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首页> 外文学位 >Nanostructured L3-templated silica thin films for enhancing the sensitivity of resonators.
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Nanostructured L3-templated silica thin films for enhancing the sensitivity of resonators.

机译：纳米结构的L3模板二氧化硅薄膜，用于增强谐振器的灵敏度。

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摘要

Nanostructured materials have become prevalent in a large number of applications, such as molecular sieves, high surface area catalysts and nano-composites. The nanostructure of a material used needs to be well characterized to facilitate its use in these applications. In this thesis we describe the synthesis and characterization of thin films of one such nanostructured material: L3-templated silica for its use in improving the sensitivity of gravimetric piezoelectric resonators (e.g. quartz crystals).;We detail the characterization of L3-templated silica films, beginning with a study of the structure of the dry surfactant (CpCl) and ending with a description of the nanostructured silica thin films synthesized from the surfactant. Grazing incidence small angle x-ray scattering (GISAXS) and water vapor accumulation isotherms are used to characterize the film structure. Water vapor accumulation allowed us to quantify the structural features of the material such as specific surface area and the channel opening. By varying the conditions under which thin films of the material are synthesized we are able to tune the nanostructure within the films to have structural properties desirable for sensing applications.;Following the characterization of the L3-templated silica films, we used quartz crystals as the resonators and coated them with three different thin films (< 1 mum thick) of porous silica: silica xerogel, silica templated by an ordered hexagonal phase of surfactant micelles, and silica templated by an isotropic L3 phase surfactant micellar system. We compared the sensitivity of coated resonators to the presence of water vapor. The crystals coated with hexagonal phase-templated silica displayed a sensitivity enhancement up to 100-fold compared to an uncoated quartz crystal in the low pressure regime. L3 phase-templated silica displayed the highest sensitivity (>1000 fold) in the high partial pressure regimes, which is attributed to an optimal combination of high surface area, channel size uniformity and channel accessibility. This approach to increasing resonator sensitivity is not limited to the detection of water vapor; it should be directly applicable to the sensing of other gasses. Some of the ideas presented can also be extended to improve the performance of sensors used in liquid environments.
机译：纳米结构材料已经在许多应用中变得普遍，例如分子筛，高表面积催化剂和纳米复合材料。需要很好地表征所用材料的纳米结构，以促进其在这些应用中的使用。在这篇论文中，我们描述了一种这样的纳米结构材料的薄膜的合成和表征：L3模板二氧化硅，用于提高重力压电谐振器（例如石英晶体）的灵敏度。;我们详细介绍了L3模板二氧化硅薄膜的表征。首先，对干燥表面活性剂（CpCl）的结构进行研究，最后对由该表面活性剂合成的纳米结构二氧化硅薄膜进行描述。掠入射小角度X射线散射（GISAXS）和水蒸气累积等温线用于表征薄膜结构。水蒸气的积累使我们能够量化材料的结构特征，例如比表面积和通道开口。通过改变合成材料薄膜的条件，我们能够调整薄膜内的纳米结构，使其具有感测应用所需的结构性能。根据L3模板二氧化硅膜的特性，我们使用石英晶体作为共振器，并用三种不同的多孔二氧化硅薄膜（厚度小于1微米）涂覆它们：二氧化硅干凝胶，通过表面活性剂胶束的有序六方相模板化的二氧化硅和通过各向同性L3相表面活性剂胶束体系模板化的二氧化硅。我们将涂层谐振器的灵敏度与水蒸气的存在进行了比较。与在低压状态下未涂覆的石英晶体相比，涂覆有六方相模板二氧化硅的晶体显示出高达100倍的灵敏度增强。 L3相模板二氧化硅在高分压状态下显示出最高的灵敏度（> 1000倍），这归因于高表面积，通道尺寸均匀性和通道可及性的最佳组合。这种提高谐振器灵敏度的方法不仅限于检测水蒸气；它还可以检测水蒸气。它应直接适用于其他气体的感测。提出的一些想法也可以扩展以改善液体环境中使用的传感器的性能。

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  • 作者

    Bhansali, Shilpa Harendra.;

  • 作者单位

    Princeton University.;

  • 授予单位 Princeton University.;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 168 p.
  • 总页数 168
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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