有机/无机复合功能材料倒脊型波导热光开关

利用溶胶-凝胶技术自主合成了一种具有优良光学特性和高热稳定性的有机/无机复合芯层材料.这种功能材料的分子中含有有机柔性侧链,可形成环氧交联.与无机SiO2-TiO2体系相比,具有较高的热光系数（量级为10－4/K）,以及更好的成膜性和可加工性.通过与实验室自行配制的P(MMA-GMA)包层材料相匹配,设计制备了基于这种有机/无机复合功能材料的倒脊型波导马赫-曾德尔型热光开关.器件的波导与热电极性能良好.插入损耗为10 dB,驱动功率15 mW,开关时间小于1 ms,消光比15 dB.     

核/壳结构的ZnS:Mn/SiO_2纳米粒子的制备及发光性质研究

采用溶剂热法制备了Mn离子掺杂的ZnS纳米粒子(ZnS∶Mn),然后利用正硅酸乙酯(TEOS)的水解反应对其进行了不同厚度的SiO2无机壳层包覆。采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)及荧光发射光谱(PL)对样品的结构及光学性质进行了表征和研究。包覆SiO2壳层后,粒子的粒径明显增大并且在ZnS∶Mn纳米粒子表面可以观察到明显的SiO2壳层。XPS测试印证了ZnS∶Mn/SiO2的核壳结构。随着SiO2壳层的增厚,ZnS∶Mn/SiO2的Mn离子的发光先增强后减弱,这是因为SiO2壳层同时具有表面修饰和降低发光中心浓度这两种相反的作用。当壳层厚度(壳与核的物质的量的比)达到5时,发光效果达到最好,其强度达到未包覆样品的7.5倍。     

超细金属铁颗粒的高分子修饰及其悬浮液的磁流变性能

报道了γ射线辐照方法合成具有良好分散性的高分子复合金属铁粒子,分别选择十二烷基硫酸钠、溴化十六锘三甲基胺、Ｔｗｅｅｎ－８０、ＴｒｉｔｏｎＸ－２００和ＯＰ－１０表面活必睡有机单体、无机铁颗粒一起制备乳状液,通过对这种含有超细金属铁颗粒乳状液稳定性的比较,以寻求合适的乳化剂,并对以ＴｒｉｔｏｎＸ－２００为乳化剂时合成出的高聚物复合铁颗进行了ＸＲＤ、ＴＥＭ和ＩＲ表征,还将实验中所获得的高聚物复合铁粒子与     

黄土区金盏菊幼苗根部细胞壁对Pb/Cd复合胁迫响应的FTIR和Raman光谱

植物修复法是新兴的重金属污染土壤修复手段,也是未来极富应用潜力的主流技术之一。植物根部细胞壁作为重金属/土壤/植物相的交界面,天然地成为修复效能调控过程的关键部位和信号通道。植物细胞壁与重金属离子的作用行为具有物理化学和生理生化的双重属性,但以光谱技术为切入点,原位解析植物根部细胞壁对土壤重金属离子的响应关系还不多见。以黄土区修复植物金盏菊幼苗为研究对象,分析Pb/Cd复合胁迫对其根部细胞壁形貌的影响,借助X射线荧光光谱(XRF)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和拉曼光谱(Raman)揭示细胞壁对Pb/Cd胁迫的响应信号。结果发现:Pb/Cd胁迫导致金盏菊根部细胞壁弯曲萎缩,表面分布若干点状深色沉积物颗粒;XRF证实细胞壁Pb/Xd含量增加,但XRD图谱没有发现典型Pb/Xd结晶峰。FTIP图谱中—OH振动峰定位于3 416 cm~(-1)处,表明Pb/Cd离子与—OH间可能存在配位键合;1 701和1 593 cm~(-1)处的特征峰分别移动到1 736和1 618 cm~(-1),说明Pb/Cd胁迫改变了金盏菊根部细胞壁蛋白质结构属性。Raman光谱中2 960 cm~(-1)附近峰强增加,暗示Pb/Cd胁迫影响了细胞壁纤维素分子排列方向。可以认为,细胞壁组分(果胶、蛋白质、纤维素等)和典型官能团(—OH,N—H,C=O等)对于减缓Pb/Cd胁迫引起的金盏菊根部细胞壁毒害效应贡献较大。     

