Colloidal Monolayer Structural Colors for Anti-Counterfeit Labeling

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Solution Overview

Problem

Existing authentication methods for goods are either complex to implement and easily copied, or difficult to authenticate, and there is a need for a visually appealing, environmentally friendly, and robust identification mark that provides strong certification and easy authentication.

Innovation Solution

An assembly comprising a circular polycrystalline colloidal monolayer tethered on a solid substrate, featuring uniformly sized particles in juxtaposed single-crystal domains that emit domain-specific structural colors, utilizing a method involving an aqueous dispersion and cationic surfactants for deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If laser coding and printing technologies are used for authentication, then authentication capability is provided, but the method is complex to implement and can be copied by counterfeiters

Engineering Contradiction:

Improveauthentication capabilityVSAvoidimplementation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses structural colors generated by colloidal particles arranged in single-crystal domains. These domains reflect specific wavelengths of light, producing vivid, angle-dependent colors that are inherently difficult to replicate. The color pattern emerges from the physical arrangement of particles rather than pigments, providing authentication through optical properties that are simple to observe but complex to forge.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The authentication mark is self-generated through the self-assembly of colloidal particles during droplet evaporation. The system automatically forms the authentication pattern without requiring complex external equipment or processes. The particles spontaneously organize into domains with specific orientations, creating a unique optical signature that serves as its own authentication mechanism.

Inventive Principle:

Principle #25Self-service

2Reliability

If stochastic processes are used for authentication, then strong protection against duplication is achieved, but the method is difficult to implement and not adapted for easy authentication by consumers

Engineering Contradiction:

Improveprotection against duplicationVSAvoidease of authentication

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent employs structural colors that are visually striking and easily distinguishable. The multiple domains exhibit different colors and orientations that create a complex, non-reproducible pattern visible to the naked eye or with simple magnification. This stochastic color pattern provides strong anti-counterfeiting protection while remaining easily observable and verifiable by consumers using only a magnifying lens and white light source.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent replaces complex mechanical or electronic authentication systems with a simple optical observation method. Instead of requiring specialized equipment or complex procedures, the authentication relies on visual inspection of the structural color pattern under white light, dramatically simplifying the authentication process for end users while maintaining high security.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If complex patterns of structural colors are created, then aesthetic appeal and visual enjoyment are enhanced, but the complexity of the system increases

Engineering Contradiction:

Improveaesthetic appealVSAvoidsystem complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The complex multi-color pattern emerges automatically from the self-assembly process of colloidal particles during droplet evaporation. The particles spontaneously form domains with different orientations and sizes, each producing distinct structural colors. This self-organizing process generates aesthetically complex patterns without requiring complex manufacturing equipment or multiple processing steps, achieving high aesthetic value through natural physical processes.

Inventive Principle:

Principle #25Self-service

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 assembly offers a unique, non-clonable, visually arresting, and environmentally friendly authentication solution that is easy to detect with a white light source, providing strong certification and aesthetic appeal while resisting external aggressions.

Implementation Method 1

maintaining the solid substrate in the upside-down position to let the at least one drop of aqueous dispersion (A) evaporate

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

juxtaposed single-crystal domains which emit domain-specific structural colors when irradiated by a while light source

Methodology Applied

Scientific EffectStructural color: Reflection

Data Source

PatentUS20260015509A1Assembly comprising at least one circular polycrystalline colloidal monolayer tethered on a solid substrate

Publication Date: 2026.01.15 PARIS SCI & LETTRES

AI summary

An assembly including at least one circular polycrystalline colloidal monolayer tethered on a solid substrate; the at least one circular polycrystalline colloidal monolayer including at least one type of uniformly sized particles arranged into juxtaposed single-crystal domains which emit domain-specific structural colors when irradiated by a while light source. A method for preparing said assembly, as well as to the use of the assembly for labelling a good of interest, by direct deposition or by transfer preferably into a polymeric film.