Vehicle Sensor Repellent Coating for Low-Haze Dirty Water Shedding

The patent applies different surface properties to different regions or aspects of the coating system. The cured organic matrix provides a hydrophobic base layer with high contact angle, while the non-ionic surfactant creates a separate functional layer that reduces surface energy and prevents contaminant adhesion. This layered approach with distinct local qualities allows the coating to repel water and contaminants without significantly increasing haze, as each layer performs its specific function independently.

The patent uses a composite coating composition consisting of a cured organic matrix combined with a non-ionic surfactant. The organic matrix provides structural integrity and base hydrophobicity, while the surfactant adds surface energy modification properties. This composite material approach allows the coating to achieve both water repulsion and acceptable optical clarity by combining materials with complementary properties rather than relying on a single substance.

The patent carefully controls the concentration of low surface energy moieties in the organic matrix to achieve an optimal balance. By adjusting this parameter, the coating achieves a high enough contact angle for water repulsion while maintaining a low enough roll-off angle for effective contaminant removal. The specific concentration range is optimized to prevent the extremes where either contact angle is too low or roll-off angle is too high.

The non-ionic surfactant acts as an intermediary that mediates between the high contact angle requirement and low roll-off angle requirement. The surfactant molecules position themselves at the coating-water interface, modifying surface properties to enable water to bead up at high angles while still allowing gravity and minor disturbances to cause rolling off at low angles. This intermediary substance resolves the contradiction between contact angle stability and roll-off ease.

The patent applies the repellent composition as a preliminary protective layer before environmental contaminants can adhere to the sensor surface. The coating is applied and cured to form a durable barrier that preemptively prevents water and dirt from bonding to the underlying sensor or lens. This preliminary action maintains optical clarity by stopping contaminant accumulation before it can occur, thereby protecting both optical performance and durability simultaneously.

The cured organic matrix with non-ionic surfactant provides continuous repellent action over time. The hydrophobic surface properties and low surface energy moieties continuously prevent water and contaminant adhesion without degrading or requiring replenishment. This continuous useful action maintains both low haze values and high durability, as the coating actively protects the surface throughout its service life rather than providing temporary or intermittent protection.