**4. Characterization of carbon nanofibers (CNF)**

The characterization carried out on the CNF depends on the application to be performed on it, the CNF which has been fabricated is researched as a sensor and as a Capacitive Deionization (CDI) electrode. To find out and measure the morphology and diameter of the nanofibers, a Scanning Electron Microscope or SEM is used for short. Also from SEM we get EDX data which shows the number of elements present in the CNF sample. To determine the electrical properties of CNF, a four-point probe characterization method was used, namely by using the I-V meter four probes. The measurement results using the I-V meter show the

#### **Figure 8.**

*Carbon nanofibers (CNF) electrospinning results with a flow rate of 0.1 ml/hour and relative humidity (a) 30% d and (b) 40% and an average fiber diameter of 262 nm (a) and 309 nm (b), (c) distribution of Carbon nanofibers elements at a flow rate of 0.5 ml/hour and relative humidity of 40% and (d) CNF sheets that are ready to be applied.*

Ohmic curve on the I-V graph according to Ohm's law. The resulting Voltage and Current data are then processed according to Ohm's law to determine the conductivity value of the material.

**Figure 8** shows the electrospinning results with a flow rate of 0.1 ml/hour and relative humidity of 30% and the parameters still produce fibers with an average diameter of 262 nm, the fibers in this parameter have a morphological shape with minimum and almost no beads. Whereas the electrospinning carbon nanofibers with a flow rate of 0.1 ml/hour and relative humidity of 40% and the parameters still produce a fiber with the smallest size of 200 nm and the largest diameter of 400 nm and an average diameter of 309 nm, the fiber in this parameter has a morphological shape with minimum and almost non-existent beads and more uniform diameter sizes and a narrower size range when compared to 30% humidity parameters. The CNF fabrication results were carried out by SEM–EDX to determine the

#### **Figure 9.**

*Electrochemical characterization results. (a) diagram of the cyclic voltammogram (CV) data on the CDI electrode with a sweep rate of 5 mV/s, and (b) the specific capacitance of the carbon electrode from the cyclic voltammogram data.*

**49**

*Fabrication of PVA/Carbon-Based Nanofibers Using Electrospinning*

elements of the nanofibers fabrication as in **Figure 8c**, the distribution of carbon elements has been evenly distributed, as well as the results of nanofibers fabrication with flow rate parameters of 0.1 ml/hour and 40% humidity and fixed parameters. Based on this characterization, carbon nanofibers consists of several chemical elements. The chemical elements, namely, O (Oxygen) by 24.57%, and C (Carbon)

*The Average Value of Voltage and Resistance Sheet of Nanofibers from measurements using the I-V meter four* 

**Sample CNF diameter (nm) Voltage (mV) Sheet resistance (**Ω**/sq)** A 417 28.7510 19.9822 B 358 26.8532 18.6633 C 309 26.5402 18.4457 D 262 25.6280 17.8117

The cyclic voltammogram (CV) curve was obtained by scanning at a potential

Based on **Table 2**, there is the largest sheet resistance value owned by CNF with the largest fiber diameter, but the difference is not too significant, the smallest sheet resistance value is owned by CNF with the smallest fiber diameter. The resistance value is directly proportional to the resistivity, but the resistivity is inversely proportional to the conductivity. Thus, the sample with the highest sheet resistance

The application of CNF continues to develop today, based on the characteristics of CNF in the form of morphology and electrical properties, CNF has the potential to be applied to various fields, as shown in **Figure 10**, applications of CNF can be developed in the field of sensors, environmental applications and fields of electron-

Based on the characterization on the morphology and electrical properties of CNF, it is very possible to apply to sensor devices, the principle of chemiresistor sensors is more widely used for gas sensors because these sensors can be made easily and at relatively low cost. The chemiresistor mechanism is the reaction that occurs between the layers on the electrode and the gas which will result in a change in the

sweep rate of 5 mV/s on CNFS which had undergone temperature treatment and became a CDI electrode as shown in **Figure 9**. The CV curve shows the ideal behavior of the capacitor, the ideal CV curve with an almost square shape at different scanning sweep rates. Cyclic voltammetry testing on the three types of electrodes used in this study was carried out in a potential range of −0.5 V to 0.5 V and a potential sweep speed of 5 mV/s. The electrodes were immersed in an electrolyte solution of 0.5 M KCl with a submerged surface area of 1 cm2. Cyclic voltammetry measurement experiments were carried out at room temperature of 25 ° C. The results of the cyclic voltammetry test can be seen in **Figure 9**. On the voltammogram graph, a redox reaction is formed in an up-current pattern that shows the transfer of electrons from the electrode to the electrolyte solution, which involves the transfer of electrolyte ions based on the change in potential applied to the electrochemical cell, so this pattern increases in current indicating an increase

in ion absorption capacity and ion absorption rate at potential given.

