Fabrication of Superhydrophobic Ni-Co-BN Nanocomposite Coatings by Two-Step Jet Electrodeposition

The stability of hydrophobic surface has an important influence on the application of superhydrophobic function. The destruction of hydrophobic micro-nano structures on the material surface is the main factor leading to the loss of superhydrophobic property. In order to improve the corrosion resistance of superhydrophobic surface, Ni-Co-BN nanocomposite coatings with superhydrophobic property were prepared on 45 steel by two-step jet electrodeposition. The surface morphology, water contact angle, and corrosion resistance of the samples were measured and characterized by scanning electron microscope, surface contact angle measuring instrument, and electrochemical workstation. The results of electrochemical analysis show that the superhydrophobic property improved the corrosion resistance of Ni-Co-BN nanocomposite coating. The enhanced corrosion resistance is of great significance to the integrity of the microstructure and the durability of the superhydrophobic function.

Lignocellulose aerogel and amorphous silica nanoparticles from rice husks

Rice Husks (RHs) are one of the most abundant sources of biomass in the world due to rice consumption. Lignocellulose and silica are two of the main components of RHs, which allow RHs to be applied in different areas. Lignocellulose can be partially dissolved in 1-butyl-3-methylimidazolium chloride (BMIMCl), which is a simple way of competing with the traditional extraction methods that suffer from high chemical consumption. A lignocellulose freeze gel is obtained via a cyclic liquid nitrogen freeze-thaw (NFT) process. Multi-functional self-assembled lignocellulose aerogel is obtained after CO2 supercritical drying. Based on the aerogel’s special properties, two routes are developed for practical applications. On one hand, the aerogel is coated to exhibit a superhydrophobic property that can be applied as an absorbent for oil spills. On the other hand, a carbon aerogel is synthesized via a pyrolysis process, resulting in a porous amorphous carbon. The residue after partially dissolving lignocellulose in BMIMCl is further calcined to obtain amorphous silica nanoparticles, achieving a comprehensive application of RHs. Graphical abstract

Superhydrophobic Ceramic Hollow Fibre Membranes for Trapping Carbon Dioxide from Natural Gas Via the Membrane Contactor System

The membrane contactor system is one of the most important technologies to trap CO2 from natural gas. To apply this technology, hollow fibre membranes with a superhydrophobic surface must be used. Three types of fluoroalkyl silane (FAS) molecules [C6, C8, C10] at different immersion times (6, 24, 48,72 h) were used to modify kaolin hollow fiber membrane into the superhydrophobic property to capture CO2 from natural gas via contacting gas-liquid system. The kaolin was chosen due to its abundantly available at an affordable price as well as a high amount of groups hydroxyl (OH) in the surface which easily reacts with (FAS) during the grafting process. Superhydrophobicity was distinguished by Fourier transforms infrared (FTIR), scanning electron microscope (SEM), liquid entry pressure of water (LEPw) measurement, and contact angle (CA). The chosen superhydrophobic kaolin membrane was tested for carbon dioxide (CO2) capture via the membrane contactor system. With increasing time of immersion, the hydrophobicity phenomena raised gradually until superhydrophobicity property was obtained. It was proved that the 48 hours was sufficient time to obtain the desired superhydrophobicity property to avoid wetting pores of the membranes. Besides, the perfect type of FAS for separation CO2 was C8 based on sufficient LEPw and contact angle. The reduction of pH was observed after testing the performance of using membrane contactor to separate CO2 by water as absorbent where pH value was reduced from 6.6 to 4.3 within one hour, which concludes that the success of the gas-liquid system to remove CO2 from natural gas.

