A5053755801- Advanced Sensor and Energy Harvesting Materials
- Carbon Nanotubes in Composites
- Advanced Materials and Mechanics
- Conducting polymers and applications
- Graphene research and applications
- Supercapacitor Materials and Fabrication
- Dielectric materials and actuators
- Porphyrin and Phthalocyanine Chemistry
- Nonlinear Optical Materials Research
- Organic Electronics and Photovoltaics
- Innovative Energy Harvesting Technologies
- Diamond and Carbon-based Materials Research
- Thermal properties of materials
- Electrospun Nanofibers in Biomedical Applications
- Advanced Thermoelectric Materials and Devices
- Advancements in Battery Materials
- MXene and MAX Phase Materials
- Photochemistry and Electron Transfer Studies
- Fiber-reinforced polymer composites
- Photonic Crystals and Applications
- Acoustic Wave Phenomena Research
- Nanotechnology research and applications
- Mechanical and Optical Resonators
- Graphene and Nanomaterials Applications
- Silk-based biomaterials and applications
The University of Texas at Dallas
2016-2025
University of Dallas
2021
Beijing Graphene Institute
2015-2017
Luleå University of Technology
2012
Laser Expertise (United Kingdom)
2012
University of Kentucky
1996-2000
Institute for Molecular Science
1993-1996
Advanced Science Research Center
1996
Institute of Physics
1992
Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths the range from 514.5 to 1320 nanometers. Numerous peaks were observed and identified vibrational modes of armchair symmetry ( n , ) SWNTs. The spectra good agreement lattice dynamics calculations based on C-C force constants used fit two-dimensional, experimental phonon dispersion a single graphene sheet....
Individual carbon nanotubes are like minute bits of string, and many trillions these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per by cooperatively rotating in vertically oriented nanotube arrays (forests) made 5-centimeter-wide, meter-long transparent sheets. These self-supporting sheets initially formed as a highly anisotropic electronically conducting aerogel that can densified into strong thin 50...
The high cost of powerful, large-stroke, high-stress artificial muscles has combined with performance limitations such as low cycle life, hysteresis, and efficiency to restrict applications. We demonstrated that inexpensive high-strength polymer fibers used for fishing line sewing thread can be easily transformed by twist insertion provide fast, scalable, nonhysteretic, long-life tensile torsional muscles. Extreme twisting produces coiled contract 49%, lift loads over 100 times heavier than...
Nanotube Yarn Actuators are used to convert heat, light, or electricity into a twisting tensile motion, and often described as artificial muscles. Most materials that show actuation either provide larger forces with small-amplitude motions, such the alloy NiTi, motions much less force, polymeric materials. Other problems actuators can include slow response times short lifetimes. Lima et al. (p. 928 , see Perspective by Schulz ) range of guest-filled, twist-spun carbon nanotube yarns be for...
Improved electrically powered artificial muscles are needed for generating force, moving objects, and accomplishing work. Carbon nanotube aerogel sheets the sole component of new that provide giant elongations elongation rates 220% (3.7 × 10 4 )% per second, respectively, at operating temperatures from 80 to 1900 kelvin. These solid-state–fabricated enthalpic rubbers having gaslike density specific strength in one direction higher than those steel plate. Actuation decreases can be...
Carbon nanotube yarns are used to make fast, multirotational torsional actuators.
It is a challenge to fabricate graphene bulk materials with properties arising from the nature of individual sheets, and which assemble into monolithic three-dimensional structures. Here we report scalable self-assembly randomly oriented sheets additive-free, essentially homogenous sponge that provide combination both cork-like rubber-like properties. These sponges, densities similar air, display Poisson's ratios in all directions are near-zero largely strain-independent during reversible...
Composite stretchable conducting wires Think how useful a electronic “skin” could be. For example you place it over an aircraft fuselage or body to create network of sensors, processors, energy stores, artificial muscles. But is difficult make interconnects and strain sensors that can stretch such surfaces. Liu et al. created superelastic fibers by depositing carbon nanotube sheets onto prestretched rubber core (see the Perspective Ghosh). The nanotubes buckled on relaxation core, but...
Abstract Flexible reduced graphene oxide (rGO) sheets are being considered for applications in portable electrical devices and flexible energy storage systems. However, the poor mechanical properties conductivities of rGO limiting factors development such devices. Here we use MXene (M) nanosheets to functionalize platelets through Ti-O-C covalent bonding obtain MrGO sheets. A sheet was crosslinked by a conjugated molecule (1-aminopyrene-disuccinimidyl suberate, AD). The incorporation AD...
