Bio Inspired Carbon Nanotube Polymer Composite Yarns with Hydrogen Bond Mediated Lateral Interactions (original) (raw)
Nanomaterials
In this report, networks of carbon nanotubes (CNTs) are transformed into composite yarns by infusion, mechanical consolidation and polymerization of dicyclopentadiene (DCPD). The microstructures of the CNT yarn and its composite are characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and a focused ion beam used for cross-sectioning. Pristine yarns have tensile strength, modulus and elongation at failure of 0.8 GPa, 14 GPa and 14.0%, respectively. In the composite yarn, these values are significantly enhanced to 1.2 GPa, 68 GPa and 3.4%, respectively. Owing to the consolidation and alignment improvement, its electrical conductivity was increased from 1.0 × 105 S/m (raw yarn) to 5.0 × 105 S/m and 5.3 × 105 S/m for twisted yarn and composite yarn, respectively. The strengthening mechanism is attributed to the binding of the DCPD polymer, which acts as a capstan and increases frictional forces within the nanotube bundles, making...
Scratch-Resistant, Highly Conductive, and High-Strength Carbon Nanotube-Based Composite Yarns
2010
High-strength and conductive carbon nanotube (CNT) yarns are very attractive in many potential applications. However, there is a difficulty when simultaneously enhancing the strength and conductivity of CNT yarns. Adding some polymers into CNT yarns to enhance their strength will decrease their conductivity, while treating them in acid or coating them with metal nanoparticles to enhance their conductivity will reduce their strength. To overcome this difficulty, here we report a method to make high-strength and highly conductive CNTbased composite yarns by using a continuous superaligned CNT (SACNT) yarn as a conductive framework and then inserting polyvinyl alcohol (PVA) into the intertube spaces of the framework through PVA/dimethyl sulphoxide solution to enhance the strength of yarns. The as-produced CNT/PVA composite yarns possess very high tensile strengths up to 2.0 GPa and Young's moduli more than 120 GPa, much higher than those of the CNT/ PVA yarns reported. The electric conductivity of as-produced composite yarns is as high as 9.2 ؋ 10 4 S/m, comparable to HNO 3 -treated or Au nanoparticle-coated CNT yarns. These composite yarns are flexible, lightweight, scratch-resistant, very stable in the lab environment, and resistant to extremely humid ambient and as a result can be woven into high-strength and heatable fabrics, showing potential applications in flexible heaters, bulletproof vests, radiation protection suits, and spacesuits.
Functionalization of carbon nanotube yarn by acid treatment
International Journal of Smart and Nano Materials, 2014
Carbon nanotube (CNT) yarn was functionalized using sulfuric and nitric acid solutions in 3:1 volumetric ratio. Successful functionalization of CNT yarn with carboxyl and hydroxyl groups (e.g., COOH, COO-, OH, etc.) was confirmed by attenuated total reflectance spectroscopy. X-ray diffraction revealed no significant change to the atomic in-plane alignment in the CNTs; however, the coherent length along the diameter was significantly reduced during functionalization. A morphology change of wavy extensions protruding from the surface was observed after the functionalization treatment. The force required to fracture the yarn remained the same after the functionalization process; however, the linear density was increased (310%). The increase in linear density after functionalization reduced the tenacity. However, the resistivity density product of the CNT yarn was reduced significantly (234%) after functionalization.
