In-situ pull-off of ZnO nanowire from carbon fiber and improvement of interlaminar toughness of hierarchical ZnO nanowire/carbon fiber hydrid composite laminates

Abstract

Zinc oxide (ZnO) has attracted much attention for various applications because of its unique electrical, optical, magnetic and piezoelectric properties. ZnO nanowires (NWs) are often grown onto the carbon fiber (CF) surface to improve the electrical conductivity and flexibility of ZnO, and it is important to understand and further enhance the interaction between ZnO NWs and CFs. Herein, ZnO NWs were grown onto carbon fabrics through a facile hydrothermal method, and the pull-off force to detach an individual ZnO nanowire from CF was measured using a nano-manipulator inside a scanning electron microscope chamber. Also, a novel dopamine-based functionalization method was developed to improve the interfacial adhesion between ZnO NWs and CFs. It was found that introducing polydopamine (PDA) on CF could increase significantly the adhesion strength between CF and ZnO NW and their interfacial shear strength with epoxy as measured by the single fiber microbond test. The hierarchical ZnO NWs on CF fabrics were then utilized to fabricate the laminates. The highest mode I and mode II interlaminar toughness were obtained in those laminates comprising CF/PDA/ZnO NWs owing to the high chemical bonding between ZnO NWs and PDA modified CF surface and strong mechanical interlocking between ZnO NWs and epoxy.

Building Hierarchical Micro-Structure on the Carbon Fabrics to Improve Their Reinforcing Effect in the CFRP Composites

“…CF/ZnO NWs has intrinsically poor interfacial adhesion because of insufficient functional groups on the CF surface that connects with ZnO, the current chemical oxidative methods including acid or plasma treatments are utilized to introduce the functional groups onto the CF surface to improve the CF/ZnO NWs interfacial adhesion, but oxidation functionalization can etch the fiber substrate and thus decrease the CF strength, which is undesirable for all applications. To address this problem, we [26] recently introduces Polydopamine (PDA) onto the CF surface to bond with the ZnO NWs, because PDA owns a robust chelating capability toward metal ions and can act as nucleation sites to form a metal oxide-PDA core/shell structure, the experimental results showed uniform and vertical aligned ZnO nanowires are well grown in the CF surface modified by PDA. In fact, the formed PDA layer has many functional groups such as quinone, carboxyl, catechol, amino and imino groups, which formed the main interaction, namely, the coordination between the catechol groups and the Zn 2+ ion, this interaction gradually promotes the ZnO seed layer, from which ZnO NWs are nucleated and grow on the PDA-modified CF.…”

Photoluminescence Study of the Influence of Additive Ammonium Hydroxide in Hydrothermally Grown ZnO Nanowires

“…The need of a facile, industrially scalable and substrate independent synthesis of ZnO NWs has seen significant advancements towards the hydrothermal growth process [11,12]. Hydrothermal growth (HTG) is a low temperature process where single-crystalline 1D material can be produced on various substrates, including plastics or even textile fibers [25]. In general, HTG grown ZnO NWs show intense defect level band peak in photoemission spectra which expands from blue to red color wavelength emission depending on type of defects in the nanomaterial [26].…”

Modification of carbon fibers surfaces with polyetheramines: The role of interphase microstructure on adhesion properties of CF/epoxy composites

“…Grafting of polymer or micromolecule to CFs can offer a method to acquire a controlled, ordered, and active structure . Amine groups can react with epoxy groups, and the grafting of CF with amine‐containing polymers should result in good bridge formation between the CF and epoxy matrix, which has been demonstrated to be an effective modification method . Some molecules with active amine groups, like hexamethylene diamine (HMD) , tetraethylenepentamine (TEPA) , poly (amido amine) (PAMAM) dendrimer , polydopamine , polyethyleneimine (PEI) have been reported to bridge CFs and epoxy resin and improved significantly the interfacial properties of composites, but acyl chloride reaction was usually introduced to intensify chemical bonding, which could bring toxic chlorination, prolong reaction time, and deteriorate the fiber tensile strength.…”