AEROSIL Fumed Silica Grade Comparison
Jun 24, 2026|
View:2025
Hello, I’m Mina, team leader of the Additives Expert Library at Evergreen Chemicals.
With years of experience in chemical additives and formulation support, I help customers select suitable additives for coatings, adhesives, sealants, polyester resins, vinyl ester systems, epoxy formulations and composites.
AEROSIL® fumed silica is widely used for rheology control, thickening, anti-sagging and anti-settling. While AEROSIL® 200 is a well-known standard grade, different applications may require grades with stronger thickening, lower dust, hydrophobicity or better resin compatibility.
This guide compares 12 commonly requested AEROSIL® grades and explains how to choose the right model for your formulation.
Mina
Additives ExpertWhat Is AEROSIL® Fumed Silica?
AEROSIL® is a fumed silica series widely used as a rheology control additive, thickening agent, anti-settling additive, anti-sagging agent, reinforcing filler and free-flow aid.
In liquid systems such as resins, coatings, adhesives and sealants, fumed silica helps build a three-dimensional network. This network can improve viscosity, prevent filler sedimentation, reduce sagging on vertical surfaces and support better storage stability.
In powder systems, fumed silica can improve flowability and reduce caking. In silicone rubber and elastomer systems, selected grades can also provide reinforcement.
The key selection factors are:
- Hydrophilic or hydrophobic surface
- Specific surface area / BET surface area
- Dispersibility and processing behavior
- Compatibility with resin polarity
- Target effect: thickening, anti-sagging, anti-settling, reinforcement or free-flow
AEROSIL® Fumed Silica Grade Comparison Table
| Product Grade | Surface Type | BET Surface Area | Key Features | Recommended Applications |
|---|---|---|---|---|
| AEROSIL® 200 | Hydrophilic | 175–225 m²/g | Standard universal grade; good dispersibility; balanced rheology control | Coatings, unsaturated polyester resins, vinyl ester resins, gel coats, adhesives, sealants, silicone rubber |
| AEROSIL® 200 F | Hydrophilic | 175–225 m²/g | High-purity hydrophilic grade; suitable where cleaner handling and documentation are required | Powder flow improvement, anti-caking, coatings, adhesives, sealants and selected industrial formulations |
| AEROSIL® 200 V | Hydrophilic, densified | 175–225 m²/g | Reduced dust development; improved incorporation and handling | Coatings, HTV silicone rubber, adhesives, sealants, printing inks, cable compounds |
| AEROSIL® 200 HV | Hydrophilic | 270–330 m²/g | Higher surface area than AEROSIL® 200; stronger rheological effect | High-efficiency thickening, coatings, transparent systems after good dispersion, anti-settling applications |
| AEROSIL® 300 | Hydrophilic | 350–410 m²/g | Very high surface area; high thickening efficiency; high transparency after proper dispersion | High-performance coatings, cable compounds, unsaturated polyester resins, strong anti-sag and anti-settling systems |
| AEROSIL® R 106 | Hydrophobic | 220–280 m²/g | Excellent rheology effect; pseudoplastic flow behavior; recommended for 2K epoxy systems | 2-pack epoxy resins, high-build coatings, anti-sag coatings, silicone rubber, sealants, thermoplastics |
| AEROSIL® R 202 | Hydrophobic | 80–120 m²/g | Very good thickening in polar resin systems; strong thixotropy | Epoxy resins, vinyl ester resins, gel coats, structural adhesives, sealants, cable gels |
| AEROSIL® R 812 | Highly hydrophobic | 230–290 m²/g | High surface area; excellent hydrophobicity; high transparency in suitable systems | High-performance coatings, 2K PU coatings, automotive clear coats, powder coatings, toner and cosmetic systems |
| AEROSIL® R 8200 | Hydrophobic, structure modified | 135–185 m²/g | Low thickening effect; allows higher loading at lower viscosity | Silicone systems, adhesives, sealants, defoamers, toner, scratch and abrasion resistance applications |
| AEROSIL® R 972 | Hydrophobic | 90–130 m²/g | Standard hydrophobic recommendation; easy to disperse; broad compatibility | Coatings, silicone rubber, sealants, adhesives, inks, cable compounds, water-resistant systems |
| AEROSIL® R 974 | Hydrophobic | 150–190 m²/g | Universal hydrophobic grade; good transparency and anti-sag performance | Industrial coatings, coil coatings, automotive coatings, plastic coatings, anti-settling and corrosion-resistant systems |
Hydrophilic vs. Hydrophobic AEROSIL®: Which One Should You Choose?
