Single-Step SLIPS Coating for Durable Liquid Repellency
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Solution Overview
Problem
Existing surface coatings with ultrafine structures for liquid repellency suffer from low mechanical durability, light scattering, and inability to handle low surface energy liquids, requiring complex two-step processes for Slippery Liquid Infused Porous Surfaces (SLIPS) formation.
Innovation Solution
A coating composition comprising particles, a binder resin, and a lubricating liquid with specific properties, applied in a single step to form a porous underlayer and liquid film, allowing liquids to slide down without the need for a two-step process, using a solvent with affinity for the lubricating liquid and particles that are bound together by the resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ultrafine surface structure is formed for liquid repellency, then liquid droplets can roll down the surface, but the mechanical durability is low because the structure is easily broken
Solution Approach 1:
The patent uses a composite coating composition containing ultrafine particles (10-100 nm diameter), binder resin, and lubricating liquid. The ultrafine particles form a porous underlayer that provides liquid repellency, while the binder resin binds the particles together to create a mechanically durable structure. The lubricating liquid infuses the porous structure to enable liquid droplets to roll down, thus combining the benefits of ultrafine surface structure with mechanical strength.
Solution Approach 2:
The patent creates a porous underlayer by forming a coating film containing ultrafine particles that maintain a porous structure after drying. This porous structure has controlled pore size and distribution that allows it to hold lubricating liquid while providing mechanical strength through the particle-binder resin matrix. The porous structure enables the SLIPS (Slippery Liquid-Infused Porous Surface) effect while maintaining durability.
2Reliability
If an ultrafine surface structure is formed for liquid repellency, then droplets can roll down, but light is scattered by the surface structure leading to decreased transmittance
Solution Approach 1:
The patent applies different properties to different parts of the coating structure. The ultrafine particles (10-100 nm) are used specifically in the underlayer where they provide liquid repellency through their high surface area and porous structure. The lubricating liquid is infused into this porous underlayer to create the rolling effect. This localized application of ultrafine particles in the underlayer rather than the entire coating allows light transmittance to be maintained in the visible spectrum while achieving liquid repellency.
3Reliability
If a spherical liquid structure is formed for liquid repellency, then water can roll down, but low surface energy liquids such as ethanol and acetone cannot roll down due to high surface tension
Solution Approach 1:
The patent changes the surface energy parameters of the coating by selecting specific lubricating liquids with appropriate surface tension values. The lubricating liquid is chosen to have a surface tension that is lower than that of water but compatible with low surface energy liquids like ethanol and acetone. This parameter adjustment allows the coating to work with a broader range of liquids while maintaining the rolling effect.
4Strength
If SLIPS is formed using a two-step process with porous underlayer and lubricating liquid infusion, then mechanical durability and transparency are improved, but the process complexity increases
Solution Approach 1:
The patent merges the formation of the porous underlayer and the infusion of lubricating liquid into a single coating step. The coating composition is formulated to contain ultrafine particles, binder resin, and lubricating liquid in specific proportions. When applied, the solvent evaporates, the binder resin binds the particles, and the lubricating liquid remains infused in the porous structure, all in one process. This eliminates the need for separate underlayer formation and liquid infusion steps, reducing process complexity while maintaining mechanical durability and transparency.
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 solution provides a durable, transparent, and efficient liquid-repellent surface that allows low surface energy liquids to slide down, enhancing mechanical durability and transparency while simplifying the coating process.
Implementation Method 1
a binder resin for fixedly binding the particles together
Implementation Method 2
a lubricating liquid that has a nonaffinity for the liquid of interest, but has an affinity for the binder resin
Implementation Method 3
a solvent that has an affinity for the lubricating liquid
Implementation Method 4
it is then possible to produce a coating film having a lubricating surface by simple application of said coating liquid on the desired article
Data Source
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AI summary
The invention provides a coating composition for forming a coating film having a lubricating surface by coating, a process of forming the same, a lubricating article kit using the same, and a washer liquid. The coating composition contains particles, a binder resin for fixedly binding the particles together, a lubricating liquid having a nonaffinity for the liquid of interest, but an affinity for the lubricating liquid, and solvent having a affinity for the lubricating liquid, wherein the lubricating liquid has a contact angle of 0° upon dropwise addition onto a substrate made of the same material as said particles as measured in the atmosphere, and a contact angle of 0° upon dropwise addition onto the substrate made of the same material as said particles as measured in said liquid of interest, a volume ratio of said lubricating liquid relative to a total amount of said solvent and said lubricating liquid ranges from 0.09 to 0.95 inclusive, and a content of said binder resin relative to the total amount of said solvent and said lubricating liquid ranges from 0.0004 g/mL to 0.05 g/mL inclusive.