NTI Research
Permanent URI for this collectionhttps://hdl.handle.net/10735.1/3658
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Browsing NTI Research by Subject "Carbon nanotubes"
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Item Bio-Inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn MusclesKim, Shi Hyeong; Kwon, Cheong Hoon; Park, Karam; Mun, Tae Jin; Lepro, Xavier; Baughman, Ray H.; Spinks, Geoffrey M.; Kim, Seon Jeong; 0000 0003 5232 4253 (Baughman, RH); 0000-0002-0166-3127 (Lepró, X); Lepró, Xavier; Baughman, Ray H.Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg⁻¹), which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture driven muscle. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space.Item Biothermal Sensing of a Torsional Artificial Muscle(Royal Soc Chemistry, 2016-01-25) Lee, Sung-Ho; Kim, Tae Hyeob; Lima, M©rcio D.; Baughman, Ray H.; Kim, Seon Jeong; 0000 0003 5232 4253 (Baughman, RH); Lima, M©rcio D.; Baughman, Ray H.Biomolecule responsive materials have been studied intensively for use in biomedical applications as smart systems because of their unique property of responding to specific biomolecules under mild conditions. However, these materials have some challenging drawbacks that limit further practical application, including their speed of response and mechanical properties, because most are based on hydrogels. Here, we present a fast, mechanically robust biscrolled twist-spun carbon nanotube yarn as a torsional artificial muscle through entrapping an enzyme linked to a thermally sensitive hydrogel, poly(N-isopropylacrylamide), utilizing the exothermic catalytic reaction of the enzyme. The induced rotation reached an equilibrated angle in less than 2 min under mild temperature conditions (25-37 ⁰C) while maintaining the mechanical properties originating from the carbon nanotubes. This biothermal sensing of a torsional artificial muscle offers a versatile platform for the recognition of various types of biomolecules by replacing the enzyme, because an exothermic reaction is a general property accompanying a biochemical transformation.Item A Carbon Nanotube-based Raman-imaging Immunoassay For Evaluating Tumor Targeting Ligands(Royal Society of Chemistry, 2014-04-16) Bajaj, Pooja; Mikoryak, Carole; Wang, Ruhung; Bushdiecker II, David K.; Memon, Pauras; Draper, Rockford K.; Dieckmann, Gregg R.; Pantano, Paul; Musselman, Inga H.; Pantano, Paul; Musselman, Inga H.Herein, we describe a versatile immunoassay that uses biotinylated single-walled carbon nanotubes (SWNTs) as a Raman label, avidin-biotin chemistry to link targeting ligands to the label, and confocal Raman microscopy to image whole cells. Using a breast tumor cell model, we demonstrate the usefulness of the method to assess membrane receptor/ligand systems by evaluating a monoclonal antibody, Her-66, known to target the Her2 receptors that are overexpressed on these cells. We present two-dimensional Raman images of the cellular distribution of the SWNT labels corresponding to the distribution of the Her2 receptors in different focal planes through the cell with validation of the method using immunofluorescence microscopy, demonstrating that the Her-66-SWNT complexes were targeted to Her2 cell receptors.;Item Conductive Functional Biscrolled Polymer and Carbon Nanotube Yarns(2013-10-10) Kim, S. H.; Sim, H. J.; Shin, M. K.; Choi, A. Y.; Kim, Y. T.; Lima, Marcio D.; Baughman, Ray H.; Kim, S. J.; 0000 0003 5232 4253 (Baughman, RH); Lima, Marcio D.; Baughman, Ray H.Biscrolling aligned electrospun fiber (AEF) sheets and carbon nanotube (CNT) sheets were fabricated for conductive, functional yarns by a versatile dry composite method. Our biscrolling (twist-based spinning) method is based on spinnable polymer fiber sheets and spinnable CNT sheets unlike the previous biscrolling technique using unspinnable nanopowders and spinnable CNT sheets. The CNT sheet in composite yarns acted as effective electrical wires forming dual Archimedean multilayer rolled-up nanostructures. The weight percent of the electrospun polymer fibers in the composite yarns was over 98%, and the electrical conductivity values of the composite yarns was 3 orders higher than those of other non-conducting polymer/CNT composite fibers which were electrospun from polymer solutions containing similar loading of CNTs. We also demonstrate that biscrolled yarns having various structures can be fabricated from spinnable AEF sheets and spinnable CNT sheets.Item Electrochemically Gated Organic Photovoltaic with Tunable Carbon Nanotube Cathodes(2013-10-18) Cook, Alexander B.; Yuen, Jonathan D.; Zakhidov, Anvar A.; 0000 0003 5287 0481 (Zakhidov, AA); Zakhidov, Anvar A.We demonstrate an organic photovoltaic (OPV) device with an electrochemically gated carbon nanotube (CNT) charge collector. Bias voltages applied