Applications of Polymer Nanofibers. Группа авторов

Applications of Polymer Nanofibers - Группа авторов


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from 0.1% to 2.0% (w/v) increased the fiber diameter from ~75 to 200 nm (Arayanarakul et al. 2006). The increase in the fiber diameters has been attributed to the increased electrostatic force acting on a jet segment that either delays the occurrence of the bending instability or increases the mass throughput (Arayanarakul et al. 2006). However, it is difficult to isolate the effect of conductivity because the additive also often changes the surface tension, viscosity, and dielectric constant (Andrady 2008). Therefore, observed changes cannot be uniquely attributed to changes in conductivity.

      1.5.1 Nonpolymer Electrospinning

Material Solvent Concentration Fiber diameter (μm)
Phospholipids (McKee et al. 2006) CHCl3/DMF 43 wt% 2.8
Gemini surfactants (Cashion et al. 2010) Water/methanol 28–30 wt% 0.9–7
42–44 wt% 4–5
Phosphonium Gemini surfactants (Hemp et al. 2014) Chloroform 52 wt% 0.7–1.3
HPβCD (Celebioglu and Uyar 2012; Manasco et al. 2012) Water, DMF, DMAc 120–160% (w/v) 0.7–1.4
Water 70 wt% 1–1.2
HPγCD (Celebioglu and Uyar 2012; Manasco et al. 2012) Water, DMF, DMAc 125–160% (w/v) 1.2–6.4
MβCD (Celebioglu and Uyar 2012; Manasco et al. 2012) Water, DMF, DMAc 140–160% (w/v) 0.1–1.2
Water 70 wt% 0.4–0.5
Diphenylalanine (FF) (Singh et al. 2008) HFIP 13–17.5 wt% 0.4–0.85
Fmoc‐FG (Fmoc‐Phe‐Gly) (Nuansing et al. 2013) HFIP 18 wt% 0.3
FF‐Tetraphenylporphyrin (Nuansing et al. 2014) HFIP 9.1 wt% <0.2–1.6

      Cyclodextrin, a toroid‐shaped oligosaccharide (~1000 g/mol) has also been successfully electrospun into uniform fibers (Celebioglu and Uyar 2012; Manasco et al. 2012). For example, modified cyclodextrins such as hydroxypropyl‐β‐cyclodextrin and methyl‐β‐cyclodextrin have been used for electrospinning at high concentrations, e.g. 70 wt%. Fiber formation has been attributed due to hydrogen‐bonding‐induced aggregation behavior indicated by the increase in solution viscosity. Such fibers are promising for drug delivery applications (Celebioglu and Uyar 2011; Celebioglu et al. 2014; Vigh et al. 2013).

      Other small molecules have also been successfully electrospun into fibers. These small molecules require high concentrations and a solvent that is highly volatile and electrophilic such as hexafluoro‐2‐propanol (HFIP) or trifluoroacetic acid (TFA) (Nuansing et al. 2013). Peptides such as diphenylalanine have been electrospun into 400–850 nm fibers due to π‐interaction of the phenyl groups entangling the molecules (Singh et al. 2008). Fmoc‐FG (Fmoc‐Phe‐Gly) is another peptide with aromatic groups that would allow for π‐stacking and hydrogen bonding to form continuous fibers. At 18 wt% Fmoc‐FG produced circular fibers, whereas at higher concentrations, it produced ribbons with a needle‐like topography (Nuansing et al. 2013). Tetraphenylporphyrin, a porphyrin derivate used in photovoltaic devices, has been electrospun at a concentration over 9 wt% to produce a beads‐on‐a‐string morphology. The entanglement of these molecules was enhanced by addition of diphenylalanine which increased π‐stacking due to the presence of phenyl groups (Nuansing et al. 2014).

      Recently, colloid electrospinning has been explored as means to create nanofibers with unique properties. Suspensions containing colloids (inorganic or organic, i.e. polymeric) and a small amount (~few wt%) of a fiber‐forming polymer has been used as a template. Inorganic nanoparticles, e.g. metal, metalloid oxide, aluminosilicates, hydroxyapatite, and nonoxide ceramics, are the most common. Silica and polymer particle electrospinning dispersed in a solution of a second incompatible polymer has also been considered. As the jet thins, the particles are in close contact leading to high‐packing densities in the resulting fibers. Due to the timescale of particle arrangement (milliseconds), the resulting structure is less ordered than classical hexagonal packing observed in films (Crespy et al. 2012). Bead formation during electrospinning may lead to colloid aggregation. Adding salt to increase the net charge density can reduce bead formation. The resulting hierarchical structures are especially promising for superhydrophobic materials.


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