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US 2023/0203264 A1Published application
Photonic crystal micropatterns and anti-counterfeiting films, methods of making, and methods of use
AssigneeUniversity of Florida Research Foundation, Inc.
InventorsPeng Jiang, Calen Leverant, Yifan Zhang
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Abstract
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.
Claims21
A method for fabricating a porous polymer material, comprising:
- providing a plurality of particles in a volume between a first surface of a first substrate and at least one opposing second surface of a second substrate, wherein the plurality of particles includes an ordered array of nanoparticles;
- adding a shape memory polymerizable material into the volume between the opposing first and second surfaces to surround the particles;
- polymerizing the shape memory polymerizable material to form a polymer framework around the particles;
- removing the particles to form an ordered array of voids in the polymer framework;
- transitioning the porous polymer material to a deformed state in which the array of voids is in a collapsed state by applying a first stimulus, causing the voids to collapse;
- placing a mask over the porous polymer material to form masked regions and exposed regions;
- and
- exposing the porous polymer material to UV radiation, causing the voids in the exposed regions to remain permanently in the collapsed state.
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A method of revealing a hidden anti-counterfeiting pattern comprising:
- contacting a chromogenic sensor with a trigger solvent, causing the chromogenic sensor to reveal the hidden anti-counterfeiting pattern;
- wherein the chromogenic sensor comprises a porous polymer material comprising an ordered array of voids separated by a polymer framework, wherein the porous polymer material has a first region having the hidden anti-counterfeiting pattern and a second region;
- wherein the first region of the porous polymer material has a deformed state and a recovered state;
- wherein when in the deformed state, the voids are collapsed and the first region has a characteristic of being substantially transparent, wherein when the first region of the porous polymer material is in the recovered state, the voids are uncollapsed and the first region has a characteristic of having an iridescent color;
- wherein the second region has been exposed to UV radiation during a programming step, thereby causing the voids of the second region to irreversibly remain in a collapsed state and has a characteristic of remaining transparent;
- wherein the hidden anti-counterfeiting pattern is not visible when the first region is in a deformed state since both the first and second regions have the characteristic of being substantially transparent;
- and
- wherein the contacting occurs when the first region is in a deformed state, and contacting causes the first region of the porous polymer material to return to the recovered state thereby revealing the anti-counterfeiting pattern.
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19-21. (canceled)
A chromogenic sensor having a hidden anti-counterfeiting pattern comprising:
- a porous polymer material comprising an ordered array of voids separated by a polymer framework,
- wherein the porous polymer material has a first region having the hidden anti-counterfeiting pattern and a second region;
- wherein the first region of the porous polymer material has a deformed state and a recovered state,
- wherein when the first region is in the deformed state, the voids are collapsed and the first region has a characteristic of being substantially transparent, wherein when the first region is in the recovered state, the voids are uncollapsed and the first region has a characteristic of having an iridescent color;
- wherein the second region has been exposed to a programming step, thereby causing the voids of the second region to irreversibly remain in a collapsed state and wherein the second region has a characteristic of remaining transparent;
- wherein the hidden anti-counterfeiting pattern is not visible when the first region is in a deformed state since both the first and second regions have the characteristic of being substantially transparent;
- and
- wherein when the first region is in a deformed state, contacting the chromogenic sensor with a trigger solvent causes the first region of the porous polymer material to be in the recovery state thereby revealing the anti-counterfeiting pattern.
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Dependencies are inferred from the claim text.