Sol-gel films

Sol-gel film.s deposited on a grit-blasted aluminum surface give performance close to PAA bonds (Fig. 22) with generally cohesive failures observed in wedge tests. Given that one application of this treatment is repair, the performance is... 

S.3.2 Sol-Gel Encapsulation of Reactive Species Another new and attractive route for tailoring electrode surfaces involves the low-temperature encapsulation of recognition species within sol-gel films (41,42). Such ceramic films are prepared by the hydrolysis of an alkoxide precursor such as, Si(OCH3)4 under acidic or basic condensation, followed by polycondensation of the hydroxylated monomer to form a three-dimensional interconnected porous network. The resulting porous glass-like material can physically retain the desired modifier but permits its interaction with the analyte that diffuses into the matrix. Besides their ability to entrap the modifier, sol-gel processes offer tunability of the physical characteristics... 

Sodium-silicate glass, 151 Sol-gel films, 120, 173 Solid electrodes, 110 Solid state devices, 160 Solvents, 102 Speciation, 84 Spectroelectrochenristry, 40 Spherical electrode, 6, 8, 9, 61 Square-wave voltammetry, 72, 92 Staircase voltammetry, 74 Standard potential, 3 Standard rate constant, 12, 18 Stripping analysis, 75, 79, 110 Supporting electrolyte, 102 Surface-active agents, 79... 

McDonagh C., MacCraith B.D., McEvoy A.K., Tailoring of Sol-Gel Films for Optical Sensing of Oxygen in Gas and Aqueous Phase, Anal. Chem. 1998 70 45-50. 

Over the last several years, the number of studies on application of artificial neural network for solving modeling problems in analytical chemistry and especially in optical fibre chemical sensor technology, has increase substantially69. The constructed sensors (e.g. the optical fibre pH sensor based on bromophenol blue immobilized in silica sol-gel film) are evaluated with respect to prediction of error of the artificial neural network, reproducibility, repeatability, photostability, response time and effect of ionic strength of the buffer solution on the sensor response. 

The pH measurement can by realized using sol-gel films and evanescent-wave sensors method74. To incorporate a near-infrared pH sensitive fluorescent dye, a thin-film coating on the core of a multimode fiber was used. By evanescent wave excitation an absorption or fluorescent based sensor can be realized for use in high pH regions. 

The physical and chemical properties of MgO films prepared by the sol-gel technique were the area interest of the examinations presented by Shukla75. The aim of mentioned work was to produce films with nano size particles so as to employ them for the sensor applications, as adsorption in such films increases many folds due to the increase of surface area. Infra-red spectroscopic studies indicated the presence of solvent in the precursor, which helped in decomposition to nano-particles during nucleation of the film. The MgO sol-gel films were deposited on the glass rod bend in U-shape for humidity sensor. 

The Japanese scientists tested the fiber optic carbon dioxide sensor86, prepared by dip-coating method - the sol-gel film containing indicator dye, thymol blue, was deposited on unclad fiber. The sensitive film had both organic and inorganic parts with good permeability. The differences between attenuation in N2 gas and in CO2/N2 mixture gas increased with the CO2... 

McEvoy A.K., McDonagh C.M., MacCraith B.D., Development of a fiber opic dissolved oxygen sensor based on quenching of a ruthenium complex entrapped in a porous sol-gel film, SPIEProc. 2508, 190-198, (1995). 

Javaid M., Keay P., A generic technique for coating doped sol-gel films onto the inside of tubes for use as colorimetric sensors,/. Sol-Gel Sci. Technol. 2000 17 55-59. 

Suah F.B.M., Ahmad M., Taib M.N., Applications of artificial neural network on signal processing of optical fibre pH sensor based on bromophenol blue doped with sol-gel film, Sens. Actuat B 2003 90 182-188. 

Blue R., Stewart G., Fibre-optic evanescent wave ph sensing with dye doped sol-gel films, Intern. J. Optoelectron. 1995 10 211-222. 

J. Yu and H.X. Ju, Amperometric biosensor for hydrogen peroxide based on hemoglobin entrapped in titania sol-gel film. Anal. Chim. Acta 486, 209—216 (2003). 

Q.L. Wang, G.X. Lu, and B.J. Yang, Hydrogen peroxide biosensor based on direct electrochemistry of haemoglobin immobilized on carbon paste electrode by a silica sol-gel film. Sens. Actuators, B Chem. 99, 50-57 (2004). 

Figure 2.8. Scanning electron microscopy (SEM) photomicrographs of (a) a micro-diffractive optical element mold fabricated by a focused ion beam (FIB) and (b) the transferred optical element on a sol-gel film. [Reprinted with permission from Ref. 98.]... 

Figure 2.18 Fourier transform infrared spectrum of sol-gel film composed of three layers and containing 10% vancomycin after 14 days of immersion in phosphate-buffered saline (weight measurements and release study showed 90% weight loss and 80% release). Intense silica bands and the bands associated with vancomycin (centred at 1660,1500 and 1397 cm-1) suggest the presence of a sol-gel film with vancomycin that remains after 14 days of immersion. (Reproduced from ref. 13, with permission.)...

S. Radin and P. Ducheyne, Controlled release of vancomycin from thin sol-gel films on titanium alloy fracture plate material, Biomaterials, 2007, 28, 1721. 

Figure 4.13 Atomic force microscopy topography of a hybrid sol-gel film. (Reproduced from ref. 21, with permission.)...

Homogeneity of dispersion and the homogeneous nature of the hybrid ORMOSIL systems result in intensely coloured films even at low thickness. Compared to organic polymers, the coloured hybrid films have enhanced mechanical properties such as greater hardness and stronger abrasion resistance. With respect to inorganic sol-gel films, hybrid films also have several advantages such as much better adhesion,... 

D. Mandler and Y. Tamar, Corrosion inhibition of magnesium by combined zirconia silica sol-gel films, Electrochim. Acta, 2008, 53, 5118. 

S. Marx, A. Zaltsman, I. Turyan and D. Mandler, Parathion sensor based on molecularly imprinted sol-gel films, Anal. Chem., 2004, 76, 120. 

M. Ahmad, N. Mohammad and J. Abdullah, Sensing material for oxygen gas prepared by doping sol-gel film with tris(2,2 -bipyridyl)dichlororuthe-nium complex, J. Non-Crystal. Solids, 290(1) (2001) 86-91. 

---