Sintering Aerogels

Studies of the densification kinetics and structural evolution of non-crystalline aerogels during sintering are examined in light of theory. In most respects, the theory of viscous sintering is capable of quantitatively accounting for the experimentally observed behavior, as long as the initial pore size distribution is known. Unfortunately, it is difficult to obtain adequate structural information; in particular, measurements using nitrogen desorption and thermoporometry often erroneously indicate the presence of macroporosity. Some authors have claimed that large pores contract more quickly than small pores during sintering; under certain circumstances this is predicted by the theory.