碱催化多孔SiO_2/PI杂化薄膜的制备与力学性能研究

采用碱催化正硅酸乙酯(TEOS)的溶胶-凝胶法与分子模板法相结合,通过旋转涂覆在硅衬底上制备掺杂聚酰亚胺(PI)的纳米多孔SiO2薄膜,并在其表面制备致密过渡膜。利用差热分析(DSC-TGA)、原子力显微镜(AFM)、台阶仪(Atomic-Profiler)、微纳力学性能测试仪(Universal Nano+Micro Mechanical Tester)等对薄膜的性能进行了分析表征。结果表明,所制备的SiO2/PI杂化多孔薄膜具有较好的力学性能和热稳定性;一层膜和两层膜的平均厚度分别为917和1288nm;镀有过渡膜的样品具有最为平整的表面形貌和最小的表面动摩擦系数。     

PI掺杂多孔SiO2薄膜的制备及性能研究进展

近年来对掺杂纳米SiO2的聚酰亚胺薄膜的各种性能进行了充分的研究,而对以少量PI掺杂的多孔SiO2薄膜的研究较少.介绍了PI掺杂多孔SiO2薄膜制备过程中影响薄膜性能及应用的两个关键因素(相分离和热处理固化成膜),理论分析了PI掺杂多孔SiO2薄膜的力学性能和绝热性能,最后讨论了目前存在的一些问题和今后的发展趋势.     

掺杂TiO2的纳米多孔SiO2薄膜的制备及性能研究

采用溶胶-凝胶法、分子模板法及旋转涂覆法在硅衬底上制备掺杂TiO2的SiO2薄膜，并采用差热分析（DSC-TGA）、红外吸收光谱（FTIR）、X射线衍射、小角衍射（SAXS）、原子力显微镜（AFM）、台阶仪（Atomic-Profiler）以及纸擦拭法（paper-wiping method）和胶带剥离法（adhesive tpe-stripping method）对薄膜的性能进行了分析与表征，结果表明，薄膜的最佳热处理温度为400℃，所制备的掺杂TiO2的SiO2薄膜为多孔结构的无定形态，具有较好的机械性能，平均孔径随着膜层的增加而减小，一层膜和两层膜的平均孔径分别为87.4nm和62.8nm，厚度分别为538.7nm和1032.3nm。     

SiO_2预涂层对TiO_2多层膜结构与亲水性能的影响

采取溶胶-凝胶法制备了TiO2与SiO2的前驱溶液。并利用SiO2薄膜固有的多孔特性,在普通载玻片上以SiO2为模板成功制得了具有较大粗糙度以及多孔特性的多层TiO2薄膜,其表面粗糙度亦达到14.7nm;利用热重-差热分析仪(TGA-DSC)对TiO2溶胶进行分析;采用X射线衍射仪(XRD)、扫描探针显微镜(CSPM)和扫描电镜(SEM)对薄膜的结构与形貌进行了表征。并考察了不同层数TiO2薄膜性能的差异,实验结果表明,未预涂SiO2的TiO2膜表面光滑平整,而预涂了SiO2的TiO2表面呈现出均匀的微孔结构。前者在避光6h后完全失去超亲水性;而预涂1层SiO2的TiO2薄膜在经过30h避光处理后,接触角依然小于10°,其中两层TiO2薄膜接触角仅为6.7°,润湿性得到了很好的保持。     

纳米ZrO2薄膜的制备与表征

用水热盐溶液水解法可合成含有单斜相晶态纳米ZrO2颗粒的ZrO2溶胶体.用匀胶法制备的纳米ZrO2薄膜厚度约160 nm,折光率为1.56.纳米ZrO2薄膜表面质量良好,无表面裂隙,台阶仪研究表明薄膜表面粗糙度算术差Ra=2.7 nm,均方根差Rq=3.7 nm.以ZrO2为高折射率膜层,碱催化的溶胶凝胶SiO2为低折射率膜层,制备了SiO2/ZrO2多层高反射率薄膜,10周期的SiO2/ZrO2多层膜系,在1.06 μm波段处透过率为1%,薄膜表面抗激光损伤阈值约15 J/cm2(1.06 μm,2.5 ns高功率激光作用下).     

