Water-repellant transparent coating-substrate assembly and process for producing the same
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Solution Overview
Problem
Existing water-repellent coatings face issues with uniform silicon oxide fine particle deposition, leading to insufficient adhesion, strength, and reproducibility, as well as a decrease in water repellency due to abrasion and weather resistance.
Innovation Solution
A water-repellent transparent coating-substrate assembly is developed with an inorganic oxide fine particle layer and an overcoating layer, featuring specific irregularities in shape and size, including depressions and protrusions, to enhance adhesion, scratch resistance, and maintain water repellency over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional water-repellent coating is applied to achieve water repellency, then water repellency is improved, but adhesion and strength are insufficient
Solution Approach 1:
The patent applies composite materials by combining an inorganic oxide fine particle layer (providing water repellency through fractal structure) with an overcoating layer (providing adhesion and mechanical strength). This multi-layer composite structure resolves the contradiction by assigning different functional properties to different layers, allowing simultaneous achievement of water repellency and structural integrity.
Solution Approach 2:
The coating is segmented into distinct functional layers: the inorganic oxide fine particle layer responsible for water repellency and the overcoating layer responsible for adhesion and strength. This segmentation allows each layer to be optimized for its specific function without compromising the other, resolving the contradiction between water repellency and mechanical properties.
2Reliability
If a water-repellent coating is applied to achieve high water repellency, then water repellency is improved, but scratch resistance and abrasion resistance deteriorate
Solution Approach 1:
The composite structure combines the inorganic oxide fine particle layer (providing water repellency) with the overcoating layer (providing scratch and abrasion resistance). The overcoating layer acts as a protective barrier that prevents mechanical damage to the underlying water-repellent structure, thereby maintaining both water repellency and mechanical durability.
Solution Approach 2:
By segmenting the coating into specialized layers, the inorganic oxide layer can be optimized for water repellency while the overcoating layer is optimized for mechanical durability. This segmentation allows the water-repellent fractal structure to remain intact and functional while the overcoating provides the necessary scratch and abrasion resistance.
3Reliability
If a water-repellent coating is applied to achieve water repellency, then water repellency is improved, but durability against abrasion and weather deteriorates
Solution Approach 1:
The patent creates a composite material system where the inorganic oxide fine particle layer provides water repellency and the overcoating layer provides durability against abrasion and weathering. The overcoating layer serves as a protective barrier that shields the underlying water-repellent structure from environmental degradation, ensuring long-term durability while maintaining water repellency.
Solution Approach 2:
The coating is segmented into functional layers with distinct roles: the inorganic oxide layer maintains water repellency through its fractal structure while the overcoating layer provides durability against abrasion and weather. This segmentation ensures that the water-repellent properties are preserved while the overcoating protects against environmental factors over extended periods.
4Reliability
If silicon oxide fine particles are deposited to form a coating, then water repellency is improved, but uniformity of deposition and reproducibility deteriorate
Solution Approach 1:
The coating process is segmented into multiple steps: first forming the inorganic oxide fine particle layer with controlled fractal structure, then applying the overcoating layer. This segmentation allows precise control over the deposition process and enables better reproducibility by breaking down the complex coating formation into manageable stages with specific parameters for each layer.
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 coating achieves high water repellency, excellent adhesion, transparency, hardness, and abrasion resistance, making it suitable for applications in automobiles and electronic devices.
Implementation Method 1
a fractal structure enhances the hydrophilicity of a hydrophilic solid surface to change the solid surface to superhydrophilic, and, on the other hand, renders a hydrophobic solid surface superhydrophobic by increasing water repellency
Implementation Method 2
the superhydrophobic coating includes projections formed of masses of fine particles and a water-repellent film
Implementation Method 3
the water-repellent transparent coating having a water contact angle in the range of 130 to 180°
Data Source
AI summary
A water-repellent transparent coating-substrate assembly includes a substrate and a water-repellent transparent coating disposed on a surface of the substrate, the transparent coating including an inorganic oxide fine particle layer containing inorganic oxide fine particles, and an overcoating layer disposed on the inorganic oxide fine particle layer, the surface of the water-repellent transparent coating having irregularities including depressions and protrusions in which the protrusions have an average height (TF) in the range of 30 to 500 nm and an average protrusion interval (pitch width) (WF) in the range of 50 to 1000 nm, the water-repellent transparent coating having a water contact angle in the range of 130 to 180°.