Effects of poly(ethylene oxide) and pH on the electrospinning of whey protein isolate

Abstract

Poly(ethylene oxide) (PEO) is known for facilitating the electrospinning of biopolymer solutions, which are otherwise not electrospinnable. The objective of this study was to improve the understanding of the positive effects of PEO on the electrospinning of whey protein isolate (WPI) solutions under different pH conditions. Alterations in protein secondary structure and polymer solution properties (viscosity, conductivity, and dynamic surface tension), as induced by pH changes, significantly affected the electrospinning behavior of WPI/PEO (10% w/w: 0.4% w/w PEO) solutions. Acidic solutions resulted in smooth fibers (707 6 105 nm) while neutral solutions produced spheres (2.0 6 1.0 lm) linked with ultrafine fibers (138 6 32 nm). In comparison, alkaline solutions produced fibers (191 6 36 nm) that were embedded with spindle-like beads (1.0 6 0.5 lm). 13 C NMR and FTIR spectroscopies showed that the increase in random coil and a-helix secondary structures in WPI were the main contributors to the formation of bead-less electrospun fibers. The electrospinning-enabling properties of PEO on aqueous WPI solutions were attributed to physical chain entanglement between the two polymers, rather than specific polymer-polymer interactions.

Development of novel pea flour‐based nanofibres by electrospinning method

“…HPMC is a nonionic polymer (Sovilj & Petrovic, 2006). The result was in accordance with study conducted by Vega-Lugo & Lim (2012). HPMC was also a natural polymer.…”

“…Electrical conductivity determines the ability of electrical charge to move to the surface of the pendant droplet, directly affecting the creation of an electrostatic repulsion force that is critical to initiate jetting (Vega-Lugo & Lim, 2012). In other words, electrospinning process requires the transfer of electric charges from the electrode to the spinning droplet.…”

Electrospinning of Xanthan Polysaccharide

“…The electrical conductivity of xanthan solutions was increased significantly ( p < 0.05) with the increase of the polysaccharide concentration (Table ), as result of the increase of xanthan negative charges at higher concentrations . Such an increase of the solution conductivity induces greater transfer of the surface charges of the polymer jet, enhanced electrostatic repulsion, promoting elongation, stretching, and the formation of electrospun nanofibers . Moreover, the high dielectric constant of formic acid (57.9) contributes positively to the development of charges within the jet, facilitating the formation of electrospun xanthan nanofibers.…”

“…[28] Such an increase of the solution conductivity induces greater transfer of the surface charges of the polymer jet, enhanced electrostatic repulsion, promoting elongation, stretching, and the formation of electrospun nanofibers. [29][30][31][32][33] Moreover, the high dielectric constant of formic acid (57.9) contributes positively to the development of charges within the jet, facilitating the formation of electrospun xanthan nanofibers.…”

Melt electrospinning in a parallel electric field

“…As an efficient, direct, and simple method of producing polymer nanofibers, electrospinning has attracted increasing attention because of its versatility and potential for application in diverse fields . Although the setup, materials, and conditions of electrospinning processes vary, fiber instability often occurs, especially when the jet is near the collector.…”