New printer uses sound waves to shape ink droplets
Recently, researchers at
Harvard University have discovered a new printing technique that uses sound
waves to generate droplets from waves, which occur with an unprecedented range
of structure and viscosity. This technique can finally enable the creation of
many new biopharmaceuticals, cosmetics, and food and expand the possibilities
of optical and conductive materials, and this printing method can be used for
drop-on-demand printing. In acoustophoretic printing, the sound waves
produce a controlled force that pulls each drop out of the nozzle when it
reaches a specific size and removes it toward the printing target - like
picking apples from a tree!
At
present, liquid droplets are used in many applications from printing inks on
paper to create microcapsules for drug delivery. Inkjet printing is the most
common technique used for liquid droplets of patterns, but it is only suitable
for liquids that are nearly ten times more sticky than water. Yet for many
researchers, many of the fluids of interest are more sticky. For example,
biopolymers and cell-laden solutions, which are important for
biopharmaceuticals and bioprinting, are at least 100 times more sticky than
water. Some Chinese-based biopolymers can be sticky in the form of honey, which
is 25,000 times more sticky than water. The viscosity of these liquids also
dramatically changes with temperature and structure, making it even more
difficult to optimize printing standards to control the size of the droplets.
"By
using the acoustic forces, we have created a new technology that enables the
inventory of printing of numerous materials to be printed in a drop-on-demand
manner, said Jennifer Lewis, the Hansjorg Wyss Professor of Biologically
Inspired Engineering at the Harvard John A. Paulson School of Engineering and
Applied Sciences."Our technology should have an immediate effect on the
pharmaceutical industry. However, we believe that it will become an important
platform for many industries.
"Our
goal was to develop viscosity of the picture by developing a printing system
which is free, the physical properties of the fluid," said Daniele
Foresti, first author of the paper, the Branco Weiss Fellow and Research
Associate in Materials Science and Mechanical Engineering at SEAS. "Thanks
to gravity, any liquid drip-from water leaking from the tap to the experience
of pitch drop throughout the century. With gravity alone, droplets are still
large and difficult to control. The temperature, which has a viscosity of
nearly 200 billion times the water, makes one drop in each decade. To enhance
the formation of projection, the research team relies on generating sound
waves. These pressure waves have typically been used to challenge gravity, as
is the case in acoustic altitude. Now, used by researchers to help gravity,
dubbing this new technique of audio printing".
"Researchers
have developed a new printing platform using acoustic forces, which, unlike
other methods, are independent of materials, thus providing multiple uses for
printing. The application space is limitless. This is a great example of the
breadth and reach of collaborative research, said Dan Finotello, director of
NSF's MRSEC program. "The researchers built an acoustic resonance with an
underwater length that could generate a very limited acoustic field, resulting
in a pull force exceeding 100 times the normal gravitational force (G 1) at the
tip of the printer nozzle - more than four times the gravitational force on the
sun's surface. This controllable force pulls every drop of a nozzle when it
reaches a certain size and directs it toward the printing target. The greater
the amplitude of sound waves, the fewer droplets, regardless of the viscosity
of the liquid. The researchers tested the process on a wide range of
materials from honey to stop cell inks, optical resins, biopolymers, and even
liquid metals. Most importantly, sound waves do not pass through droplets,
making this method safe to use even with sensitive biological charges, such as
living cells or proteins. As mentioned above, acoustic waves were previously
used to raise liquid droplets. The latest technology uses sound waves to
enhance gravity rather than help. The formation of normal low and normal
droplets leads to small capsules being very large and high. By pushing droplets
more efficiently, scientists can produce smaller, more precise deposits. The
greater the sound waves, the smaller the droplets, Dan Finotello
explained.
General Preference:
This
story is published in Science Advances, 2018, with the title
“Acoustophoretic printing” and distributed by many websites with the title
"Sound can be used to print droplets that couldn't be printed
before."
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New printer uses sound waves to shape ink droplets
Reviewed by The Scientific World
on
September 08, 2018
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