Novel low-dielectric-constant fluorine-functionalized polysulfone with outstanding comprehensive properties

In this work, a series of fluorine-functionalized polysulfone (F-PSU) copolymers with intrinsic low dielectric constants (low epsilon) are reported, which are derived from the polycondensation reaction of 4,4 '-dichlorophenyl sulfone with bisphenol A and bisphenol F (BPF) compounds. The resulting F-PSU copolymers show high glass transition temperatures (T-g) varying from 187 to 201 degrees C and are thermally stable up to 500 degrees C under an N-2 atmosphere. The introduction of BPF units into the PSU copolymers imparts enhanced hydrophobic properties to the F-PSU films with increased water contact angle values from 66.2 degrees to 93.7 degrees. Moreover, the dielectric constant and dielectric loss of the F-PSU (sample V) film are as low as 2.2 and 0.003 at 1 kHz, respectively. Interestingly, the dielectric properties are relatively stable to near the glass transition temperature, which is because of the existence of BPF structures in the molecular backbone. Furthermore, the F-PSU copolymers are soluble in common solvents and can be readily fabricated into flexible transparent films by the spin casting method. (c) 2020 Society of Chemical Industry