NIR-Activated Thermochromic Composition Using PCM Phase Change
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing NIR-responsive photo-switchable materials face challenges such as complex synthesis, high excitation power requirements, limited photoisomerization probabilities, photodegradation, and undesirable photochrome interconversion under continuous illumination, especially when used in the solid state or dispersed in solid matrices.
Innovation Solution
A photoinduced thermochromic or thermoluminescent composition comprising nanoparticles that absorb NIR radiation and convert it into heat, combined with phase change materials (PCMs) and dyes, allowing for low-energy activation and tunable color or emission changes without direct photoisomerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If photochrome-based smart materials are used to achieve light-responsive color and emission changes, then the materials can respond to optical stimuli with precise time and spatial control, but they suffer from complex and time-consuming synthesis, high excitation power requirements, and limited photoisomerization probabilities
Solution Approach 1:
The patent introduces nanoparticles as an intermediary component that absorbs NIR radiation and converts it to heat, which then triggers the phase change of PCMs. This mediator approach allows the system to respond to light stimuli without requiring the photochrome molecules themselves to undergo complex photoisomerization, thereby simplifying the overall system while maintaining optical responsiveness
Solution Approach 2:
The patent utilizes phase transitions of phase change materials (PCMs) as the primary mechanism for color and emission changes. Instead of relying on photoisomerization of photochrome molecules, the system uses NIR-induced heating to trigger phase transitions in PCMs, which then modulate the optical properties of associated dyes. This approach simplifies synthesis and improves photoisomerization efficiency by using a well-established physical phenomenon
2Ease of operation
If photochrome-based materials are activated with high-energy UV radiation to achieve switching, then the switching response is achieved, but photodegradation effects are provoked under continuous illumination
Solution Approach 1:
The patent changes the excitation parameter from high-energy UV radiation to low-energy NIR radiation. By using NIR radiation to heat nanoparticles, which then transfer thermal energy to trigger PCM phase changes, the system achieves switching without exposing photochrome molecules directly to harmful UV photons, thereby significantly improving photostability and reducing photodegradation
Solution Approach 2:
The patent converts the typically harmful effect of continuous illumination (which causes photodegradation) into a beneficial thermal effect. By using NIR radiation that is absorbed by nanoparticles and converted to heat, the system utilizes the energy from continuous illumination to drive PCM phase transitions without directly exciting and degrading the photochrome molecules, thus turning potential harm into benefit
3Ease of manufacture
If direct photoisomerization of dye molecules is used to achieve color changes, then the switching mechanism is straightforward, but the choice of colour/fluorescence modulator is limited to specific types of molecules
Solution Approach 1:
The patent segments the photo-responsive system into distinct functional components: NIR-absorbing nanoparticles for heat generation, PCMs for phase transition and optical modulation, and dyes for color/emission display. This segmentation allows each component to be independently optimized and selected from a wide range of materials, greatly expanding dye selection versatility while maintaining a straightforward switching mechanism through thermal triggering
4Measurement precision
If photochrome interconversion is allowed under continuous illumination for monitoring, then real-time color and emission measurement is achieved, but undesirable photochrome interconversion occurs which becomes a severe restriction
Solution Approach 1:
The patent replaces the photochemical switching mechanism with a thermal switching mechanism. By using NIR-induced heating to trigger PCM phase transitions, the system allows continuous monitoring of color and emission changes without causing unwanted photoisomerization, as the thermal mechanism does not involve the same photochemical pathways that lead to destructive interconversion under illumination
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 composition achieves higher absorptivity, photostability, and spectral tunability, with a homogeneous distribution of nanoparticles that prevent photodegradation and enable a broader range of dyes, providing a rapid, clear optical response and strong color/emission changes.
Implementation Method 1
nanoparticles capable of absorbing near-infrared radiation (NIR) and converting the NIR radiation into heat
Implementation Method 2
photoinduced thermochromic or thermoluminescent composition
Implementation Method 3
photoinduced thermochromic or thermoluminescent composition
Implementation Method 4
one or more phase change materials (PCM)
Data Source
AI summary
The present invention relates to a photoinduced thermochromic or thermoluminescent composition, comprising: a) nanoparticles capable of absorbing near-infrared (NIR) radiation and converting the NIR radiation into heat, in particular metal gold nanoparticles; b) one or more phase change materials (PCM) selected from the group consisting of: b1) a PCM capable of acting as chromic or fluorochromic promoter; and b2) a PCM uncapable of acting as chromic or fluorochromic promoter; c) one or more dyes selected from the group consisting of: c1) a dye capable of modifying its colour- or emission-properties when the PCM changes between the solid state and the liquid state; and c2) a dye uncapable of modifying its colour- or emission-properties when the PCM between the solid state and the liquid state; and articles containing it. It also relates to processes for their preparation and their uses in therapy, cosmetics, diagnostics, optics and anti-fake technology.