Low‐Cost and Scaled‐Up Production of Fluorine‐Free, Substrate‐Independent, Large‐Area Superhydrophobic Coatings Based on Hydroxyapatite Nanowire Bundles

Abstract

To date, the scaled-up production and large-area applications of superhydrophobic coatings are limited because of complicated procedures, environmentally harmful fluorinated compounds, restrictive substrates, expensive equipment, and raw materials usually involved in the fabrication process. Herein, the facile, low-cost, and green production of superhydrophobic coatings based on hydroxyapatite nanowire bundles (HNBs) is reported. Hydrophobic HNBs are synthesised by using a one-step solvothermal method with oleic acid as the structure-directing and hydrophobic agent. During the reaction process, highly hydrophobic C-H groups of oleic acid molecules can be attached in situ to the surface of HNBs through the chelate interaction between Ca ions and carboxylic groups. This facile synthetic method allows the scaled-up production of HNBs up to about 8 L, which is the largest production scale of superhydrophobic paint based on HNBs ever reported. In addition, the design of the 100 L reaction system is also shown. The HNBs can be coated on any substrate with an arbitrary shape by the spray-coating technique. The self-cleaning ability in air and oil, high-temperature stability, and excellent mechanical durability of the as-prepared superhydrophobic coatings are demonstrated. More importantly, the HNBs are coated on large-sized practical objects to form large-area superhydrophobic coatings.

Customized Cellulose Fiber Paper Enabled by an In Situ Growth of Ultralong Hydroxyapatite Nanowires

“…To gain a deep insight into the in situ growth mechanism of HAPNWs, the morphology evolution with reaction time is investigated by an SEM observation. At an early stage (0.5 h), the calcium oleate precursor reacts with PO 4 3– to form the amorphous products, which are distributed on the surface of CFs (Figure S5a). This quasi-continuous layer of the amorphous products can act as nucleation sites for the growth of HAPNWs .…”

“…3− to form the amorphous products, 45 which are distributed on the surface of CFs (Figure S5a). This quasi-continuous layer of the amorphous products can act as nucleation sites for the growth of HAPNWs.…”

Transferrable Electrospinning Nanofiber Meshes as Strongly Adhered Scaffolds for Slippery Liquid-Infused Porous Surfaces

“…Variations of SLIPS have utilized different methods for their applications. These include using direct growth of porous material onto the targeted substrates, − deposition of nanomaterials during hydrothermal synthesis, , laser ablation to produce a porous surface, dip coating, spin coating, spray-on, , and electrospinning nanofibers onto the subject. − Of these options, electrospinning is a convenient way to directly deposit continuous nanofibers onto a substrate surface. Afterward, infusion of protective oil into the mesh of electrospinning nanofibers can yield a coating with SLIPS properties.…”

Hydroxyapatite Nanowire-Reinforced Poly(ethylene oxide)-Based Polymer Solid Electrolyte for Application in High-Temperature Lithium Batteries

“…To address these issues, many efforts have been made to boost the basic electrochemical performance, especially for poly­(ethylene oxide) (PEO)-based hybrid solid polymer electrolytes. − Commonly, two types of fillers, active- and inner-inorganic ceramics, could be introduced into the PEO matrix to improve the ionic conductivities by orders of magnifications. − Thanks to recent advances, the ionic conductivities of PEO-based solid electrolytes already reached up to 10 –4 to 10 –5 S/cm. − However, it is still a big challenge to improve the comprehensive performance of the solid composite polymer electrolytes simultaneously, such as high ionic conductivities, wide electrochemical voltage windows, excellent mechanical properties, good interfacial affinity with electrodes, superior heat resistance, and thermal/mechanical stabilities at high temperatures. − Very recently, Hu et al reported that a hydroxyapatite (HAP) nanowire membrane could be employed as a separator, especially for high-temperature lithium-ion battery applications. As is known to all, HAP is the main inorganic component of human or animal bones and teeth. − It is also a renewable biomass material with nontoxic biocompatibility, good mechanical strength, and excellent thermal stability. − What is more, the surface functional groups of HAP would be expected to interact with anions of lithium salts, further increase the concentration of free Li ions, and improve the ionic conductivities.…”