Durable Self-Cleaning Radiative Cooling Coatings for Building Energy Efficiency.

Passive daytime radiative cooling (PDRC) is an energy-saving technology without an additional energy supply or environmental pollution. At present, most PDRC coatings for buildings are only aiming at high solar reflectivity () and high mid-infrared emissivity () while ignoring practicalities such as adhesion strength, scalability, and durability. In this work, modified calcined kaolin/(ethylene trifluorochloroethylene copolymer-polydimethylsiloxane) (MK/(FEVE-PDMS)) coating with super practicability is prepared by using MK as a filler, FEVE as an adhesive, and PDMS as a hydrophobic modifier.

Application of Surface Wettability to Control Spreading of an Impacting Droplet.

While the simplest outcome of a normal impact on a flat stationary solid surface is radially symmetric spreading, it is important to note that asymmetric spreading can intrinsically occur with a tangential velocity along the surface. However, no previous attempt has been made to restore the symmetry of a lamella that intrinsically spreads asymmetrically. Adjusting the lamella's asymmetric shape to a symmetric one is achieved in this work by varying wettability to affect the receding velocity of the contact line, according to the Taylor-Culick theory.

Innovative Solid Slippery Coating: Uniting Mechanical Durability, Optical Transparency, Anti-Icing, and Anti-Graffiti Traits.

Slippery coatings, such as the slippery liquid-infused porous surface (SLIPS), have gained significant attention for their potential applications in anti-icing and anti-fouling. However, they lack durability when subjected to mechanical impact. In this study, we have developed a robust slippery coating by blending polyurethane acrylate (PUA) with methyltriethoxysilane (MTES) and perfluoropolyether (PFPE) in the solvent of butyl acetate.

A harsh environment resistant robust Co(OH)@stearic acid nanocellulose-based membrane for oil-water separation and wastewater purification.

Traditional membranes are inefficient in treating highly toxic organic pollutants and oily wastewater in harsh environments, which is difficult to meet the growing demand for green development. Herein, the Co(OH)@stearic acid nanocellulose-based membrane was prepared by depositing Co(OH) on the nanocellulose-based membrane (NBM) through chemical soaking method, which enables efficient oil/water mixtures separation and degradation of pollutants by photocatalysis in harsh environments. The Co(OH)@stearic acid nanocellulose-based membrane (Co(OH)@stearic acid NBM) shows good photocatalytic degradation performance for methylene blue pollutants in harsh environment, and has significant degradation rate (93.

Experimental Investigation of Dropwise Condensation Shedding by Shearing Airflow in Microgravity Using Different Surface Coatings.

The shedding kinematics of water droplets in a condensation environment when exposed to aerodynamic forces in microgravity was studied. Understanding the shedding of droplets from a surface is a critical part of the dropwise condensation process for improving heat transfer. Because gravity as a droplet removal technique is not available in space, the use of airflow to shed droplets is considered for condensing heat exchangers in environmental control and life support systems.

Perturbative vibration of the coupled hydrogen-bond (O:H-O) in water.

Perturbation Raman spectroscopy has underscored the hydrogen bond (O:H-O or HB) cooperativity and polarizability (HBCP) for water, which offers a proper parameter space for the performance of the HB and electrons in the energy-space-time domains. The OO repulsive coupling drives the O:H-O segmental length and energy to relax cooperatively upon perturbation. Mechanical compression shortens and stiffens the O:H nonbond while lengthens and softens the HO bond associated with polarization.

Folding characteristics of membranes in capillary origami.

A study was conducted to understand the effects of membrane shape, thickness, contact angle, surface tension and large deflection on capillary origami. For experiments, square and triangular membranes made of PDMS with various thicknesses and sizes were used to encapsulate different liquids. Models for membranes under pure bending were developed using the energy balance between interfacial energies (liquid-vapor, solid-liquid and solid-vapor energies) and bending energy evaluated by a small-deflection and a large-deflection assumptions.

Fabrication of polydimethylsiloxane-attached solid slippery surface with high underwater transparency towards the antifouling of optical window for marine instruments.

Marine optical instruments are commonly suffering serious biofouling problem caused by the adhesion of marine microorganisms, which severely affects the instruments to monitor the marine environment. Herein, we developed a robust solid slippery surface (SSS) by fabricated a covalently attached polydimethylsiloxane (PDMS) layer on glass substrate to solve the biofouling problem of marine optical instrument windows. The SSS could effectively inhibit the settlements of marine microorganism (bacteria and alga) in various environmental conditions, resulting from the high flexibility of PDMS molecular chains, and thus could maintain its high underwater-transparency.

Novel SLIPS based on the photo-thermal MOFs with enhanced anti-icing/de-icing properties.