Journal of Applied Polymer Science, 2013
The current research discusses the efforts to achieve yarns coated with composite nanofibers and investigates some of their properties. Polyacrylonitrile/dimethyl formamide solutions containing various mass concentrations of single-wall and multiwall carbon nanotubes (SWCNTs and MWCNTs) and also functionalized SWCNTs were electrospun onto an acrylic staple yarn to produce hybrid yarns. The effect of the CNT addition on the final morphologies of the nanofibers was evaluated using SEM. The fibers prepared with higher CNT concentrations had larger diameters than those of fibers obtained by lower concentrations. The SEM, the optical microscope, and the microtome were used to investigate the structural morphology of the hybrid yarns. The conductivity and the viscosity of the solutions at different SWCNT concentrations were measured. The surface electrical resistance and the mechanical properties of the hybrid yarns composed of the nanofibers as sheath were analyzed. V
Manufacturing polymer/carbon nanotube composite using a novel direct process
Nanotechnology, 2011
A direct process for manufacturing polymer carbon nanotube (CNT) based composite yarns is reported. The new approach is based on a modified dry spinning method of CNT yarn and gives a high alignment of the CNT bundle structure in yarns. The aligned CNT structure was combined with a polymer resin and, after being stressed through the spinning process, the resin was cured and polymerized, with the CNT structure acting as reinforcement in the composite. Thus the present method obviates the need of special and complex treatments to align and disperse CNTs in a polymer matrix. The new process allows of producing the polymer/CNT composite with properties that may satisfy various engineering specifications. The structure of the yarn was investigated using scanning electron microscopy coupled with a focused ion beam system. The tensile behavior was characterized using a dynamic mechanical analyzer. Fourier transform infrared spectrometry was also used to chemically analyze the presence of polymer on the composites. The process allows development of polymer/CNT based composite with different mechanical properties suitable for a range of applications by using various resins. Recently, CSIRO has successfully developed a modified dry spinning process for converting CNT forest into yarn where the CNT structure is more aligned and the mechanical properties of yarn are significantly improved [22]. The aim of this work was to demonstrate a different approach, based on the modified dry spinning process, for producing the polymer/CNT composite yarns with properties that may satisfy many different engineering specifications, especially in biocompatible applications. 2. Review of the modified dry spinning process Pure CNT based products (yarns and sheets) have two structural levels, the individual CNTs (molecular level) and bundles of aggregated CNTs held by van der Waals forces [23-24]. When gathered from a CNT forest the CNT bundles form a continuous network, called the web. In CNT structures of web, sliver, sheet or yarn, some free space or porosity is present, even at a high packing factor, that is, there is space not only between the CNTs but also between CNT bundles (see figure 1). The success of the dry spinning process was attributed in part to the degree of twist applied during spinning [17, 25]. In fact, the role of twist was to increase the van der Waals forces between the CNTs in the bundles as well as the interaction between the CNT bundles, which produced the required interbundle lateral cohesion. This cohesion in a macro-structure, however, is only optimal if the alignment and tension is controlled.
Preparation and characterization of hybrid conducting polymer–carbon nanotube yarn
Nanoscale, 2012
Hybrid polypyrrole (PPy)-multi walled carbon nanotube (MWNT) yarns were obtained by chemical and electrochemical polymerization of pyrrole on the surface and within the porous interior of twisted MWNT yarns. The material was characterized by scanning electron microscopy, electrochemical, mechanical and electrical measurements. It was found that the hybrid PPy-MWNT yarns possessed significantly higher mechanical strength (over 740 MPa) and Young's modulus (over 54 GPa) than the pristine MWNT yarn. The hybrid yarns also exhibited substantially higher electrical conductivity (over 235 S cm À1 ) and their specific capacitance was found to be in excess of 60 F g À1 . Measurements of temperature dependence of electrical conductivity revealed semiconducting behaviour, with a large increase of band gap near 100 K. The collected low temperature data are in good agreement with a threedimensional variable range hopping model (3D-VRH). The improved durability of the yarns is important for electrical applications. The composite yarns can be produced in commercial quantities and used for applications where the electrical conductivity and good mechanical properties are of primary importance.
Structure and process-dependent properties of solid-state spun carbon nanotube yarns
Journal of Physics: Condensed Matter, 2010
The effects of processing conditions and apparent nanotube length on properties are investigated for carbon nanotube yarns obtained by solid-state drawing of an aerogel from a forest of multi-walled carbon nanotubes. Investigation of twist, false twist, liquid densification and combination methods for converting the drawn aerogel into dense yarn show that permanent twist is not needed for obtaining useful mechanical properties when nanotube lengths are long compared with nanotube diameters. Average mechanical strengths of 800 MPa were obtained for polymer-free twist-spun multi-walled carbon nanotube (MWNT) yarns and average mechanical strengths of 1040 MPa were obtained for MWNT yarns infiltrated with 10 wt% polystyrene solution. Strategies for increasing the mechanical properties are suggested based on analysis of intra-wall, intra-bundle and inter-bundle stress transfer.
Polymers, 2021
In this work, the influence of carbon nanotubes (CNTs) content on the mechanical and electrical properties of four series of polymeric matrix were made and their cytotoxicity on cells was evaluated to consider their use as a possible artificial muscle. For that, polymer composite yarns were electrospun using polymeric solutions at 10 wt.%. of poly(styrene-co-acrylonitrile) P(S:AN) and P(S:AN-acrylic acid) P(S:AN-AA) at several monomeric concentrations, namely 0:100, 20:80, 40:60, 50:50 (wt.%:wt.%), and 1 wt.% of AA. Carbon nanotubes (CNTs) were added to the polymeric solutions at two concentrations, 0.5 and 1.0 wt.%. PMCs yarns were collected using a blade collector. Mechanical and electrical properties of polymeric yarns indicated a dependence of CNTs content into yarns. Three areas could be found in fibers: CNTs bundles zones, distributed and aligned CNTs zones, and polymer-only zones. PMCs yarns with 0.5 wt.% CNTs concentration were found with a homogenous nanotube dispersion and...