Silver Nanoparticle Ink Manufacturing via Wet Cake Processing
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Solution Overview
Problem
Current methods for manufacturing conductive inks using silver nanoparticles face challenges such as high annealing temperatures required to remove stabilizers, adhesion issues with substrates, and safety concerns due to handling of small particles, which limit their application in printed electronics.
Innovation Solution
A method involving the formation of a wet cake of stabilized metal nanoparticles that are not actively dried before being incorporated into a solvent containing a polyvinyl alcohol derivative, reducing the need for high-temperature processing and minimizing exposure to nanoparticles during handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large molecular weight stabilizers are used to ensure solubility and stability of silver nanoparticles, then nanoparticle stability is improved, but annealing temperature must be raised above 200°C which damages low-cost plastic substrates
Solution Approach 1:
The patent extracts and removes the large molecular weight stabilizers from the nanoparticle system. By using stabilizer-free or minimally-stabilized silver nanoparticles, the invention eliminates the need for high-temperature annealing while maintaining nanoparticle stability through alternative means such as controlled synthesis conditions and immediate processing in the wet state.
Solution Approach 2:
The invention changes the chemical composition parameters by eliminating or minimizing stabilizer content in the nanoparticle formulation. This parameter change allows the system to achieve both nanoparticle stability and compatibility with low-temperature substrates, resolving the contradiction between stability and temperature requirements.
2Productivity
If dried silver nanoparticle powder is handled and processed, then manufacturing efficiency is improved, but occupational exposure to airborne nanoparticles increases creating safety hazards
Solution Approach 1:
The patent employs liquid-phase processing methods where silver nanoparticles are handled in solution or slurry form rather than as dry powder. This hydraulic approach maintains manufacturing efficiency while eliminating airborne nanoparticle generation, thereby removing the occupational exposure hazard associated with dry powder handling.
Solution Approach 2:
The invention changes the physical state parameter of the nanoparticles from solid powder to liquid suspension. By processing nanoparticles in wet form throughout the manufacturing sequence, the system maintains productivity while eliminating the safety hazards of airborne exposure that occur during drying, weighing, and handling of dry powder.
3Ease of operation
If conventional drying methods are used to prepare nanoparticle powder, then material handling is simplified, but adhesion to substrates deteriorates and printed features become easily damaged
Solution Approach 1:
The patent applies preliminary protective action by incorporating adhesion promoters and binders into the liquid nanoparticle formulation before substrate deposition. This preliminary action ensures strong adhesion is established during the printing process itself, eliminating the need for subsequent drying steps that would compromise adhesion strength.
Solution Approach 2:
The invention maintains liquid or slurry form of nanoparticles throughout processing, using the fluid medium to carry adhesion-promoting components that bond the nanoparticles to the substrate. This hydraulic approach provides both ease of handling during deposition and strong adhesion, resolving the contradiction between handling convenience and bond strength.
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
This approach enhances the safety of the manufacturing process, improves adhesion to substrates, and allows for the use of lower annealing temperatures, making the method more suitable for low-cost plastic substrates and reducing health hazards associated with handling silver nanoparticles.
Implementation Method 1
forming a slurry by precipitating stabilized metal nanoparticles in the first solvent
Implementation Method 2
adding a reducing agent to the first solvent, adding a metal salt to the first solvent and forming a slurry by precipitating stabilized metal nanoparticles
Data Source
AI summary
In an embodiment, there is a method of preparing a conductive ink formulation. The method can include dissolving a stabilizer in a first solvent, adding a reducing agent to the first solvent, adding a metal salt to the first solvent and forming a slurry by precipitating stabilized metal nanoparticles in the first solvent. The method can also include forming a wet cake of the stabilized metal nanoparticles and adding the wet cake to a second solvent. The second solvent can include at least one of a polyvinyl alcohol derivative. The wet cake may not be actively dried prior to being added to the second solvent.