Surface Modification of Textiles with Nanomaterials …
31
4.5.1 Fabric-Based Temperature Sensor
To achieve the requirement of self-monitoring of body temperature, wearable health
care devices plays an important role with the superimposed advantages of noninvasive methodologies and quantitative monitoring. These sensors are biocompatible, light-weight, flexible and highly sensitive towards temperature (35–42 °C). The
principle of detection is based on resistometric mechanism. Initially, electron hopping was utilized at the interfaces to enhance the sensitivity. For instance, carbon
derivatives and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:
PSS) mixed in water towards the fabrication of hypersensitive temperature sensor.
The mixed solution was imprinted on the surface of fabrics via pattering technique.
Finally, the surface modified fabric is cured at 70 °C for 1 h. Due to electron hopping between the interface [152], change in resistance was observed as a function of
temperature in the developed sensing element.
4.5.2 Pressure Monitoring Fabrics
Integration of wearable sensor network with electrodes on life jacket/belt for remote
health care monitoring could be employed (e.g., ECG, EG and EMG). As a primary
platform, incorporation of nanostructured materials on fabrics can support a variety of sensing applications. For instance, flexible e-Nanoflex band-aid based sensors
have been utilized for monitoring respiratory function, blood pressure, pulse rate and
other parameters. Also, conductive carbon nanotubes (CNT) based fabrics have been
developed as a strain and temperature-based sensor [152]. Piezo-resistive conductive polymers with their composites have also been receiving significant importance
due to their excellent flexibility and biocompatibility for the development of strain
sensors. The working mechanism behind pressure-based sensors could be realized
through the following scheme:
The flexible pressor sensor consists of two different substrates, namely, flexible conductive material medium and suitable substrates. Under external pressure,
changes in contact resistance between the substrate and the printed electrodes are
observed [153],
(i) Under a constant voltage of 0.01 V, an increase in the current was observed.
When an external pressure was applied, it caused a tiny deformation of the
porous substrate (fabric) and established a closer contact between the substrate
and the interdigitated electrodes, thus increased the conductivity.
(ii) Under unloading of external pressure, the deformed porous substrate returned
back to its native state thereby increasing the contact area between the substrate
and interdigitated electrodes, thus reducing the current flow.
These materials are robust for longer duration under temperatures ranging from
−50 to +200 °C, which is also dependent on conductive phase content. The data
obtained from these wearable fabrics is communicated to a nearby storage device,
which is then examined by the medical team. By utilizing the wearable fabrics, blood
31
4.5.1 Fabric-Based Temperature Sensor
To achieve the requirement of self-monitoring of body temperature, wearable health
care devices plays an important role with the superimposed advantages of noninvasive methodologies and quantitative monitoring. These sensors are biocompatible, light-weight, flexible and highly sensitive towards temperature (35–42 °C). The
principle of detection is based on resistometric mechanism. Initially, electron hopping was utilized at the interfaces to enhance the sensitivity. For instance, carbon
derivatives and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:
PSS) mixed in water towards the fabrication of hypersensitive temperature sensor.
The mixed solution was imprinted on the surface of fabrics via pattering technique.
Finally, the surface modified fabric is cured at 70 °C for 1 h. Due to electron hopping between the interface [152], change in resistance was observed as a function of
temperature in the developed sensing element.
4.5.2 Pressure Monitoring Fabrics
Integration of wearable sensor network with electrodes on life jacket/belt for remote
health care monitoring could be employed (e.g., ECG, EG and EMG). As a primary
platform, incorporation of nanostructured materials on fabrics can support a variety of sensing applications. For instance, flexible e-Nanoflex band-aid based sensors
have been utilized for monitoring respiratory function, blood pressure, pulse rate and
other parameters. Also, conductive carbon nanotubes (CNT) based fabrics have been
developed as a strain and temperature-based sensor [152]. Piezo-resistive conductive polymers with their composites have also been receiving significant importance
due to their excellent flexibility and biocompatibility for the development of strain
sensors. The working mechanism behind pressure-based sensors could be realized
through the following scheme:
The flexible pressor sensor consists of two different substrates, namely, flexible conductive material medium and suitable substrates. Under external pressure,
changes in contact resistance between the substrate and the printed electrodes are
observed [153],
(i) Under a constant voltage of 0.01 V, an increase in the current was observed.
When an external pressure was applied, it caused a tiny deformation of the
porous substrate (fabric) and established a closer contact between the substrate
and the interdigitated electrodes, thus increased the conductivity.
(ii) Under unloading of external pressure, the deformed porous substrate returned
back to its native state thereby increasing the contact area between the substrate
and interdigitated electrodes, thus reducing the current flow.
These materials are robust for longer duration under temperatures ranging from
−50 to +200 °C, which is also dependent on conductive phase content. The data
obtained from these wearable fabrics is communicated to a nearby storage device,
which is then examined by the medical team. By utilizing the wearable fabrics, blood