Structuring multiscale porous architecture in polyether sulfone films for ultra-low dielectric constant

Ultra-low dielectric constant materials possess a broad prospect for application in microelectronics devices and communication systems. The most efficient method for fabricating low dielectric constant materials is the incorporation of porous structure into the materials. However, it is vital and remains a great challenge to pre-cisely control the size, distribution and number of pore structures for porous films to maintain comprehensive properties. Herein, a series of novel multiscale porous polyether sulfone-polyhedral oligomeric silsesquioxanes (PES-POSS) films with ultra-low dielectric constants were fabricated by solvent phase inversion approach. Specifically, the prepared PES-60%POSS (P60) films demonstrate an ultra-low dielectric constant and dielectric loss of 1.31 and 0.00078 at 1 kHz. Multiscale pores ranging from micron to nano and low molar polarization of POSS nano-hybrids are the key to its low dielectric properties of the resultant materials. Moreover, the interface enhancement by the covalent bonding of POSS and PES skeleton ensures that the composite hybrid films maintain reliable thermal and mechanical properties while possess low dielectric properties. The measurements of contact angle and water absorption show the PES-POSS films have favorable water resistance. That is bene-ficial to the dielectric stability and service life of films. In addition, the average transmissivity coefficient of P60 films in X-band is high up to 95.6%, which show the potential of application as an excellent wave transmitting material.