**3. Electrospinning control parameters**

The electrospinning method has many parameters that must be controlled to produce nanofibers. The parameters that influence are high voltage, field, electricity, nozzle to collector distance, solution concentration, and humidity. The formation of jet polymer in the electrospinning method results in the morphological shape of the nanofibers. The polymer jet itself is influenced by environmental conditions, one of which is humidity. Humidity parameters greatly affect the diameter of the nanofibers, at high humidity, the fiber diameter will increase (Medeiros et al., 2018). The application of high voltage to electrospinning is very important in influencing the diameter and morphology of the nanofibers. The increase in high voltage causes an increase in the electric field as well as this affects the decrease in the diameter of the nanofibers and shortens the time of the solution from the tip of the needle to the collector. The flow rate in electrospinning is the flow of fluid from the syringe pump to the collector. The rate of solution (flowrate) affects the formation of fiber diameter and morphology. This process affects the material transfer rate and jet speed. The diameter of the fiber will increase as the rate of solution used increases [25].

Viscosity is the thickness of a solution; this viscosity is influenced by the concentration of the solution. High viscosity is difficult to force the solution out of the syringe so that the control on the needle is unstable, the higher the viscosity, the higher the fiber diameter. The diameter and morphology of the nanofibers are basically influenced by the distance between the needle tip and the collector. Distance affects fiber diameter and morphology because distance can determine the deposition time, evaporation rate, and polymer jet instability [26]. Therefore, an optimum nozzle to collector distance is needed to form carbon nanofibers with the desired diameter and fiber morphology. Several studies have studied the effect of the nozzle to collector distance and concluded that increasing the distance makes the fiber diameter decrease but the polymer jet instability increases [25].

The effect of relative humidity on the morphology of carbon nanofibers polymers is about the size of the diameter of the nanofibers which is strongly influenced by humidity during the spinning process seen from **Figure 7**. An environment with high humidity helps skin form rapidly with clear boundaries, whereas if there is less moisture, solvents will easily evaporate. When the polymer is hydrophobic, water acts as a non-solvent so that the fiber shell is more easily formed. This makes PMMA, PVC,

#### **Figure 7.**

*Parameters affecting the size of the diameter of the nanofibers. (a) collector Distance (cm), (b) electric field (V/m), (c) flowrate (ml/hour), (d) concentration (%wt), (e) Relative humidity (%).*

**47**

**Figure 8.**

*ready to be applied.*

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

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

or PS in DMF, PMMA or PS in toluene have porous fibers when electros are in an environment with a relative humidity of more than 30%, while PVA is a hydrophilic polymer solution, water acts as a solvent so that the formation skin is easy to form humidity 20%. and there was no pore formation at all at a relative humidity value of 20% -80%. PVA nanofibers were successfully made in the relative humidity range of 20% -80%, but at high relative humidity, the morphology of the fibers contained

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

*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* 

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

more beads [27].

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

*Nanofibers - Synthesis, Properties and Applications*

The effect of relative humidity on the morphology of carbon nanofibers polymers is about the size of the diameter of the nanofibers which is strongly influenced by humidity during the spinning process seen from **Figure 7**. An environment with high humidity helps skin form rapidly with clear boundaries, whereas if there is less moisture, solvents will easily evaporate. When the polymer is hydrophobic, water acts as a non-solvent so that the fiber shell is more easily formed. This makes PMMA, PVC,

*Parameters affecting the size of the diameter of the nanofibers. (a) collector Distance (cm), (b) electric field* 

*(V/m), (c) flowrate (ml/hour), (d) concentration (%wt), (e) Relative humidity (%).*

**46**

**Figure 7.**

or PS in DMF, PMMA or PS in toluene have porous fibers when electros are in an environment with a relative humidity of more than 30%, while PVA is a hydrophilic polymer solution, water acts as a solvent so that the formation skin is easy to form humidity 20%. and there was no pore formation at all at a relative humidity value of 20% -80%. PVA nanofibers were successfully made in the relative humidity range of 20% -80%, but at high relative humidity, the morphology of the fibers contained more beads [27].
