Spiropyran Polymer Composite for Stable Photochromic Security Tags
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Solution Overview
Problem
Spiropyran derivatives face issues with low stability when exposed to light and heat, leading to decomposition and phase separation in polymer matrices, limiting their repetitive use and photocoloration rate in polymer films compared to liquid solutions.
Innovation Solution
A composition comprising a spiropyran compound of formula (I) embedded in polymers such as Poly(ethylene oxide), Polypropylene, Polydimethylsiloxane, and Ethylene propylene diene monomer (EPDM), which enhances stability and maintains photochromic functionality, allowing for repeated color changes and improved photocoloration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spiropyran derivatives are dispersed in high polymer substance, then photochromic functionality is achieved, but the derivative dissolves out or separates out through phase separation due to low compatibility
Solution Approach 1:
The patent uses a composite material system where spiropyran derivative is combined with specific high polymer substances. The patent identifies that certain polymer matrices provide better compatibility and prevent phase separation, creating a stable composite photochromic system that maintains both functionality and compositional stability.
Solution Approach 2:
The patent modifies parameters such as the chemical structure of the polymer matrix and the concentration of spiropyran derivative to optimize compatibility. By changing these parameters, the system achieves better integration between the photochromic derivative and the polymer substrate, preventing dissolution and phase separation.
2Productivity
If spiropyran derivative is repeatedly exposed to light and heat for coloration and decolorization, then photochromic cycling is achieved, but side reactions decompose or deteriorate the spiropyran derivative
Solution Approach 1:
The patent employs protective measures by selecting polymer matrices that provide a stabilizing environment for the spiropyran derivative before degradation occurs. The polymer matrix acts as a protective medium that cushions against harmful side reactions during repeated light and heat exposure, extending the operational lifetime of the photochromic system.
Solution Approach 2:
The patent creates an inert environment by using specific polymer matrices that protect the spiropyran derivative from oxidative and other chemical degradation during repeated photochromic cycling. The polymer matrix provides a chemically inert environment that prevents side reactions while allowing the desired photochromic transitions.
3Stability of the object's composition
If spiropyran is inserted into polymer films, then stability is improved, but photocoloration rate decreases compared to liquid solutions
Solution Approach 1:
The patent applies local quality by creating specific microenvironments within the polymer matrix where the spiropyran derivative experiences favorable conditions for fast photocoloration. By optimizing the local polymer structure and composition around the photochromic molecules, the system achieves both stability and fast response kinetics.
Solution Approach 2:
The patent modifies parameters such as polymer chain mobility, free volume, and chemical composition to optimize the photocoloration rate. By changing these parameters, the system maintains the stability benefits of polymer embedding while reducing the kinetic penalty through optimized molecular environment.
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 spiropyran compound embedded in these polymers demonstrates improved stability and faster color change kinetics, with a modulated half-life of the merocyanine form, suitable for applications like security tags and dynamic devices.
Implementation Method 1
Spiropyran is one of the photochromic compounds, it changed to blue color upon exciting with UV light and the reaction is reversible under visible or thermal conditions.
Implementation Method 2
The color produced by the formation of merocyanine.
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
The present invention discloses the spiropyran compound of formula (I), process for preparation thereof and a composition comprising spiropyran compound of formula (I) on a support, wherein said support selected from polymers such as Poly (ethylene oxide), Polydimethylsiloxane (PDMS), Ethylene propylene diene monomer (EPDM).