US-12617672-B2 - On-demand scalable nano-scale 3D printing system

US12617672B2US 12617672 B2US12617672 B2US 12617672B2US-12617672-B2

Abstract

In one embodiment, a 3D printing system includes: a stage on which a substrate is disposed; first and second syringe pumps; first and second syringes; a hydrodynamic flow focusing nozzle having a central channel coupled to the first syringe to receive a printing ink and two side channels on two sides of the central channel and coupled to the second syringe to receive a sheath fluid to pinch the central channel; and a pulse generator to apply an electric potential between the hydrodynamic flow focusing nozzle and the substrate to deposit the printing ink on the substrate on-demand and control ejection frequency of the printing ink. The first syringe pump is controllable to adjust a printing ink flow rate of the printing ink to deposit the printing ink onto the substrate. The second syringe pump is controllable to adjust a sheath fluid flow rate of the sheath fluid.

Inventors

Kyoo D. Jo
Sungmin Hong
Yin Song
Donald M. Cropek
Seung J. OH
Hyunjung Anna Kim

Assignees

UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE ARMY

Dates

Publication Date: 20260505
Application Date: 20230508

Claims (14)

1 . A 3D printing system comprising: a substrate; a first syringe pump and a second syringe pump; a first syringe coupled to the first syringe pump and a second syringe coupled to the second syringe pump; a hydrodynamic flow focusing nozzle having a central channel coupled to the first syringe to receive a printing ink and two side channels disposed on two sides of the central channel and coupled to the second syringe to receive a sheath fluid; and a pulse generator to apply an electric potential between the hydrodynamic flow focusing nozzle and the substrate to deposit the printing ink on the substrate on-demand and control ejection frequency of the printing ink from the hydrodynamic flow focusing nozzle; the first syringe pump being controllable to adjust a printing ink flow rate of the printing ink through the first syringe to the central channel of the hydrodynamic flow focusing nozzle to deposit the printing ink onto the substrate; and the second syringe pump being controllable to adjust a sheath fluid flow rate of the sheath fluid through the second syringe to the two side channels of the hydrodynamic flow focusing nozzle to pinch the printing ink in the central channel using the sheath fluid flowing through the two side channels.
2 . The 3D printing system of claim 1 , further comprising: wherein the first syringe pump and the second syringe pump are independently controllable to adjust the sheath fluid flow rate of the sheath fluid independently of the printing ink flow rate of the printing ink, so as to control a dimension of the printing ink flowing from the hydrodynamic flow focusing nozzle to the substrate.
3 . The 3D printing system of claim 1 , wherein the hydrodynamic flow focusing nozzle comprises a microfluidic nozzle having microfluidic channels having widths of about 40-60 μm.
4 . The 3D printing system of claim 1 , wherein the hydrodynamic flow focusing nozzle has a printing ink nozzle surface for contacting the printing ink; and wherein the printing ink has a higher dielectric constant than the printing ink nozzle surface.
5 . The 3D printing system of claim 4 , wherein the printing ink nozzle surface of the hydrodynamic flow focusing nozzle includes a gold coating.
6 . The 3D printing system of claim 1 , wherein the printing ink comprises at least one of an AuNP solution or gold nanoparticles with controlled sizes in a range of about 3.2-5.2 nm.
7 . A 3D printing system comprising: a substrate; a first syringe pump and a second syringe pump; a first syringe coupled to the first syringe pump and a second syringe coupled to the second syringe pump; a hydrodynamic flow focusing nozzle having a central channel coupled to the first syringe to receive a printing ink and two side channels disposed on two sides of the central channel and coupled to the second syringe to receive a sheath fluid; a pulse generator to apply an electric potential between the hydrodynamic flow focusing nozzle and the substrate to deposit the printing ink on the substrate on-demand and control ejection frequency of the printing ink from the hydrodynamic flow focusing nozzle; first means for controlling the first syringe pump to adjust a printing ink flow rate of the printing ink through the first syringe to the central channel of the hydrodynamic flow focusing nozzle to deposit the printing ink onto the substrate; and second means for controlling the second syringe pump to adjust a sheath fluid flow rate of the sheath fluid through the second syringe to the two side channels of the hydrodynamic flow focusing nozzle to pinch the printing ink in the central channel using the sheath fluid flowing through the two side channels.
8 . The 3D printing system of claim 7 , wherein the second means comprises means for controlling the second syringe pump to adjust the sheath fluid flow rate of the sheath fluid through the second syringe to the two side channels of the hydrodynamic flow focusing nozzle independently of the printing ink flow rate of the printing ink as generated by the first syringe pump, so as to control a dimension of the printing ink flowing from the hydrodynamic flow focusing nozzle to the substrate.
9 . The 3D printing system of claim 7 , wherein the second means comprises means for controlling the second syringe pump to adjust the sheath fluid flow rate of the sheath fluid flowing through the two side channels to pinch the printing ink in the central channel of the hydrodynamic flow focusing nozzle to a diameter of inner vesicles of less than 10 nm.
10 . The 3D printing system of claim 7 , wherein the second means comprises means for controlling the second syringe pump to adjust the sheath fluid flow rate of the sheath fluid flowing through the two side channels to pinch the printing ink in the central channel of the hydrodynamic flow focusing nozzle to a diameter of inner vesicles of about 3-7 nm.
11 . The 3D printing system of claim 7 , wherein the hydrodynamic flow focusing nozzle comprises a microfluidic nozzle having microfluidic channels having widths of about 40-60 μm.
12 . The 3D printing system of claim 7 , wherein the hydrodynamic flow focusing nozzle has a printing ink nozzle surface for contacting the printing ink; and wherein the printing ink has a higher dielectric constant than the printing ink nozzle surface.
13 . The 3D printing system of claim 12 , wherein the printing ink nozzle surface of the hydrodynamic flow focusing nozzle includes a gold coating.
14 . The 3D printing system of claim 7 , wherein the printing ink comprises at least one of an AuNP solution or gold nanoparticles with controlled sizes in a range of about 3.2-5.2 nm.

