Hydrophobic Substrate Double Priming Abrasion Resistance
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Solution Overview
Problem
Current hydrophobic coatings used in glass and ceramic substrates face issues with abrasion, UV resistance, and chemical inertness, particularly in meeting stringent salt corrosion specifications required by the automotive industry, which limits their development and application.
Innovation Solution
A process involving a dense SiO2 priming layer and a subsequent bis-silane layer, optionally etched for increased roughness, is applied to the substrate, followed by a fluorinated alkylsilane coating, creating a three-layer hydrophobic coating structure that enhances chemical inertia and resistance to abrasion and UV radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer hydrophobic coating is applied to the substrate, then the initial hydrophobic properties are achieved, but the resistance to abrasion, UV radiation, and salt corrosion deteriorates
Solution Approach 1:
The coating is divided into three distinct layers: a dense SiO2 priming layer for adhesion and chemical resistance, a bis-silane intermediate layer for enhanced bonding, and a fluorinated alkylsilane top layer for hydrophobicity. This segmentation allows each layer to specialize in specific functions, collectively achieving superior durability without requiring excessive complexity in any single layer.
Solution Approach 2:
The invention uses a composite coating structure combining different material types (silica, silane, fluorinated compounds) with complementary properties. The dense SiO2 provides chemical inertness, the bis-silane provides bridging functionality, and the fluorinated layer provides water repellency, creating a synergistic composite system that exceeds the sum of individual layer performances.
2Reliability
If the substrate is treated with priming agents to increase adhesion, then the hydrophobic coating adhesion improves, but the chemical inertness deteriorates
Solution Approach 1:
The priming function is segmented into two separate layers: the dense SiO2 layer provides chemical resistance and substrate bonding, while the bis-silane layer provides intermediate adhesion enhancement. This segmentation allows the fluorinated top layer to maintain its chemical inertness while still achieving strong overall adhesion through the specialized priming layers below.
Solution Approach 2:
The bis-silane layer acts as an intermediary between the dense SiO2 priming layer and the fluorinated hydrophobic layer. It provides chemical bridging functionality that enhances adhesion without compromising the chemical inertness of the fluorinated top layer, as the bis-silane is positioned and designed to handle the chemical bonding functions.
3Reliability
If the hydrophobic coating is made thicker to improve durability, then the resistance to abrasion and corrosion improves, but the contact angle and hydrophobic properties deteriorate
Solution Approach 1:
The coating thickness is segmented across three layers with the fluorinated hydrophobic layer maintained at an optimal thin thickness (5-20 nm) to preserve contact angle properties, while the durability function is distributed to the thicker dense SiO2 priming layer and bis-silane layer below, which provide the mechanical and chemical resistance without interfering with the surface hydrophobicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting hydrophobic coating demonstrates superior resistance to abrasion, UV radiation, and salt corrosion, meeting stringent automotive industry specifications while maintaining initial hydrophobic properties and mechanical resistance, as evidenced by improved performance in contact angle retention and Neutral Salt Spray tests.
Implementation Method 1
these silicon compounds having at least two hydrolyzable functions. In a well-known manner, one of the two hydrolyzable functions allows chemical bonding to the substrate by an oxygen atom linked to the silicon atom
Implementation Method 2
The property of non-wettability of a substrate, more commonly referred to as hydrophobicity, is characterized by a high contact angle between water and this substrate
Data Source
AI summary
The invention relates to a glass, ceramic, or glass/ceramic, but preferably glass substrate coated with a hydrophobic coating, said substrate including: a first silicon dioxide SiO2 priming layer that optionally includes an element from the group formed of Al, B, C, Zr, the density of said layer being at least 1.9 g/cm3 and preferably at least 2.0 g/cm3; and a second priming layer that includes Si-R3-Si groupings, R3 being selected from within the group formed of straight, branched, or aromatic, but preferably straight alkyl chains wherein the number of carbons establishing the bond between the two silicon atoms is less than 6 and preferably between 1 and 4 inclusive. Said substrate moreover includes a coating layer that has hydrophobic properties bonded with said priming layer, and includes fluorinated groupings.