, which is increased by five percent compared with bare quartz substrate. Simultaneously, the superhydrophobic property endows the AR coating with water-repellent ability. Such superhydrophobic AR coatings can effectively avoid the disturbance of water vapor on their AR property and are expected to be applicable under humid environments.     

SiO2 溶胶及其静电自组装薄膜的制备

Silica sols were prepared by hydrolysis of Si（OC2H5）4（TEOS）using HCl,NH3·H2O,HCl/NH3·H2O as catalyzers,and the different granularities of SiO2 sols which catalyzed by HCl first and then NH3·H2O have the same terminal pH value were prepared. The silica colloidal particles were investigated with Transmission Electron Microscope（TEM）. The results showed sol catalyzed by HCl possesses very little particle,catalyzed by NH3·H2O has particle configuration,catalyzed by HCl/NH3·H2O possesses consecutive configuration. Poly（diallyldimethylammonium chloride）（PDDA）and SiO2 nanoparticulate complex thin films were prepared by electrostatic self-assembly multiplayer（ESAM）method. After assembling films,thin films surface conformation was observed with Electron Microscope and their transmittance was tested with 721 Spectrophotometer. The results showed that the silica sol catalyzed with HCl is not good for the fabrication of ESAM films and the silica sol catalyzed with HCl first and then NH3·H2O or by NH3·H2O only are very suitable for ESAM film fabrication. TEM data indicate that the microstructure of PDDA/ SiO2 prepared from silica sol catalyzed with HCl first and then NH3·H2O is consecutive and that the microstructure of PDDA/ SiO2 prepared from silica sol catalyzed by NH3·H2O only is particulate-parking like. The dependence of the transmittance of assembled films on the bilayer number of the films and the anti-scratching properties of the films were investigated. The results show that PDDA/ SiO2 films prepared from silica sol catalyzed by NH3·H2O only possess higher transmittance but lower anti-scratching properties. The effect of granularity of sols on optical performances of the thin films was studied,results showed the less the granularity of sol,the better the optical performances. For the sake of improving the light transmittance of films,we can reduce the granularity of sol,but it may play down its mechanical damage resist intensity.     

Multilayers of oppositely charged SiO2 nanoparticles: effect of surface charge on multilayer assembly

The growth behavior of all-silica nanoparticle multilayer thin films assembled via layer-by-layer deposition of oppositely charged SiO2 nanoparticles was studied as a function of assembly conditions. Amine-functionalized SiO2 nanoparticles were assembled into multilayers through the use of three different sizes of negatively charged SiO2 nanoparticles. The assembly pH of the nanoparticle suspensions needed to achieve maximum growth for each system was found to be different. However, the surface charge /z/ of the negatively charged silica nanoparticles at the optimal assembly pH was approximately the same, indicating the importance of this parameter in determining the growth behavior of all-nanoparticle multilayers. When /z/ of the negatively charged nanoparticles lies between 0.6z(0) and 1.2z(0) (where z(0) is the pH-independent value of the zeta-potential of the positively charged nanoparticles used in this study), the multilayers show maximum growth for each system. The effect of particle size on the film structure was also investigated. Although nanoparticle size significantly influenced the average bilayer thickness of the multilayers, the porosity and refractive index of multilayers made from nanoparticles of different sizes varied by a small amount. For example, the porosity of the different multilayer systems ranged from 42 to 49%. This study further demonstrates that one-component all-nanoparticle multilayers can be assembled successfully by depositing nanoparticles of the same material but with opposite surface charge.     

TiO2/SiO2纳米薄膜的光催化活性和亲水性

通过sol gel工艺在钠钙玻璃表面制备了均匀透明的TiO2/SiO2复合纳米薄膜.实验结 果表明: 当SiO2添加量较高时, TiO2/SiO2复合纳米薄膜的光催化活性明显降低;当SiO2添加 量较低时,TiO2/SiO2复合薄膜的光催化活性无明显变化.在TiO2薄膜中添加SiO2,可以抑制薄 膜中TiO2晶粒的长大,同时薄膜表面的羟基含量增加, 水在复合薄膜表面的润湿角下降, 亲 水能力增强.当SiO2含量为10％－20％（摩尔分数）时获得了润湿角为0°的超亲水性薄膜.     

