Electrochemical probing of the sol–gel–xerogel evolution

Abstract

Chronoamperometry has been performed on ferrocene embedded in silica and zirconia gels. The diffusion coefficient of ferrocene was measured along the sol-gel-xerogel transformations. Such electrochemical measurements are a sensitive probe of the structural and textural changes occurring in the sol-gel process.

Exciting new directions in the intersection of functionalized sol–gel materials with electrochemistry

“…Diffusion in sol-gel based materials has been studied using a number of different techniques, including time dependent methods, 312,313 Raman spectroscopy, 314,315 fluorescence correlation spectroscopy (bulk and single molecule), [316][317][318][319] and electrochemical methods. 80,309,310,[320][321][322][323][324][325][326][327][328][329] Electrochemical methods have primarily been used to study diffusion in monoliths, but the information obtained is applicable to thin films as well. Electrochemical methods are particularly useful because they provide direct information about the diffusion of an assortment of different size and charged species both before and after gelation as well as through the early stages of drying in both functionalized and nonfunctionalized materials.…”

Analytical Applications of Silica-Modified Electrodes -A Comprehensive Review

“…They observed that the diffusion of the analyte, and hence, its electrochemical response, was dependent upon the degree of cross-linking of the inorganic polymer. Other free redox species or reactive redox monomers (based on methylviologen or ferrocene derivatives) were used in connection to electrochemical techniques to probe transitions during sol-gel processing [194,195]. It was also found that the fraction of water within the gel did not affect the peak currents over a 1000-min time window, making materials prepared by sol-gel chemistry promising alternatives to organic ionomers as solid electrolytes for amperometric sensors [27].…”

Molecular design of hybrid organic-inorganic nanocomposites synthesized via sol-gel chemistry

“…The physical properties associated to organic probes, embedded in gels, allow to investigate the growth and the aggregation of the polymeric species conling from the hydrolysis-condensation of alkoxides precursors. The changes, occurring on a microscopic scale in sol-gel systems, have been monitored by EFISH (Electrical Field Induced Second Hnrmonic) 1241, luminescence [9] and chronoamperometry [32]. This research acti~nlly deals with clt~estions similar to the ones involved in the measurement and the comprehensiorl of 1iiolecu1;tr dynamic in restricted geometry.…”