Silver Nanoparticle Composition with Carboxylic and Sulfonic Acid Polymer Stabilizer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aqueous silver nanoparticle dispersions face challenges in achieving high concentrations with low viscosity, colloidal stability, and excellent electrical conductivity after sintering, while also being water reducible and suitable for various printing techniques.
Innovation Solution
Aqueous silver nanoparticle dispersions are formulated with a water-soluble polymer having both carboxylic acid and sulfonic acid groups, allowing for silver concentrations greater than 10% by weight, with a polymer-to-silver weight ratio of 0.0005 to 0.11, which enhances stability, handleability, and conductivity, and can be used in various printing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver nanoparticle concentration is increased to achieve high conductivity, then electrical conductivity improves, but viscosity increases making the dispersion difficult to handle and print
Solution Approach 1:
The patent changes the chemical parameters of the stabilizing agent by using a copolymer with specific functional groups (carboxylic acid and sulfonic acid) in specific ratios. This parameter change allows the system to maintain low viscosity even at high silver concentrations (up to 75-90 wt%), resolving the contradiction between conductivity and handleability
Solution Approach 2:
The patent uses a composite stabilizing agent system comprising a copolymer with both carboxylic acid and sulfonic acid groups. This composite material approach provides synergistic effects where the different functional groups work together to prevent aggregation while maintaining fluidity, enabling high silver content dispersions with manageable viscosity
2Manufacturing precision
If multiple passes of inkjet printing are used to achieve sufficient silver coverage, then conductive pattern formation improves, but processing time increases and conductivity remains poor
Solution Approach 1:
The patent modifies the chemical composition parameters of the silver nanoparticle dispersion, specifically using a copolymer stabilizer with optimized functional group ratios. This enables single-pass inkjet printing to achieve sufficient silver deposition and formation of highly conductive patterns, eliminating the need for multiple passes and reducing processing time
3Reliability
If high concentrations of silver nanoparticles are used to achieve low resistivity, then electrical conductivity improves, but colloidal stability deteriorates leading to aggregation
Solution Approach 1:
The patent employs a composite stabilizing polymer containing both carboxylic acid groups (for strong binding to silver surface) and sulfonic acid groups (for providing steric stabilization and water solubility). This composite material structure maintains colloidal stability even at very high silver concentrations by preventing particle aggregation through combined electrostatic and steric mechanisms
Solution Approach 2:
The patent optimizes the molecular weight and functional group ratio parameters of the copolymer stabilizer. These parameter adjustments ensure that the stabilizer provides sufficient coverage and protection to silver nanoparticles at high concentrations, maintaining both colloidal stability and electrical conductivity
4Stability of the object's composition
If high molecular weight polymers are used as stabilizers to improve colloidal stability, then stability improves, but viscosity increases and electrical conductivity after annealing decreases
Solution Approach 1:
The patent carefully controls the molecular weight parameter of the copolymer stabilizer, keeping it in an optimal range that provides sufficient stabilization without excessive viscosity. The functional group composition is also optimized to maximize stabilizing efficiency per unit mass, allowing use of lower polymer concentrations that maintain stability while preserving electrical conductivity after annealing
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 dispersions exhibit good stability, low viscosity, and high conductivity, enabling the formation of highly conductive silver traces that can be easily printed, with silver nanoparticle sizes tunable for specific applications and achieving resistivity close to that of pure silver.
Implementation Method 1
a water-soluble polymer having both carboxylic acid and sulfonic acid groups; and silver nanoparticles dispersed in the water
Implementation Method 2
The electrical resistivity generated at such conditions is greater than 0.2 ohms/square. The requirement of multi-pass and the resultant poor conductivity are perhaps due to the low weight percentage of silver nanoparticles in the inks and the particular stabilizers used which could lead to poor curing of silver nanoparticles during sintering.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A metal nanoparticle composition includes water and a water- soluble polymer having both carboxylic acid and sulfonic acid groups. Silver nanoparticles are dispersed in the water such that the weight percentage of silver in the composition is greater than 10%.