Page 29 - Plastcs News August 2017

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Indian scientists use tiny bubbles to draw plastic circuits

Indian scientists have found a way to use micro-bubbles to draw complex plastic circuits with
lasers, an advance that may lead to low-cost flexible electronic devices.

n a first, Indian scientists have found a way to use micro- material which partially absorbs the light, so that the
Ibubbles to draw complex plastic circuits with lasers, local temperature increases very rapidly. However, these
an advance that may lead to low-cost flexible electronic also can be dispensed easily by just redirecting the laser
devices. Solution-printed electronics is one of the fastest or shutting it off. “In the case with the SoMs, the student
growing areas in the industry primarily due to its very low observed that when he tried to move the laser away, the
cost and flexibility, researchers from the Indian Institute bubble followed it, and in the process generated a pattern
of Science Education and Research (IISER) in Kolkata said. in its wake,” Banerjee said.
It is mostly based on conducting plastics,that are doped to
increase conductivity. The process of synthesising, doping “We then proceeded to unravel this mystery, and in the
and designing circuits separately is
often complex and time consuming.
For the first time, scientists led by
Ayan Banerjee and Soumyajit Roy
from IISER Kolkata, have developed a
simple and inexpensive technique to
simultaneously synthesise and pattern
conductive polymers on a glass surface
in a matter of minutes.

They exposed a solution of charged
metal oxide, known as soft oxometalate
(SoM) and organic molecules in a glass
chamber to optical tweezers – a tightly
focused laser. Absorbing the beam,
oxometalate stuck to the chamber
surface to form a micro-bubble around
which the metal oxide and organic molecules assembled
themselves to form conductive polymers.“This patterning process understood the phenomenon, which took more
than a year,” he said. “The research revealed fascinating
technique was discovered somewhat serendipitously
when one of my graduate students was working with explanations, which then led to us think of various
applications,” he added.
SoMs in optical tweezers and noticed these bubbles grow
unexpectedly,” said Banerjee, Associate Professor at IISER This method can be used for complex electronic circuits
Kolkata. which are useful for fabricating electronic devices such
as micro-capacitors. According to Roy, associate professor
Solution-printed electronics is one of the fastest growing
areas in the industry primarily due to its very low cost at IISER Kolkata, the method is cheaper and much easier
than several existing technologies. “The method can even
and flexibility. Bubbles in optical tweezers often occur
when the tightly focused laser hits some accumulated be used to make biodegradable flexible plastic circuits,”
Roy said.

29 Aug ust 2017 | Plastics News