A photo-thermal anti-icing/de-icing SLIPS coating is designed based on porous light-responsive MOFs. Due to the strong light absorption and high light-thermal conversion, the as-synthetic SCMOFs exhibited prolonged freezing delay time and depressed water crystallization point under light irradiation. Meantime, the SCMOFs exhibit good deicing properties.

Improving the curing and flame retardancy of epoxy resin composites by multifunctional Si-containing cyclophosphazene derivatives.

Novel star-like molecules containing P, N and Si with dual functions of flame retardance and curing promotion (abridged as HCCP-KH540) were successfully synthesized through the nucleophilic substitution reaction of hexachlorocyclotriphosphazene (HCCP) and 3-aminopropyltrimethoxysilane (KH540). HCCP-KH540 was incorporated with the matrix of epoxy resin (EP) to form a flame retardant composite abridged as E-HK. The activation energy of the curing reaction of the E-HK composite was reduced but the curing reaction rate was accelerated by HCCP-KH540.

Water and mildew proof SiO & ZnO/silica sol superhydrophobic composite coating on a circuit board.

In order to improve the waterproof and mildew resistance of electronic equipment, a superhydrophobic coating was prepared on a circuit board. First, hexadecyl trimethoxysilane was used to modify the nano silica and nano zinc oxide particles, and then the modified nanoparticles were mixed with the silica sol. Then the superhydrophobic coating was prepared on the surface of the printed circuit board by a spraying process.

A multifunctional and environmentally safe superhydrophobic membrane with superior oil/water separation, photocatalytic degradation and anti-biofouling performance.

Wastewater is typically complicated with spilled oil, water soluble toxic dyes and microorganisms, making it hard to be processed and causing a significant threat to the environmental safety and human health. In this paper, we demonstrate a simple solution immersion method to obtain a multifunctional cellulose-based membrane (CBM) that possesses both superhydrophobicity with a water contact angle of 163° and superior functionalities including self-cleaning, oil-water separation, anti-biofouling, and photocatalytic degradation capabilities. The achievement of separation efficiency (96%), comparatively high flux (141 L·m·h) and recyclable (7 times) oil/water separation performance is attributed to the robust superhydrophobicity enabled by the synergy of metal oxide (i.

Porous Ultrahigh Molecular Weight Polyethylene/Functionalized Activated Nanocarbon Composites with Improved Biocompatibility.

Ultrahigh molecular weight polyethylene (UHMWPE) materials have been prevalent joint replacement materials for more than 45 years because of their excellent biocompatibility and wear resistance. In this study, functionalized activated nanocarbon (FANC) was prepared by grafting maleic anhydride polyethylene onto acid-treated activated nanocarbon. A novel porous UHMWPE composite was prepared by incorporating the appropriate amount of FANC and pore-forming agents during the hot-pressing process for medical UHMWPE powder.

Stable, superfast and self-healing fluid coating with active corrosion resistance.

Fluid material can recover from damage rapidly with no demand of external triggering in contrast with the traditional self-healing material which presents low healing efficiency and demands external triggering, such as heat, light, moisture, electricity, etc. However, due to its low viscosity, fluid material is easy to flow away from the surface and thus it is difficult to form a stable coating on the surface to provide practical corrosion resistance to the substrate. Herein, a stable and superfast self-healing coating on steel substrate has been obtained by incorporating carbon nanotube (CNT) into the fluid matrix of epoxy resin (EP) or silicone oil (OIL).

Durable Superhydrophobic Wood via One-Step Immersion in Composite Silane Solution.

A superhydrophobic coating endows pristine hydrophilic wood with excellent water/moisture repellency and thus prolongs its service life. Generally, the superhydrophobic coating on wood is fabricated by a two-step process in which the nanoparticles are first introduced onto the surface and then modified by low-surface-energy molecules. Herein, for the first time, we have fabricated the superhydrophobic wood via a one-step process free of nanoparticles by immersing the pristine hydrophilic wood, such as pine, balsawood, and basswood, into a composite silane solution of hexadecyltrimethoxysilane and methyltrimethoxysilane.

Biochar Nanocomposite Derived from Watermelon Peels for Electrocatalytic Hydrogen Production.

Water splitting is the most potential method to produce hydrogen energy, however, the conventional electrocatalysts encounter the hindrances of high overpotential and low hydrogen production efficiency. Herein, we report a carbon-based nanocomposite (denoted as CCW-, stands for the calcination temperature) derived from watermelon peels and CoCl, and the as-synthesized CCW- is used as the electrocatalyst. The overpotential and the Tafel slope of CCW-700 for oxygen evolution reaction (OER) is 237 mV at 10 mA cm and 69.

Spray-On Nanocomposite Coatings: Wettability and Conductivity.

