Electrospinning of Chitosan

Abstract

Summary: An electrospun nonwoven fabric of a cationic polysaccharide, chitosan, was successfully prepared. The present study focuses on the effect of the electrospinning solvent and the chitosan concentration on the morphology of the resulting nonwoven fabrics. The solvents tested were dilute hydrochloric acid, acetic acid, neat formic acid and trifluoroacetic acid. As the chitosan concentration was increased, the morphology of the deposition on the collector changed from spherical beads to interconnected fibrous networks. The addition of dichloromethane to the chitosan‐TFA solution improved the homogeneity of the electrospun chitosan fiber. Under optimized conditions, homogenous (not interconnected) chitosan fibers with a mean diameter of 330 nm were prepared.Effects of the coexisting dichloromethane (MC) in the prespun chitosan‐TFA solution on the morphology of the electrospun chitosan fibers. The volume ratio of TFA:MC was 70:30 (×5 000).magnified imageEffects of the coexisting dichloromethane (MC) in the prespun chitosan‐TFA solution on the morphology of the electrospun chitosan fibers. The volume ratio of TFA:MC was 70:30 (×5 000).

Fabrication and application of coaxial polyvinyl alcohol/chitosan nanofiber membranes

“…Chitosan is soluble in acidic solution but the chitosan solution becomes highly viscous when its concentration goes high, making the preparation of chitosan nanofibers by electrospinning quite problematic. To overcome this difficulty, chitosan has to dissolve in high concentration of acetic acid or organic solvents such as trifluotoacetic acid (TFA) and hexafluoroisopropanol (HFIP) [14][15][16]. However, TFA and HFIP are highly corrosive and expensive.…”

Effect of neutralization and cross-linking on the thermal degradation of chitosan electrospun membranes

“…Chitosan was successfully electrospun into fibers from dissolution of the polymer in trifluoracetic acid (TFA) [10,11] or a co-solvent system of TFA with dichloromethane (DCM) [12], and it was reported that the last solvent improve fiber spinability. Further, Ohkawa et al [10] refers that the success of the chitosan dissolution in TFA was probably a result of the formation of salts between TFA and amino groups along the chitosan chain leading to a smaller interaction between chitosan molecules, which results in a more stable solution to perform electrospinning.…”

“…Further, Ohkawa et al [10] refers that the success of the chitosan dissolution in TFA was probably a result of the formation of salts between TFA and amino groups along the chitosan chain leading to a smaller interaction between chitosan molecules, which results in a more stable solution to perform electrospinning. However, the resulting chitosan membranes lose their fibrous structure when in contact with a neutral or weak basic aqueous media, due to the dissolution of the trifluoracetate salts that are formed when chitosan is dissolved in TFA [13].…”

Nanofibrous Structure of Chitosan for Biomedical Applications

“…The associative properties of chitosan chains arises due to the presence of strong hydrogen bonding between -NH 2 and -OH groups of chitosan molecules causing it to be unspinnable. Nevertheless, several research groups have succeeded in the preparation of chitosan based fibers by either blending it with other surfactants like synthetic polymers such as polyethylene oxide (PEO) and polyvinyl alcohol (PVA) or by mixing it with strong organic acids [33,49,50]. The decrease in viscosity with addition of synthetic polymers can be attributed to the change in inter and intramolecular interactions of chitosan chains.…”

“…The most common way to produce chitosan nanofibers is by preparing chitosan solution in trifluoroacetic acid (TFA) and/or acetic acid [50,51] . These solvents are best known to improve the fluidity in chitosan solution by disrupting the 3-D networks of chitosan so that ultrafine fibers can be produced.…”