value has the greatest resistivity but the lowest conductivity.

ics and electronics. Optical devices including energy storage fields.

**5. Applications of carbon nanofibers**

value of resistance or conductivity.

*DOI: http://dx.doi.org/10.5772/intechopen.96175*

by 75.43%.

**Table 2.**

*probes.*

*Fabrication of PVA/Carbon-Based Nanofibers Using Electrospinning DOI: http://dx.doi.org/10.5772/intechopen.96175*


**Table 2.**

*Nanofibers - Synthesis, Properties and Applications*

tivity value of the material.

Ohmic curve on the I-V graph according to Ohm's law. The resulting Voltage and Current data are then processed according to Ohm's law to determine the conduc-

**Figure 8** shows the electrospinning results with a flow rate of 0.1 ml/hour and relative humidity of 30% and the parameters still produce fibers with an average diameter of 262 nm, the fibers in this parameter have a morphological shape with minimum and almost no beads. Whereas the electrospinning carbon nanofibers with a flow rate of 0.1 ml/hour and relative humidity of 40% and the parameters still produce a fiber with the smallest size of 200 nm and the largest diameter of 400 nm and an average diameter of 309 nm, the fiber in this parameter has a morphological shape with minimum and almost non-existent beads and more uniform diameter sizes and a narrower size range when compared to 30% humidity parameters. The CNF fabrication results were carried out by SEM–EDX to determine the

*Electrochemical characterization results. (a) diagram of the cyclic voltammogram (CV) data on the CDI electrode with a sweep rate of 5 mV/s, and (b) the specific capacitance of the carbon electrode from the cyclic* 

**48**

**Figure 9.**

*voltammogram data.*

*The Average Value of Voltage and Resistance Sheet of Nanofibers from measurements using the I-V meter four probes.*

elements of the nanofibers fabrication as in **Figure 8c**, the distribution of carbon elements has been evenly distributed, as well as the results of nanofibers fabrication with flow rate parameters of 0.1 ml/hour and 40% humidity and fixed parameters. Based on this characterization, carbon nanofibers consists of several chemical elements. The chemical elements, namely, O (Oxygen) by 24.57%, and C (Carbon) by 75.43%.

The cyclic voltammogram (CV) curve was obtained by scanning at a potential sweep rate of 5 mV/s on CNFS which had undergone temperature treatment and became a CDI electrode as shown in **Figure 9**. The CV curve shows the ideal behavior of the capacitor, the ideal CV curve with an almost square shape at different scanning sweep rates. Cyclic voltammetry testing on the three types of electrodes used in this study was carried out in a potential range of −0.5 V to 0.5 V and a potential sweep speed of 5 mV/s. The electrodes were immersed in an electrolyte solution of 0.5 M KCl with a submerged surface area of 1 cm2. Cyclic voltammetry measurement experiments were carried out at room temperature of 25 ° C. The results of the cyclic voltammetry test can be seen in **Figure 9**. On the voltammogram graph, a redox reaction is formed in an up-current pattern that shows the transfer of electrons from the electrode to the electrolyte solution, which involves the transfer of electrolyte ions based on the change in potential applied to the electrochemical cell, so this pattern increases in current indicating an increase in ion absorption capacity and ion absorption rate at potential given.

Based on **Table 2**, there is the largest sheet resistance value owned by CNF with the largest fiber diameter, but the difference is not too significant, the smallest sheet resistance value is owned by CNF with the smallest fiber diameter. The resistance value is directly proportional to the resistivity, but the resistivity is inversely proportional to the conductivity. Thus, the sample with the highest sheet resistance value has the greatest resistivity but the lowest conductivity.
