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

Abstract

a b s t r a c tBlend solutions of chitosan (Cs) and poly(ethylene oxide) (PEO) at different acidities were electrospun to produce membranes of nanofibers with different diameters. The use of polysorbate surfactant Tween 20 to improve functionality of these nanofibers was studied. The procedure was as follows: 5% (w/v) of two high deacetylation degree Cs with different molecular weights (Mw = 148 kDa and 68 kDa) were dissolved in solutions with different acetic acid concentrations (10%, 50% and 90% (v/v)) then mixed with PEO. The influence of molecular weight and acidity on the morphology and physicochemical properties of solutions and formed nanofibers was also investigated. Results revealed that pure Cs dissolved in different acidities did not form fibers and instead it deposited as beads. Addition of PEO was necessary to electrospin all Cs solutions. Average fiber diameters and size distribution differ with acidity and molecular weight. Composite solutions of Cs, synthetic polymer PEO, and surfactant can be effectively electrospun. The presence of surfactant resulted in decrease of surface tension and in the formation of smooth or beaded fibers. This may be important for new applications since active nanofibers could serve as carriers of components such as drugs or additives.

Antimicrobial electrospun membranes of chitosan/poly(ethylene oxide) incorporating poly(hexamethylene biguanide) hydrochloride

“…1 indicated that the zero-shear viscosity of 2.5% chitosan was 0.43 Pa s while, a 2.5 wt% composite solution of chitosan/PEO with 75:25 ratio showed a higher viscosity (0.73 Pa s) than both of its precursor solutions. This is possibly due to the strong interactions between chitosan and large expanded PEO chains which make sufficient entanglement and facilitate electrospinning (Pakravan et al, 2011;Ziani et al, 2011). The addition of PHMB to chitosan solution with PEO slightly reduced the viscosity to 0.65 Pa s. However, increasing PHMB content to 1 mM, led to reduction in the zero shear viscosity by 10% (0.58 Pa s).…”

“…Pure chitosan did not form fibers and only beads or drops in the range of 328 nm were deposited. It has been hypothesized that the repulsive forces between ionic groups within polymer backbone increased due to the application of a high electric field during electrospinning restricted formation of continuous fibers and produced particles (Pakravan et al, 2011;Ziani et al, 2011). Addition of PEO to the chitosan solution, disrupt the self-association of chitosan chains by formation of additional hydrogen bondings between its hydroxyl groups and water molecules.…”

“…Recently, many attempts have been made to produce composite chitosan nanofibrous by blending chitosan with other synthetic biodegradable polymers such as poly(ethylene oxide) (PEO) (Pakravan, Heuzey, & Ajjia, 2011;Ziani et al, 2011) and poly(vinyl alcohol) (PVA) (Ignatova, Starbova, Markova, Manolava, & Rashkov, 2006). In these blends, the fiber forming ability of the co-spinning agent is utilized to facilitate polymer entanglement and generation of a polymer jet (Kriegel, Kit, McClements, & Weiss, 2009).…”

“…In these blends, the fiber forming ability of the co-spinning agent is utilized to facilitate polymer entanglement and generation of a polymer jet (Kriegel, Kit, McClements, & Weiss, 2009). Electrospinning of chitosan in the presence of poly(ethylene oxide) (PEO), a well-suited fiber-forming polymer, have been widely documented (Bhattarai et al, 2005;Klossner, Hailey, Queen, Coughlin, & Krause, 2008;Kriegel et al, 2009;Ma et al, 2011;Subramanian et al, 2005;Zhang, Venugopal, et al, 2008;Ziani et al, 2011).…”

“…Incorporation of micelles into nanofibers could modulate the molecular structure and interactions of polymer molecules and further spinnability of the solutions and thus influencing fiber morphology. Ziani et al (2011) studied the use of Tween 20 and Kriegel et al (2009) evaluated the effect of anionic sodium dodecyl sulfate (SDS), nonionic polyoxyethylene glycol lauryl ether (Brij 35), and cationic dodecyl trimethyl ammonium bromide (DTAB) on the electrospinning of the cationic chitosan. They reported that the addition of cationic surfactant to polymer solutions increases the positive charge density on the surface of fibers and enhances the whipping instability.…”