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Mechanical and dielectric properties of self-assembled, periodic nanoporous silica and organosilica materials.

机译：自组装的周期性纳米多孔二氧化硅和有机二氧化硅材料的机械和介电性能。

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摘要

In recent years self-assembled, organic supramolecular or colloidal arrays have been used as templates for the design of a wide range of novel nanostructured porous materials, using sol-gel chemistry. Herein, mesoporous silica and organosilica films, and colloidal crystal (opal) films, have been synthesized, and various mechanical and dielectric properties investigated.; A series of spin-coated mesoporous silica films were synthesized using a surfactant template, using evaporation-induced self-assembly (EISA). The porosity was controlled by the surfactant/silica molar ratio, thermally-induced collapse at 300--900°C, and deposition within the channels. The Young's modulus (E) and hardness (H) were measured using nanoindentation, and the results have been compared with conventional models for porous materials. A series of molecular mechanics atomic models of mesoporous silica were used to simulate the elastic and plastic deformation as a function of pore diameter.; Highly-ordered, periodic mesoporous organosilica (PMO) thin films were synthesized from bridged silsesquioxane precursors of the type (EtO) 3SiRSi(OEt)3 (where R is an organic group), and a novel three-ring [(EtO)2Si( CH2)]3 precursor. Detailed structural characterization has been performed using PXRD, SAXS, SEM, and TEM. PMO films may have important applications as low dielectric constant (k) materials in microelectronics. Capacitance measurements showed that k decreased with organic content to ∼1.8. A novel 'self-hydrophobization' behaviour has been demonstrated, using a bridge-terminal transformation of the organic groups at 400--550°C, to lower k and make the films highly resistant to moisture adsorption. A series of novel dendrimer and 'semi-dendrimer' PMO thin films have been synthesized using cationic and block copolymer templates, to further increase the organic content. As a result, the number of organic bridges attached to each Si is increased as a series, from 0 to 4.; Finally, chemical vapour deposition (CVD) was used to sinter silica opal films to systematically control the optical Bragg diffraction and the structural connectivity. SiCl4 and Si(OMe)4 vapour were used to deposit silica layers to grow necks between silica spheres. Nanoindentation was used to measure E and H as a function of the silica deposition.
机译：近年来，自组装的有机超分子或胶体阵列已被用作模板，用于使用溶胶-凝胶化学设计多种新型纳米结构多孔材料。在此，已经合成了介孔二氧化硅和有机二氧化硅膜以及胶体晶体（蛋白石）膜，并且研究了各种机械和介电性能。使用表面活性剂模板，使用蒸发诱导自组装（EISA）合成了一系列旋涂介孔二氧化硅薄膜。孔隙率由表面活性剂/二氧化硅的摩尔比，300--900°C的热诱导塌陷以及通道内的沉积来控制。使用纳米压痕法测量杨氏模量（E）和硬度（H），并将结果与​​多孔材料的常规模型进行比较。使用一系列的介孔二氧化硅分子力学原子模型来模拟弹性和塑性变形与孔径的关系。由（EtO）3SiRSi（OEt）3（其中R为有机基团）类型和新型三环[（EtO）2Si（）的桥接倍半硅氧烷前体合成了高度有序的周期性介孔有机硅（PMO）薄膜CH2）] 3前体。使用PXRD，SAXS，SEM和TEM进行了详细的结构表征。 PMO膜作为微电子中的低介电常数（k）材料可能具有重要的应用。电容测量结果表明，随着有机物含量的增加，k值降低至约1.8。通过在400--550°C下使用有机基团的桥末端转化来降低k并使膜对水分的吸收具有高度抵抗力，已证明了一种新颖的``自疏水化''行为。使用阳离子和嵌段共聚物模板合成了一系列新颖的树状聚合物和“半树状” PMO薄膜，以进一步提高有机含量。结果，附着在每个Si上的有机桥的数量从0增加到4。最后，化学气相沉积（CVD）用于烧结二氧化硅蛋白石膜，以系统地控制光学布拉格衍射和结构连接性。使用SiCl4和Si（OMe）4蒸气沉积二氧化硅层，以在二氧化硅球之间生长颈。纳米压痕用于测量E和H，其是二氧化硅沉积的函数。

著录项

  • 作者

    Hatton, Benjamin D.;

  • 作者单位

    University of Toronto (Canada).;

  • 授予单位 University of Toronto (Canada).;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 176 p.
  • 总页数 176
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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