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By replacing absolute ethanol, water was used as a ubiquitous and low-cost solvent to dissolve metal nitrates and organic additives to obtain a precursor solution that showed long-term stability and reproducibility. This precursor solution was used to deposit a CuMn 2 O 4 ceramic film on a stainless steel substrate using the convenient and inexpensive sol-gel dip-coating technique. The X-ray diffraction (XRD) profile of the ceramic film annealed for 1 h at 450 °C was found to coincide with that of crystalline CuMn 2 O 4 in the JCPDS database. The CuMn 2 O 4 ceramic film obtained at an annealing temperature of 500 °C exhibited excellent solar absorptance ( α s =0.905) and thermal emittance ( ε 100 =0.120). By optimizing the deposition parameters, we systematically investigated the effect of the chemical components, surface texture, and thickness of the ceramic film on its optical properties. Subjected to a thermal stability test at 252 °C, the CuMn 2 O 4 ceramic film showed good thermal stability with performance criterion (PC) values below 0.05. [ABSTRACT FROM AUTHOR]

Spinel Cu 1.5 Mn 1.5 O 4 thin films were fabricated by one step sol-gel dip-coating method using aqueous solution. The effect of deposition parameters on thickness, surface feature, and optical property of thin films was systematically studied. The results revealed that the increased withdrawal speeds and high concentration of metal ions in precursor were conducive to obtaining thicker films which exhibited excellent solar absorptance. Furthermore, the surface feature derived from the different concentrations of metal ions had a significant effect on optical behavior of the thin film. Consequently, excellent spectral selectivity of the thin film would be achieved by tuning those deposition parameters. [ABSTRACT FROM AUTHOR]

Cu 1.5 Mn 1.5 O 4 -based ceramic spectrally selective (CSS) coating was deposited on aluminum substrate using a sol–gel dip-coating method. The citric acid introduced in the precursor system lowered the required calcining temperature of crystalline Cu 1.5 Mn 1.5 O 4 . X-Ray diffraction (XRD) peaks of coatings annealed above 450 °C were found to coincide exactly with that of crystalline Cu 1.5 Mn 1.5 O 4 in JCPDS database. By optimizing the withdrawal rate and calcining temperature, coating with spectral selectivity as good as α s = 0.876 and ε 100 = 0.057 was achieved after only one dipping/annealing cycle. Subjected to an accelerated ageing test at 259 °C, the obtained CSS coating showed an excellent thermally durability with the performance criterion (PC) values below 0.05. [ABSTRACT FROM AUTHOR]

A series of spinel-type CuMn 2 O 4 ceramic pigments were prepared by a facile and low-cost sol-gel solution combustion method and used as cost-effective materials to fabricate thickness sensitive spectrally selective (TSSS) paint coatings by a convenient spray-coating technique. The chemical component, crystalline morphology, and optical property of the copper manganese oxide ceramic pigment could be accurately controlled by altering the annealing temperature. X-ray diffraction (XRD) analysis confirmed that the ceramic pigments annealed at 500 °C for 1 h coincided well with the XRD patterns of crystalline CuMn 2 O 4 in the JCPDS database, and there were segregated phases of CuO and Mn 2 O 3 . Furthermore, the pure spinel CuMn 2 O 4 phase could be achieved at 900 °C for 1 h. The copper manganese oxide ceramic pigments could serve as an effective pigment for fabricating the TSSS paint coating, and the TSSS paint coatings based on ceramic pigments calcined at 900 °C showed solar absorptance of 0.895–0.905 and thermal emittance of 0.186–0.310. In addition, the accelerated thermal stability test revealed that the TSSS paint coating exhibited good thermal stability when it was exposed to air at a temperature of 300 °C for 300 h. Hence, the fabricated TSSS paint coating could be used as a solar absorber coating in the low-to-mid temperature domain. [ABSTRACT FROM AUTHOR]

The superamphiphobic coatings with high thermal conductivity and wear resistance have attracted wide attention in academic fields, but its construction through sheet fillers is very challenging. Herein, the graded filling of modified flake graphite and modified Al 2 O 3 was used to prepare epoxy resin/polytetrafluoroethylene powder/modified flake graphite/modified Al 2 O 3 (EP/PTFE/FG/Al 2 O 3) coating by two-step spray method, which can ensure stable nonwetting performance toward water, acid-base solutions (pH = 1–14), glycerol and ethylene glycol. More importantly, it also promised excellent wear resistance (1000 cycle wear times) and high thermal conductivity (1.822 ± 0.023 W/(m·K)). Furthermore, salt spray tests indicated that the EP/PTFE/FG/Al 2 O 3 coating had an outstanding anticorrosion. It can be foreseen that the simple but effective superamphiphobic coatings are applied in the fields of heat conduction and anticorrosion. • Graded fillers method enhanced the thermal conductivity, anticorrosion and superamphiphobicity of coating. • Superamphiphobic coatings have excellent wear resistance, strong adhesive ability and nonwetting stability. • Robust superamphiphobic coatings can be prepared on a large scale by two-step spraying method. [ABSTRACT FROM AUTHOR]

Abstract: CuCr x Mn2−x O4 (x=0.5, 1) spinels, novel pigments for spectrally selective paints, have been prepared through a sol–gel combustion synthesis process. Thickness Sensitive Spectrally Selective (TSSS) paint coatings, using CuCr x Mn2−x O4 (x=0.5, 1) obtained at varied calcined temperatures (500∼1100°C) as pigment, were deposited on top of aluminum substrates by an cost-effective spray coating method and characterized by reflectance measurements over the spectral range of 0.3–20μm. Influence of pigment species and coating thickness on optical properties of paint coatings was investigated. Results suggest that CuCr0.5Mn1.5O4-based coatings are more favorable than CuCrMnO4-based ones and coatings using 700°C calcined CuCr0.5Mn1.5O4 as pigment exhibit the optimum spectral selectivity (α s=0.92∼0.93, ε T=0.22∼0.31). Difference in powder thermal emittances reveals that suitable pigments can be pre-chosen before fabricating paint coatings to obtain optimum spectral selectivity. Long-term stability tests of the TSSS paint coatings were performed according to the methodology worked out within IEA-SHC Task X and the results confirmed that coatings in this study could be safely used during collector''s lifetime without degradation in performance. [Copyright &y& Elsevier]

Abstract: This article describes a divergent strategy to prepare grafted polymer chains with functional end groups for surface modification of nanoparticles with other functional groups. This preparation is achieved through a combination of surface-initiated atom transfer radical polymerization (ATRP) and click chemistry. First, the surface of the silica nanoparticles was modified with polystyrene (PSt) brushes via the “grafting from” approach. The terminal bromides of PSt-grafted silica nanoparticles were then substituted with azido groups. These azido-terminated PSt brushes on the nanoparticle surface were reacted with various alkyne-terminated functional end groups via click reactions. In all cases, FTIR and 1H NMR spectra indicated quantitative transformation of the chain ends of polystyrene brushes on silica nanoparticles into the desired functional group. [Copyright &y& Elsevier]