Ti^3＋掺杂SiO2／甲基三乙氧基硅烷复合薄膜的制备

采用溶胶-凝胶(sol-gel)法,以正硅酸乙酯TEOS/甲基三乙氧基硅烷(MTES)为先驱物,浓盐酸为催化剂,制备了掺杂不同三氯化钛(TiCl3)浓度的SiO2/MTES复合薄膜.采用荧光分光光度计、扫描探针显微镜、红外光谱仪、X光衍射仪等仪器对膜层性质进行了分析.结果表明,掺杂4%、3%、2%、1%TiCl3的SiO2/MTES复合薄膜分别在250nm附近有一弱激发峰,294nm附近有一强激发峰,在393nm附近出现一强发射峰;掺杂3%的复合薄膜荧光发射强度达到值最大.与Ti3 掺杂的常规SiO2薄膜比较,Ti3 掺杂的SiO2/MTES复合薄膜的荧光强度更稳定.     

SiO2气凝胶柔性保温隔热薄膜

由SiO2气凝胶、聚酰亚胺和镀铝层(SiO2／PI／Al)组成的柔性多层薄膜具有很好的保温隔热特性和广泛的应用前景。采用溶胶-凝胶方法制备的SiO2气凝胶具有很高的气孔率和很低的体积密度，尝试了在溶胶-凝胶过程申先酸性后碱性的二步法催化．使孔洞率提高到97％，体积密度降低为50kg／m^3，成为优秀的保温隔热的主体材料。选择柔性耐温隔热的聚酰亚胺作为骨架材料，并用真空蒸发镀制上金属铝膜与多孔SiO2气凝胶复合成保温隔热薄膜。当薄膜叠加到10层时其保温隔热效果可提高5倍。     

二氧化钛过渡层对脉冲激光沉积钛酸锶钡薄膜微结构和介电性质的影响

选取极薄Ti02作为过渡层,采用脉冲激光沉积法分别在Si(100)和Pt(111)/Ti/SiO2/Si(100)基底上制备了Bao.6Sro.4TiO3(BST)薄膜,研究过渡层对BST薄膜微结构及电学性质的影响.发现厚度20纳米以内的锐钛矿相结晶TiO2过渡层可使BST薄膜由无规则取向转变为(111)择优取向,而非晶和较厚TiO2过渡层对BST薄膜的取向无影响.结晶的TiO2过渡层也使薄膜的表面颗粒变细.还研究了不同厚度TiO2对BST薄膜电学性质的影响,结果表明BST薄膜在Pt(111)底电极上加入极薄的结晶TiO2过渡层后电学性质有明显改善,薄膜的介电常数和可调谐度提高,而介电损耗降低.加入膜厚约5nm的TiO2过渡层后,测试频率为10 kHz时薄膜相应介电常数、介电损耗及可调谐度分别为513、0.053和36.7%.     

纳米多孔二氧化硅薄膜的制备及其光学性质研究

以正硅酸乙酯(TEOS)为先驱体，采用溶胶-凝胶法，结合旋转涂胶和超临界干燥等工艺，在硅片上制备了纳米多孔SiO2薄膜。XRD和AFM表明该SiO2薄膜为无定形态，具有多孔网络结构，表面均匀平整，其SiO2基本粒子和孔隙的直径为30～40nm。利用椭偏光谱仪测量了SiO2薄膜在波长245～1650nm的椭偏光谱，采用Si／cauchy／rough结构模型对该光谱进行了拟合，获得了SiO2薄膜的厚度和光学常数。SiO2薄膜的厚度为500～1100nm；折射率为1．13～1．21；孔隙率为56％～70％；介电常数为1．9～2．3。     

高模量、低热膨胀系数聚酰亚胺杂化薄膜的制备

通过在聚酰胺酸中加入正硅酸乙酯(TEOS)和硅烷偶联剂(KH550),制备了不同SiO2含量的PI/SiO2杂化薄膜.采用FTIR、TMA、SEM以及TGA分析了PI/SiO2杂化薄膜的性能和结构.结果表明,TEOS经水解缩合与聚酰亚胺(PI)形成了有机-无机杂化网络结构,SiO2均匀分散在聚酰亚胺基体中;SiO2和偶联剂的引入提高了杂化薄膜的热稳定性;随着SiO2含量的增加,PI/SiO2杂化薄膜的拉伸强度降低,但当SiO2含量达到20%时,弹性模量增大到3.4GPa.     

