Formulators use particles to enhance the functionality of existing polymer matrices used in adhesive and sealant products. Fumed silica is commonly used as a rheology control additive to provide sag resistance, prevent filler settling, and shear thinning viscosity. The generic term "fumed silica" defines a range of products with different surface chemistry-from hydrophilic to hydrophobic. These products have different compatibility with polymer systems, allowing formulators to fine-tune rheological properties.

By controlling particle-to-particle interactions and particle-to-matrix interface adhesion, at the same time, formulators can enhance the viscoelastic response of coatings or the material properties of curing systems. This interaction provides a way to tightly bond the added hard materials, which can extend the path of fracture and dissipate energy at the interface junction1. These properties can enhance coatings and solids.

In addition to documented benefits in rheology control, fumed silica can also enhance the strength of cured adhesives