Printable Nafion Dispersion with Tunable Viscosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The commercially available Nafion™ polymer dispersions are not suitable for large-scale production of printed electronics due to their low viscosity and strong acidic properties, which are not compatible with screen printing processes.
Innovation Solution
A method involving the neutralization of an acidic polymer with a base to form a salt, which is then dispersed in a solvent system with high-boiling-point solvents, allowing for the creation of a printable dispersion with tunable viscosity suitable for screen printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available Nafion™ polymer dispersions are used, then the material provides suitable ionic properties for sensors, but the low viscosity is not suitable for screen printing
Solution Approach 1:
The patent changes the viscosity parameter of the polymer dispersion by replacing low-viscosity solvents (1-propanol, ethanol, mixed ethers, VOC solvents) with high-viscosity solvents (glycerol, ethylene glycol, propylene glycol, butylene glycol, and their mixtures). This parameter change makes the dispersion suitable for screen printing while maintaining the ionic properties of Nafion™
Solution Approach 2:
The patent uses commercially available Nafion™ polymer dispersion as a starting material and modifies it through a simple solvent replacement process, avoiding the need to synthesize new polymer materials. This approach is cost-effective and suitable for large-scale production
2Reliability
If commercially available Nafion™ polymer dispersions are used, then the material provides suitable ionic properties, but the strong acidic properties cause corrosion and oxidation issues
Solution Approach 1:
The patent neutralizes the strong acidic properties (pKa ≈ -6) of Nafion™ by adding a base (such as NaOH, KOH, or organic bases like triethylamine) to the dispersion. This converts the harmful acidic characteristics into beneficial neutral or slightly basic properties, eliminating corrosion and oxidation issues while preserving the ionic conductivity needed for sensor applications
3Stability of the object's composition
If low viscosity solvents are used in Nafion™ dispersions, then the material is easy to disperse, but the viscosity is too low for screen printing processes
Solution Approach 1:
The patent systematically changes the viscosity parameter by selecting solvents with progressively higher viscosities. The recommended solvent hierarchy includes glycerol (highest viscosity), followed by ethylene glycol, propylene glycol, butylene glycol, and their mixtures. This parameter change achieves the optimal viscosity range for screen printing (typically 10-1000 cP) while maintaining homogeneous dispersion of the polymer
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 printable dispersion enables large-scale printing applications, including sensors and fuel cells, with improved viscosity and pH neutrality, reducing corrosion and oxidation issues during printing.
Implementation Method 1
reacting a polymer with a base to form a salt thereof
Implementation Method 2
The polymer is dispersed or dissolved in a solvent system comprising one or more original solvents
Data Source
AI summary
A copolymer of polytetrafluoroethylene and a perfluoro acid (e.g., Nafion™) is neutralized by a base to yield its corresponding salt, and a high-boiling-point compatible solvent is used as a substituting solvent, with the original, low-boiling-point solvent being removed by rotor evaporation. The resulting dispersion is screen printable, and its viscosity is controllable by adjusting its solids content. This screen-printable salt dispersion is especially useful in printed electronics applications such as sensors.