Brian C. Auman

Synthesis of a new fluoroalkylated diamine, 5-[1H,1 H-2-bis(trifluoromethyl)- heptafluoropentyl]-1,3-phenylenediamine, and polyimides prepared therefrom

Abstract The preparation of a new perfluoroalkylated diamine, 5-[1H,1H-2-bis(trifluoromethyl)heptafluoropentyl]-1,3-phenylenediamine, is described. Poly(amic acid)s and polyimides were prepared from this new diamine and polyimides were evaluated as films for electronics applications. The polyimides evaluated were found to yield low dielectric constant and low moisture absorption, but were found to have exceptionally high thermal expansion coefficient. The materials are envisioned to have applications in electronics, where a low and humidity-stable dielectric constant is required.

Reduced residual DC voltages in LCDs by using fluorinated polyimides

— The effect of a fluorinated alignment layer in reducing image retention in liquid-crystal displays has been quantified. In our experiments, image retention is characterized by measuring the residual DC (RDC) value, which for both planar cells and vertical-alignment cells are shown to be very small for a fluorinated alignment layer. The lowered dielectric constant of a fluorinated alignment layer is shown to be correlated with RDC improvement. A result of this work is the demonstration that fluorinated alignment layers have great potential to be used in low-refresh-rate LCDs for reducing power consumption.

41.2: The Use of Fluorinated Alignment Layers to Reduce Image Retention in Liquid Crystal Displays

We find the residual DC value in vertical alignment (VA) cells and planar cells can be reduced with polyimides with low dielectric constant. The RDC value is induced by the ion absorption on the alignment layers. This process is significantly affected by the dielectric properties of the polyimide layer. The low dielectric constant property of polyimides can reduce the ion absorption in the alignment layers, which further reduces the RDC value in both planar cells and VA cells. Additionally, the rubbing effect of the polyimide is also needed to be considered for planar cells.