Self-Cleaning Coating Using Composite Particles for Adhesion

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Solution Overview

Problem

Conventional hydrophobic surfaces for self-cleaning coatings lack sufficient mechanical strength and adhesion, and those modified with low surface energy materials often fail to maintain a high water contact angle or exhibit poor adhesion.

Innovation Solution

A method involving the use of micro- or nano-particles treated with a hydrophobic agent and an additive to form larger particles with enhanced hydrophobicity and bonding capabilities, combined with a binder or crosslinker to create a durable self-cleaning coating with improved mechanical strength and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a rough structure is created on a hydrophobic surface, then water contact angle increases (>130°), but mechanical strength and adhesion decrease

Engineering Contradiction:
Improvesurface roughnessVSAvoidmechanical strength and adhesion
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent uses composite particles consisting of a core shell structure where the core provides mechanical strength and adhesion while the shell provides hydrophobicity. This composite structure allows simultaneous achievement of both mechanical properties and water repellency, resolving the contradiction between rough surface structure and mechanical strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different functional properties to different parts of the particle structure: the core region provides mechanical reinforcement and adhesion, while the surface shell region provides hydrophobicity. This local differentiation allows each region to optimize its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

2Shape

If low surface energy materials are used to modify a rough surface, then hydrophobicity increases, but adhesion and mechanical strength decrease

Engineering Contradiction:
ImprovehydrophobicityVSAvoidadhesion
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent employs composite particles with a core-shell architecture where the core material provides adhesion and mechanical strength, while the shell material provides hydrophobicity. This composite approach allows both adhesion and hydrophobicity to be achieved simultaneously, overcoming the limitation of using low surface energy materials alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent assigns different functional characteristics to different regions: the core region is designed for adhesion and mechanical reinforcement, while the surface shell region is designed for hydrophobicity. This local functional differentiation resolves the contradiction between adhesion and hydrophobicity.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If conventional hydrophobic coatings are applied, then self-cleaning effect is achieved, but durability and service life decrease due to insufficient adhesion

Engineering Contradiction:
Improveself-cleaning effectVSAvoidservice life
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent uses composite particles with core-shell structure where the core provides durable adhesion to the substrate while the shell provides the self-cleaning hydrophobic effect. This composite structure ensures long service life through strong adhesion while maintaining the self-cleaning functionality.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent localizes different functions: the core region ensures durable adhesion and mechanical strength for long-term durability, while the surface shell region provides the self-cleaning hydrophobic effect. This local differentiation enables both long service life and effective self-cleaning.

Inventive Principle:
Principle #3Local quality

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 method produces coatings with high water contact angles (>110°) and enhanced adhesion and mechanical strength, suitable for long-lasting self-cleaning applications, including facade paints and anti-corrosive coatings, capable of withstanding extensive scrub tests.

Implementation Method 1

treating the particles with a hydrophobic agent... to form larger particles with the hydrophobic agent and the additive bonded thereto

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

an additive capable of reaction with the particles to form larger particles with the hydrophobic agent and the additive bonded thereto

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

attaching a binder or crosslinker to the larger particles by forming chemical bonds with at least one of the additive, the hydrophobic agent, and the particles

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 4

drying or curing the coating material to form a solid coating having a microstructured, hydrophobic surface

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS7744953B2Method for forming self-cleaning coating comprising hydrophobically-modified particles
Publication Date: 2010.06.29 IND TECH RES INST

AI summary

A method for forming self-cleaning coating comprising hydrophobically-modified particles. Micro- or nano-particles are treated with a hydrophobic agent and an additive to form larger particles with the hydrophobic agent and the additive bonded thereto. A binder or crosslinker is attached to the larger particles by forming chemical bonds with at least one of the additive, the hydrophobic agent, and the particles, thus forming a coating material capable of forming self-cleaning coating.