The monitoring of the breathing air quality today is of great importance,
due the numerous particles, chemical and biological agents that
can damage the health. For this reason, the use of a micro sensor
system for monitoring the contamination like allergens, gas, dust,
pollen and / or pathogens in enclosed spaces, such as Hospitals,
public buildings, airports, trains, etc., is very relevant issue today.
For example, viruses are among the main causes of disease [14 -16]
and provide an increasing risk as a means of biological warfare and
terrorism [11- 13]. Therefore, the detection of pathogens (virus) is an
important issue. Today nanofibers have been an object of interest for
different kind of applications like sensor, Bio-sensor, Tissue, actuators,
etc, because of their extraordinary properties in comparison to
film and bulk materials. Properties like the huge surface to volume
ratio that increases the sensitivity of the fiber. Therefore is natural to
want to know and investigate the properties of the polymer nanofibers
for its application as sensors and as actuator element.
Patolsky et al. [3] has reported a FET-biosensor prototype based on
the conductance change of silicon nanowires where it’s electrical
and mechanical properties are well known in comparison to the
polymer nanofiber. Hence, are very important the geometrical, mechanical
and electrical properties of the fibers in order to determine
for example the working range, the sensibility and the minimal detection
limits of the polymer nanofiber. This is the base for the motivation
of the PhD thesis.
The aim of the thesis is to characterize the mechanical, geometrical
and electrical properties of polymer nanofibers and this way contribute
to have a base to develop and build a bio- and/or gas sensor
using the nanofiber or electrospun as sensing element to detect the
pathogens or gas in an enclosed space. This work presents the
results for the transversal E modulus which is not only important for
sensor development, also is important for the tissue engineering and for actuators technology. The electrical properties is analyze through the impedance spectroscopy method, for this task we have develop a coplanar micro strip (CPμS) waveguide which can measured the ac complex impedance of the polymer electrospun in the frequency range. The idea of the detection principle is based on the impedance change in the low frequency range. The results for the prototype CPμS/electrospun sensor system shown that is possible the measurement of the ac impedance change of the PEO electrospun and its electronic properties as the conductance and capacitance. Therefore, it has a big potential to be used as gas o biosensor. The polyethylene oxide electrospun (PEO-nanofibers) was produced by the electrospinning method, which can produce nanofibers with a diameter less than 100 nm.