Mechanical energy harvesters are needed for diverse applications, including self-powered wireless sensors, structural and human health monitoring systems, the extraction of from ocean waves. We report carbon nanotube yarn that electrochemically convert tensile or torsional mechanical into electrical without requiring an external bias voltage. Stretching coiled yarns generated 250 watts per kilogram peak power when cycled up to 30 hertz, as well 41.2 joules cycle, normalized harvester weight....
Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up 95 weight percent otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these in galleries irregular scroll sacks whose observed complex structures related twist-dependent extension Archimedean...
Getting the most out of muscles Materials that convert electrical, chemical, or thermal energy into a shape change can be used to form artificial muscles. Such materials include bimetallic strips host-guest coiled fibers yarns (see Perspective by Tawfick and Tang). Kanik et al. developed polymer bimorph structure from an elastomer semicrystalline where difference in expansion enabled thermally actuated Iterative cold stretching clad could tailor dimensions mechanical response, making it...
Abstract Smart textiles that sense, interact, and adapt to environmental stimuli have provided exciting new opportunities for a variety of applications. However, current advances largely remained at the research stage due high cost, complexity manufacturing, uncomfortableness environment‐sensitive materials. In contrast, natural textile materials are more attractive smart their merits in terms low cost comfortability. Here, water fog humidity‐driven torsional tensile actuation thermally set...
Continuously operating thermo-electrochemical cells (thermocells) are of interest for harvesting low-grade waste thermal energy because their potentially low cost compared with conventional thermoelectrics. Pt-free thermocells devised here provide an output power 12 W m-2 interelectrode temperature difference (ΔT) 81 °C, which is sixfold higher than previously reported planar at ambient pressure.
By controlling the SWNT-rGO electrode composition and thickness to attain appropriate porosity tortuosity, electroactive surface area is maximized while rapid diffusion of electrolyte through maintained. This leads an increase in exchange current density between which results enhanced thermocell performance. As a service our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized for online delivery, but not...
Spider silks show unique combinations of strength, toughness, extensibility, and energy absorption. To date, it has been difficult to obtain spider silk-like mechanical properties using non-protein approaches. Here, we report on an artificial silk produced by the water-evaporation-induced self-assembly hydrogel fibre made from polyacrylic acid silica nanoparticles. The consists hierarchical core-sheath structured fibres, which are reinforced ion doping twist insertion. exhibits a tensile...
Pump it up Carbon nanotube yarns can be used as electrochemical actuators because infiltration with ions causes a contraction in length and an expansion diameter. Either positive or negative cause this effect. Chu et al. constructed all-solid-state muscle that eliminated the need for electrolyte bath, which may expand potential its use applications. By infiltrating charged polymers, fibers start partially swollen, so increase through loss of ions. It is thus possible to overall stroke...
Graphene and two-dimensional transition metal carbides and/or nitrides (MXenes) are important materials for making flexible energy storage devices because of their electrical mechanical properties. It remains a challenge to assemble nanoplatelets these at room temperature into in-plane isotropic, free-standing sheets. Using nanoconfined water-induced basal-plane alignment covalent π-π interplatelet bridging, we fabricated Ti
Actuation is normally dramatically enhanced by introducing so much yarn fiber twist that the becomes fully coiled. In contrast, we found usefully high muscle strokes and contractile work capacities can be obtained for non-twisted MXene (Ti 3 C 2 T x ) fibers comprising nanosheets are stacked in direction. The artificial muscles called MFAMs. We MFAMs have modulus both radial axial directions spinning a solution containing dispersed an aqueous cellulose solution. observed highly reversible...
Degassing of bundles single-walled carbon nanotubes in vacuum at 500 K is found to drive the thermoelectricpower (TEP) strongly negative, indicating that degassed metallic tubes a bundle are n type. The magnitude negative TEP indicates important asymmetry electronic pi bands exists near Fermi energy. Easily measurable increases ( approximately 5-10 &mgr;V/K) and resistivity 2%-10%) observed upon exposure N2 He, suggesting even gas collisions with nanotube wall can contribute significantly...
We report intercalation of charged polyiodide chains into the interstitial channels in a single-wall carbon nanotube (SWNT) rope lattice, suggesting new chemistry for nanotubes, distinctly different from that graphite and ${\mathrm{C}}_{60}$. This structural model is supported by results Raman spectroscopy, x-ray diffraction, $Z$-contrast electron microscopy, electrical transport data. Iodine-doped SWNTs are found to be air stable, permitting use variety techniques explore effect charge...
Abstract Nanocarbon‐based thermocells involving aqueous potassium ferro/ferricyanide electrolyte are investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. The dependencies of power output on thermocell parameters, such cell orientation, electrode size, spacing, concentration and temperature, examined provide practical design elements principles. Observation discharge behavior provides understanding the three primary internal resistances (i.e.,...