skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Novel Use of Laser Zone‐Drawing on Nanofibers Enables Ultra‐Fast Thermal Kinetics and Precise Diameter Control
Abstract Laser zone‐drawing is shown to significantly enhance control over nanofiber properties. This study investigates the dynamics of nanofiber laser zone‐drawing. It is hypothesized that the equilibrium between heating and cooling guides fiber temperature. The high heating rate of laser irradiation and the high convective cooling rate of nanofibers facilitate fast heating and cooling kinetics. Results showed fiber thinning in the presence of laser irradiation until reaching a steady‐state diameter. Final fiber diameter is correlated to laser power independent of initial fiber diameter. The relationship between final fiber diameter and laser power is used to estimate the heat transfer coefficient, which is used to create a computational model of the thermodynamic system. These simulations predict rapid heating and cooling up to 36 000 K min−1for the lowest fiber diameters tested experimentally. While laser‐induced softening of polymer nanofibers is described in detail, the forces driving fiber drawing, particularly under different thermal kinetics, remain unexplored. This research showcases the capabilities of laser zone‐drawing in nanofiber manufacturing and facilitates future investigations aimed at enhancing fiber processing by producing highly aligned molecular structures via rapid cooling. This work signifies a pivotal methodological leap, promising transformative nanofiber materials useful across multiple industries including aerospace, electronics, and biomedicine.  more » « less
Award ID(s):
2110027
PAR ID:
10650734
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Advanced Materials Technologies
Volume:
10
Issue:
8
ISSN:
2365-709X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; (, Electroanalysis)
    Abstract An effective method to study and predict the complex mechanism of electrospinning is needed. A combination of design of experiments (DOEs) and finer tuning of the experimental parameters were used to investigate the effect of individual and interactions of solution, electrospinning, and environmental conditions on the dimensions and morphology of polyacrylonitrile (PAN) nanofibers. Analyses on DOEs determined that solution viscosity, controlled by the concentration of polymer precursor, was the predominant factor in manipulating the PAN nanofiber diameter. Similarly, reduced surface tension controlled by the addition of surfactant contributed to smoother nanofibers. An appropriate applied voltage for stable formation of Taylor cone was established. DOE on environmental conditions revealed the absolute moisture content played a significant role in causing beads. A minimum polyacrylonitrile (PAN)‐based fiber diameter of 42±7 nm was achieved with solution containing 3.25 wt. % PAN, 0.1 wt. % BYK® surfactant in N,N‐dimethylformamide (DMF). PAN nanofibers were subsequently stabilized then carbonized. BET analysis of the carbonized nanofibers showed the specific surface area increased as a function of nanofiber diameter, reaching 684 m2/g at 407 nm. Preliminary results from the electrochemical characterization of the carbon nanofibers showed the double‐layer capacitance increased with decreasing fiber diameter, showing suitable potential for electrode applications. 
    more » « less
  2. ; ; ; ; ; ; ; (, Physical review)
    In an effort to develop and design next generation high power target materials for particle physics research, the possibility of fabricating nonwoven metallic or ceramic nanofibers by electrospinning process is explored. A low-cost electrospinning unit is set up for in-house production of various ceramic nanofibers. Yttria-stabilized zirconia nanofibers are successfully fabricated by electrospinning a mixture of zirconium carbonate with high-molecular weight polyvinylpyrrolidone polymer solution. Some of the inherent weaknesses of electrospinning process like thickness of nanofiber mat and slow production rate are overcome by modifying certain parts of electrospinning system and their arrangements to get thicker nanofiber mats of millimeter order at a faster rate. Continuous long nanofibers of about hundred nanometers in diameter are produced and subsequently heat treated to get rid of polymer and allow crystallize zirconia. Specimens were prepared to meet certain minimum physical properties such as thickness, structural integrity, thermal stability, and flexibility. An easy innovative technique based on atomic force microscopy was employed for evaluating mechanical properties of single nanofiber, which were found to be comparable to bulk zirconia. Nanofibers were tested for their high-temperature resistance using an electron beam. It showed resistance to radiation damage when irradiated with 1 MeV Kr2+ ion. Some zirconia nanofibers were also tested under high-intensity pulsed proton beam and maintained their structural integrity. This study shows for the first time that a ceramic nanofiber has been tested under different beams and irradiation condition to qualify their physical properties for practical use as accelerator targets. Advantages and challenges of such nanofibers as potential future targets over bulk material targets are discussed. 
    more » « less
  3. ; ; ; ; ; ; ; (, Nano Letters)
    Polymer nanofibers hold promise in a wide range of applications owing to their diverse properties, flexibility, and cost effectiveness. In this study, we introduce a polymer nanofiber drawing process in a scanning electron microscope and focused ion beam (SEM/FIB) instrument with in situ observation. We employed a nanometer-sharp tungsten needle and prepolymer microcapsules to enable nanofiber drawing in a vacuum environment. This method produces individual polymer nanofibers with diameters as small as ∼500 nm and lengths extending to millimeters, yielding nanofibers with an aspect ratio of 2000:1. The attachment to the tungsten manipulator ensures accurate transfer of the polymer nanofiber to diverse substrate types as well as fabrication of assembled structures. Our findings provide valuable insights into ultrafine polymer fiber drawing, paving the way for high-precision manipulation 
    more » « less
  4. ; ; ; ; ; ; ; ; (, Macromolecular Bioscience)
    Abstract This study focuses on the fabrication, characterization and anticancer properties of biocompatible and biodegradable composite nanofibers consisting of poly(vinyl alcohol) (PVA), oxymatrine (OM), and citric acid (CA) using a facile and high‐yield centrifugal spinning process known as Forcespinning. The effects of varying concentrations of OM and CA on fiber diameter and molecular cross‐linking are investigated. The morphological and thermo‐physical properties, as well as water absorption of the developed nanofiber‐based mats are characterized using microscopical analysis, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. In vitro anticancer studies are conducted with HCT116 colorectal cancer cells. Results show a high yield of long fibers embedded with beads. Fiber average diameters range between 462 and 528 nm depending on OM concentration. The thermal analysis results show that the fibers are stable at room temperature. The anticancer study reveals that PVA nanofiber membrane with high concentrations of OM can suppress the proliferation of HCT116 colorectal cancer cells. The study provides a comprehensive investigation of OM embedded into nanosized PVA fibers and the prospective application of these membranes as a drug delivery system. 
    more » « less
  5. ; ; ; ; ; ; ; ; ; ; et al (, The Astrophysical Journal)
    Abstract We present a study of the orbital light curves of the recurrent nova IM Normae since its 2002 outburst. The broad “eclipses” recur with a 2.46 hr period, which increases on a timescale of 1.28(16) × 106yr. Under the assumption of conservative mass transfer, this suggests a rate near 10−7M⊙yr−1, and this agrees with the estimatedaccretionrate of the postnova, based on our estimate of luminosity. IM Nor appears to be a close match to the famous recurrent nova T Pyxidis. Both stars appear to have very high accretion rates, sufficient to drive the recurrent-nova events. Both have quiescent light curves, which suggest strong heating of the low-mass secondary, and very wide orbital minima, which suggest obscuration of a large “corona” around the primary. And both have very rapid orbital period increases, as expected from a short-period binary with high mass transfer from the low-mass component. These two stars may represent a final stage of nova—and cataclysmic variable—evolution, in which irradiation-driven winds drive a high rate of mass transfer, thereby evaporating the donor star in a paroxysm of nova outbursts. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email