With the rapid development of flexible electronics technology, silicone rubber has become an important basic material for flexible electronic devices due to its excellent flexibility, chemical stability, and biocompatibility. By regulating the electrical properties of silicone rubber, functional materials with conductive, insulating, or dielectric characteristics have been developed, providing innovative solutions for fields such as flexible sensors and wearable devices.
In the preparation of conductive silicone rubber, adding conductive fillers is the most direct method. Carbon-based fillers (such as graphene and carbon nanotubes) and metal fillers (such as silver nanowires and copper powder) are widely used. For example, when graphene is uniformly dispersed in a silicone rubber matrix, its high conductivity and large specific surface area can form an effective conductive network. When the graphene content reaches the percolation threshold (approximately 0.5-2 wt%), the electrical conductivity of the silicone rubber can jump from an insulator (10⁻¹⁵ S/cm) to a semiconductor or conductor level (10⁻³ - 10² S/cm). This conductive silicone rubber can be used to prepare flexible strain sensors, where the resistance change shows a linear relationship with strain. The strain sensitivity coefficient (GF value) can reach 5-10, enabling the detection of subtle deformations such as human joint movements and breathing.
Insulating silicone rubber plays a crucial role in high-voltage power transmission, electronic packaging, and other fields. By optimizing the molecular structure of silicone rubber and selecting appropriate fillers, its insulating performance can be significantly improved. For example, using high-purity methyl vinyl silicone rubber as the matrix and adding nano-alumina (Al₂O₃) fillers, a dense insulating layer is formed through the high insulation of alumina and its interfacial interaction with silicone rubber. Experiments show that silicone rubber filled with 20 wt% nano-Al₂O₃ has a volume resistivity exceeding 10¹⁶ Ω·cm and a breakdown field strength of over 25 kV/mm, making it suitable for insulating seals in high-voltage cable terminations.
Dielectric silicone rubber shows great potential in energy storage and conversion fields. By regulating the dielectric constant and loss factor of silicone rubber, high-performance dielectric materials can be prepared. For example, introducing barium titanate (BaTiO₃) nanoparticles into silicone rubber leverages their ferroelectric properties to increase the dielectric constant. When the BaTiO₃ content is 30 vol%, the dielectric constant of the silicone rubber can reach 20-30 while maintaining a low dielectric loss (tanδ < 0.05), making it suitable for dielectric layers in flexible supercapacitors. Additionally, introducing polar groups (such as cyano groups) through molecular design can further enhance the dielectric properties of silicone rubber.
Fluoro Silicone Gum