TiO_2/SiO_2纳米薄膜的光催化活性和亲水性

通过 sol-gel工艺在钠钙玻璃表面制备了均匀透明的 TiO2/SiO2复合纳米薄膜 .实验结果表明 : 当 SiO2添加量较高时 , TiO2/SiO2复合纳米薄膜的光催化活性明显降低 ;当 SiO2添加量较低时 ,TiO2/SiO2复合薄膜的光催化活性无明显变化 .在 TiO2薄膜中添加 SiO2,可以抑制薄膜中 TiO2晶粒的长大 ,同时薄膜表面的羟基含量增加 , 水在复合薄膜表面的润湿角下降 , 亲水能力增强 .当 SiO2含量为 10％－ 20％（摩尔分数）时获得了润湿角为 0°的超亲水性薄膜 .     

Spray-layer-by-layer assembly can more rapidly produce optical-quality multistack heterostructures

Automated spray-layer-by-layer (LbL) assembly was used to create highly reflective structurally colored thin films with high reflectance at near-UV light wavelengths. Reflectance peaks were tuned by fabricating alternating stacks of high (TiO(2) nanoparticles) and low (SiO(2) nanoparticles) refractive index materials using a non-quarter-wave design. Spray-assembled multilayer heterostructures fabricated with up to 840 individual polymer or nanoparticle deposition steps presented similar roughness and refractive index values compared to Bragg stacks obtained via immersion LbL assembly. Such complex multilayer heterostructures, however, could be fabricated in significantly shorter times; the time required to deposit a complete bilayer was only about 90 s, compared to 36 min for the immersion assembly of the same system. Optimization of the experimental parameters was performed to achieve uniform coatings and relatively smooth interfaces and surfaces. We observed that the spraying times of the nanoparticle and polymer solutions are the main parameters that determine the thickness, optical properties, and uniformity of the assembled films. Ellipsometry, atomic force microscopy (AFM), UV-vis spectroscopy, and transmission electron microscopy (TEM) were used to characterize the samples. The nanoparticle thin films were iridescent and presented relatively narrow peaks of high reflectance (～90%) at visible and near-UV wavelengths of light.     

Aerosol assisted chemical vapor deposition using nanoparticle precursors: a route to nanocomposite thin films

Gold nanoparticle and gold/semiconductor nanocomposite thin films have been deposited using aerosol assisted chemical vapor deposition (CVD). A preformed gold colloid in toluene was used as a precursor to deposit gold films onto silica glass. These nanoparticle films showed the characteristic plasmon absorption of Au nanoparticles at 537 nm, and scanning electron microscopic (SEM) imaging confirmed the presence of individual gold particles. Nanocomposite films were deposited from the colloid concurrently with conventional CVD precursors. A film of gold particles in a host tungsten oxide matrix resulted from co-deposition with [W(OPh)(6)], while gold particles in a host titania matrix resulted from co-deposition with [Ti(O(i)Pr)(4)]. The density of Au nanoparticles within the film could be varied by changing the Au colloid concentration in the original precursor solution. Titania/gold composite films were intensely colored and showed dichromism: blue in transmitted light and red in reflected light. They showed metal-like reflection spectra and plasmon absorption. X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis confirmed the presence of metallic gold, and SEM imaging showed individual Au nanoparticles embedded in the films. X-ray diffraction detected crystalline gold in the composite films. This CVD technique can be readily extended to produce other nanocomposite films by varying the colloids and precursors used, and it offers a rapid, convenient route to nanoparticle and nanocomposite thin films.     

TiO2光致亲水性及其在免处理版材中的应用研究

用溶胶-凝胶法制备了SiO₂和TiO₂薄膜,并涂覆于玻璃基片上,研究了TiO₂薄膜在紫外光照射下其超亲水性能的变化与光照时间的关系,分析了SiO₂薄膜对覆于其上的TiO₂薄膜的耐摩擦性能的影响.结果表明:TiO₂薄膜经紫外光照射后,疏水性急剧降低,显示亲水性能,与水的接触角可达到5°以下;当其覆膜于载玻片上后,具有良好的耐摩擦性和耐候性;TiO₂薄膜的超亲水性使其有望成为一种新型的环保可重复利用的印刷版材.