Preparation of poly(acrylic)/SiO2/EuL3 x 2H2O, hybrid thin films from monodispersed colloidal silica

In this study, poly(acrylic)/SiO2/EuL3 x 2H2O hybrid thin films were prepared from various acrylic monomers (MMA and EDMA/TMPTA), lanthanide metal complexes (EuL3 x 2H2O, L = pyridine carboxylic acid), and monodispersed colloidal silica with a coupling agent, 3-(trimethoxysilyl)propyl methacrylate (MSMA). It is a combination of the sol-gel reaction, thermal polymerization, and spin coating. The silica content in the hybrid thin films is fixed at 20 wt%, and the EuL3 x 2H2O content is varied from 0.01 g to 0.07 g. FTIR and EA analysis confirms the chemical structure of the prepared EuL3 x 2H2O and poly(acrylic)/SiO2/EuL3 x 2H2O hybrid thin films. UV-Vis spectra and n&k analysis shows that the hybrid thin film has good transparency in visible light. The refractive index of hybrid thin films can be effectively controlled through the EuL3 x 2H2O content. The PL spectra shows that the strongest emission peak occurs at 615 nm and the emission intensity increases to the peak maximum at an EuL3 x 2H2O content of 0.05 g. Both TGA and PL analysis show that the prepared hybrid thin films from the crosslinked acrylic polymer moiety have much better film uniformity, thermal stability, and fluorescence properties. The TEM diagram shows that the MSMA/SiO2/EuL3 x 2H2O particles with a size 15-20 nm are well dispersed in the reaction solution. The SEM diagram shows that the particle distribution in the prepared hybrid thin films is uniform and no phase separation is observed. Finally, AFM analysis indicates that the prepared hybrid thin films have an excellent surface planarity.     

溶胶-凝胶法制备氧化硅-氧化铝共掺杂聚酰亚胺薄膜及其性能

采用溶胶-凝胶法制备纳米二氧化硅及氧化铝溶胶,将溶胶混合后掺入正在反应的聚酰胺酸中,制得聚酰亚胺/二氧化硅-氧化铝杂化薄膜。利用扫描电子显微镜对杂化薄膜的微观形貌进行了表征,并测试了无机组分含量不同的杂化薄膜的力学性能、热稳定性及介电性能。试验结果表明,杂化薄膜材料中无机相呈现纤维结构和颗粒结构,有效地提高了薄膜的力学性能。杂化薄膜与纯膜相比,热分解温度有较大提高,且随着无机组分含量增大,热分解温度呈现先上升后下降的趋势。介电性能分析表明,杂化薄膜的介电常数和介电损耗与频率的关系符合德拜松弛极化机理。     

The growth mechanism for silicon oxide nanowires synthesized from an Au nanoparticle/polyimide/Si thin film stack

During pyrolysis of polyimide (PI) thin film, amorphous silicon oxide nanowires (SiO(x)NWs) were produced on a large scale through heat treatment of an Au nanoparticle/PI/Si thin film stack at 1000?°C. It was shown that carbonization of the PI film preceded the nucleation of the SiO(x)NWs. The formation of the SiO(x)NWs was sustained by the oxygen derived from carbonization of the polyimide thin film while Si was provided from the substrate. Au nanoparticles promoted the SiO(x)NW growth by inducing localized melting of the Si substrate and by catalyzing the nanowire growth.     

聚乳酸/聚乙二醇/SiO2杂化薄膜的制备及性能研究

以正硅酸乙酯、聚乳酸与聚乙二醇为主要原料，采用溶胶-凝胶法在玻璃衬底上制备有机与无机杂化薄膜，研究了制备条件对薄膜性能的影响。结果表明：所制备的薄膜与衬底有很好的附着力；在380-800nm波段范围，镀有薄膜的玻璃对光的平均透过率在92％以上，且不需要光照就能长时间保持超亲水性达20天以上；pH值及溶胶陈化时间是影响薄膜亲水性的重要因素。     

The fabrication of tunable nanoporous oxide surfaces by block copolymer lithography and atomic layer deposition

