Composite Dye Particles for Stable Optical Filtration in Lenses
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Solution Overview
Problem
Existing ophthalmic lenses suffer from dye degradation due to organic peroxides used in polymerization, leading to yellowing and reduced light filtering effectiveness, and surface-coated optical filters are prone to photobleaching.
Innovation Solution
Encapsulating dyes in core-shell nanoparticles with hydrophobic or hydrophilic free radical scavengers within amphiphilic block copolymers to protect them from peroxide-induced degradation and UV damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dyes are added to the bulk liquid polymerizable solution before polymerization, then the lenses can absorb specific wavelengths of light, but the organic peroxide catalyst degrades the dyes through free radical exposure, causing yellowing and loss of optical filtering effectiveness
Solution Approach 1:
The dye is segmented from the bulk polymerizable solution by encapsulating it within nanoparticles. This segmentation isolates the dye from the organic peroxide catalyst and free radicals, preventing degradation while maintaining optical filtering functionality.
Solution Approach 2:
Nanoparticles serve as an intermediary barrier between the dye and the organic peroxide catalyst. The nanoparticle structure allows the dye to maintain its optical properties while protecting it from harmful free radical exposure during polymerization.
2Reliability
If optical filters are added through thin film coating on the lens surface, then the lenses can filter light, but the surface-coated dyes are exposed to UV and high-energy visible light, causing photobleaching and faded color
Solution Approach 1:
Nanoparticle shells provide a protective flexible barrier around the dye molecules. This shell structure protects the dye from direct exposure to UV and high-energy visible light, preventing photobleaching while allowing the optical filtering function to operate.
Solution Approach 2:
The dye is transitioned from a two-dimensional surface coating to a three-dimensional encapsulated structure within nanoparticles embedded in the bulk lens material. This dimensional change provides enhanced protection from photochemical damage while maintaining optical filtering capability.
3Stability of the object's composition
If free radical scavengers are used to protect dyes from degradation, then dye stability is improved, but the free radicals required for polymerization of the ophthalmic lens monomer are also neutralized
Solution Approach 1:
Free radical scavengers are segmented and localized within the nanoparticle structure alongside the dye. This segmentation allows the scavengers to protect the dye from free radicals generated during polymerization without interfering with the bulk polymerization process, as the scavengers are confined to the nanoparticle interior.
Solution Approach 2:
The nanoparticle structure creates local zones with different chemical properties. The interior of the nanoparticle has high scavenger concentration to protect the dye, while the exterior allows free radical access for polymerization. This local quality differentiation resolves the contradiction between protection and reactivity.
Data Source
AI summary
The present disclosure relates to a composite particle comprising a dye, an amphiphilic block copolymer and a free radical scavenger, and the use thereof in the preparation of ophthalmic lenses and/or thin-film coating such as sol-gel coating on ophthalmic lenses. The present disclosure also relates to methods of optical filtration using the composite particles of the present disclosure.