Microfluidic active mixing nozzle for three-dimensional printing of viscoelastic inks
The present disclosure relates to a device for three-dimensional ink deposition from an impeller-driven active mixing microfluidic printing nozzle. The device is configured to receive a material property associated with the plurality of fluids and receive a structure property of the printing nozzle. The device then determines a threshold relation between a rotating speed Ω of an impeller in the nozzle and a volumetric flow rate Q of fluids that flow through the nozzle based on the material property of the plurality of fluids, the structure property of the printing nozzle. Based on the threshold relation, the device then determines an actual volumetric flow rate of the fluids and actual rotation speed of the impeller.
1. A device for three-dimensional ink deposition from an impeller-driven active mixing microfluidic printing nozzle, the device comprising:
a microfluidic printing nozzle comprising:
a mixing chamber; and
an impeller rotatably disposed in the mixing chamber to mix a plurality of fluids to form a mixed ink;
an electronic controller in electrical communication with the printing nozzle, the controller configured to:
receive a material property associated with each of the plurality of fluids;
receive a structure property of the printing nozzle;
receive a predetermined volumetric flow rate Q of the plurality of fluids in the mixing chamber;
determine a threshold rotating speed Ω of the impeller based on the material property of the plurality of fluids, the structure property of the printing nozzle, and the predetermined volumetric flow rate Q;
introduce the plurality of fluids into the mixing chamber at the predetermined volumetric flow rate; and
rotate the impeller with a rotating speed higher than the threshold rotating speed Ω to mix the plurality of fluids, thereby forming the mixed ink.
2. The device of claim 1 , wherein the material property comprises a diffusion transport rate of the plurality of fluids and a degree of completeness of mixture ε of the plurality of fluids, and
the structure property of the nozzle comprises a length l of the mixing chamber, a diameter d of the mixing chamber, and a diameter δ of the impeller.
3. The device of claim 2 , wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable laminar flow of the plurality of fluids, the threshold rotating speed of the impeller takes a form of:
Ω
=
Q
ld
2
α
c
1
ɛ
Q
l
α
𝒟
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 1 is a constant value.
4. The device of claim 2 , wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable chaotic flow of the plurality of fluids, the threshold rotating speed of the impeller takes a form of:
Ω
=
Q
α
ld
2
log
4
c
2
ɛ
Q
α
l
𝒟
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 2 is a constant value.
5. The device of claim 2 , wherein, when at least one of the plurality of fluids includes non-Brownian particles, the material property associated with the at least one plurality of fluids further comprises particle size d p of the non-Brownian particles, and
the threshold rotating speed of the impeller takes a form of:
Ω
=
c
3
ɛ
Q
α
l
d
2
ln
d
d
p
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 3 is a constant value.
6. The device of claim 1 , wherein the controller is further configured to:
introduce the plurality of fluids via a plurality of fluids inlets in communication with the mixing chamber; and
rotate the impeller by an electric motor operationally coupled to the impeller and electrically controlled by the controller;
extrude a filament of mixed ink over a substrate; and
move at least one of the nozzle and the substrate in a predetermined way to form a predesigned 3D structure using the mixed ink.
7. The device of claim 6 , wherein the 3D structure comprise a soft robot.
8. The device of claim 1 , wherein the mixed ink comprises an elastomeric ink.
9. A method for three-dimensional ink deposition from an impeller-driven active mixing microfluidic printing nozzle, the method comprising:
providing a microfluidic printing nozzle comprising:
a mixing chamber; and
an impeller rotatably disposed in the mixing chamber to mix a plurality of fluids to form a mixed ink;
receiving by a controller in electrical communication with the printing nozzle:
a material property associated with each of the plurality of fluids;
a structure property of the printing nozzle;
a predetermined volumetric flow rate Q of the plurality of fluids in the mixing chamber;
determining a threshold rotating speed Ω of the impeller based on the material property of the plurality of fluids, the structure property of the printing nozzle, and the predetermined volumetric flow rate Q;
introducing the plurality of fluids into the mixing chamber at the predetermined volumetric flow rate; and
rotating, under control of the controller, the impeller with a rotating speed higher than the threshold rotating speed 106 to mix the plurality of fluids, thereby forming the mixed ink.
