Electrospinning of nanocomposite nanofibers from cyclodextrin and laponite

Abstract

Herein, the electrospinning of nanocomposite nanofibers from a non-polymeric system using cyclodextrin (CD)and Laponite was reported. Laponite, a hectorite-type synthetic clay, was used as an additive in the aqueoussolutions of CD molecules, and its influence on the polymer-free electrospinning of CD was investigated. Flowtests showed that the viscosity of CD solutions increased with a Laponite content rise at low shear rates and anunequalled degree of shear thinning at high shear rates. The morphology of the CD/Laponite nanofibers wasexplored by SEM, which revealed the formation of smooth nanofibers at low Laponite content (0.62 wt%) andnon-smooth nanofibers at Laponite content over 1.56 wt% due to enhanced electrostatic interactions betweenthe charged surface of Laponite and hydroxyl groups of CD. Further increasing Laponite content to 12.5 wt% ledto only micro-sized beads instead offibers due to electrospraying, suggesting that the embedded Laponite sig-nificantly disturbed hydrogen bonds among CD molecules. The presence of Laponite in the nanofibers wasconfirmed over chemical analysis by EDX and XPS. TEM analysis displayed homogeneous distribution of theexfoliated Laponite in the CD nanofibers, as supported by the disappearance of the diffraction patterns ofLaponite by WAXS. The nanocomposite CD/Laponite mats with Laponite content of≤1.56 wt% maintained theirself-standing andflexible structure to some extent, as revealed by tensile tests. In brief, this study reports thepolymer-free electrospinning of nanocomposite nanofibers based on CD and Laponite and investigates the impactof the incorporated clay on the polymer-free electrospinning of CD molecules.