The first decision is whether the formulation needs a hydrophilic or hydrophobic fumed silica.
Hydrophilic AEROSIL® grades
Hydrophilic grades such as AEROSIL® 200, AEROSIL® 300 and AEROSIL® 380 have surface silanol groups. They are widely used for viscosity adjustment, thixotropy control, anti-settling and anti-sagging in many coating, resin and adhesive systems.
For many general-purpose formulations, AEROSIL® 200 is the starting point. It offers a good balance of thickening performance, dispersibility and cost efficiency.
When stronger thickening is needed, AEROSIL® 300 or AEROSIL® 380 can be considered. The higher the BET surface area, the stronger the interaction between silica particles and the liquid system. This can help improve sag resistance and suspension stability, but it may also increase viscosity and require stronger dispersion conditions
Hydrophobic AEROSIL® grades
Hydrophobic grades such as AEROSIL® R 972, AEROSIL® R 974, AEROSIL® R 202, AEROSIL® R 106, AEROSIL® R 812 and AEROSIL® R 8200 are surface-treated to reduce water affinity and improve compatibility in selected organic systems.
They are especially useful when the formulation requires:
- Better moisture resistance
- Improved compatibility with non-aqueous systems
- Strong thixotropy in epoxy, vinyl ester or polyurethane systems
- Reduced sensitivity to humidity
- Improved anti-settling for heavy fillers
- Better performance in corrosion-resistant coatings
For epoxy, vinyl ester and high-build coating systems, hydrophobic grades often provide more stable rheology than standard hydrophilic grades.
Selection Guide by Application
1. Resin Thickening and Anti-Sag Control
For unsaturated polyester resin, vinyl ester resin and gel coat systems, AEROSIL® 200 is often the standard starting grade. It can help improve viscosity, reduce dripping and improve application control on vertical surfaces.
For stronger anti-sag performance, AEROSIL® 300 or AEROSIL® 380 may be used. These grades provide a higher surface area and stronger rheological effect.
For epoxy and vinyl ester systems where hydrophobicity and stronger thixotropy are required, AEROSIL® R 202 is a strong option.
Recommended grades: AEROSIL® 200, AEROSIL® 300, AEROSIL® 380, AEROSIL® R 202
2. Coatings and Paints
In industrial coatings, fumed silica helps improve anti-settling, anti-sagging and storage stability. AEROSIL® 200 is suitable for many general coating systems, while AEROSIL® 300 and AEROSIL® 380 are used when stronger rheology control is required.
For solventborne, high-build, corrosion-resistant and 2K coating systems, hydrophobic grades such as AEROSIL® R 972, AEROSIL® R 974, AEROSIL® R 106 and AEROSIL® R 812 can be considered.
AEROSIL® R 812 is especially useful when high transparency and strong hydrophobicity are important, such as in automotive clear coats and high-performance coating systems.
Recommended grades: AEROSIL® 200, AEROSIL® 300, AEROSIL® 380, AEROSIL® R 972, AEROSIL® R 974, AEROSIL® R 106, AEROSIL® R 812
3. Adhesives and Sealants
In adhesives and sealants, fumed silica can control slump, improve bead stability and support long-term storage stability. For general sealants, AEROSIL® 200 and AEROSIL® 200 HV are frequently considered.
For structural adhesives based on epoxy, polyurethane or vinyl ester chemistry, AEROSIL® R 202 is often selected for its strong thixotropic effect in polar resin systems.
For systems that require lower viscosity at higher silica loading, AEROSIL® R 8200 may be considered because of its structure-modified design and lower thickening effect.
