Encapsulated Dye Coating for Non-Destructive Moisture Detection

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Solution Overview

Problem

Existing methods for detecting moisture in surfaces are either destructive, imprecise, or limited to local measurements, and there is a need for a non-destructive, precise, and cost-effective method that can analyze the whole surface at once.

Innovation Solution

A coating composition comprising encapsulated dyes that do not absorb in the visible spectrum but show absorption in the non-visible part of the spectrum, utilizing a core-shell structure with a pH-sensitive polymer that changes absorption properties under solvent influence, such as moisture, allowing for non-destructive and simple moisture detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional moisture detection methods are used, then moisture can be detected, but the methods are either destructive, imprecise, or limited to local measurements

Engineering Contradiction:
Improvemoisture detection precisionVSAvoiddestructive measurement
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs a pH-sensitive dye that changes its absorption properties in response to pH changes caused by moisture. The dye transitions between different absorption states based on the protonation state of its functional groups, enabling optical detection of moisture without damaging the substrate. This resolves the contradiction by providing a non-destructive method with high measurement precision through optical signal changes.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent replaces mechanical/destructive measurement methods (such as pin insertion) with an optical detection system. By using a dye whose absorption properties change with moisture-induced pH changes, the system substitutes physical contact and damage with non-contact optical measurement, achieving both non-destructive operation and high precision moisture detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Area of stationary object

If local moisture measurement methods are used, then measurement simplicity is maintained, but only local areas can be measured not the whole surface

Engineering Contradiction:
Improvemeasurement coverage areaVSAvoiddetection system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent creates a coating that can be applied over large surfaces and provides uniform moisture detection across the entire coated area. The coating system integrates the pH-sensitive dye within a polymer matrix that can be spread extensively, allowing a single application to monitor moisture across the whole surface rather than requiring multiple localized measurement points, thus achieving full-surface coverage without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Difficulty of detecting and measuring

If visible spectrum dyes are used for signalling, then colour change detection is easy, but the coatings change colour under environmental influence which is undesired for decorative purposes

Engineering Contradiction:
Improvesignal detection easeVSAvoidcoating colour stability
Core Design Contradiction:
Difficulty of detecting and measuringVSStability of the object's composition

Solution Approach 1:

The patent shifts the detection wavelength from the visible spectrum to the ultraviolet or near-infrared region. The pH-sensitive dye exhibits strong absorption changes in these non-visible regions in response to moisture-induced pH changes, while remaining optically stable in the visible spectrum. This allows the coating to maintain its decorative appearance (no visible colour change) while providing detectable signals in the UV or NIR dimension for moisture monitoring.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables rapid, non-destructive, and precise moisture detection across large surfaces without requiring costly equipment, using conventional means like a modified camera to detect changes in absorption properties.

Implementation Method 1

The invention makes use of a pH sensitive dye, i.e. of a dye which changes its absorption properties in response to a change in pH

Methodology Applied
Scientific EffectpH sensitivity:

Implementation Method 2

the dye which changes its absorption properties in response to a change in pH and which only shows absorption in the non-visible part of the spectrum

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP3027693B1A coating composition comprising a dye and a method to detect moisture in objects
Publication Date: 2025.07.02 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP3027693B1 patent drawingFigure 1
  • EP3027693B1 patent drawingFigure 2
  • EP3027693B1 patent drawingFigure 3

AI summary

The present invention relates to a coating composition comprising a system comprising a dye encapsulated in a matrix of a polymer, wherein the dye only shows absorption in a non-visible part of the light spectrum, wherein the encapsulated system is able to undergo a detectable change in the absorption properties under the influence of moisture. The invention further describes a method to detect moisture in objects, the method comprising the steps of (a) providing an object with a signalling layer, said signalling layer showing light absorption in a non-visible part of the light spectrum and a change in this light absorption under the influence of moisture, and (b) measuring the light absorption or reflectance of the coated object in the non-visible part of the light spectrum.