to the gate electrode reconfigure the common CNT electrode from an anode into a cathode which effectively collects photogenerated electrons, dramatically increasing all solar cell parameters to achieve a power conversion efficiency of ∼3%. This device requires very little current to initially charge and the leakage current is negligible compared to the photocurrent. This device can also be viewed as a hybrid tandem OPV-supercapacitor with a common CNT electrode. Other regimes of operation are briefly discussed.Item High-Performance Biscrolled MXene/Carbon Nanotube Yarn Supercapacitors(Wiley-VCH Verlag) Wang, Z.; Qin, S.; Seyedin, S.; Zhang, J.; Wang, J.; Levitt, A.; Li, Na; Haines, Carter; Ovalle-Robles, R.; Lei, W.; Gogotsi, Y.; Baughman, Ray H.; Razal, J. M.; 0000 0003 5232 4253 (Baughman, RH); 0000-0001-5845-5137 (Baughman, RH); Li, Na; Haines, Carter; Baughman, Ray H.Yarn-shaped supercapacitors (YSCs) once integrated into fabrics provide promising energy storage solutions to the increasing demand of wearable and portable electronics. In such device format, however, it is a challenge to achieve outstanding electrochemical performance without compromising flexibility. Here, MXene-based YSCs that exhibit both flexibility and superior energy storage performance by employing a biscrolling approach to create flexible yarns from highly delaminated and pseudocapacitive MXene sheets that are trapped within helical yarn corridors are reported. With specific capacitance and energy and power densities values exceeding those reported for any YSCs, this work illustrates that biscrolled MXene yarns can potentially provide the conformal energy solution for powering electronics beyond just the form factor of flexible YSCs.Item Highly Stretchable Hybrid Nanomembrane Supercapacitors(2016-03-04) Kim, Keon Jung; Lee, Jae Ah (UT Dallas); Lima, Márcio D. (UT Dallas); Baughman, Ray H.; Kim, Seon Jeong; 0000 0003 5232 4253 (Baughman, RH); Baughman, Ray H.Supercapacitors that are lightweight, mechanically deformable (stretchable, flexible) and electrochemically stable have potential for various applications like portable, wearable, and implantable electronics. Here we demonstrate a stretchable and high-performing hybrid nanomembrane supercapacitor. The hybrid nanomembrane is prepared by vapour phase polymerization (VPP) based nanoscopic PEDOT coating on carbon nanotube sheets (CNS) transferred onto an elastomeric substrate to form a wavy structure. The resulting wavy structured hybrid nanomembrane based supercapacitor exhibits high electrochemical performance and mechanical stretchability, simultaneously. The high specific capacitances and energy density (82 F g⁻¹, 11 mF cm⁻², and 7.28 W h kg⁻¹ at 0% strain) are retained under large mechanical deformation (77 F g⁻¹ and 6.87 W h kg⁻¹ at a biaxial strain of 600%). Moreover, there is only <1% degradation of capacitance ratio after 1000 cycles stretching/releasing and bending/unbending. This high mechanical cyclic stability is shown even during stretching/releasing and bending/unbending measured by dynamic cyclic voltammetry (CV). These results suggest that our supercapacitor is valuable in a wide range of applications that require it to be electrochemically stable under large mechanical deformation, such as strain sensors, wearable electronics and biomedical devices.Item Magnetic Torsional Actuation of Carbon Nanotube Yarn Artificial Muscle(Royal Society of Chemistry) Lee, D. W.; Kim, S. H.; Kozlov, Mikhail E.; Lepró, Xavier; Baughman, Ray H.; Kim, S. J.; 0000 0003 5232 4253 (Baughman, RH); 0000-0002-0166-3127 (Lepró, X); 0000-0001-5845-5137 (Baughman, RH); Kozlov, Mikhail E.; Lepró, Xavier; Baughman, Ray H.Magnetically driven torsional actuation of a multiwalled carbon nanotube (MWNT) yarn was realized by first biscrolling NdFeB magnetic particles into helical yarn corridors to make a magnetic MWNT yarn. The actuating device comprised a pristineMWNT yarn that was connected to the magnetic MWNT yarn, with a paddle attached between these yarns. The application of a magnetic field reversibly drove torsional actuation of up to 80° within ∼0.67 seconds. This magnetic actuator was remotely powered, and its actuation stroke was the same when the muscle array was at 20 °C and at -100 °C.Item Microwave Conductance of Aligned Multiwall Carbon Nanotube Textile Sheets(2014-12-30) Brown, Brian L.; Bykova, Julia S.; Howard, Austin R.; Zakhidov, Anvar A.; Shaner, Eric A.; Lee, Mark; Brown, Brian L.; Bykova, Julia S.; Howard, Austin R.; Zakhidov, Anvar A.; Lee, MarkMultiwall carbon nanotube (MWNT) sheets are a class of nanomaterial-based multifunctional textile with potentially useful microwave properties. To understand better the microwave electrodynamics, complex AC conductance measurements from 0.01 to 50 GHz were made on sheets of highly aligned MWNTs with