Methyltrimethoxysilane丨CAS 1185-55-3

Methyltrimethoxysilane丨CAS 1185-55-3 is a silane coupling agent that features a methyl group bonded to silicon and three methoxy groups. It has the molecular formula CH₃Si(OCH₃)₃ and is widely used in a range of industrial applications due to its reactivity, volatility, and ability to form siloxane bonds. MTMS plays a crucial role in surface treatment, crosslinking, and hydrophobic modification processes in materials science, electronics, coatings, and construction.

1. Surface Modification Agent
Methyltrimethoxysilane丨CAS 1185-55-3 is extensively used to modify the surface properties of inorganic materials like glass, metal oxides, silica, and ceramics:
● Hydrophobic treatment: When applied to surfaces, MTMS forms a thin, covalently bonded hydrophobic layer. This reduces water absorption, improves weather resistance, and increases the durability of treated materials.
● Improved adhesion: MTMS acts as a coupling agent, promoting better adhesion between organic polymers (e.g., epoxy, polyurethane) and inorganic substrates.
Typical applications include:
● Glass fiber reinforcement
● Silica-filled rubber and resins
● Coating adhesion promoters
2. Crosslinking Agent in Silicone Systems
MTMS is commonly used as a crosslinker in the production of RTV (room-temperature vulcanizing) silicone rubbers and silicone resins:
● It reacts with hydroxyl-terminated siloxanes or silanols to form 3D network structures.
● Offers good thermal and moisture resistance in the final cured products.
This application is especially useful in:
● Sealants
● Adhesives
● Coatings and protective films
3. Water Repellents in Construction
MTMS is widely used in the construction industry as a key component in water-repellent coatings for concrete, bricks, stones, and other porous materials:
● Prevents water ingress without significantly affecting breathability
● Helps protect surfaces from freeze-thaw damage, efflorescence, and biological growth
● Often used in conjunction with other silanes for penetrating sealers
4. Sol-Gel Chemistry and Aerogels
In sol-gel processes, MTMS serves as a precursor for silicon-based networks, contributing to the formation of hybrid organic-inorganic materials:
● MTMS-based sol-gels can be tailored to produce transparent coatings, thin films, or nanostructured aerogels
● Used in optical coatings, anticorrosion barriers, and flame-retardant materials
Aerogels synthesized using MTMS tend to be flexible, hydrophobic, and suitable for thermal insulation applications.
5. Electronics and Semiconductor Industry
In electronics, MTMS is used as:
● A barrier coating or moisture sealant for circuit boards
● A surface treatment in semiconductor wafer processing for anti-stiction and dielectric modification
Its low dielectric constant and compatibility with silicon-based materials make it attractive in microelectronics.
6. Coating and Paint Additive
Methyltrimethoxysilane丨CAS 1185-55-3 enhances the performance of coatings by:
● Improving durability and UV resistance
● Providing water and dirt repellency
● Enhancing scratch resistance when used in clearcoats or topcoats

1. Hydrophobicity
MTMS-treated surfaces exhibit strong water repellency, making them ideal for use in outdoor, marine, and wet-environment applications.
2. Chemical Compatibility
It can bond with both organic polymers and inorganic substrates, improving adhesion and compatibility between dissimilar materials.
3. Low Volatility During Cure
Though volatile initially, once hydrolyzed and cured, MTMS forms stable siloxane networks with excellent resistance to heat, chemicals, and UV exposure.
4. Environmentally Friendly in Cured State
Unlike some fluorinated treatments, MTMS-modified surfaces are fluorine-free while still providing good hydrophobic and oleophobic performance.
5. Enhanced Longevity
Used in protective coatings, MTMS can significantly extend the lifespan of materials exposed to harsh environments, reducing maintenance and replacement costs.

Conclusion
Methyltrimethoxysilane丨CAS 1185-55-3 is a highly versatile silane compound valued across industries for its surface treatment, hydrophobicity, crosslinking ability, and chemical durability. From high-performance coatings and construction materials to electronics and silicone rubber systems, MTMS offers a balance of reactivity and performance, making it indispensable in modern material science and industrial applications. When used properly, it contributes to improved functionality, durability, and environmental resistance of treated materials.