Abstract
In this study, a novel and convenient bio-inspired modification strategy was used to create stable superhydrophobic structures on halloysite clay nanotubes (HNTs) surfaces. The polydopamine (PDA) nanoparticles can firmly adhere on HNTs surfaces in a mail environment of pH 8.5 via the oxidative self-polymerization of dopamine and synthesize a rough nano-layer assisted with vitamin M, which provides a catechol functional platform for the secondary reaction to graft hydrophobic long-chain alkylamine for preparation of hierarchical micro/nano structures with superhydrophobic properties. The micromorphology, crystal structure, and surface chemical composition of the resultant superhydrophobic HNTs were characterized by field emission scanning electron (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The as-formed surfaces exhibited outstanding superhydrophobicity with a water contact angle (CA) of 156.3 ± 2.3°, while having little effect on the crystal structures of HNTs. Meanwhile, the resultant HNTs also showed robust stability that can conquer various harsh conditions including strong acidic/alkaline solutions, organic solvents, water boiling, ultrasonic cleaning, and outdoor solar radiation. In addition, the novel HNTs exhibited excellent packaged capabilities of phase change materials (PCMs) for practical application in thermal energy storage, which improved the mass fractions by 22.94% for stearic acid and showed good recyclability. These HNTs also exhibited good oil/water separation ability. Consequently, due to the superior merits of high efficiency, easy operation, and non-toxicity, this bionic surface modification approach may make HNTs have great potentials for extensive applications.
Highlights
In the past several years, superhydrophobic surfaces have attracted remarkable interest due to their unique wettability for potential applications in self-clean, anti-fog, anti-ice, anti-bacteria, oil-water separation, energy-storage, and drug-release [1,2,3,4,5,6,7]
Various nanoparticles including noble metal (Ag) [36], metallic oxide (Fe3 O4 ) [37], and silicon oxide [38] were incorporated through the catechol coordinate bonds and hydrogen bonds to create primary hierarchical structures on halloysite clay nanotubes (HNTs) surfaces, this most-used approach suffered from a lot of disadvantages, such as high cost, time-consuming, and poor stability
contact angle (CA) continued to decline in s, and got to the minimum value below. These results continued to decline in 150 s, and got to the minimum value below 10. These results suggested suggested simpleasdopamine a modifier can hardly generate thelayers hydrophobic onwhich that simplethat dopamine a modifierascan hardly generate the hydrophobic on HNTlayers surface, surface, which was ascribed to the hydrophilic groups existing on the was ascribed to the hydrophilic groups existing on the PDA moleculePDA
Summary
In the past several years, superhydrophobic surfaces have attracted remarkable interest due to their unique wettability for potential applications in self-clean, anti-fog, anti-ice, anti-bacteria, oil-water separation, energy-storage, and drug-release [1,2,3,4,5,6,7] To obtain these special wetting properties, surface modification has been developed to establish hierarchical micro/nano structures with hydrophobic chemical groups by learning from the exquisite tissues and organs in the biological world, such as lotus leaves and pond skater legs with super hydrophobicity [8].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
