Browsing by Subject "Ambient pressure drying"

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    Highly transparent, flexible, and thermally stable superhydrophobic ORMOSIL aerogel thin films
    (American Chemical Society, 2011) Budunoglu, H.; Yildirim, A.; Güler, Mustafa O.; Bayındır, Mehmet
    We report preparation of highly transparent, flexible, and thermally stable superhydrophobic organically modified silica (ORMOSIL) aerogel thin films from colloidal dispersions at ambient conditions. The prepared dispersions are suitable for large area processing with ease of coating and being directly applicable without requiring any pre- or posttreatment on a variety of surfaces including glass, wood, and plastics. ORMOSIL films exhibit and retain superhydrophobic behavior up to 500 °C and even on bent flexible substrates. The surface of the films can be converted from superhydrophobic (contact angle of 179.9°) to superhydrophilic (contact angle of <5°) by calcination at high temperatures. The wettability of the coatings can be changed by tuning the calcination temperature and duration. The prepared films also exhibit low refractive index and high porosity making them suitable as multifunctional coatings for many application fields including solar cells, flexible electronics, and lab on papers. © 2011 American Chemical Society.
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    Influence of various sol-gel parameters on the physico‐chemical properties of sulfuric acid chelated zirconia aerogels dried at ambient pressure
    (Wiley-VCH Verlag, 2020) Bangi, U. K. H.; Patil, Bhushan; Pawar, R. C.; Park, H.-H.
    This work represents the influence of various sol–gel parameters on the physico‐chemical properties of sulfuric acid chelated zirconia aerogels dried at ambient pressure. The sol–gel parameters such as concentrations of precursor, chelating agent and catalyst are found to be the dominant factors which influence the physical, chemical and textural properties of the aerogels. Therefore, the influence of concentration of Zr precursor, ZrPr:H2SO4 molar ratio and ZrPr:H2O molar ratio on these properties of zirconia aerogels is studied. Zirconia lacogels are formed by the hydrolysis and condensation of zirconium n‐propoxide in n‐propanol chelated with sulfuric acid (18.4 M) and catalyzed with deionized water. Aerogels are obtained by subsequent solvent exchange, silylation, washing and ambient pressure drying. The physico‐chemical properties of as synthesized zirconia aerogels are carried out using FESEM, EDS, BET analysis and FTIR spectroscopy. The good quality zirconia aerogels are obtained using the molar ratio of ZrPr:PrOH:H2SO4:H2O:HMDZ::1:2.93:1.18:1.77:0.59. They possess the density of 0.54 g cm‐3, BET surface area of 328 m2 g‐1 and micropore volume of 0.028 cm3 g‐1. These aerogels can be applied as heterogeneous catalysts in many fields.