PVK/SiO2纳米粒子复合体系能量传递的研究

通过溶胶反应在乙醇溶液中合成了60nm的SiO2纳米粒子，将其与聚乙烯咔唑（PVK）共混，得到了不同质量分数的PVK／SiO2复合体系，利用荧光光谱，吸收光谱，研究了PVK／SiO2复合体系的荧光效应，光致发光的研究表明在PVK与SiO2纳米粒子之间存在界面能量传递过程，这种能量传递的必要条件是PVK的发射谱与SiO2纳米粒子的吸收谱有重叠，以上研究表明PVK／SiO2复合体系存在较强的界面效应，是研究有机与无机纳米体系界面效应的良好模型。     

TiO2/SiO2的表面化学修饰及其DRS和Raman光谱分析

以氯化醇钛盐表面反应法制备系列TiO2/SiO2,根据XRD,Raman和DRS表征分析,载体表面具有分子级分散的锐钛矿型TiO2微晶粒子和非晶TiOx物种.与本体TiO2相比,TiO2/SiO2的吸收带边显著蓝移,能隙增大为3.96 eV.当金属M(M:Pd,Cu和Ni)负载于TiO2/SiO2表面,可使其光吸收域扩展到可见光区,并引起吸收带边红移.相对Pd的负载,Cu,Ni的负载对TiO2/SiO2的LMCT带影响更大,其中Cu-TiO2/SiO2的能隙减小为3.68 eV.当金属氧化物MoO3负载于TiO2/SiO2上时,可以调变TiO2/SiO2的吸收带边并增强对可见光的吸收;随MoO3载量的增加,表面物种的相互作用增强,形成Mo-O-Ti复合结构,增强了LMCT带的吸收强度,并使能隙减小为3.81 eV.     

复合纳米光学变色薄膜

用热蒸发和磁控溅射的物理镀膜方法和溶胶-凝胶化学涂布的方法相结合制备了有机和无机复合纳米光学变色薄膜。光学变色薄膜为多层薄膜,当有自然光进入光学变色薄膜时,随着入射光和视角的变化在薄膜上可以看到明显的光变色效果。这种薄膜可以单独或与油墨组合作为一种新颖的防伪材料。根据多层复合膜光干涉原理经设计和计算确定薄膜为PET／Cr／介质／Al膜系结构。介质分别是有机高聚物和SiO2。SiO2是多孔纳米材料,用溶胶-凝胶方法制备,通过调节催化和凝胶的方式和条件,折射率在1.15～1．45之间。介绍了制作方法和薄膜特性。     

有机/无机复合功能材料倒脊型波导热光开关

利用溶胶-凝胶技术自主合成了一种具有优良光学特性和高热稳定性的有机/无机复合芯层材料.这种功能材料的分子中含有有机柔性侧链,可形成环氧交联.与无机SiO2-TiO2体系相比,具有较高的热光系数(量级为10-4/K),以及更好的成膜性和可加工性.通过与实验室自行配制的P(MMA-GMA)包层材料相匹配,设计制备了基于这种有机/无机复合功能材料的倒脊型波导马赫-曾德尔型热光开关.器件的波导与热电极性能良好.插入损耗为10dB,驱动功率15mW,开关时间小于1ms,消光比15dB.     

SiO2溶胶及其静电自组装薄膜的制备

采用HCl催化、NH3 ·H2 O催化、HCl与NH3 ·H2 O分步催化三种途径制备了SiO2 胶体 ,用透射电镜观察了胶体粒子的形貌 .用静电自组装 (ESAM)法制备了聚电解质PDDA与SiO2 胶体粒子的有机 /无机复合光学薄膜 .实验结果表明 ,用HCl催化制备的SiO2 透明溶胶不适合于用ESAM法制备薄膜 ,用HCl与NH3 ·H2 O分步催化以及用NH3 ·H2 O单独催化制备的SiO2 胶体适合于用ESAM法制备光学薄膜 .薄膜的透射电镜微观察结果表明 ,以HCl与NH3 ·H2 O分步催化的SiO2 胶体制备的PDDA/SiO2 薄膜为连续结构 ,NH3 ·H2 O单独催化的为颗粒堆积 .研究了薄膜透光率与薄膜层数的关系 ,考察了薄膜的机械强度 .结果显示 ,以NH3 ·H2 O单独催化的SiO2 胶体制备的光学薄膜的增透效果较好 ,但耐机械擦伤强度较弱     

