Scholarlink

<p>A novel ester-containing dianhydride, 9,9-bis[4-(3,4-dicarboxybenzoyloxy)phenyl]fluorene (BAPFTA), featuring bulky biphenylfluorene side groups, was designed to enhance the dielectric properties of polyimides. Two corresponding polyimides were synthesized via one-step high-temperature polymerization of BAPFTA with two trifluoromethyl-containing diamines: 2,2’-Bis(trifluoromethyl)benzidine (TFDB) and 9,9-Bis(4-(4-amino-2-(trifluoromethyl)phenoxy)-3-(trifluoromethyl)phenyl)fluorene (BAFPF). Structural analyses revealed that the trifluoromethyl groups induce steric hindrance, which increases interchain distance and weakens intermolecular interactions. Concurrently, the synergistic electron-withdrawing effect of the adjacent -CF<sub>3</sub> groups and the ester oxygen atoms in BAPFTA synergistically modulates the electron distribution, effectively reducing the electron-accepting character of the BAPFTA unit, significantly reducing the polarity of the imide ring and the overall molecular dipole moments. The resulting polyimides exhibit outstanding dielectric performance (2.60 at 10&#xa0;GHz), high optical transparency (&gt; 89% at 450&#xa0;nm), and improved solubility. However, their reduced chain packing density compromises thermal and mechanical properties, as reflected in a glass transition temperature of 309&#xa0;°C, a coefficient of thermal expansion of 42 ppm/K, and a tensile strength of approximately 230&#xa0;MPa. This work elucidates the synergistic role of biphenylfluorene and trifluoromethyl groups in tailoring polyimide properties, offering new insights for the development of high-performance dielectric and optical materials.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Synergistic design of ester- and fluorene-based polyimides for low-κ and high-transparency applications

  • 期刊论文

  • 发表日期：

    2026年4月20日

查看全文
  • Wei Yang,
  • Jun Peng,
  • Liming Wang,
  • Na Ji,
  • Anmin Huang,
  • Yuhan Liu,
  • Jin Wang,
  • Jun Yang,
  • Haiyang Yang

摘要

A novel ester-containing dianhydride, 9,9-bis[4-(3,4-dicarboxybenzoyloxy)phenyl]fluorene (BAPFTA), featuring bulky biphenylfluorene side groups, was designed to enhance the dielectric properties of polyimides. Two corresponding polyimides were synthesized via one-step high-temperature polymerization of BAPFTA with two trifluoromethyl-containing diamines: 2,2’-Bis(trifluoromethyl)benzidine (TFDB) and 9,9-Bis(4-(4-amino-2-(trifluoromethyl)phenoxy)-3-(trifluoromethyl)phenyl)fluorene (BAFPF). Structural analyses revealed that the trifluoromethyl groups induce steric hindrance, which increases interchain distance and weakens intermolecular interactions. Concurrently, the synergistic electron-withdrawing effect of the adjacent -CF3 groups and the ester oxygen atoms in BAPFTA synergistically modulates the electron distribution, effectively reducing the electron-accepting character of the BAPFTA unit, significantly reducing the polarity of the imide ring and the overall molecular dipole moments. The resulting polyimides exhibit outstanding dielectric performance (2.60 at 10 GHz), high optical transparency (> 89% at 450 nm), and improved solubility. However, their reduced chain packing density compromises thermal and mechanical properties, as reflected in a glass transition temperature of 309 °C, a coefficient of thermal expansion of 42 ppm/K, and a tensile strength of approximately 230 MPa. This work elucidates the synergistic role of biphenylfluorene and trifluoromethyl groups in tailoring polyimide properties, offering new insights for the development of high-performance dielectric and optical materials.

Graphical Abstract