INVESTIGADORES
BARBERO Cesar Alfredo
artículos
Título:
Pressure and microwave sensors/actuators based on smart hydrogel/conductive polymer nanocomposite
Autor/es:
R. RIVERO; MARIA A. MOLINA; CLAUDIA R. RIVAROLA; CESAR A BARBERO
Revista:
SENSORS AND ACTUATORS A-PHYSICAL
Editorial:
ELSEVIER SCIENCE SA
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 190 p. 270 - 278
ISSN:
0924-4247
Resumen:
A nanocomposite is fabricated by formation of a conductive polymer,
using in situ oxidative polymerization, inside a thermosensitive
crosslinked hydrogel. FE-SEM micrographs show the nanometric domains of
the conductive material (polyaniline, PANI) dispersed in the hydrogel
matrix based on cross linked poly(N-isopropylacrylamide) (PNIPAm). The
thermosensitive properties of PNIPAm and copolymers with
2-acrylamido-2-methyl propane sulfonic acid (AMPS) are not affected by
the presence of conductive polymer nanoparticles. The incorporation of
PANI improves the mechanical properties of the hydrogel allowing it to
swell up to 30,000% without breaking. Since the conductive polymer
absorbs strongly microwave radiation at pH < 4 and heats up, the
nanocomposite containing PANI suffer phase transition upon microwave
irradiation. At pH > 4, PANI is not conductive and the nanocomposite
becomes insensitive to microwaves. However, using a pH insensitive
conductive polymer (polypyrrole, PPy) in the nanocomposite makes it
sensitive to microwaves at all pH values. The nanocomposite is used in a
chemomechanical actuator where drug release is driven remotely by
microwave irradiation. Since the PNIPAm-co-2%AMPS/PANI nanocomposite is
soft and electronically conductive, could be used as pressure/force
sensor. It is shown that a compressive force applied on a cylinder of
that nanocomposite increases the conductivity of material. Additionally a
switch is built which turns off upon microwave irradiation. Therefore,
the nanocomposites are potential candidates for different technological
applications, such as: a force/pressure electrical sensor, a drug
delivery device driven remotely by microwaves, pH or temperature
electrical switches and an electric switch driven by microwaves.