CHARACTERIZATION OF SILICA AEROGEL WITH THE ATOMIC-FORCE MICROSCOPE AND SAXS

The tapping atomic force microscope is the most convenient atomic forc e microscope mode to provide 3D surface measurements of mechanically w eak materials like aerogels (dried with CO2 at supercritical condition ) down to the nanometer scale. The paper illustrates the variation of particle size as function of the water ratio in the precursor polyetho xydisiloxane. When the water ratio in the hydrolysis process is increa sed, the particle size of the samples decreases, which explains the sh ift of Rayleigh scattering in the UV region. For image interpretation, power spectrum analysis is introduced as a technique to compare the a tomic force microscope images presented in the reciprocal space with s cattering results. The radially averaged power spectrum of the images is in good agreement with the scattering data. The convolution of text ure features with the atomic force microscope tip is quite important f or structural features in the vicinity of the tip size.