Electrospinning of nanocomposite nanofibers from cyclodextrin and laponite

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 aqueous solutions of CD molecules, and its influence on the polymer-free electrospinning of CD was investigated. Flow tests showed that the viscosity of CD solutions increased with a Laponite content rise at low shear rates and an unequalled degree of shear thinning at high shear rates. The morphology of the CD/Laponite nanofibers was explored by SEM, which revealed the formation of smooth nanofibers at low Laponite content (0.62 wt%) and non-smooth nanofibers at Laponite content over 1.56 wt% due to enhanced electrostatic interactions between the charged surface of Laponite and hydroxyl groups of CD. Further increasing Laponite content to 12.5 wt% led to only micro-sized beads instead of fibers due to electrospraying, suggesting that the embedded Laponite significantly disturbed hydrogen bonds among CD molecules. The presence of Laponite in the nanofibers was confirmed over chemical analysis by EDX and XPS. TEM analysis displayed homogeneous distribution of the exfoliated Laponite in the CD nanofibers, as supported by the disappearance of the diffraction patterns of Laponite by WAXS. The nanocomposite CD/Laponite mats with Laponite content of <= 1.56 wt% maintained their self-standing and flexible structure to some extent, as revealed by tensile tests. In brief, this study reports the polymer-free electrospinning of nanocomposite nanofibers based on CD and Laponite and investigates the impact of the incorporated clay on the polymer-free electrospinning of CD molecules.