Correlation of Chitosan’s Rheological Properties and Its Ability to Electrospin

Abstract

Chitosan-based, defect-free nanofibers with average diameters ranging from 62 +/- 9 nm to 129 +/- 16 nm were fabricated via electrospinning blended solutions of chitosan and polyethylene oxide (PEO). Several solution parameters such as acetic acid concentration, polymer concentration, and polymer molecular weight were investigated to optimize fiber consistency and diameter. These parameters were evaluated using the rheological properties of the solutions as well as images produced by scanning electron microscopy (SEM) of the electrospun nanofibers. Generally, SEM imaging demonstrated that as total polymer concentration (chitosan + PEO) increased, the number of beads decreased, and as chitosan concentration increased, fiber diameter decreased. Chitosan-PEO solutions phase separate over time; as a result, blended solutions were able to be electrospun with the weakest electric field and the least amount of complications when solutions were electrospun within 24 h of initially being blended. The addition of NaCl stabilized these solutions and increased the time the blended solutions could be stored before electrospinning. Pure chitosan nanofibers with high degrees of deacetylation (about 80%) were unable to be produced. When attempting to electrospin highly deacetylated chitosan from aqueous acetic acid at concentrations above the entanglement concentration, the electric field was insufficient to overcome the combined effect of the surface tension and viscosity of the solution. Therefore, the degree of deacetylation is an extremely important parameter to consider when attempting to electrospin chitosan.

Designing electrospun nanofiber mats to promote wound healing – a review

“…Only once the polymer concentration is above the critical concentration, can ber spinning ensue. [33][34][35] Other properties of the precursor solution-conductivity, surface tension, viscosity, and polymer concentration-can be optimized by appropriate polymer and solvent selection. Different solvents and salts can be used to adjust the conductivity and surface tension of the system.…”

Preparations, properties and applications of chitosan based nanofibers fabricated by electrospinning

“…Poly(ethylene oxide) (PEO) is also a biocompatible polymer that has been used as cartilage tissue repair [35] and wound dressing [36]. Many nanofibers of the blends of PEO and chitosan have also been fabricated by electrospinning [37][38][39][40][41][42]. For examples, Klossner et al [37] fabricated defect-free nanofibers with average diameters ranging from 62±9 to 129±16 nm by electrospinning of blended solutions of chitosan and PEO in acetic acid.…”

“…Many nanofibers of the blends of PEO and chitosan have also been fabricated by electrospinning [37][38][39][40][41][42]. For examples, Klossner et al [37] fabricated defect-free nanofibers with average diameters ranging from 62±9 to 129±16 nm by electrospinning of blended solutions of chitosan and PEO in acetic acid. Their study showed that as total polymer concentration (chitosan + PEO) increased, the number of beads decreased, and as chitosan concentration increased, fiber diameter decreased.…”

Effect of nonionic surfactant and acidity on chitosan nanofibers with different molecular weights

“…For the use of different rates of acetic acid, the increasing of acidity for both high degree of deacetylation Cs used in this work leeds to an increase of the amount of charge of free amine on the chain. As the charge on the chain increases, the conformation of the chain in solution expands and the viscosity increases substantially (Klossner, Queen, Coughlin, & Krause, 2008). For the use of surfactant, Tween 20 as a nonionic surfactant would be expected to show no electrostatic interaction and instead may interact with polymers solely by hydrophobic bonding.…”