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首頁> 外文學位 >Synthesis and characterization of branched and hyperbranched polyetherimides and selective chemistry on the nanolithographically defined silicon(100) surface.
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Synthesis and characterization of branched and hyperbranched polyetherimides and selective chemistry on the nanolithographically defined silicon(100) surface.

機譯：納米光刻定義的硅（100）表面上的支化和超支化聚醚酰亞胺的合成，表征和選擇性化學。

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摘要

Part I of this thesis describes the synthesis and characterization of new hyperbranched derived from AB2 monomers and new branched copolyetherimides derived from AB and AB2 monomers where the extent of branching is stoichiometrically controlled. The materials were synthesized using a highly efficient single step process involving a rapid fluoride catalyzed arylation reaction and allowed access to high molecular weight hyperbranched polyetherimides (HBPEI) with varying degrees of branching ranging from 66% to 42%. Initial studies indicate that blending small amounts of the hyperbranched polyetherimide with linear polyimides effectively modifies the surface properties of linear polyimides. The synthesis and characterization of a series of polyetherimide copolymers covering a wide range of branching contents shows that there exists a small window of AB/AB2 monomer ratios (2.5% to 7.5% AB2 ) which produce copolymer materials having a combination of the mechanical properties seen for the pure linear polyetherimide polymer, but with the lowered solution viscosities typically seen for highly branched materials.; Part II of this thesis describes studies regarding spatially defined, area selective chemistry on the Si(100)-2 x 1 surface. Using the tip of a scanning tunneling microscope (STM) as a localized electron beam, hydrogen can be site selectively removed from the hydrogen-terminated Si(100)-2 x 1 surface in ultrahigh vacuum (UHV) to expose nanometer sized, highly reactive “templates” of clean Si(100). The inherent reactivity differences between the clean and hydrogen terminated surface allow for the selective reaction of organic olefins such as norbornadiene and metal precursors such as titanium tetrachloride were shown to chemoselectively react with the nanopatterned Si(100) surface. Additional studies of the hydrogen-terminated Si(100) exposed to ambient conditions showed that the UHV prepared hydrogen-terminated silicon surface is stable and that using proper precautions the exposed surface can be reintroduced into UHV without damage or contamination. This will provide new opportunities for ex-situ chemical elaboration of chemically modified nanopatterned areas on the silicon surface.
機譯：本文的第一部分描述了AB 2 單體衍生的新超支鏈和AB和AB 2 單體衍生的新的支鏈共聚醚酰亞胺的合成和表征，其中支化程度是化學計量的受控。使用高效的單步工藝合成材料，該工藝涉及快速的氟化物催化的芳基化反應，并允許使用支化度范圍為66％至42％的高分子量超支化聚醚酰亞胺（HBPEI）。初步研究表明，將少量超支化聚醚酰亞胺與線性聚酰亞胺共混可有效修飾線性聚酰亞胺的表面性能。一系列涵蓋廣泛支化含量的聚醚酰亞胺共聚物的合成和表征表明，存在一個很小的AB / AB 2 單體比率窗口（2.5％至7.5％AB 2 < ； /）生產出共聚物材料，該共聚物材料具有純線性聚醚酰亞胺聚合物所見的機械性能的組合，但具有高支化材料通常所見的較低的溶液粘度。本論文的第二部分描述了關于在Si（100）-2 x 1表面上空間定義的區(qū)域選擇性化學的研究。使用掃描隧道顯微鏡（STM）的尖端作為局部電子束，可以在超高真空（UHV）中從氫封端的Si（100）-2 x 1表面選擇性地除去氫，從而暴露出納米級的高反應活性干凈的Si（100）的“模板”。清潔的表面和氫終止的表面之間固有的反應性差異使得有機烯烴（如降冰片二烯）與金屬前體（如四氯化鈦）發(fā)生選擇性反應，這表明它們與納米圖案化的Si（100）表面發(fā)生化學選擇性反應。對暴露于環(huán)境條件下的氫封端的Si（100）的其他研究表明，特高壓制備的氫封端的硅表面是穩(wěn)定的，并且通過采取適當的預防措施，可以將裸露的表面重新引入特高壓中而不會造成損壞或污染。這將為硅表面化學修飾的納米圖案區(qū)域的非原位化學修飾提供新的機會。

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  • 作者

    Thompson, David Scott.;

  • 作者單位

    University of Illinois at Urbana-Champaign.;

  • 授予單位 University of Illinois at Urbana-Champaign.;
  • 學科 Chemistry Organic.; Chemistry Polymer.; Engineering Materials Science.
  • 學位 Ph.D.
  • 年度 2000
  • 頁碼 168 p.
  • 總頁數 168
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 有機化學;高分子化學（高聚物）;工程材料學;
  • 關鍵詞

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