Surface modification of PTFE/SiO2 composite films through the deposition of polydopamine (PDA) and the modified adhesive properties.

Polytetrafluoroethylene (PTFE) and its composite films are difficult to bond with other materials due to the molecular chain structure of PTFE, which limits the application in the electronic fields. In this work, surface modification of PTFE/SiO2 composite films are realized through the polydopamine (PDA) deposition. The chemical and morphological results exhibit that PDA is successfully deposited on the surface of the PTFE/SiO2 films. The deposition of PDA changes the polarity and wettability of PTFE/SiO2 composite films. Thus, a significant development in the adhesive performance is obtained, and the peel strength increases from 0.34 to 0.42 N/mm. Moreover, the dielectric property and mechanical performance of the films are maintained. After immersed in 3.0 g/L DAH solution for 24 h, the dielectric constant of the composite films is still as low as 2.44 (10 GHz), and the dielectric loss decreases from 0.002 to 0.00035 (10 GHz). The tensile strength and elongation at break are barely reduced. Therefore, the surface deposition of PDA is considered as a profound modification for the PTFE/SiO2 films in the electronic industry. [ABSTRACT FROM AUTHOR]