Dielectric properties of oxydianiline-based polyimide thin films according to the water uptake

Choonkeun Lee, Yonggun Shul, Haksoo Han

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

For polyimide thin films, the dielectric properties were investigated with the capacitance and optical methods. The dielectric constants of the 4,4′-oxydianiline (ODA)-based polyimide thin films varied from 2.49 to 3.10 and were in the following decreasing order: 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)-ODA > 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA)-ODA > 4,4′-hexafluoroisopropylidene diphthalic dianhydride (6FDA)-ODA. According to the absorption of water, the diffusion coefficients in the films varied from 4.8 × 10-10 to 7.2 × 10-10 cm2/s and were in the following increasing order: BPDA-ODA < PMDA-ODA < 6FDA-ODA. The dielectric constants and diffusion coefficients of the polyimides were affected by the morphological structures, including the molecular packing order. However, because of the water uptake, the changes in the dielectric constants in the polyimide thin films varied from 0.49 to 1.01 and were in the following increasing order: BPDA-ODA < 6FDA-ODA < PMDA-ODA. Surprisingly, 6FDA-ODA with bulky hexafluoroisopropylidene groups showed less of a change in its dielectric constant than PMDA-ODA. The total water uptake for the polyimide thin films varied from 1.43 to 3.19 wt % and was in the following increasing order: BPDA-ODA < 6FDA-ODA < PMDA-ODA. This means that the changes in the dielectric constants in the polyimide thin films were significantly related to the morphological structure and hydrophobicity of hexafluoroisopropylidene groups. Therefore, the morphological structure and chemical affinity in the polyimide thin films were important factors in controlling the dielectric properties.

Original languageEnglish
Pages (from-to)2190-2198
Number of pages9
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume40
Issue number19
DOIs
Publication statusPublished - 2002 Oct 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Dielectric properties of oxydianiline-based polyimide thin films according to the water uptake'. Together they form a unique fingerprint.

  • Cite this