Fluorographene with High Fluorine/Carbon Ratio: A Nanofiller for Preparing Low-κ Polyimide Hybrid Films

Abstract

Sufficient amounts of fluorographene sheets with different sheet-size and fluorine/carbon ratio were synthesized for preparing of fluorographene/polyimide hybrids in order to explore the effect of fluorographene on the dielectric properties of hybrid materials. It is found that the fluorine/carbon ratio, width of band gap, and sheet-size of fluorographene play the important roles in determining the final dielectric properties of hybrids. The fluorographene with high fluorine/carbon ratio (F/C ≈ 1) presents broaden band gap, enhanced hydrophobicity, good dispersity and thermal stability, etc. Even at a very low filling, only 1 wt %, its polyimide hybrids exhibited drastically reduced dielectric constants as low as 2.1 without sacrificing thermal stability, improved mechanical properties obviously and decreased water absorption by about 120% to 1.0 wt %. This provides a novel route for improving the dielectric properties of materials and a new thought to carry out the application of fluorographene as an advanced material.

Polyimide nanohybrid films with electrochemically functionalized graphene

“…The weight loss at up to 240 °C was 0.7 wt%. The other weight loss at 500–700 °C is due to the destruction of C–F bonds, but no change in mass was observed for graphite. The weight loss at up to 700 °C was 5.5 wt%.…”

Dielectric properties of photocrosslinkable polyimide/functional graphene oxide composites

“…When FGO disperses homogeneously in PI matrix, a large amount of heterojunction takes shape. The strong self-polarization-induced electrons due to the heterostructure will reduce the response to the external electric field, and lead to a significant decrease of k [13]. However, the k value may increase due to the interfacial polarization originated from the poor dispersion of FGO in matrix.…”

Nonmainstream Out‐Plane Fluoro‐ and Amino‐Cofunctionalized Graphene for a Striking Electrocatalyst: Programming Substitutive/Reductive Defluorination toward Graphite Fluoride

“…Consequently, halogen heteroatoms must stick out of graphene basal plane when they are covalently bound to graphene sheets . For instance, when graphene is fluorinated, F atoms of the as‐prepared product (i.e., fluorinated graphene, also called fluorographene, graphene fluoride) are sp 3 ‐hybridized and stand on double sides of the graphene surface . Using halogen functionalization, it is well established that the bandgap of graphene (intrinsically gapless) is finely engineered by regulating halogenated extent, rendering graphene to be multifunctional materials spanning from metal‐like conductor to silicon‐like semiconductor, even to Teflon‐like insulator .…”