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Self-Cleaning Textiles Based on Superhydrophobic Nanocoatings
Published in Mangala Joshi, Nanotechnology in Textiles, 2020
Wang et al. published research dealing with the production of durable superhydrophobic coated fabrics based on tridecafluorooctyl-triethoxysilane and modification of silicon dioxide nanoparticles with polydimethylsiloxane (PDMS). Coated fabrics exhibited high abrasion resistance and excellent chemical resistance along with a sliding angle of 3° and a CA of 170°. The coated fabrics displayed durable superhydrophobicity where a sliding angle of less than 6° and a CA of 165° were obtained after repeated laundering for 500 cycles [78].
Organic Catalysis by Clay-Supported Reagents
Published in Benny K.G. Theng, Clay Mineral Catalysis of Organic Reactions, 2018
Barloy et al. (1990, 1992) used the montmorillonite-intercalated tetracationic Mn(TMPyP)4+ complex, where TMPyP denotes tetrakis(4-N-methyl-4-pyridiniumyl)porphyrin, for the epoxidation of alkenes in the presence of iodosylbenzene (PhIO) as oxidant. This clay-supported reagent could also catalyze the hydroxylation of alkanes, while showing a marked preference for small, linear molecules to the more bulky substrates. Similar results were obtained by Martinez-Lorente et al. (1996) using a K10-supported Mn(III) porphyrin complex and H2O2 as the oxidant, while Machado et al. (2002) and Nakagaki et al. (2006) reported the preferential formation of cyclohexanol to cyclohexanone during the oxidation of cyclohexane by Fe(III) porphyrin complexes immobilized on montmorillonite and chrysotile. Montmorillonite-supported Mn(TMPyP)4+ was also efficient in catalyzing the oxidation of mono- and di-meric lignin model compounds (Crestini et al. 2004), and 2,4,6-trichlorophenol could be oxidatively degraded by a montmorillonite-hemin complex (Xiong et al. 2014). Intercalation of a Mn-porphyrin complex into a previously silanized montmorillonite and kaolinite gave rise to biomimetic catalysts for the enhanced oxidation of catechol by H2O2 (Nuzzo and Piccolo 2013). Bizaia et al. (2009)prepared an interlayer complex of kaolinite with [meso-tetrakis(pentafluorophenyl)porphinato]iron(III) by first expanding the clay layers with dimethylsulfoxide (DMSO) and then displacing the intercalated DMSO with ethanolamine. The resultant kaolinite-porphyrin complex was highly effective in catalyzing the epoxidation of cyclooctene as well as in converting cyclohexane into cyclohexanone. More recently, Jondi et al. (2016) used the tetra(4-pyridylporphyrinato-Mn(III)) complex, intercalated into natural clays, to catalyze the hydrosilylation reaction of 1-octene and triethoxysilane to yield the linear tri(oxy)silyl-1-octene as the sole product. Bouhlel et al. (1993) reported that impregnation of nickel acetylacetonate into K10 montmorillonite gave a complex capable of promoting the epoxidation of olefins by molecular oxygen in the presence of isobutyraldehyde (as a sacrificial reductant). Pereira et al. (2008) used laponite and K10 montmorillonite, before and after grafting with 3-aminopropyl triethoxysilane (APTES), as supports of vanadyl acetylacetonate for the epoxidation of geraniol, and tert-butyl hydroperoxide as oxidant. A K10-supported molybdenum acetylacetonate complex was used by Farias et al. (2011) for the epoxidation of soybean and castor oils, and by Zhang et al. (2014) for the aerobic oxidation of 5-hydroxymethylfurfural to 5-hydroxymethyl-2-furancarboxylic acid. Likewise, Kameyama et al. (2006) were able to obtain 1,2-epoxycyclohexane from cyclohexene using montmorillonite-intercalated cobalt porphyrins. Interestingly, intercalation into a synthetic fluorohectorite made Co(TMPyP)4+ less active than the unsupported (free) counterpart in the oxidation of 2,6-di-tert-butylphenol by dioxygen, apparently because the cobalt porphyrin complex adopted such a surface orientation as to restrict substrate access (Chibwe et al. 1996; Dias et al. 2000).
