Hierarchical Concavo-Convex Super Water Repellent Surface
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Solution Overview
Problem
Current methods fail to achieve a contact angle of 150° or more for super water repellency on glass surfaces, which is necessary for self-cleaning and clear vision, especially in rainy conditions, due to limitations in controlling both surface chemical properties and geometric structures.
Innovation Solution
A process involving the formation of a hierarchical concavo-convex structure on a substrate surface using spherical beads and subsequent etching, followed by coating with a fluorine compound, to create a super water repellent surface with controlled transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low surface energy materials are used to reduce surface energy, then water droplets become spherical and roll down, but contact angle reaches only 100°-130° instead of 150° or more
Solution Approach 1:
The invention combines low surface energy fluorine-based chemical materials with micro/nano hierarchical geometric structures to create a composite surface treatment. This composite approach integrates both chemical hydrophobicity and geometric microstructure, enabling contact angles of 150° or more while maintaining water droplet sphericity and roll-off capability.
Solution Approach 2:
The invention creates local quality variations by forming micro/nano hierarchical structures with different scale features at different locations on the surface. The micro-scale protrusions and nano-scale roughness elements work together locally to enhance water repellency, with each structural level contributing to the overall contact angle enhancement.
2Reliability
If micro/nano hierarchical structures are formed on glass surfaces, then contact angle reaches 150° or more, but surface complexity increases and manufacturing becomes difficult
Solution Approach 1:
The invention segments the hierarchical structure formation into distinct procedural steps: first forming micro-scale protrusions through controlled etching or deposition, then adding nano-scale roughness elements through additional treatment. This segmentation allows each structural level to be optimized independently while maintaining overall water repellency.
Solution Approach 2:
The invention transitions from two-dimensional surface treatment to three-dimensional hierarchical structures by adding vertical protrusions and micro/nano-scale height variations. This dimensional transformation creates the micro/nano hierarchical architecture that enables super water repellency while managing surface complexity through controlled geometric progression.
3Ease of manufacture
If conventional surface treatment methods are used, then glass surfaces remain relatively simple, but water forms inhomogeneous films causing light scattering and reduced visibility
Solution Approach 1:
The invention converts the harmful effect of water film formation into a beneficial self-cleaning mechanism. By creating super water repellent surfaces with contact angles of 150° or more, water droplets maintain sphericity and roll off the surface, carrying away contaminants. This transforms the water film from a harmful obscuring layer into a beneficial cleaning agent that enhances visibility.
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 process effectively achieves a contact angle of 150° or more, providing enhanced water repellency and self-cleaning capabilities while allowing for adjustable transparency, thereby improving visibility and maintenance of glass surfaces.
Implementation Method 1
By significantly reduce the surface energy of the glass surface, it will be possible to make the shape of water droplets spherical, so that they may roll down off the surface
Implementation Method 2
The surface of which has numerous micro-sized cilia and is coated with a waxy substance. The wax coating also has been identified to have a regular nanostructure. It is known that such a micro/nano hierarchical structure results in a super water repellent surface
Implementation Method 3
By significantly reduce the surface energy of the glass surface, it will be possible to make the shape of water droplets spherical, so that they may roll down off the surface
Data Source
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AI summary
The present invention provides a process for the preparation of a super water repellent surface comprising the steps of arranging a plurality of spherical beads on the surface of a substrate to form a (N)-th bead layer, etching the substrate surface with the (N)-th bead layer as etching mask, arranging a plurality of spherical beads, which are larger than the (N)-th beads in diameter, on the substrate surface to form a (N+1)-th bead layer, etching the substrate surface with the (N+1)-th bead layer as etching mask, removing the beads from the etched substrate surface and coating a fluorine compound on the substrate surface on which a hierarchical concavo-convex structure has been formed, wherein the (N+1)-th bead layer forming step and the (N+1)-th etching step are repeated for N times.