4.1.3. Surface tension
Surface tension is the contractive tendency of a liquid surface
that resists change due to external force and depends on the
characteristics of the solvent and solute. Surface tension definitely
interferes with the electrospinning process, because it is the main
force acting against Taylor cone formation and further jet
elongation. The effect of surface tension on the morphology of
nanofibers has been investigated by numerous authors (Bhardwaj
and Kundu, 2010; Hohman et al., 2001; Jarusuwannapoom et al.,
2005; Zhang et al., 2005; Zuo et al., 2005); however, a decisive link
between fiber morphology and surface tension value has not been
established yet. Fig. 4 shows the correlation between surface
tension and morphology of the electrospun product. Generally, low
surface tension values result in the formation of fibers without
beads and low voltages can be applied in electrospinning. Surface
tension can be manipulated by the addition of surface-active
substances. However, a low surface tension cannot solve problems
that occur as a result of too low molecular weight of polymer used.