Patterned nanoscale materials with controllable characteristic feature sizes and periodicity are of considerable interest in a wide range of fields, with various possible applications ranging from biomedical to nanoelectronic devices. Block-copolymer (BC)-based lithography is a powerful tool for the fabrication of uniform, densely spaced nanometer-scale features over large areas. Following this bottom-up approach, nanoporous polymeric films can be deposited on any type of substrate. The nanoporous periodic template can be transferred to the underlying substrate by dry anisotropic etching. Nevertheless the physical sizes of the polymeric mask represent an important limitation in the implementation of suitable lithographic protocols based on BC technology, since the diameter and the center-to-center distance of the pores cannot be varied independently in this class of materials. This problem could be overcome by combining block copolymer technology with atomic layer deposition (ALD): by means of BC-based lithography a nanoporous SiO2 template, with well-reproducible characteristic dimensions, can be fabricated and subsequently used as a backbone for the growth of perfectly conformal thin oxide films by ALD. In this work polystyrene-b-poly(methylmethacrylate) (PS-b-PMMA) BC and reactive ion etching are used to fabricate hexagonally packed 23 nm wide nanopores in a 50 nm thick SiO2 matrix. By ALD deposition of Al2O3 thin films onto the nanoporous SiO2 templates, nanostructured Al2O3 surfaces are obtained. By properly adjusting the thickness of the Al2O3 film the dimension of the pores in the oxide films is progressively reduced, with nanometer precision, from the original size down to complete filling of the pores, thus providing a simple and fast strategy for the fabrication of nanoporous Al2O3 surfaces with well-controllable feature size.     

Patterned ion beam implantation of Co ions into a SiO2 thin film via ordered nanoporous alumina masks

Spatially patterned ion beam implantation of 190 keV Co(+) ions into a SiO(2) thin film on a Si substrate has been achieved by using nanoporous anodic aluminum oxide with a pore diameter of 125 nm as a mask. The successful synthesis of periodic embedded Co regions using pattern transfer is demonstrated for the first time using cross-sectional (scanning) transmission electron microscopy (TEM) in combination with analytical TEM. Implanted Co regions are found at the correct relative lateral periodicity given by the mask and at a depth of about 120 nm.     

Ordered mesoporous silicon through magnesium reduction of polymer templated silica thin films

This paper describes the process of making ordered mesoporous silicon (Si) thin films. The process begins with mesoporous silica (SiO 2) thin films that are produced via evaporation induced self-assembly (EISA) using sol-gel silica precursors with a diblock copolymer template. This results in a film with a cubic lattice of 15 nm diameter pores and 10 nm thick walls. The silicon is produced through reduction of the silica thin films in a magnesium (Mg) vapor at 675 degrees C. Magnesium reduction preserves the ordered pore-solid architecture but replaces the dense silica walls with 10-17 nm silicon crystallites. The resulting porous silicon films are characterized by a combination of low and high angle X-ray diffraction, combined with direct SEM imaging. The result is a straightforward route to the production of ordered nanoporous silicon.     

溶胶-凝胶法制备有机硅/SiO2杂化涂料的稳定性

以正硅酸乙酯(TEOS)、二乙氧基二甲基硅烷(DDS)、有机硅烷偶联剂(MPTMS和VTMS)为原料,采用sol-gel法制备了可UV固化的有机硅/SiO2杂化涂料,并考察了原料配比对杂化涂料稳定性的影响。结果表明:DDS-MPTMS/SiO2比DDS-VTMS/SiO2稳定性更好;乙醇用量增加有利于提高储存稳定性;随着陈化时间延长,杂化涂料粒径变大,分布变宽,漆膜透光率下降。当各组分的摩尔比为nDDS/nTEOS=2/3,nMPTMS/nTEOS=1/3,nHCl/nSi-O=0.006,nEtOH/nSi-O=1,nH2O/nSi-O=0.6时,杂化涂料稳定性最佳。在此条件下制备的杂化涂料平均粒径3.6 nm,凝胶时间大于300 d,经UV固化后漆膜的性能最好。     

交流量热法测量SiO2薄膜的热扩散率

介绍了交流量热法测量薄膜热扩散率的原理和系统组建，用脉宽为纳秒级的超短激光脉冲作为热源，测量了Si衬底上厚度为100nm和500nm的SiO2薄膜水平方向上的热扩散率，实验结果表明该结构的热扩散率比SiO2体材料的要小，并且随着SiO2层厚度的减小，热扩散率也减少。