Diels–Alder polysulfones as dielectric materials: Computational guidance & synthesis

Herein, we describe the synthesis and characterization of polymers formed by the Diels–Alder (DA) reaction between various difurans and divinylsulfone, and evaluate their dielectric properties. These syntheses were planned with computational support a priori in the form of HOMO/LUMO calculations for the dienes and dienophiles, with the calculated ΔE for the DA reactions ranging between 9.33 and 9.42 eV. We describe the structure–property relationship observed when changing an atom in the linking unit between two furan rings (–CH2–, –O-, –S-, –NH–) with respect to the dielectric constant and loss tangent. Dielectric constants for the polymers range between 4.96 and 5.98, with dielectric loss tangents ranging from 0.4 to 0.9% at 1 kHz and room temperature. Bandgaps of the polymers are elucidated with UV/Visible spectroscopy, and range from 2.15 to 2.61 eV. The retro DA onset is determined using three analytical methods: thermogravimetric analysis, dynamic scanning calorimetry, and gas chromatography/mass spectrometry polymer desorption spectroscopy, and is determined to be over 125 °C in all cases.