Buy good quality Hydrophobic Fumed Silica 200 to 300 m2/g grade high Specific Surface Area at Wedge India. Hydrophobic fumed silica is a type of fumed silica that has been surface-treated to make it water-repellent (hydrophobic). This modification involves treating the silica particles with hydrophobic chemicals, such as organosilanes or siloxanes, which attach to the surface of the silica and create a water-repellent layer.
 
Properties of Hydrophobic Fumed Silica
1. Water Repellency:
• The primary characteristic of hydrophobic fumed silica is its resistance to water absorption. Unlike hydrophilic fumed silica, which readily absorbs moisture, hydrophobic fumed silica repels water, making it suitable for use in moisture-sensitive applications.
2. Low Surface Energy:
• The surface treatment lowers the surface energy of the silica particles, enhancing their dispersibility in non-polar and less polar systems, such as oils and organic solvents.
3. Rheology Control:
• Hydrophobic fumed silica provides thixotropic properties, helping to control the flow and viscosity of liquid systems, especially in formulations where water interaction needs to be minimized.
4. Anti-Caking and Flow Improvement:
• It is often used in powders and granulated products to prevent clumping and improve flowability by repelling moisture.
5. Improved Mechanical Properties:
• When used as a reinforcing agent, hydrophobic fumed silica enhances the mechanical properties of materials like silicone rubber, making them more resistant to wear, tear, and environmental degradation.
 
Applications of Hydrophobic Fumed Silica
1. Coatings and Paints:
• Hydrophobic fumed silica is used in coatings and paints to improve water resistance, control rheology, and enhance scratch and abrasion resistance. It is especially valuable in exterior coatings, where exposure to moisture is a concern.
2. Adhesives and Sealants:
• It is used to modify the viscosity and improve the performance of adhesives and sealants, particularly in applications where moisture resistance is critical, such as in construction or automotive industries.
3. Cosmetics and Personal Care Products:
• In cosmetics, hydrophobic fumed silica is used to improve the texture and stability of products, such as creams and lotions, and to enhance the spreadability of makeup powders.
4. Pharmaceuticals:
• It can be used in pharmaceutical formulations as an anti-caking agent to improve the flow of powders and granules, ensuring uniform dosage and preventing clumping.
5. Plastics and Elastomers:
• In silicone rubber and other elastomers, hydrophobic fumed silica acts as a reinforcing agent, improving the material’s strength, elasticity, and resistance to environmental factors.
6. Defoamers:
• Hydrophobic fumed silica is used in defoaming agents to prevent foam formation in industrial processes, particularly in non-aqueous systems.
7. Powder Processing:
• It is commonly used to improve the flow properties of hygroscopic powders and granules, reducing the tendency of these materials to cake or agglomerate due to moisture.
 
Advantages of Hydrophobic Fumed Silica
• Enhanced Moisture Resistance:
• The hydrophobic treatment makes it ideal for use in environments where moisture resistance is required, extending the life and performance of the products in which it is used.
• Versatility in Non-Polar Systems:
• It is highly compatible with non-polar and organic systems, making it suitable for a wide range of applications, including those in the cosmetics and personal care industries.
• Long-Term Stability:
• Hydrophobic fumed silica offers long-term stability in formulations, reducing the risk of degradation over time due to moisture exposure.
 
Considerations
• Cost:
• Hydrophobic fumed silica is generally more expensive than hydrophilic fumed silica due to the additional surface treatment process.
• Dispersion:
• Proper dispersion techniques are necessary to achieve optimal performance in formulations, especially in systems with varying polarities.
 
Hydrophobic fumed silica is a versatile material that provides significant benefits in moisture-sensitive and non-polar applications, making it a crucial component in many industrial, cosmetic, and pharmaceutical formulations.