Fabrication of Waterproof Artificial Compound Eyes with Variable Field of View Based on the Bioinspiration from Natural Hierarchical Micro–Nanostructures

Planar and curved microlens arrays (MLAs) are the key components of miniaturized microoptical systems. In order to meet the requirements for advanced and multipurpose applications in microoptical field, a simple manufacturing method is urgently required for fabricating MLAs with unique properties, such as waterproofness and variable field-of-view (FOV) imaging. Such properties are beneficial for the production of advanced artificial compound eyes for the significant applications in complex microcavity environments with high humidity, for instance, miniature medical endoscopy. However, the simple and effective fabrication of advanced artificial compound eyes still presents significant challenges. In this paper, bioinspired by the natural superhydrophobic surface of lotus leaf, we propose a novel method for the fabrication of waterproof artificial compound eyes. Electrohydrodynamic jet printing was used to fabricate hierarchical MLAs and nanolens arrays (NLAs) on polydimethylsiloxane film. The flexible film of MLAs hybridized with NLAs exhibited excellent superhydrophobic property with a water contact angle of 158°. The MLAs film was deformed using a microfluidics chip to create artificial compound eyes with variable FOV, which ranged from 0° to 160°.

The preparation and characterization of uniform nanoporous structure on glass

A novel fabrication method of uniform porous structures on the glass surface is proposed. The hydrofluoric acid fog formed by air-jet atomization etches the glass surface to fabricate nanoporous structure (NPS) on glass surface. This NPS shows the enhanced average light transmittance of approximately 92.9% and the superhydrophilic property with a contact angle less than 1° which presents an excellent anti-fog property. Passivated by fluorosilane, the NPS shows nearly the superhydrophobic property with a contact angle of 141.2°. This fabrication method has shown promising application prospects due to its simplicity, low cost and efficiency, which can be easily applied to large-scale industrial production.

A Convenient Approach to Constructing Superhydrophobic Paper Sensor for Gas Detection with High Immunity to Humidity

Despite the resistance-type gas sensors attracting intensive research interest, the vulnerability to the interference of humidity is a great challenge for their large-scale productions and applications. Herein, a convenient “gas-sensitized sensing material + adhesive” approach for the fabrication of superhydrophobic interface has been proposed to settle the problem. The multiwalled carbon nanotubes (MWCNTs)/styrene-ethylene/butylene-styrene block copolymer (SEBS) layer formed by spraying the cyclohexane suspension of MWCNTs and SEBS with micro/nanostructure endows the sensor with outstanding superhydrophobic property, presenting that the apparent contact angles (CA) are up to 179.6∘. The superhydrophobic paper sensor exhibited high sensing performance for acetone vapor and most importantly exceptional anti-humidity. The response of as-prepared sensor for other gaseous chemicals was consistent with that of MWCNTs, which indicated that the “gas-sensitized sensing [Formula: see text]” approach did not change the MWCNTs gas-sensitive characteristics. The approach builds an efficient bridge between gas-sensitive particles and flexible, superhydrophobic systems, inspiring a new simple way to the development of gas sensor with high immunity to humidity.

Dimensional stability of lotus leaf-like nanostructure superhydrophobic bamboo by modification using xylan

Xylan extracted from corncobs was used to modify bamboo and to improve its dimensional stability. A lotus leaf-like surface was prepared on the modified bamboo using a fresh lotus leaf and polydimethylsiloxane (PDMS) as the template and seal via soft lithography. The dimensional stability of bamboo was tested via anti-shrinkage efficiency (ASE), moisture excluding efficiency (MEE), weight percent gain (WPG), and its superhydrophobic property. The microstructures of lotus-like bamboo surface were analyzed via water contact angle (WCA), scanning electron microscopy, and atomic force microscopy (AFM). The study found that with increasing mass fraction of xylan content, the anti-swelling property and WPG of modified bamboo increased accordingly. When the mass fraction of xylan was 10%, its WPG was the largest (2.21%), and xylan had a better compatibilization effect on bamboo. The dimensional stability of bamboo was improved to a certain extent by xylan. Moreover, the anisotropy and superhydrophobicity of the lotus leaf-like bamboo treated by xylan were noticeably improved after modification, such that the WCA of the transverse, radial, and tangential sections were 157.5º, 145.5º, and 137.5º, respectively. This research lays a foundation for studies of dimensional stability of bamboo and the mechanism of modification to achieve hydrophobic properties.