Nanocomposite coatings, i.e., a combination of nanocompounds, and a polymer matrix together with suitable additives and solvents is a very versatile method for producing multifunctional coatings.

Functionalized cellulose nanocrystals as the performance regulators of poly(β-hydroxybutyrate-co-valerate) biocomposites.

To investigate the relationship between functional groups on cellulose nanocrystals (CNC) and the performance of poly(β-hydroxybutyrate-co-valerate) (PHBV), the surface of CNC was modified by surface graft modification and PHBV/CNC biocomposites were prepared by melt blending. To demonstrate the interfacial adhesion difference between hydrophobic PHBV and hydrophilic CNC, palmitoyl chloride and ε-caprolactone had been used to tailor the oleophilic property of CNC. Results showed that CNC had heterogeneous nucleation effect on the crystallization process of PHBV, while the entanglement of molecular chains weakened the promoting functions of CNC-g-C16 (CNC grafted with palmitoyl chloride) and CNC-g-CL (CNC grafted with ε-caprolactone).

Mechanically Robust and Repairable Superhydrophobic Zinc Coating via a Fast and Facile Method for Corrosion Resisting.

Zinc coatings and superhydrophobic surfaces have their own characteristics in terms of metal corrosion resistance. Herein, we have prepared a robust and repairable superhydrophobic zinc coating (SZC) based on a widely commercially available cold galvanized paint via a fast (within 10 min) and facile process for corrosion resistance. Specifically, the cold galvanized paint was sprayed onto the iron substrate, followed by acetic acid (HAc) etching and stearic acid (STA) hydrophobizing.

Graphene-Wrapped Ni(OH)2 Hollow Spheres as Novel Electrode Material for Supercapacitors.

Graphene-wrapped Ni(OH)2 hollow spheres were prepared via electrostatic interaction between poly(diallyldimethylammonium chloride) (PDDA) modified Ni(OH)2 and graphene oxide (GO) in an aqueous dispersion, followed by the reduction of GO. Morphological and structural analysis by field-emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis confirmed the successful coating of graphene on Ni(OH)2 hollow spheres with a content of 3.8 wt%.

Green Approach to the Fabrication of Superhydrophobic Mesh Surface for Oil/Water Separation.

We report a simple and environment friendly method to fabricate superhydrophobic metallic mesh surfaces for oil/water separation. The obtained mesh surface exhibits superhydrophobicity and superoleophilicity after it was dried in an oven at 200 °C for 10 min. A rough silver layer is formed on the mesh surface after immersion, and the spontaneous adsorption of airborne carbon contaminants on the silver surface lower the surface free energy of the mesh.

In situ separation and collection of oil from water surface via a novel superoleophilic and superhydrophobic oil containment boom.

We have prepared a porous, superoleophilic and superhydrophobic miniature oil containment boom (MOCB) for the in situ separation and collection of oils from the surface of water. The MOCB was fabricated by a one-step electrodepositing of Cu2O film on Cu mesh surface without using low surface energy materials. Oils on water surface could be fast contained in the MOCB while water was completely repelled out of the MOCB, thus achieving the separation of oil from water surface.

Superoleophobic textured copper surfaces fabricated by chemical etching/oxidation and surface fluorination.

We report a convenient route to fabricate superoleophobic surfaces (abridged as SOS) on copper substrate by combining a two-step surface texturing process (first, the substrate is immersed in an aqueous solution of HNO3 and cetyltrimethyl ammonium bromide, and then in an aqueous solution of NaOH and (NH4)2S2O8) and succeeding surface fluorination with 1H,1H,2H,2H-perfluorodecanethiol (PFDT) or 1-decanethiol. The surface morphologies and compositions were characterized by field emission scanning electron microscopy and X-ray diffraction, respectively. The results showed that spherical micro-pits (SMP) with diameter of 50-100 μm were formed in the first step of surface texturing; in the second step, Cu(OH)2 or/and CuO with structures of nanorods/microflowers/microballs were formed thereon.

One-step solution immersion process to fabricate superhydrophobic surfaces on light alloys.

A simple and universal one-step process bas been developed to render light alloys (including AZ91D Mg alloy, 5083 Al alloy, and TC4 Ti alloy) superhydrophobic by immersing the substrates in a solution containing low-surface-energy molecules of 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS, 20 μL), ethanol (10 mL), and H2O (10 mL for Al and Mg alloy)/H2O2 (15%, 10 mL for Ti alloy). Field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and water contact angle measurements have been performed to characterize the morphological features, chemical composition, and wettability of the surfaces, respectively. The results indicate that the treated light alloys are rough-structured and covered by PFOTS molecules; consequently, the surfaces show static contact angles higher than 150° and sliding angles lower than 10°.