Improvement of adhesion between liquid crystalline polyester films by plasma treatment

Yasuhiro Kurihara, Hiroyuki Ohata, Masahiko Kawaguchi, Shinichi Yamazaki, Kunio Kimura

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Surface modification of thermotropic liquid crystalline aromatic polyester (LCP) films was carried out by low-pressure plasma treatment to improve the initial adhesion as well as the long-term adhesion reliability, a measure of durability between the LCP films used as substrates for printed circuit boards. Plasma irradiation was carried out in various plasma gases with different plasma modes such as reactive-ion-etching, and direct-plasma (DP) with pressures ranging from 6.7 Pa to 26.6 Pa. The introduction of polar groups on the film surface such as phenolic hydroxyl groups and carboxyl groups enhanced the initial adhesion by increased chemical interaction. However, if the concentration of polar groups became too high, the longterm adhesion reliability estimated by the pressure cooker test was degraded due to the acceleration of the penetration of water molecules into the interface. A large surface roughness was also effective in preventing the decrease in the long-term adhesion reliability. However, too much increase in surface roughness decreases the long-term adhesion reliability. The DP-treatment in the O2 atmosphere at a gas pressure of 6.7 Pa was found to be the best plasma condition for both the initial adhesion as well as the long-term adhesion reliability between the LCP films.

Original languageEnglish
Pages (from-to)1985-2002
Number of pages18
JournalJournal of Adhesion Science and Technology
Volume22
Issue number16
DOIs
Publication statusPublished - Oct 1 2008

Fingerprint

Polyesters
polyesters
adhesion
Adhesion
Crystalline materials
Plasmas
Liquids
liquids
Pressure
Plasma Gases
surface roughness
Surface roughness
Atmosphere
Hydroxyl Radical
Reactive ion etching
printed circuits
carboxyl group
circuit boards
Gases
durability

Keywords

  • Adhesion
  • Cold plasma
  • Liquid-crystalline polymers
  • Printed circuit board
  • Surface modification

ASJC Scopus subject areas

  • Mechanics of Materials
  • Surfaces, Coatings and Films
  • Materials Chemistry
  • Chemistry(all)
  • Surfaces and Interfaces

Cite this

Improvement of adhesion between liquid crystalline polyester films by plasma treatment. / Kurihara, Yasuhiro; Ohata, Hiroyuki; Kawaguchi, Masahiko; Yamazaki, Shinichi; Kimura, Kunio.

In: Journal of Adhesion Science and Technology, Vol. 22, No. 16, 01.10.2008, p. 1985-2002.

Research output: Contribution to journalArticle

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