As a nanoscale inorganic material, fumed silica has sparked a "waterproofing revolution" in the high-end industrial field due to its unique hydrophobic modification technology. Its native particle size is only 7-80 nanometers, with a specific surface area of over 100 ㎡/g, and the surface is covered with silanol (- OH) groups, naturally possessing hydrophilicity. Through chemical bonding reactions with silane compounds such as hexamethyldisilazane (HMDS), hydroxyl groups are replaced by hydrophobic methyl (- CH3) or siloxane groups, forming a stable three-dimensional hydrophobic network structure.


Taking the HB-620 model produced by Huifu Nano as an example, this product undergoes deep HMDS treatment to convert the hydrophilic HL-200 into a hydrophobic one, increasing the contact angle from 20 ° to over 150 °. It can prevent structuring in hot vulcanized silicone rubber and achieve a dual effect of anti sagging and thickening in coatings. HDK from Wacker Chemie in Germany ®  H20 series adopts chlorosilane modification technology. When 15% is added to the epoxy resin system, the viscosity will only increase by 8%, while the addition of 5% to traditional products will lead to gel of the system.


This modification technology breaks through the limitations of traditional inorganic fillers, allowing the material to maintain high purity (≥ 99.8%) while also possessing the processing characteristics of organic materials. In the sealant of new energy vehicle batteries, hydrophobic gas-phase white carbon black can reduce the water absorption rate from 3% to 0.2%, significantly improving the insulation performance; In the coating of 5G base station antenna cover, its hydrophobic angle maintains above 120 ° for 5 years, far exceeding the 6-month lifespan of ordinary coatings.