A new glass-forming molecule having a fluorene skeleton: synthesis and conversion to the polymer with a low dielectric constant, high hydrophobicity and thermostability

Abstract

A new glass-forming molecule having a fluorene skeleton and thermally cross-linkable trifluorovinyl-ether side chains is reported here. This molecule shows a glass transition temperature (T_g) of 72 °C, and has good film-forming ability. When heated to high temperature (>150 °C), the film changes to a cross-linked network, exhibiting a low k value (<2.32, at 30 MHz) as well as good hydrophobicity (water contact angle >103°) and flexibility. TGA data show that the cross-linked network has a 5 wt% loss at a temperature of 431 °C and a residue of 59% at 1000 °C under N₂. Furthermore, the crosslinked film exhibits high hardness and Young's modulus. These results imply that the new molecular glass has potential application in the microelectronic industry.