Papers by Keyword: Nanoweb

Abstract: Nanoweb fabricated by electrospinning has a large specific area and a small pore size which can be controlled through a spinning process to enable a strong adsorption and selective permeability. It is required to produce nanofiber of different polymer mixture with a limited miscibility for improvement of physical, chemical, or biological properties. In this study, poly (vinyl alcohol) (PVA)/polyurethane (PU) nanofibers were produced by coaxial electrospinning. PVA (core)/PU (shell) nanofibers were defect-free and had a uniform thickness. The pseudo core/shell structure of PVA/PU nanofibers was confirmed by transmission electron microscopy. The presence of PVA and PU in the nanofibers was identified by ¹³C solid state nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, and X-ray diffraction analysis. Water contact angle was reduced by incorporation of PVA in a core of PU nanofiber. For variety of biomedical applications, bioactive substances such as antibiotics and proteins can be incorporated in a core of hydrophobic PU nanofiber by coaxial electrospinning of water-soluble polymer/bioactive substance mixture.

Abstract: Polyvinylidene fluoride (PVDF) based electrospun nanoweb fibers with outstanding piezo-, pyro- and ferroelectric behavior are being intensely studied by many researchers, especially for touch-sensor applications. In order to further improve the advantageous characteristics of PVDF nanoweb fibers, we focused our attention on studying the effect of filling PVDF solution with calculated amount of calcium chloride (CaCl2) or multi-walled carbon nanotube (MWCNT), and their electrospun nanoweb fibers were analyzed for the changes in β-crystalline phase, and its associated piezoelectric characteristics using a custom-made sensor set-up developed in our lab. FT-IR spectroscopy was used to confirm the changes in the β-crystalline content with varying content of CaCl2 and MWCNT. SEM data revealed the reducing fiber diameter with increasing CaCl2 content. PVDF nanoweb subjected to pressure showed changes in touch sensing property as analyzed using an oscilloscope integrated with Labview program. Overall, the PVDF nanoweb containing the additives used in our study exhibited greater sensitivity-in-touch for use in smart apparel applications compared to unmodified PVDF nanoweb, and the results are reported in detail here.