Background and development
Clear vision under adverse weather conditions remains a critical challenge for automotive glass, particularly for windscreens exposed to high rain loads, dirt, and repetitive mechanical wear from wipers. Conventional hydrophobic treatments often suffer from limited durability, insufficient chemical resistance, or optical side effects over time.
EXOCOAT® CLEARVIEW was developed as a permanent, inorganic–organic hybrid coating, built on sol‑gel chemistry, to overcome these limitations while maintaining full optical transparency and long‑term performance on glass substrates. Internal R&D work has been complemented by independent testing and validation confirming both performance and robustness under automotive‑relevant conditions.
Sol‑gel basis: a PFAS‑free hybrid inorganic–organic network
At the core of EXOCOAT® CLEARVIEW lies a sol‑gel derived siloxane hybrid network, specifically developed to deliver permanent hydrophobic performance without the use of PFAS‑based chemistry. During development, particular attention was paid to replacing conventional fluorinated water‑repellent additives (PFAS) still widely used in automotive glass.
During application, molecular sol‑gel precursors undergo controlled hydrolysis and condensation, forming a dense network that chemically bonds to the glass surface via covalent Si–O–Si interactions. Hydrophobic functionality is incorporated through PFAS‑free precursor building blocks that are covalently integrated into this inorganic backbone, ensuring long‑term stability and resistance to leaching or degradation.
This chemisorption mechanism distinguishes EXOCOAT® CLEARVIEW from conventional water‑repellent treatments based on fluorinated polymers or waxes, which rely on physical deposition and gradual sacrificial loss. In contrast, the sol‑gel network of EXOCOAT® CLEARVIEW forms an ultra‑thin, permanently anchored layer that combines ceramic‑like hardness with durable hydrophobic behavior, while remaining fully compliant with current and upcoming PFAS regulatory expectations.
Hydrophobic performance: contact angle and sliding behavior
The water repellency of EXOCOAT® CLEARVIEW is characterized not only by high static water contact angles of around 105°, and more importantly by low sliding angles of less than 25°.
In practical terms, the low sliding angles enable water droplets to detach from the glass surface under minimal airflow or gravity. This behavior is critical for automotive windscreens, where rapid droplet removal at low speeds significantly improves driver visibility in rainy conditions.
Mechanical and chemical robustness under automotive conditions
Automotive windscreens are exposed to repetitive wiper abrasion, washer fluids, acids, alkaline cleaners, and temperature cycling. EXOCOAT® CLEARVIEW demonstrates a high level of resistance to these stressors due to its inorganic network structure.
Laboratory data show strong resistance against nylon brush abrasion and detergent‑containing washing simulations, while chemical resistance against acidic and alkaline solutions preserves hydrophobic functionality over extended use
Unlike soft polymeric coatings, the ceramic hybrid layer does not smear, haze, or degrade optically over time, maintaining near‑perfect transparency relative to uncoated glass.
Applications on other glass surfaces (automotive, marine, architectural, and more)
EXOCOAT® CLEARVIEW is designed for straightforward application on a wide range of glass surfaces, including automotive windscreens and side windows, yacht and marine glazing, architectural building glass (facades and windows), shower glass, and other glass installations. Once applied and cured at ambient conditions, the coating forms a permanent, wear‑resistant layer chemically anchored to the glass surface.
In real‑world driving scenarios, this translates into:
- Faster droplet runoff
- Improved visual clarity
- Lower accumulation of mineral deposits and dirt
Because the coating layer is ultra‑thin and optically neutral, it preserves optical clarity and is compatible with demanding visibility requirements. For modern automotive glazing in particular, it is designed not to interfere with sensors, HUD systems, or other optical performance requirements.