A conventional electrospinning setup was upgraded by two turnable plate-like auxiliary high-voltage electrodes that allowed aligned fiber deposition in adjustable directions. Fiber morphology was analyzed by scanning electron microscopy and attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR). The auxiliary electric field constrained the jet bending instability and the fiber deposition became controllable. At target speeds of 0.9 m s −1 90% of the fibers had aligned within 2 • , whereas the angular spread was 70• without the use of auxiliary electrodes. It was even possible to orient fibers perpendicular to the rotational direction of the target. The fiber diameter became smaller and its distribution narrower, while according to the FTIR-ATR measurement the molecular orientation of the polymer was unaltered. This study comprehensively documents the feasibility of directed fiber deposition and offers an easy upgrade to existing electrospinning setups.
We
successfully tested the hypothesis that the nanohybrid shish-kebab
(NHSK) structure, i.e., polymer kebabs on a CNT shish, can be created in situ during electrospinning. In addition, the resulting
nanofibers containing the NHSKs were used to create a hierarchical
structure by introducing a second level of shish-kebabs: the nanofiber
shish-kebab (NFSK), i.e., polymer kebabs on the nanofiber shish. A
multiwalled CNT/poly(ε-caprolactone) (MWCNT)/(PCL) solution
was electrospun to form nanofibers of Ø ≈ 100 nm. The
MWCNTs aligned in fiber direction within the MWCNT/PCL nanofibers.
The first time creation of the NHSK during electrospinning was confirmed
by bright field diffraction contrast in the transmission electron
microscope. The NFSK was created by incubating the NHSK containing
nanofibers in a supersaturated PCL solution. A simple model explaining
the in situ NHSK formation is presented. The hierarchical
structure based on the shish-kebab morphology is proposed as a high-performing
building block in future advanced materials.
Polyoxometalates (POMs) using {MoV} as an example, dissolved in water, can interact with amine-terminated polydimethylsiloxane (PDMS-NH) dissolved in toluene at the water/toluene interface to form POM-surfactants that significantly lower the interfacial tension and can be used to stabilize liquids via interfacial elasticity. The jamming of the POM-surfactants at the water/oil interface with consequent wrinkling occurs with a decrease in the interfacial area. The packing density of the POM-surfactants at the interface can be tuned by varying the strength of screening with the addition of cations with differing hydrated radii.
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