金盏菊根际圈黄土溶解性有机质对Pb/Cd赋存形态原位调控机制的光谱学证据

在污染场地植物修复过程中,植物根系通过释放活性分泌物主动适应和抵御污染胁迫,直(间)接影响根际圈土壤DOM的结构组成。现阶段,植物修复的关注点主要集中于污染物的吸收、转运、累积和解毒行为,对于根际圈土壤DOM的探讨略显不足。以Pb/Cd复合污染黄土区金盏菊幼苗为研究对象,分析根际圈黄土Pb/Cd赋存形态、金盏菊生长状况等宏观差异,借助紫外可见光谱(UV)、傅里叶变换红外光谱(FTIR)和三维荧光光谱(3D-EEMs)明确Pb/Cd胁迫前后根际圈黄土DOM的微观性质。结果表明:根际圈黄土Pb/Cd以残渣态和可交换态为主,金盏菊生长周期结束后可交换态Pb/Cd含量有所升高。Pb/Cd胁迫抑制了金盏菊株高和出苗率,其生长周期有助于改善黄土理化性质。胁迫后金盏菊根部呈现细长、弯曲且萎缩的迹象;DOM紫外光谱最大吸收区间位于200~240nm,但胁迫后的图谱波峰更加尖锐,峰强更大。Pb/Cd胁迫导致DOM红外吸收峰分别从3 444和1 637cm-1移动至3 440和1 645cm-1,其中存在重金属离子与OH和C=O结合效应。DOM荧光峰集中在λex/em=240/430附近(紫外区类富里酸荧光峰),Pb/Cd胁迫对荧光峰强干扰较大,而对荧光峰位基本没有影响。金盏菊根际圈黄土DOM能够提供重要的微生态环境信息,光谱学手段能够一定程度上揭示其与Pb/Cd赋存形态的构效关系。     

Synthesis and characterization of TiO2/Ag/polymer ternary nanoparticles via surface-initiated atom transfer radical polymerization

We report on the novel ternary hybrid materials consisting of semiconductor (TiO₂), metal (Ag) and polymer (poly(oxyethylene methacrylate) (POEM)). First, a hydrophilic polymer, i.e. POEM, was grafted from TiO₂ nanoparticles via the surface-initiated atom transfer radical polymerization (ATRP) technique. These TiO₂-POEM brush nanoparticles were used to template the formation of Ag nanoparticles by introduction of a AgCF₃SO₃ precursor and a NaBH₄ aqueous solution for reduction process. Successful grafting of polymeric chains from the surface of TiO₂ nanoparticles and the in situ formation of Ag nanoparticles within the polymeric chains were confirmed using transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FT-IR spectroscopy also revealed the specific interaction of Ag nanoparticles with the CO groups of POEM brushes. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the semiconductor, producing ternary hybrid inorganic-organic nanomaterials.     

Polymer assisted assembling of the semiconductor particles: Structural and electrical studies

CdS and Si semiconductor nanopraticles were embedded in a polymer matrix and characterized using various techniques. The surface properties and size distribution of the nanoparticles were monitored by POM and SEM and found to be uniform but around the crystalline frameworks of the polymer. XRD and FTIR analysis have been used to ensure the composite nature and particle size of the semiconductor loaded films. The electrical conductivity of these films were evaluated and found to increase with semiconductor dispersion and attains a percolation threshold at optimum composition. This composition and the distribution of the clusters is shown to vary with the type of the semiconductor, i.e., CdS or Si.     

Magnetic response of NiFe2O4 nanoparticles in polymer matrix

We report the magnetic properties of magnetic nano-composite, consisting of different quantity of NiFe₂O₄ nanoparticles in polymer matrix. The nanoparticles exhibited a typical magnetization blocking, which is sensitive on the variation of magnetic field, mode of zero-field-cooled/field-cooled experiments and particle quantity in the matrix. The samples with lower particle quantity showed an upturn of magnetization down to 5 K, whereas the blocking of magnetization dominates at lower temperatures as the particle quantity increases in the polymer. We examine such magnetic behaviour in terms of the competitive magnetic ordering between core and surface spins of nanoparticles, taking into account the effect of inter-particle (dipole-dipole) interactions on nanoparticle magnetic dynamics.     

Polymer photodegradation initiated by ZnO nanoparticles

The photodegradation initiated by semiconductor nanoparticles in an acrylic photocurable polymer doped with p-ZnO nanoparticles has been investigated. A mechanism and formula of the photoinduced chemical reaction stimulated by primary photochemical processes of water photolysis on the surface of semiconductor ZnO nanoparticles are proposed. The mass loss in this reaction reaches 12%, which confirms the validity of photodegradation for polymer waste disposal.     

