Copper Nanoparticle Coatings via UV Crosslinking
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Solution Overview
Problem
There is a need for water-soluble polymeric complexes that contain reducible copper ions, which can be readily reduced and form uniform copper nanoparticle coatings or patterns, and are durable after application to a substrate, while also being capable of crosslinking with UV light to become water-insoluble and highly durable.
Innovation Solution
A copper-containing article comprising a substrate with a copper-containing composition of a reactive polymer that includes greater than 1 mol % of recurring units with sulfonic acid or sulfonate groups and at least 5 mol % of recurring units capable of crosslinking via [2+2] photocycloaddition, allowing for the formation of copper nanoparticles with an average diameter of 2 nm to 500 nm, and optional pendant groups such as amide, amine, hydroxyl, lactam, phosphonic acid, or carboxylic acid groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-soluble polymeric complexes with reducible copper ions are used, then ease of manufacture and application are improved, but durability and water resistance deteriorate
Solution Approach 1:
The patent applies preliminary action by incorporating UV-reactive groups into the polymer structure before application, allowing the coating to be crosslinked and made water-insoluble after application through UV exposure. This enables the coating to start in a water-soluble state for easy application, then transforms to a durable, water-resistant state afterward.
Solution Approach 2:
The patent utilizes parameter changes by transforming the polymer from water-soluble to water-insoluble through UV-induced crosslinking. The chemical structure parameter changes from linear/branched chains to a crosslinked network, fundamentally altering the solubility and durability properties of the coating.
2Reliability
If copper ions are reduced to form copper nanoparticles, then antimicrobial activity is improved, but uniformity and control of nanoparticle size deteriorate
Solution Approach 1:
The patent uses the polymer itself as an intermediary and reducing agent to control copper ion reduction. The polymer's functional groups (such as hydroxyl, carboxyl, or amine groups) mediate the reduction process, enabling controlled formation of uniform copper nanoparticles with consistent sizes ranging from 2 nm to 500 nm.
Solution Approach 2:
The patent controls nanoparticle formation by adjusting parameters such as pH, temperature, and polymer-to-copper ratio. By optimizing these parameters, the reduction of copper ions proceeds uniformly, producing nanoparticles with controlled and consistent sizes that maintain antimicrobial activity.
3Reliability
If UV crosslinking is performed to make coating water-insoluble, then durability is improved, but processing flexibility and patternability deteriorate
Solution Approach 1:
The patent applies preliminary action by applying the water-soluble coating first, which allows for easy patterning, printing, or masking before UV exposure. Once the desired pattern is established, UV crosslinking is performed to lock in the design and provide durability, ensuring that patternability is not compromised by premature crosslinking.
Solution Approach 2:
The patent employs a dynamic, two-stage process where the coating transitions from a flexible, water-soluble state during application and patterning to a rigid, water-insoluble state after UV crosslinking. This dynamic approach allows the coating to adapt to different processing requirements at different stages.
4Reliability
If silver salts are used for antimicrobial activity, then antimicrobial effectiveness is improved, but cost and color stability deteriorate
Solution Approach 1:
The patent applies this principle by using copper, which is significantly cheaper than silver, as the antimicrobial agent. While copper may have different longevity characteristics, it provides effective antimicrobial activity at much lower cost, making it economically viable for widespread application.
Solution Approach 2:
The patent addresses color stability by using copper compounds that do not exhibit the photosensitivity problems of silver salts. Copper-based coatings maintain their color over time and do not darken with light exposure, providing both aesthetic and functional advantages.
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 solution enables the creation of high-resolution, antimicrobial coatings with enhanced durability and patternability, facilitating the inhibition of microbial colonization and growth, and allows for roll-to-roll manufacturing using simple water-bath processing.
Implementation Method 1
at least 5 mol % of recurring units comprising a pendant group capable of crosslinking via [2+2] photocycloaddition
Implementation Method 2
contain reducible copper ions or copper nanoparticles
Data Source
AI summary
A water-soluble composition includes reducible copper ions or copper nanoparticles complexed with a reactive polymer. The reactive polymer can be crosslinked using suitable irradiation to provide copper-containing water-insoluble complexes. The water-soluble composition can be used to provide various articles and electrically-conductive materials that can be assembled in electronic devices. The reactive polymer has greater than 1 mol % of recurring units comprising sulfonic acid or sulfonate groups, at least 5 mol % of recurring units comprising a pendant group capable of crosslinking via [2+2] photocycloaddition, and optionally at least 1 mol % of recurring units comprising a pendant amide, amine, hydroxyl, lactam, phosphonic acid, or carboxylic acid group.