Aerogels characterization

Hunt, A.J. (1998) Light scattering for aerogel characterization. /. Non-Cryst. Solids, 225, 303-306. 

Long JW, Swider KE, Merzbacher Cl, Rolison DR. Voltammetric characterization of ruthenium oxide-based aerogels and other Ru02 solids The nature of capacitance in nanostructured materials. Langmuir 1999 15(3) 780-5. 

Cao Y, Hsu JC, Hong ZS, Deng JF, Fan KN (2002) Characterization of high-surface-area zirconia aerogel synthesized from alcohothermal and supercritical fluid diying techniques. Catal Lett 81 107-112... 

NaY zeolite at 60.1 ppm. The image was obtained for a 3mm slice with full chemical shift imaging (note that for thermally polarised Xe this type of imaging experiment would be far more demanding in terms of experimental time even than chemical shift resolved imaging, as practiced for the Aerogel samples[30]), and was obtained in 30 min. Thus, the improvement in imaging with HP xenon over thermally polarized xenon is impressive, and indicates that there are real prospects for applications in the characterization of materials. 

A detailed discussion of the properties of aerogels can be found in several recent review articles (51—55) and the references therein. This section provides a physical basis for these properties by focusing on the microstructure of an aerogel. The intent is to provide a bridge between the two previous sections, which discuss the preparative and drying parameters that affect microstructure, and the next one, which outlines the potential applications made possible by unique structural features. The emphasis is on silica aerogels because they have been the most extensively characterized. 

O. B. Koper, I. Lagadic, A. Volodin, and K. J. Klabunde, Alkaline-earth oxide nanoparticles obtained by aerogel methods. Characterization and rational for unexpectedly high surface chemical reactivities, Chem. Mater. 9, 2468-2480 (1997). 

Sunol, S.G., Sunol, A.K., Keskin, O., Guney,0., Supercritical fluid aided preparation of aerogels and their characterization , in Innovations in Supercritical Fluids Science and Technology Chapter 17, pp 258-268, edited by K. W. Hutchenson and N. R. Foster, ACS Symposium Series 608 (1995). 

Typical applications of gas-coupled ultrasonic spectroscopy include the characterization of other porous materials such as rocks [120], paper [127], wood [128] and silica aerogels [129]. 

Sol-gel and dip-coating procednres were apphed to prepare copper nanomaterials. Alnmina-snpported copper nanoparticles from Cn(acac)2 and Al(OPr-i)3 were synthesized by Kantam and coworkers by the aerogel procednre. The Cn-Al203 nanoparticles were characterized by several analytical methods and were snccessfuUy nsed as catalysts for the preparation of 1,2,3-triazoles by the reaction of terminal alkynes, NaN3 and alkyl/allyl halides. 

The application of electrochemical investigations is an efficient method to characterize the microstructure of porous electrically conducting materials. Modifications in the chemical constitution of the skeleton which do not change the BET values can be identified by the electrochemically derived surface capacitance, as demonstrated in the case of anodically oxidized carbon aerogels. 

The dependence of E of RF aerogels on water content has to be investigated further. The described investigations are not only a method to characterize the material and the parameters of the inner surface (chemistry, surface morphology, pores etc.) but might also be the first step towards RF aerogels as sensor for humidity or environmental pollution. 

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