文摘
This paper concerns the effect of changes in experimental conditions on the micrometric-scale organization observed in hybrid materials obtained from six rigid rod and semi-rigidbis-trialcoxsilylated precursors and one trisilylate after polycondensation at silicon. Differentsolvents and catalysts have been studied showing that birefringence properties are highlydependent on these parameters. A drastic effect of catalyst is observed especially in thecase of basic catalysis, which is more or less capable of inducing a catalytic cleavage of theSi-O-Si bond. For instance, with NaOH either no or very weak birefringence can beobserved, but the level of polycondensation at silicon is higher. In summary, the bestexperimental conditions for micrometric-scale organization are the use of HCl or nucleophiliccatalysis (F-) in THF, DMF, NMF, and toluene.