the alignment texture both parallel and perpendicular to the microwave electric field polarization. In both orientations, the AC conductance is modeled to first order by a parallel frequency-independent conductance and capacitance with no inductive contribution. This is consistent with low-frequency diffusive Drude AC conduction up to 50 GHz, in contrast to the "universal disorder" AC conduction reported in many types of single-wall nanotube materials.Item Orthogonal Pattern of Spinnable Multiwall Carbon Nanotubes for Electromagnetic Interference Shielding Effectiveness(Elsevier Ltd, 2019-05-022) Lee, D. W.; Kim, H.; Moon, J. H.; Jeong, J. -H; Sim, H. J.; Kim, B. J.; Hyeon, J. S.; Baughman, Ray H.; Kim, S. J.; 0000-0001-5845-5137 (Baughman, RH); Baughman, Ray H.The need for thin and lightweight electromagnetic interference shielding materials is rapidly increasing in several industries, such as aerospace and telecommunication. This research finds that a shielding material, which is developed by the orthogonal pattern of spinnable multiwall carbon nanotubes (MWNTs), is ultra-light weight, thin, and has a high shielding effectiveness (SE). An orthogonal pattern, generated by just alignment of the spinnable MWNTs without adding any support materials such as polymers, ceramics, and magnets demonstrates that it is possible to efficiently attenuate electromagnetic interference (EMI) in the X-band frequency range (8.2–12.4 GHz). EMI SE in the developed shielding material is about 19.2 dB with a specific shielding effectiveness (SSE)/t (thickness) value of 73,633 dB cm² g⁻¹ at a thickness of about 4.48 μm. In addition, absorption effectiveness in this shielding material is as high as 96.3%, which provides excellent ability to reduce the secondary damage by reflection. ©2019 Elsevier LtdItem Shape-Engineerable Composite Fibers and Their Supercapacitor Application(RSC Pub, 2016-01-12) Kim, Kang Min; Lee, Jae Ah ((UT Dallas); Sim, Hyeon Jun; Kim, Kyung-Ah; Jalili, Rouhollah; Spinks, Geoffrey M.; Kim, Seon JeongDue to excellent electrical and mechanical properties of carbon nano materials, it is of great interest to fabricate flexible, high conductive, and shape engineered carbon based fibers. As part of these approaches, hollow, twist, ribbon, and other various shapes of carbon based fibers have been researched for various functionality and application. In this paper, we suggest simple and effective method to control the fiber shape. We fabricate the three different shapes of hollow, twisted, and ribbon shaped fibers from wet spun giant graphene oxide (GGO)/single walled-nanotubes (SWNTs)/poly(vinyl alcohol) (PVA) gels. Each shaped fibers exhibit different mechanical properties. The average specific strengthes of the hollow, twist, and ribbon fibers presented here are 126.5, 106.9, and 38.0 MPa while strain are 9.3, 13.5, and 5%, respectively. Especially, the ribbon fiber shows high electrical conductivity (524 ± 64 S cm⁻¹) and areal capacitance (2.38 mF cm⁻²).Item A Simple/Green Process for the Preparation of Composite Carbon Nanotube Fibers/Yarns(2014-09-04) Rahy, Abdelaziz; Choudhury, Arup; Kim, Changheon; Ryu, Sungwoo; Hwang, Jaewon; Hong, Soon Hyung; Yang, Duck J.; Korea Center for Nanostructured Material Technology; Korea Advanced Institute of Science and TechnologyWe report a simple and green process to prepare poly(vinyl alcohol)/carbon nanotube (PVA/CNT) composite fibers having high mechanical properties. This process, an environmentally friendly one with no use of acid or hazardous solvent, produces the composite fibers utilizing a PVA layer pre-coated on a PET film. SEM micrographs indicated that the CNTs are well dispersed in the PVA matrix, and the diameter of the fiber is around 50 μm. Mechanical properties of the composite fiber treated at different thermal annealing conditions are also reported.Item Superconductivity in an inhomogeneous bundle of metallic and semiconducting nanotubes(2013-09-06) Grigorenko, I.; Zakhidov, Anvar A.; 0000 0003 5287 0481 (Zakhidov, AA); Zakhidov, Anvar A.Using Bogoliubov-de Gennes formalism for inhomogeneous systems, we have studied superconducting properties of a bundle of packed carbon nanotubes, making a triangular lattice in the bundle's transverse cross-section. The bundle consists of a mixture of metallic and doped semiconducting nanotubes, which have different critical transition temperatures. We investigate how a spatially averaged superconducting order parameter and the critical transition temperature depend on the fraction of the doped semiconducting carbon nanotubes in the bundle. Our simulations suggest that the superconductivity in the bundle will be suppressed when the fraction of the doped semiconducting carbon nanotubes will be less than 0.5, which is the percolation threshold for a two-dimensional triangular lattice.