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The rheology and spin coating of polyimide solutions
Author(s) -
Jenekhe Samson A.
Publication year - 1983
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760231508
Subject(s) - polyimide , rheology , viscoelasticity , newtonian fluid , materials science , spin coating , context (archaeology) , deborah number , viscosity , shear rate , coating , thermodynamics , polymer chemistry , composite material , physics , layer (electronics) , biology , paleontology
The rheological properties of five types of concentrated polyamic acid and polyimide solutions are characterized by non‐Newtonian shear viscosity η( \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \dot \gamma} $\end{document} ) and primary normal stress coefficient Ψ 1 ( \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \dot \gamma} $\end{document} ) measurements over a wide range of shear rates. Onset of non‐Newtonian flow of the polyamic acid solutions was observed in the shear rate range 30 to 400 s −1 and of the fully imidized polyimide solution at below 3 × 10 −2 s −1 . Significant viscoelastic properties exemplified by normal stresses were observed in all the solutions. The solution rheology results are discussed in the context of spin coating for the deposition of thin films. The relative magnitude of effects of non‐Newtonian flow on the dynamics of spin coating is assessed with a Deborah number characteristic of the flow.