Sol–gel based optically active phenolphthalein encapsulated nanomatrices for sensing application

Abstract

In this work, synthesis and characterization of phenolphthalein-immobilized titania (T-phph) and silicatitania (ST-phph) nanomatrix is reported. The thin films are deposited by sol-gel method at low temperature. The effect of host-guest chemistry in matrices, on the surface structures, optical and sensing activity of the resultant thin films is studied. The phenolphthalein-immobilized fabricated nanoparticles/nanomatrices are analyzed by field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic-force microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, surface analysis, thermogravimetric analysis, and UV-Vis spectroscopy. Thermally stable and high surface area homogeneous nanoparticles, containing nanocrystalline anatase phase with low refractive index (1.58), low roughness (5.5 nm), and high transparency (95 %) are obtained for phenolphthalein-immobilized ST-phph nanomatrix. Moreover, smaller nanoparticles (56-121 nm) with good incorporation of dye and good response of sensing are obtained. The sensor response is optimized at pH 12 with 10.

Encapsulated Colorimetric Indicators used as Additives During the Polymerization of Smart Polyethylene

“…The prepared encapsulated systems were compared with systems reported in the literature: the specific areas of the prepared system were slightly smaller than those reported by Islam [ 28,29 ] ≈450 m 2 g −1 for bromophenol blue, creosol red and phenol red and phenolphthalein encapsulated in silica by the acid‐catalyzed sol‐gel method in the presence of cetyltrimethylammonium bromide. Capelleti et al.…”

“…The encapsulated indicators tended to exhibit larger pore volumes and pore diameters than bare silica. The prepared encapsulated systems were compared with systems reported in the literature: the specific areas of the prepared system were slightly smaller than those reported by Islam [28,29] ≈450 m 2 g −1 for bromophenol blue, creosol red and phenol red and phenolphthalein encapsulated in silica by the acid-catalyzed sol-gel method in the presence of cetyltrimethylammonium bromide. Capelleti et al [30] performed a comparative analysis of the effect of the synthetic route on the encapsulation of alizarin red, brilliant yellow and acridine, and a silica specific area of ≈800 m 2 g −1 was obtained using an acid synthetic route.…”

Degradation of microcystin-LR and cylindrospermopsin by continuous flow UV-A photocatalysis over immobilised TiO2

“…The cylindrical reactor vessel was made of clear glass with stainless steel end-fittings (height 150 mm, internal diameter 31.8 mm, wall thickness 9.1 mm, volume 84 mL). Inside the reactor, 30 glass tubes (0.5 cm diameter) were coated with TiO2 (0.96%) by a modified sol-gel method described by Islam et al (2016). Uncoated glass tubes were used for experimental controls (UV-A, H2O2, UV-A/H2O2) (Table S1).…”

Organic-inorganic hybrid sol–gel membranes for pH sensing in highly alkaline environment

“…It was concluded that the developed OFS was suitable for long term monitoring of pH. In 2016, Islam et al [30] reported the development of different types of sol-gel matrices doped with phenolphthalein (phph). The prepared titania and silica-titania matrices showed a stable thermal behaviour and a strong connection between the matrix and the phph [30].…”

“…In 2016, Islam et al [30] reported the development of different types of sol-gel matrices doped with phenolphthalein (phph). The prepared titania and silica-titania matrices showed a stable thermal behaviour and a strong connection between the matrix and the phph [30]. Also in 2016, an evanescent wave pH OFS was fabricated through the encapsulation of different indicator dyes within the same organic-inorganic hybrid (OIH) matrix which was obtained by the sol-gel method using as precursors TEOS and titanium tetraisopropoxide in the presence of cetyl trimethyl ammonium bromide (CTAB) [31].…”