Influence of atmospheric fluorine plasma treatment on thermal and dielectric properties of polyimide film

Research Advances of Porous Polyimide-Based Composites with Low Dielectric Constant

With the burgeoning of the microelectronics industry, in order to improve the transmission speed between chips in large-scale integrated circuits to meet the demands of high integration, it is necessary for interlayer insulation materials to possess a lower dielectric constant (k). Polyimide (PI) has been widely used as interlayer insulation materials for large-scale integrated circuits, and the exploration on reducing their dielectric constant has attracted extensive attention in recent years. In this work, porous PI-based composites with a low dielectric constant are mainly reviewed. The application of porous SiO2, graphene derivatives, polyoxometalates, polyhedral oligomeric silsesquioxane and hyperbranched polysiloxane in reducing the dielectric constant of PI is emphatically introduced. The key technical problems and challenges in the current research of porous polyimide materials are summarized, and the development prospect of low k polyimide is also expounded.

Superhydrophobic Polytetrafluoroethylene/Heat-Shrinkable Polyvinyl Chloride Composite Film with Super Anti-Icing Property

Wind power generation is an environmentally friendly way to produce electricity, but wind turbine blades that are prone to freeze in winter will reduce the efficiency of the generator. Therefore, the preparation of anti-icing blades is important and essential. Herein, anti-icing polytetrafluoroethylene (PTFE)/heat-shrinkable polyvinyl chloride (HSPVC) composite film was prepared by depositing a PTFE coating on the surface of HSPVC film via vacuum thermal evaporation. HSPVC films were pretreated respectively by argon and carbon tetrafluoride (CF₄) plasma cleaning to introduce new groups and change their surface energy. After that, PTFE coating with a thickness of about 4 μm was deposited on the surface of HSPVC, obtaining a superhydrophobic surface with an apparent water contact angle of 150°. The results demonstrated that the breaking strength of the PTFE/HSPVC composite film using CF₄ plasma pretreatment decreased by only 3.47% after exposing to ultraviolet light with the power of 1000 W for 5 min, suggesting an excellent anti-ultraviolet property. Furthermore, compared with the pristine films, the PTFE/HSPVC composite films exhibited better adhesive strength, super anti-icing property even after 10 icing-deicing cycles, and excellent dynamic anti-icing performance. The PTFE/HSPVC composite film with good adhesive strength, anti-ultraviolet, and anti-icing properties has prospective applications in packaging of wind turbine blades.

The influence of the interface between mica and epoxy matrix on properties of epoxy-based dielectric materials with high thermal conductivity and low dielectric loss

Two strategies, including in situ grafting chemicals and polymer coating micas, were used to improve the interface between mica and epoxy matrix. The epoxy composites prepared by strategy I exhibited better overall performance.