Photonic Crystal Micropatterns for Reversible Hidden Authentication
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Solution Overview
Problem
Counterfeit products are a significant issue, and there is a need for reconfigurable chromogenic sensors that can reveal hidden patterns as anti-counterfeiting measures.
Innovation Solution
A method is developed to fabricate a porous polymer material with an ordered array of voids, where applying a stimulus causes the voids to collapse, and exposing it to UV radiation locks certain regions in a transparent state, allowing hidden patterns to be revealed by contact with a trigger solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the porous polymer material is made transparent by collapsing voids through stimulus application, then the hidden anti-counterfeiting pattern can be revealed, but the material loses its iridescent color property
Solution Approach 1:
The patent applies different treatments to different regions of the porous polymer material. Specifically, a first region is treated to be responsive to stimulus (allowing reversible collapse and pattern revelation), while a second region is UV-exposed to lock the voids in a collapsed transparent state. This local differentiation allows the material to simultaneously maintain chromogenic properties in the first region while providing a stable transparent reference in the second region, resolving the contradiction between revealing hidden patterns and maintaining optical properties.
2Stability of the object's composition
If UV radiation is applied to lock regions in a collapsed state, then those regions remain permanently transparent, but the ability to reversibly switch between states is lost in those regions
Solution Approach 1:
The porous polymer material is divided into distinct functional regions: a first region that maintains reversible stimulus-response capability for dynamic pattern revelation, and a second region that is UV-exposed to lock voids in a collapsed state for permanent transparency. This segmentation allows each region to fulfill its specific function without compromising the other, enabling both stable reference areas and dynamically switchable areas to coexist in the same material.
3Reliability
If the voids are kept in an ordered state to maintain iridescent color, then the hidden pattern remains concealed, but the material cannot reveal the anti-counterfeiting information
Solution Approach 1:
The patent pre-programs the porous polymer material with hidden anti-counterfeiting patterns during fabrication, but these patterns remain concealed as long as the voids are in their ordered iridescent state. The material is designed so that application of a specific stimulus will cause the voids to collapse and reveal the hidden pattern, while a second region is permanently locked in the collapsed state to provide a stable transparent reference. This preliminary programming with conditional revelation resolves the contradiction between maintaining concealment and enabling information access.
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 enables the creation of chromogenic sensors that can hide and reveal anti-counterfeiting patterns effectively, providing secure authentication and precise control over nanostructure regions, suitable for applications like anti-counterfeiting and optical devices.
Implementation Method 1
The porous polymer material can be transitioned to a deformed state in which the array of voids is in a collapsed state by applying a first stimulus... The porous polymer material can be exposed to UV radiation, causing the voids in the exposed regions to remain permanently in the collapsed state. The collapsed voids in the masked regions can be recovered back to the ordered state by applying a second stimulus, revealing the hidden anti-counterfeiting patterns.
Implementation Method 2
A shape memory polymerizable material can be added into the volume between the opposing first and second surfaces to surround the particles. The shape memory polymerizable material can be polymerized to form a polymer framework around the particles. The porous polymer material can be exposed to UV radiation, causing the voids in the exposed regions to remain permanently in the collapsed state.
Implementation Method 3
The porous polymer material can be transitioned to a deformed state in which the array of voids is in a collapsed state by applying a first stimulus... The collapsed voids in the masked regions can be recovered back to the ordered state by applying a second stimulus.
Data Source
AI summary
Provided herein are methods for fabricating a porous polymer material, methods for revealing hidden anti-counterfeiting patterns, chromogenic sensors having hidden anti-counterfeiting patterns, and the like. Chromogenic sensors including porous polymer materials are provided. The chromogenic sensors can reveal hidden patterns such as anti-counterfeiting patterns and the pattern can be re-hidden.