| Autor: |
Dicker KT; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375., Ratchford D; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375., Casalini R; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375., Thum MD; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375., Wynne JH; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375., Lundin JG; Chemistry Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375. |
| Abstrakt: |
Confinement of liquid crystals (LCs) in polymeric fibers offers a promising strategy to control liquid crystal response to external stimuli. Here, the confinement of 4-cyano-4'-pentylbiphenyl (5CB), a nematic liquid crystal, within the core of coaxially electrospun fibers composed of poly(vinylpyrrolidone) (PVP) containing different surfactants is discussed. The effects of surfactant type, surfactant concentration, and core flow rate (confinement) on the LC behavior were demonstrated using polarized optical microscopy, scanning electron microscopy, differential scanning calorimetry, Raman, and dielectric spectroscopy. Introduction of surfactant dopants of varying hydrophilic and hydrophobic components into the sheath altered the interfacial interaction between the PVP sheath and the 5CB core of the fibers. Significant effects on the LC nematic to isotropic phase transition were attributed to changes in surface anchoring between the sheath and core. Confinement of nematic LCs in surfactant doped polymeric fibers demonstrates a facile method for tuning LC phase behavior. |