10. The method of claim 9 , wherein the material property comprises a diffusion transport rate of the plurality of fluids and a degree of completeness of mixture ε of the plurality of fluids, and
the structure property of the nozzle comprises a length l of the mixing chamber, a diameter d of the mixing chamber, and a diameter δ of the impeller.
11. The method of claim 10 , wherein, wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable laminar flow of the plurality of fluids, the threshold rotating speed of the impeller takes a form of:
Ω
=
Q
l
d
2
α
c
1
ɛ
Q
l
α
𝒟
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 1 is a constant value.
12. The method of claim 10 , wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable chaotic flow of the plurality of fluids, the threshold rotating speed of the impeller takes a form of:
Ω
=
Q
α
ld
2
log
4
c
2
ɛ
Q
α
l
𝒟
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 2 is a constant value.
13. The method of claim 10 , wherein, when at least one of the plurality of fluids includes non-Brownian particles, the material property associated with the at least one plurality of fluids further comprises particle size d p of the non-Brownian particles, and
the threshold rotating speed of the impeller takes a form of:
Ω
=
c
3
ɛ
Q
α
l
d
2
ln
d
d
p
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 3 is a constant value.
14. The method of claim 10 , further comprising:
introducing the plurality of fluids via a plurality of fluid inlets in communication with the mixing chamber;
rotating the impeller by an electric motor operationally coupled to the impeller and electrically controlled by the controller;
extruding a filament of mixed ink over a substrate; and
moving at least one of the nozzle and the substrate in a predetermined way to form a predesigned 3D structure using the mixed ink.
15. The method of claim 14 , wherein the 3D structure comprise a soft robot.
16. The method of claim 9 , wherein the mixed ink comprises an elastomeric ink.
17. A device for three-dimensional ink deposition from an impeller-driven active mixing microfluidic printing nozzle, the device comprising:
a microfluidic printing nozzle comprising:
a mixing chamber; and
an impeller rotatably disposed in the mixing chamber to mix a plurality of fluids to form a mixed ink;
an electronic controller in electrical communication with the printing nozzle, the controller configured to:
receive a material property associated with the plurality of fluids;
receive a structure property of the printing nozzle;
receive a predetermined rotating speed Ω of the impeller;
determine a threshold volumetric flow rate Q of the plurality of fluids in the mixing chamber based on the material property of the plurality of fluids, the structure property of the printing nozzle, and the predetermined rotating speed of the impeller;
introduce the plurality of fluids into the mixing chamber at volumetric flow rate lower than the threshold volumetric flow rate Q; and
rotate the impeller at the predetermined rotating speed Ω to mix the plurality of fluids thereby forming the mixed ink.
18. The device of claim 17 , wherein the material property comprises a diffusion transport rate of the plurality of fluids and a degree of completeness of mixture ε of the plurality of fluids, and
the structure property of the nozzle comprises a length l of the mixing chamber, a diameter d of the mixing chamber, and a diameter δ of the impeller.
19. The device of claim 17 , wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable laminar flow of the plurality of fluids, the threshold volumetric flow rate of the plurality of fluids takes a form of:
Q
=
α
ld
·
d
𝒟
Ω
2
c
1
ɛ
3
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 1 is a constant value.
20. The device of claim 18 , wherein, when an inner surface of the mixing chamber and an outer surface of the impeller are configured to enable chaotic flow to the plurality of fluids, the threshold volumetric flow rate of the plurality of fluids takes a form of:
Q
log
4
c
2
ɛ
Q
α
l
𝒟
=
α
ld
2
Ω
,
wherein
α
=
(
1
-
δ
2
d
2
)
and c 2 is a constant value.