Silver Nanoparticle Dispersion for Flexible Electronics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conductive inks face challenges with poor adhesion to various substrates and require high sintering temperatures for conductivity, which is not compatible with common polymer foils like PET, limiting their application.
Innovation Solution
A silver nanoparticle dispersion comprising a vinylidene chloride copolymer as a binder and an acidic polyester as an adhesion promoting compound, which allows for improved adhesion and reduced sintering temperatures, enabling conductive layers on flexible substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional polymeric dispersants are used to stabilize metallic nanoparticle dispersions, then dispersion stability is improved, but sintering temperature increases due to full decomposition temperature of at least 350°C
Solution Approach 1:
The invention changes the chemical composition parameters of the polymeric dispersant by specifying particular polymers (polyvinylpyrrolidone with MW 10,000-1,000,000 or polyacrylic acid with MW 1,000-100,000) and controlling their decomposition characteristics to enable sintering at lower temperatures (200-300°C) while maintaining dispersion stability during storage and processing
Solution Approach 2:
The invention creates a composite system combining metallic nanoparticles with specifically selected polymeric dispersants that have complementary properties: the polymer provides steric stabilization and colloidal stability, while being thermally decomposable at moderate temperatures to leave conductive metallic networks without requiring high-temperature sintering
2Reliability
If high sintering temperatures are used to decompose organic components, then conductivity of applied patterns is improved, but compatibility with common polymer foils like PET deteriorates
Solution Approach 1:
The invention changes the thermal processing parameters by reducing sintering temperature to 200-300°C, which is below the glass transition temperature of PET (around 70-80°C) and well below its melting point, thereby maintaining substrate integrity while achieving sufficient conductivity through controlled decomposition of the polymeric dispersant and sintering of metallic nanoparticles
Solution Approach 2:
The polymeric dispersant acts as an intermediary that facilitates low-temperature sintering by providing controlled thermal decomposition that promotes nanoparticle aggregation and conductivity formation at temperatures compatible with flexible polymer substrates, eliminating the need for high-temperature processing
3Stability of the object's composition
If conventional polymeric dispersants are used, then dispersion stability is maintained, but adhesion to various substrates deteriorates
Solution Approach 1:
The invention changes the chemical structure parameters of the polymeric dispersant by selecting specific polymers (polyvinylpyrrolidone or polyacrylic acid) with functional groups that provide both colloidal stabilization in the dispersion and improved adhesion to diverse substrates through chemical or physical interactions, achieving dual functionality
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 achieves stable and conductive silver layers with enhanced adhesion to diverse substrates, including PET, at lower sintering temperatures, facilitating the use of conductive inks in flexible electronics.
Implementation Method 1
an acidic polyester as an adhesion promoting compound
Implementation Method 2
a sintering step, also referred to as curing step, at elevated temperatures is carried out to induce/enhance the conductivity of the applied patterns of layers
Data Source
AI summary
A metallic nanoparticle dispersion comprising metallic nanoparticles, a binder and a liquid carrier, characterized in that the binder is a vinylidene chloride copolymer comprising 90 wt % or less of vinylidene chloride based on the total weight of the binder.