Electrospinning ambient parameters

The following parameters and processing variables affect the electrospinning process (i) system parameters such as molecular weight, molecular weight distribution and architecture (branched, linear, etc.) of the polymer, and polymer solution properties (viscosity, conductivity, dielectric constant, and surface tension, charge carried by the spinning jet) and (ii) process parameters such as electric potential, flow rate and concentration, distance between the capillary and collection screen, ambient parameters... 

The parameters involved in the electrospinning processes that affect the nanofiber geometry and structure can be divided into two groups (i) System parameters such as polymer molecular weight, molecular weight distribution, polymer architecture (branched, linear), concentration of the polymer solution and its properties, including viscosity, electrical conductivity, and surface tension and (ii) Process parameters such as applied electric voltage, polymer flow rate, distance between the needle tip and the collector, ambient parameters such as temperature, humidity, and air velocity in the chamber, and motion of the collector (Frenot and Chronakis 2003). 

Ambient parameters, such as solution temperature, humidity, atmosphere, and air velocity in the electrospinning chamber. 

Many parameters can influence the transformation of polymer solutions into nanofibers through electrospinning. These parameters include (a) solution properties, such as viscosity, elasticity, conductivity and surface tension (b) governing/operating variables, such as hydrostatic pressure in the capillary tube, electric potential at the capillary tip and the gap (distance between the tip and the collecting screen) and (c) ambient parameters such as solution temperature, humidity and air velocity in the electrospinning chamber. ... 

The effects of temperature and humidity as two major ambient parameters are worth noting even though electrospinning is often conducted at room temperature. Increasing solution temperature can significantly reduce mean fibre diameters, which can be attributed to its indirect effect on solvent evaporation rate and solution... 

FIGURE 2.4 The electrospinning control parameters split into the cohorts of solution, processing, and ambient conditions. (Data from Haghi, A.K., ed.. Electrospinning of Nanofibres in Textiles, Apple Academic Press, Toronto, Ontario, Canada, 2011.)... 

The morphology and the diameter of the electrospun nano Hers can be affected by many electrospinning parameters including solution properties (the concentration, liqnid viscosity, surface tension, and dielectric properties of the polymer solution), processing conditions (apphed voltage, volume Cbw rate, tip to collector distance, and the strength of the apphed electric Hid), and ambient conditions (temperature, atmospheric pressure and humidity) [17-20]. 

Electrospinning parameters are the variables which can be controlled and adjusted in order to manipulate the morphology and feamres of the electrospun nanofibers. Electrospinning parameters are classified into three main categories which are (i) processing (controlled) variables, (ii) ambient (uncontrolled) variables, and (iii) the solution variables (Huang et al. 2003 Pham et al. 2006 Zander 2013). Electrospinning parameters are summarized in Table 1. 

The parameters impacting the electrospinning process can be categorized into solution parameters (surface tension, concentration, viscosity and conductivity), processing conditions (voltage, distance from needle to collector, type of collector, flow rate) and ambient conditions (humidity, pressure and temperature) [90, 91]. Based on the interaction of all these factors, the morphology and size of resultant nanofibers can be changed. 

Though easily realizable in the laboratory, electrospinning is a complex phenomenon to analyze because of the coupling between the electric field and the deformation of the fluid which in turn is determined by the rheology of the material. This seetion deals with the influence of many parameters like solution properties, processing and ambient eonditions, on the transformation of polymer solution into eleetrospim nanofibers. 

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