Adhesion behavior of different droplet on superhydrophobic surface of cotton fabric based on oxygen plasma etching
Published in The Journal of The Textile Institute, 2023
Wei Zhang, Jiming Yao, Xudong Liu, Ruosi Yan, Jianlin Xu
Hexadecyltrimethoxysilane (HDTMS, ≥ 85%), 1H,1H,2H,2H-perfluorooctyl-triethoxysilane (PFOTS, 97%), silicon dioxide (SiO2) nanoparticles (99.5%, 30±5nm) were purchased from Shanghai Macklin Biochemical Co., Ltd (China). Absolute ethanol (C2H5OH, AR), acetic acid (CH3COOH, AR), sodium hydroxide (NaOH, AR), potassium dihydrogen phosphate (KH2PO4, AR), and dibasic sodium phosphate (Na2HPO4, AR) were obtained from Tianjin Damao Chemical Reagent Factory (China). Sodium carboxymethylcellulose (NaCMC, CP) was acquired from Sinopharm Chemical Reagent Co., Ltd (China). Tween-20 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd (China). Amaranth dye (85%, FCC) was obtained from Shanghai Dyestuffs research institute Co., Ltd (China). Sterile defibrinated sheep blood (SDSB) was provided by Nanjing Jinyou Biotechnology Co., Ltd (China). Direct dye blue and direct dye red were purchased from Tianjin Yuhua Economic and Trading Corporation Dye Branch.
Asphalt pavement coated by hot-pressed hydrated lime
Published in International Journal of Pavement Engineering, 2021
Huang Man, Hongliang Zhang, Liu Jifa
Importantly, HL modification greatly improved the abrasion resistance of specimens (especially GPM). Figure 15 shows that the mass losses of the specimens can be significantly reduced via an organic modification to HL. At spreading dosages of 50 and 100 g/m2, the reduction of mass loss of the specimen covered by GPM HL (about 25% to 50%, respectively) exceeds that of EPM HL (by about 22% to 33%, respectively). The reason may be that in GPM, the organic polystyrene with low surface energy is grafted onto the inorganic material HL by using vinyl triethoxysilane through hydrolysis and dehydration to form a chemical bond. The double bond in polystyrene is more active, and it is easy to react with heteroatom or active group in asphalt. So GPM builds a ‘molecular bridge’ between asphalt and HL and improves the adhesion performance and greatly improves the abrasion resistance of asphalt pavement coated by hot-pressed HL. While EPM just increases the electrostatic interaction and van der Waals force between polystyrene and HL through activator, so, the adhesion between HL and asphalt is weaker than that of GPM HL. Therefore, it can be concluded that GPM better improved abrasion resistance compared with EPM.
Recent advances on fluorescent biomarkers of near-infrared quantum dots for in vitro and in vivo imaging
Published in Science and Technology of Advanced Materials, 2019
Shanmugavel Chinnathambi, Naoto Shirahata
Furthermore, Si QDs are nontoxic, easy availability, a long PL lifetime on μsec scale, along with brightness and it give fluorescence emission from UV to NIR wavelength range (Figure 7(b)) [115–124]. NIR-emitting Si QDs have been prepared by non-thermal Plasma or thermal disproportionation of hydrogen silsesquioxane (HSiO1.5), followed by hydrofluoric etching to liberate the Si QDs from the oxide matrix [125–127]. In most of the studies, HSiO1.5 purchased from Dow Corning (trade name FOx-17) are used for QD synthesis [128,129], but a similar compound could be derived from the hydrolysis of trichlorosilane or triethoxysilane [130,131]. Impurity doping of boron, phosphorus, or transition metals into diamond cubic Si lattice has also been achieved [132,133]. Sugimoto et al. developed a new approach for the formation of all-inorganic Si QDs that are codoped with boron and phosphorus with excellent stability in water without organic ligands, exhibit bright and stable luminescence in the NIR wavelength range [134]. Wang et al. reported for the first time the bio-medical use of Si QDs was as a fluorescence label to DNA [135]. Since then, Swihart and co-workers have significantly developed this research field [136]. As the cytotoxicity is strongly influenced by surface terminal groups [137,138], the amphiphilic molecules such as Pluronic F127 or PEG are frequently employed for encapsulating the core of Si QDs, yielding the high hydrophilicity and bio-compatibility. Si QDs exhibit a low absorption efficiency to the red-to-NIR lights. Therefore, it is difficult to attain the NIR-NIR excitation-emission bio-imaging in the single-photon excitation environment. To overcome this difficulty, He et al. reported possible compatibility of multiphoton excitation technique with Si QD [139]. Chandra et al. developed water-borne Si QD adapted for 2-photon excitation and used it to provide for the first time direct evidence of the NIR-NIR excitation-emission imaging [107]. Ravotto et al. presented a light-harvesting two-photon antenna using the emission of Si QDs. This result opens up the potential for bio-imaging applications, such as deep tissue imaging, high resolution, and low photodamage, coupled with the bright, long-lived, and oxygen-insensitive NIR luminescence of Si QDs [140]. Recently, Sakiyama et al. developed a long-lived luminescence of colloidal silicon QDs for time-gated fluorescence imaging in the second NIR window in biological tissue (Figure 7(c)) [141].