Recommended grades: AEROSIL® 200, AEROSIL® 200 HV, AEROSIL® R 202, AEROSIL® R 8200
4. Silicone Rubber and Elastomers
Fumed silica is widely used as a reinforcing filler in silicone rubber. AEROSIL® 200 V, AEROSIL® 200 HV, AEROSIL® R 106, AEROSIL® R 972 and AEROSIL® R 8200 can be considered depending on processing, reinforcement and hydrophobicity requirements.
AEROSIL® 200 V is useful when reduced dust and improved incorporation are important. AEROSIL® R 8200 is suitable when low thickening and higher loading flexibility are required.
Recommended grades: AEROSIL® 200 V, AEROSIL® 200 HV, AEROSIL® R 106, AEROSIL® R 972, AEROSIL® R 8200
5. Powder Flow and Anti-Caking
For powder systems, selected AEROSIL® grades can improve free flow and reduce caking. AEROSIL® 200 F, AEROSIL® 200 V, AEROSIL® R 972 and AEROSIL® R 8200 are useful options depending on whether the system requires hydrophilic or hydrophobic behavior.
Recommended grades: AEROSIL® 200 F, AEROSIL® 200 V, AEROSIL® R 972, AEROSIL® R 8200
Practical Formulation Advice from Mina
When customers ask me which AEROSIL® grade to choose, I usually start with three questions:
First, what is the base system?
A polyester resin, epoxy resin, polyurethane adhesive, silicone rubber or coating system will respond differently to the same fumed silica grade.
Second, what is the main problem to solve?
If the issue is sagging, we focus on thixotropy. If the issue is filler settling, we focus on suspension stability. If the issue is powder flow, we focus on free-flow performance. If the issue is moisture sensitivity, hydrophobic grades become more important.
Third, what processing equipment is available?
Fumed silica performance depends strongly on dispersion. A higher surface area grade may offer stronger thickening, but it also requires suitable mixing energy. If dispersion is insufficient, the expected transparency, stability or rheology may not be achieved.
For most customers, AEROSIL® 200 is the best starting point. From there, we move to AEROSIL® 300 or AEROSIL® 380 for stronger thickening, or to hydrophobic grades such as AEROSIL® R 202, R 972, R 974 or R 812 when better compatibility and moisture resistance are required.
Frequently Asked Questions
Is AEROSIL® 200 hydrophilic or hydrophobic?
AEROSIL® 200 is a hydrophilic fumed silica. It is widely used for rheology control, thickening, anti-settling and anti-sagging in coatings, resins, adhesives and sealants.
What is the difference between AEROSIL® 200 and AEROSIL® 200 V?
Both are hydrophilic fumed silica grades with similar BET surface area. AEROSIL® 200 V is a densified grade designed for reduced dust development and improved handling during processing.
Which AEROSIL® grade is better for epoxy resin?
For general epoxy systems, AEROSIL® 200 can be used as a starting point. For stronger thixotropy and better performance in polar resin systems, AEROSIL® R 202 or AEROSIL® R 106 may be considered.
Which AEROSIL® grade gives stronger thickening?
AEROSIL® 300 and AEROSIL® 380 generally provide stronger rheological effect than AEROSIL® 200 because of their higher surface area. However, final performance depends on formulation polarity, dosage and dispersion conditions.
Which AEROSIL® grade is suitable for high-transparency coatings?
AEROSIL® R 812 and AEROSIL® 380 can be considered where high transparency is required after proper dispersion. The final result depends on resin compatibility, dispersion equipment and formulation design.
Work with Evergreen Chemicals
Evergreen Chemicals supplies AEROSIL® fumed silica and related additive solutions for coatings, resins, adhesives, sealants, silicone rubber and composite applications.
Our Additives Team can support product comparison, sample matching, TDS/SDS documentation and application-based selection. If you are not sure whether to choose AEROSIL® 200, AEROSIL® R 972, AEROSIL® R 202, AEROSIL® R 812 or another grade, contact us with your resin type, target viscosity, application method and performance requirement.
We will help you select a suitable fumed silica grade for your formulation.