Description

STATEMENT OF GOVERNMENT INTEREST Under paragraph 1 (a) of Executive Order 10096, the conditions under which this invention was made entitle the Government of the United States, as represented by the Secretary of the Army, to an undivided interest therein on any patent granted thereon by the United States. This and related patents are available for licensing to qualified licensees. BACKGROUND Field of the Invention The present invention relates to 3D printing and, more specifically, to nano-scale 3D printing system and method. Description of the Related Art This section introduces aspects that may help facilitate a better understanding of the invention. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art. Electrohydrodynamic printing (EHDP) has become a viable high-resolution printing approach for nano-scale manufacturing. The printing resolution, however, is limited by the nozzle orifice dimension causing nozzle clogging. SUMMARY The present invention was developed to address the desire for nano-scale 3D printing technology. The research has led to an on-demand scalable nano-scale 3D printing system to create highly controlled and programmable nano and microfeatures on surfaces that imbue surfaces with a plethora of novel functionalities (including antimicrobial, camouflage, and total absorption of LASER and Infrared for concealment). Since the smallest droplet size is limited to ˜ 1/15 of the nozzle size, nanoscale nozzle fabrication is a main challenge in any nanoscale 3D printing in addition to the clogging due to the narrow nozzle dimension. Electrohydrodynamic printing (EHDP) has become a viable high-resolution printing approach for nano-scale manufacturing. EHDP utilizes an electric potential applied between a nozzle and the substrate. The electric potential causes mobile ions to accumulate near the mouth of the nozzle and due to ionic electrostatic repulsion, the polymer ink deforms into the Taylor cone. When the electrical potential exceeds the surface tension, the Taylor cone is stretched and produces a fine jet or droplet from the cone depending on the electric field strength and the frequency of pulsation. Once the ink droplet is ejected, it is accelerated by the electric field and deposited on the substrate. Owing to rapid vaporization of solvent, periodic accumulation occurs resulting in printing 3D features. Although EHDP is one of the most promising nano 3D printing technologies, the printing resolution is still limited by the nozzle orifice dimension causing nozzle clogging. Specific embodiments are directed to a 3D nano printing system. The system includes a nanostage set up in a faraday cage and a house-made microfluidic nozzle connected with a LabSmith workstation and syringe pumps. The printing system is used to successfully fabricate four pillars simultaneously by controlling the voltage, frequency, and distance between the nozzle tip and the substrate. 3D reconstruction image is also obtained to measure the height and width of pillars. The average size of pillars is measured to be 5.51±0.31 μm in height and 750±0.71 nm in width. The height and the width can be controlled to nanosize by decreasing the time of deposition and the distance between the nozzle tip and the substrate. 3D nanoprinting technology can be applied to anti-icing, contaminant-free surfaces, remediation and protection against chem/bio warfare agents, maintenance-free long-lasting structures, antimicrobial, camouflage, biosensors, and total absorption of LASER and IR for concealment. End users could print out on-demand scalable nanostructures. Examples of commercial application include airplane wings, nanolithography for IC chip fabrication, corrosion prevention including corrosion-free and contaminant-free materials, building and structures construction, prevention of airborne bacterial diseases, antimicrobial and biowarfare protection, etc. In one example, the technique is used to generate nanosized pillar(s) that will have antifouling activity. In addition, the research includes post-fabricating the surface with antibody that is specific for certain mircoorganisms bringing target-specificity. It led to antimicrobial super surfaces for target-specific bactericidal. According to an aspect the present invention, a 3D printing system comprises: a substrate; a first syringe pump and a second syringe pump; a first syringe coupled to the first syringe pump and a second syringe coupled to the second syringe pump; a hydrodynamic flow focusing nozzle having a central channel coupled to the first syringe to receive a printing ink and two side channels disposed on two sides of the central channel and coupled to the second syringe to receive a sheath fluid; and a pulse generator to apply an electric potential between the hydrodynamic flow focusing nozzle and the substrate to deposit the printing ink on the substrate o