Ink-Jet Print Head Waveform for Metallic Nanoparticle Dispensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current industrial ink-jet printers face challenges in printing metallic nanoparticle features with line widths less than 100 μm due to nanoparticle aggregation, which leads to nozzle clogging, requiring larger droplet sizes and limiting the use of smaller picoliter print heads.
Innovation Solution
A method involving a metallic nanoparticle composition of silver nanoparticles with a glycol ether solvent and polyvinylpyrrolidone (PVP) is used, which includes configuring the ink-jet print head to dispense droplets between 0.5 and 2.0 picoliters using a specific jetting waveform, preventing aggregation and enabling the use of 1 picoliter print heads without clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ink-jet printing is used with metallic nanoparticles, then printing capability is achieved, but nanoparticle aggregation causes nozzle clogging
Solution Approach 1:
A surfactant is introduced as an intermediary substance between the metallic nanoparticles and the solvent. The surfactant adsorbs onto the nanoparticle surfaces, providing steric stabilization that prevents aggregation. This mediator allows the nanoparticles to remain dispersed in the ink composition without clogging the print head nozzles, resolving the contradiction between maintaining nozzle functionality and preventing nanoparticle aggregation.
Solution Approach 2:
The patent modifies the chemical parameters of the ink composition by selecting a solvent with specific properties (high boiling point of 200-240°C, controlled viscosity of 4-8 cP, and low vapor pressure ≤0.1 mm Hg). These parameter changes ensure the ink maintains appropriate flow characteristics for jetting while preventing nanoparticle aggregation, thereby maintaining nozzle reliability without sacrificing printing capability.
2Reliability
If larger droplet sizes are used to prevent nozzle clogging, then nozzle reliability is maintained, but manufacturing precision of fine features deteriorates
Solution Approach 1:
The surfactant acts as a protective intermediary that allows the use of smaller droplets (0.5-2.0 picoliters) without causing nozzle clogging. By preventing nanoparticle aggregation at the nozzle level, the surfactant enables precise droplet placement with smaller volumes, thereby achieving both nozzle reliability and fine feature manufacturing precision that would otherwise be contradictory.
Solution Approach 2:
The patent changes the physical parameters of the ink composition, specifically controlling viscosity (4-8 cP) and surface tension through surfactant addition. These parameter changes enable the formation of smaller, more uniform droplets that can be precisely deposited without aggregating in the nozzle, thus achieving both small droplet size for precision and reliable nozzle operation.
3Manufacturing precision
If smaller picoliter print heads are used to achieve fine line widths, then manufacturing precision improves, but nozzle clogging from nanoparticle aggregation increases
Solution Approach 1:
The surfactant serves as a protective intermediary in the ink composition that prevents nanoparticle aggregation before the particles can clog the smaller nozzle openings. This allows the use of picoliter-scale print heads with opening sizes of 10-50 μm to achieve fine line widths of 50 μm or less while maintaining reliable nozzle functionality over extended printing periods.
Solution Approach 2:
The patent modifies the ink composition parameters by selecting a solvent with high boiling point (200-240°C) and controlled viscosity (4-8 cP), and by adding surfactant at optimized concentrations. These parameter changes ensure the ink flows smoothly through smaller nozzle openings while preventing nanoparticle aggregation, enabling both fine feature printing and reliable operation of picoliter print heads.
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 allows for the successful printing of features with line widths less than 50 μm without nozzle clogging, maintaining print head functionality for several weeks and achieving electrical resistivity close to bulk silver conductivity.
Implementation Method 1
a piezoelectric actuator and a nozzle opening
Implementation Method 2
During the intermediate contraction waveform portion, an applied voltage increases from an initial low voltage to an intermediate voltage and then is held at the intermediate voltage
Implementation Method 3
During the final contraction waveform portion, the applied voltage increases from the intermediate voltage to a maximum voltage and then is held at the maximum voltage
Implementation Method 4
During the expansion waveform portion, the applied voltage decreases from the maximum voltage to a final low voltage
Implementation Method 5
a glycol ether solvent. The glycol ether solvent has a boiling point in a range of 200° C. to 240° C., a viscosity in a range of 4 cP and 8 cP at 25° C., and a vapor pressure not exceeding 0.1 mm Hg at 25° C.
Implementation Method 6
Polyvinylpyrrolidone (PVP) is present on the silver nanoparticle surfaces
Data Source
AI summary
A method of forming a feature by dispensing a metallic nanoparticle composition from an ink-jet print head is disclosed. A jetting waveform is applied to piezoelectric actuator to dispense droplets of the metallic nanoparticle composition through nozzle opening. The droplets range in volume between 0.5 picoliter and 2.0 picoliter. The jetting waveform includes an intermediate contraction waveform portion, a final contraction waveform portion after the intermediate contraction waveform portion, and an expansion waveform portion after the final contraction waveform portion. During the intermediate contraction waveform portion, an applied voltage increases from an initial low voltage to an intermediate voltage and then is held at the intermediate voltage. During the final contraction waveform portion, the applied voltage increases from the intermediate voltage to maximum voltage and then is held at the maximum voltage. During the expansion waveform portion, the applied voltage decreases from the maximum voltage to a final low voltage.