Hybrid Sol–Gel Matrices Doped with Colorimetric/Fluorimetric Imidazole Derivatives

Abstract

Organic–inorganic hybrids (OIH) are materials that can be easily synthesized by the sol–gel method and combine the advantages of organic and inorganic moieties within a single polymeric matrix. Imidazole derivatives are versatile organic compounds that can change their optical properties with the variation of pH due to the protonation or deprotonation of the nitrogen atoms. This work reports the preparation of different OIHs doped with different contents of two imidazole compounds (3a,b). The obtained materials were characterized structurally by FTIR, and the dielectric properties were studied by electrochemical impedance spectroscopy. The optical properties were studied by UV-Vis absorption and fluorescence spectroscopies. The FTIR analysis showed that the presence of the imidazole does not change the structural properties of the matrices. The normalized resistance values obtained for the doped matrices ranged between 8.57 and 9.32 Ω cm2, all being higher than the undoped matrix. The σ ranged between 9.49 and 10.28 S cm−1, being all higher than the pure OIH samples. Compound 3a showed a maximum absorption peak at 390 nm, which is present in the OIH spectra, proving the presence of the compound. In the case of compound 3b, a maximum absorption wavelength at 412 nm was found, and the compound peak was not clear, which may indicate that an interaction between the compound and the matrix occurred. A synergetic effect between the intrinsic emission of the matrix and the fluorescence of 3a is found on the OIH-doped matrices.

Amino-Alcohol Organic-Inorganic Hybrid Sol-Gel Materials Based on an Epoxy Bicyclic Silane: Synthesis and Characterization

“…Figure 6 shows the transmittance spectra for the four new OIH materials. All spectra show a high-transmission region between 350 and 800 nm, as expected for these types of materials [14,15,26]. It is possible to assess that the transparency is higher in the samples with the lower Jeffamine MW, which is according to the information already reported in the literature for OIH materials synthesized with Jeffamine precursors [34].…”

“…Figure 5 shows the FTIR spectra for the four aminoalcohol materials. All four spectra show two Nanomaterials 2023, 13, 2429 7 of 14 strong bands at around 2850-2860 and 2915-2925 cm −1 , characteristic of C-H stretching vibrations [14,[25][26][27][28]. These bands are typical of the organic part from the Jeffamine moiety.…”

Halochromic Textiles for Real-Time Sensing of Hazardous Chemicals and Personal Protection

“…Other approaches that can be used for chemical sensing are based on a change in the optical response, for example, using fluorometric probes [8][9][10] and halochromic molecules [11][12][13][14]. Halochromic molecules are those capable of shifting colors in response to a variation in pH [15].…”

Formation of Composite Coatings on Galvanized Steel from Organosilane Solutions Using Electrophoresis and Sol–Gel Technology

“…To protect zinc or zinc coatings on steel from corrosion, adsorption-type corrosion inhibitors are the most effective. Among organic zinc corrosion inhibitors in aqueous solutions, carboxylates [ 1 , 2 , 3 , 4 ], azoles and their substituted forms [ 5 , 6 , 7 , 8 , 9 ], molybdates [ 10 , 11 ], alkylphosphonic acids [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] and organosilanes [ 19 , 20 , 21 ] are currently known. Their inhibitory effect is often explained by the formation of a thin protective layer on the metal surface due to chemisorption or the formation of complex compounds with Zn 2+ cations [ 5 , 11 ].…”