Core-Shell Metal Nanoparticles for Plasmonic Ink Stability
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Solution Overview
Problem
Existing plasmonic ink compositions face challenges in achieving vivid and intense colors due to limited absorption efficiency and potential agglomeration of metal nanoparticles, while also needing to reduce silver content to comply with future regulations.
Innovation Solution
A process for preparing an aqueous suspension of core-shell metal nanoparticles, where the core comprises silver or copper and the shell comprises the other metal, using a mixture of silver and copper salts, vinylpyrrolidone, ascorbic acid, an alkali base, and water, which stabilizes the nanoparticles and enhances their plasmonic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the concentration of metal nanoparticles in the ink is increased to improve vividness, then the color intensity improves, but the nanoparticles tend to agglomerate which negatively impacts vividness and increases complexity
Solution Approach 1:
The patent introduces a polymer coating as an intermediary substance that wraps around metal nanoparticles, preventing them from directly contacting and agglomerating. This polymer mediator maintains nanoparticle dispersion stability even at high concentrations, enabling improved color intensity without the negative effects of agglomeration
Solution Approach 2:
The patent creates composite structures by combining metal nanoparticles with polymer coatings to form core-shell composite materials. This composite approach integrates the plasmonic properties of metal nanoparticles with the stabilizing properties of polymers, achieving both high color intensity and nanoparticle stability
2Object-affected harmful factors
If silver content is reduced to comply with regulations, then safety improves, but the plasmonic performance and vividness may deteriorate
Solution Approach 1:
The patent applies local quality by creating core-shell structures where the core contains high silver content for optimal plasmonic performance, while the shell provides protective and stabilizing functions. This localized distribution allows reduced overall silver content while maintaining plasmonic performance in the core region
Solution Approach 2:
The patent changes the structural parameters of silver nanoparticles by coating them with polymers, transforming them from bare particles to core-shell composite structures. This parameter change enables reduced silver content while maintaining or enhancing plasmonic performance through the modified structural configuration
3Ease of manufacture
If single metal nanoparticles are used to simplify formulation, then manufacturing complexity is reduced, but absorption efficiency is limited and vividness suffers
Solution Approach 1:
The patent employs composite materials by combining different metal nanoparticles with polymer coatings to create core-shell composite structures. This composite approach enhances absorption efficiency through synergistic effects while maintaining relatively simple manufacturing processes using standard nanoparticle synthesis and coating techniques
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 resulting aqueous gel ink exhibits improved vividness and safety with reduced silver content, achieving a synergistic effect in light absorption and stability, while maintaining cost-effectiveness and simplicity in production.
Implementation Method 1
plasmonic ink compositions may be formulated with metal nanoparticles consisting of a single metal... which may have a plasmonic spectrum with well-defined peaks, but their absorption efficiency is limited
Implementation Method 2
mixing: at least one silver salt, at least one copper salt, a homopolymer or copolymer of vinylpyrrolidone... ascorbic acid, an alkali base, and water
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention relates to a process for preparing an aqueous suspension of core-shell metal nanoparticles which essentially consist of metal, wherein the core of said nanoparticles comprises at least one of silver or copper and the shell of said nanoparticles comprises at least one of the other of silver or copper, wherein the metal nanoparticles are prepared by mixing at least one silver salt, at least one copper salt, a homopolymer or copolymer of vinylpyrrolidone at an amount from 0.1 to 1.1 weight% based on the total weight of the aqueous suspension, ascorbic acid, an alkali base, and water. The present invention further relates to an aqueous suspension of core-shell metal nanoparticles, a process for preparing an aqueous gel ink, and to an aqueous gel ink comprising core-shell metal nanoparticles.