Tuning of optical properties of CdS nanoparticles synthesized in a glass matrix

Attempts were made to provide the data concerning directed synthesis of semiconductor nanoparticles in a dielectric silica-based glass matrix. These attempts involve finding out the connections between the structure, size of CdS nanoparticles, and optical properties of the nanocomposites produced. High-resolution focused ion beam scanning electron microscopy images of CdS nanoparticles incorporated in glass and SAXS results confirm the formation of uniformly distributed spherical CdS nanoparticles with an average diameter of about 6.2 nm. UV–Vis measurements show that CdS composites possess a direct bandgap wider than 2.45 eV depending on the heat treatment conditions; thus, heat treatment can be used to control nanoparticle size in each selected composite. The emission spectra showed a maximum at about 603 nm and a red shift of about 100 nm with increasing annealing temperature that is associated with the presence of defect states in the nanoparticles. In addition, semiconductor phase concentration in the glass matrix was found by using optical absorption data for the first time, which allows understanding the effect of nanocomposite structure on luminescence properties.     

Optical properties of nanocomposites based on polymers and metal nanoparticles

The optical properties of nanocomposites of metal nanoparticles and polymers of two types have been studied. Gold and silver nanoparticles were obtained by laser ablation of corresponding metal targets in acetone and chloroform. The thus formed colloidal solutions were used to prepare nanocomposites of these nanoparticles in polymer matrices of polymethylmethacrylate (PMMA) and fluorine-containing polymer LF-32. The polymer matrix is found to promote aggregation of the metal nanoparticles under study into elongated chains. In turn, metal nanoparticles affect the polymer matrix. In the case of PMMA, suppression of the vibrational peaks of polymer in the low-frequency region of its Raman spectrum occurs. In the case of LF-32, gold and silver nanoparticles amplify the Raman signal of the polymer matrix. In addition, the Raman spectra of nanocomposites indicate aggregation of disordered carbon around the nanoparticles obtained by laser ablation in organic solvents. The possibilities of studying the ultrafast (about 1 ps) optical response of the nanocomposites obtained in order to use it in photonics elements are discussed.     

掺杂无机纳米超微粒的有机聚合物体系中的光折变效应

研究了掺杂无机纳米超微粒的有机聚合物体系中的光折变效应．体系中以Ｃｕ２Ｓ／ＣｄＳ／ＺｎＳ复合超微粒为光敏剂,ＰＶＫ为载流子输运剂,电光分子为ＥＰＮＡＣ．给出了光敏剂的制备方法,ＥＰＮＡＣ的分子结构及电光特性,以及该光折变材料中的两波耦合效应的实验结果．结果表明,无机纳米超微粒可用作光折变材料中的光敏剂,这是它的一种新的应用．     

Structure and optical properties of the silver/polyacrylonitrile nanocomposites

Small-angle X-ray scattering is used to prove the formation of silver nanoparticles with sizes of 5–11 nm in siver/polyacrylonitrile nanocomposites synthesized via photopolymerization of a mixture containing silver, acrylonitrile, and photoinitiator. Optical spectra of nanocomposites obtained under different conditions are studied. The absorption spectra exhibit maxima at wavelengths of 420–450 nm related to the surface plasmon resonance of silver nanoparticles. IR spectra of the nanocomposites prove the formation of polyacrylonitrile in the course of the photopolymerization of monomer. The formation of metal nanoimpurities in polymer matrix leads to an increase in the intensity of photoluminescence and Raman scattering of polyacrylonitrile.     

合成聚丙酰胺-硫属半导体复合纳米材料的新技术

在水溶液体系中采用同步聚合－水解技术制备聚丙烯酰胺－半导体纳米复合材料,该ＳＰＨ技术是基于丙烯胺单体的聚合和ＭＳ纳米粒子的形成同步发生,使生成的半导体纳米粒子可均匀分散在聚丙烯酰胺基质中,该技术还为制备其它有机聚合物－金属硫化物纳米复合物提供了一种新途径。     

Hybrid polymer-inorganic materials: multiscale hierarchy

The paper describes a new approach to producing hybrid composite materials with multiscale morphologies. We doped polymer submicrometer spheres with semiconductor or metal (CdS or Ag, respectively) nanoparticles and used these doped microspheres as the functional building blocks in production of hybrid periodically structured materials. The preparation of hybrid polymer particles included the following stages: (i) synthesis of monodisperse polymer microspheres, (ii) in situ synthesis of the inorganic nanoparticles either on the surface, or in the bulk of the polymer beads, and (iii) encapsulation of hybrid microspheres with a hydrophobic shell. We demonstrated that by changing the composition of the polymer beads good control could be achieved over the size of the nanoparticles.