Electrospinning sensors

Polymer-supported Ag nanoparticles have been widely investigated and provide potential applications as catalysts, photonic and electronic sensors, wound dressings, body wall repairs, augmentation devices, tissue scaffolds, and antimicrobial filters [15-22]. For these applications, Ag nanoparticles have to be supported in a biocompatible polymer system [23-26]. The electrospinning technique has often been adopted for the incorporation of Ag nanoparticles into polymer porous media. In this chapter, we review the preparation methods and properties of Ag nanoparticles incorporated into polymeric nanofibers and their applications in the fields of filtration, catalysis, tissue engineering and wound dressing. 

Figure 4.9 A scheme showing the change in interactions between a CNTand a polymer chain by the self-heating of a CNT inside a conducting composite nanofiber. (Reprinted with permission from Sensors and Actuators B., Enhanced conductivity of aligned PANi/PEO/MWNT nanofibers by electrospinning by M. K. Shin, Y. J. Kim, 5. I. Kim et a ., 134, 122-126.

R. Rojas and N. J. Pinto, Using electrospinning for the fabrication of rapid response gas sensors based on conducting polymer nanowires. Sens. J., IEEE, 8, 951-953 (2008). 

Nanocable chemosensors have been formed in which an inner core fiber filament is further modified by polymerization of the conducting polymer on its surface. This was first described for sensing by Zhang et al. in which a carbon fiber was used as the template for the electrochemical polymerization of a thin film of PANI [27]. The resulting nanoelectrode sensor was used to detect changes in pH resulting from the level of protonation in the polymer backbone. PPy nanofibers have been formed by the electrospinning of nylon fibers. 

Composite fibers of poly(o-anisidine]-PS was produced by electrospinning for chemical vapor sensing. Sensibility of the composite fibers were tested under water and ethanol vapor, the sensors elements responded better to the high polarity ofthe solvent. The CSA-doped POA/PS composition seems to be stable under the submitted ambient conditions to ethanol. The sensor could be reused several times without any change in sensing behavior and/ or damage to the sensing materials. 

In the PANI.TSA/PLA blended electrospun nanofibers no phase segregation of PANI in a PLA matrix was observed, while phase segregation was observed in cast films with the same composition. Due to rapid solvent evaporation in the electrospinning process, no crystalline structures in fiber mats were formed compared to cast films. Highly homogeneous electroactive fibers can be useful in the construction of electronic devices and sensors. Similar behavior was observed in the PVDF-TrFE/PANI-PSSA electrospun nanofibers. 

Preparation of PANI nanofiber humidity sensors produced by electrospinning from the DMF solution of PANI, poly(vinyl butyral) (PVB), and PEO were shown. It was concluded that PANI nanofibers with some beads and a small content of PEO revealed... 

Lin Q., Li Y, and Yang M., Potyaniline nanofiber humidity sensor prepared by electrospinning. Sens Actuators, 2012,161,967- 972. 

The experiments indicated that PVB is suitable as a matrix to form nanofibers together with poly(ardline) (PANI) by electrospinning. Electrospun PANl/PVB nanofibers exhibited a very high sensitivity of 75 kHz/% relative humidity from 20-90% relative humidity. Further, an ultrafast response of 1-2 s for humidification and desiccation was reported. In addition, the sensor could detect humidity levels as low as 0.5% relative humidity (30). 

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