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Versatile Actuators Based on Polypyrrole-Coated Metalized Eggshell Membranes
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posted on 2018-06-23, 00:00 authored by Mihaela Beregoi, Nicoleta Preda, Alexandru Evanghelidis, Andreea Costas, Ionut EnculescuEggshell
membranes were employed as biological scaffolds for developing
soft and versatile actuators. A particular architecture, consisting
of eggshell membrane coated with polypyrrole, has been fabricated
and has been found to be a green, inexpensive, lightweight, and easy
to handle class of actuators. The polypyrrole-coated eggshell membrane
devices were tested in liquid, ambient atmosphere and controlled humidity
environment, with the recorded movements proving their versatility.
In 1 M NaCl aqueous solution, by applying successive potential pulses,
the actuator contracts/expands owing to the expulsion/insertion of
the electrolyte ions out/into polypyrrole film, producing a displacement
of ∼0.1 cm. In air, upon application of voltages from 2 to
5 V on a V-shaped geometry actuator, it bends due to water desorption
from its structure induced by Joule heating, generating a displacement
which reaches ∼0.4 cm at 5 V. In a chamber with controlled
humidity, the decrease of humidity stimulates a bending/curling motion
of the actuator, achieving a displacement of ∼2.1 cm at 50%
relative humidity. Upon modification of the humidity, these actuators
move, hold, and release delicate and lightweight objects. Such polypyrrole-coated
eggshell membrane actuators which operate in different environments
and respond to multiple stimuli can have potential applications in
biomimetic micromanipulators or artificial muscle fields.