Polyethylene Oxide Nanofibers Research Articles

Electrospinning of cyclodextrin functionalized polyethylene oxide (PEO) nanofibers

By means of the electrospinning technique we have successfully synthesized cyclodextrin (CD) functionalized polyethylene oxide (PEO) nanofibers (PEO/CD) with the ultimate goal to develop functional nanowebs. Three different types of CDs; α-CD, β-CD and γ-CD are incorporated individually in electrospun PEO nanofibers. The aqueous solutions containing different amount of PEO (3%, 3.5% and 4% (w/v), with respect to solvent) and CDs (25% and 50% (w/w), with respect to PEO) are electrospun and bead-free nanofibers are obtained. The presence of the CDs in the PEO solutions is found to facilitate the electrospinning of bead-free nanofibers from the lower polymer concentrations and this behavior is attributed to the high conductivity and viscosity of the PEO/CD solutions. The presence of CDs in the electrospun PEO nanofibers is confirmed by Fourier transform infrared (FTIR) spectroscopy studies. The 2-D X-ray diffraction (XRD) spectra of PEO/CD nanowebs did not show any significant diffraction peaks for CDs indicating that the CD molecules are distributed within the polymer matrix without any phase separated crystalline aggregates.

Nanochannels fabricated in polydimethylsiloxane using sacrificial electrospun polyethylene oxide nanofibers

The authors have used electrospun polyethylene oxide nanofibers as sacrificial templates to form nanofluidic channels in polydimethylsiloxane (PDMS). By depositing fibers on silicon templates incorporating larger structures, the authors demonstrate that these nanochannels can be integrated easily with microfluidics. They use fluorescence microscopy to image channels filled with dye solution. The utility of the hybrid micro- and nanofluidic PDMS structures for single molecule observation and manipulation was demonstrated by introducing single molecules of λ-DNA into the channels. This nanofabrication technique allows the simple construction of integrated micro- and nanofluidic PDMS structures without lithographic nanofabrication techniques.

A neural network model for the numerical prediction of the diameter of electro-spun polyethylene oxide nanofibers

This paper investigates the viability of neural network as a tool for predicting the diameter of fiber formed by an electrospinning process. Published experimental data for polyethylene oxide (PEO) aqueous solution is used to train and test the neural network model. Concentration, conductivity, flow rate, and electric field strength are used as the input variables to the neural network model. Network model selection, training and testing were conducted using the k-fold cross validation technique which is demonstrated to be the most suitable scheme for the size of dataset used in this study. A statistical study was conducted to establish 95% confidence intervals on the bias and on the limits of agreement between the experimental data and the predicted data. The computer simulation results show a very good agreement between the data, demonstrating the viability of neural network as a promising tool for predicting fiber diameter. While the proposed neural network approach is not intended to model the complete complex physics of the electrospinning process, it is demonstrated to provide an accurate nonlinear mapping between the four salient input variables and the diameter of the formed fiber. This study provides some potential insights into exploring neural network model-based feedback control techniques to regulate nanofiber diameter in an electrospinning process.

Individually Resolved DNA Molecules Stretched and Embedded in Electrospun Polymer Nanofibers

We have used the flow characteristics of an electrospinning jet to elongate and fix DNA molecules. We embedded and observed fluorescently labeled lambda bacteriophage DNA molecules in polyethylene oxide nanofibers. The embedded DNA molecules were imaged using fluorescence microscopy and found to be stretched to lengths approaching the full dyed contour length.

Polyethylene Oxide Nanofibers as Ultraviolet Sensors

ABSTRACTUsing the electrospinning technique, we have prepared [Ru (pic) 2 (dmso) 2] doped-polyethylene oxide nanofibers for ultraviolet sensing. The diameter of the as-prepared fibers is in the range of 1μm-100nm. These fibers change color from pale yellow to orange when exposed to ultraviolet light (wavelength∼350nm) and return to their original color after approximately 2-3 days. The intensity of the color increases with an increased time of exposure to UV. The color changing behavior in the nanofibrous mat is almost the same as that in cast films prepared from the same solutions. The scanning electron microscope (SEM) studies of the fibers show that the morphology of the fibers remains unchanged after exposure to UV.

Tensile test of a single nanofiber using an atomic force microscope tip

In this study, an approach using an atomic force microscope (AFM) tip to stretch a single electrospun polyethylene oxide (PEO) nanofiber is demonstrated. One end of the nanofiber is attached to a movable optical microscope stage and the other end of the nanofiber to a piezoresistive AFM cantilever tip. The nanofiber is stretched by moving the microscope stage and the force is measured via the deflection of the cantilever. The elastic modulus of PEO nanofiber is found to be about 45MPa.

Scanning Conductance Microscopy and High Frequency Scanning Gate Microscopy of Carbon Nanotubes and Polyethylene based Nanofibers

ABSTRACTWe present two new approaches that significantly enhance the analytic power of Scanning Conductance Microscopy (SCM) and Scanning Gate Microscopy (SGM). First, we present a quantitative model that explains the phase shifts observed in SCM, by considering the change in the total capacitance of the tip-sample-substrate system. We show excellent agreement with data on samples of (conducting) single wall nanotubes and insulating polyethylene oxide (PEO) nanofibers. This model is also used to determine the dielectric constant of PEO nanofibers, a general approach that can be extended to other dielectric nanowires. Second, we extend the SGM to frequencies up to 15MHz, and use it to image changes in the impedance of carbon nanotube field effect transistor (CNFET) circuits induced by the SGM-tip gate. We show that these measurements are consistent with a simple RC parallel circuit model of the CNFET, with a time constant of 0.3 μs.