Degradable dendritic polymers — A template for functional pores and nanocavities-

Degradable dendrimers are prepared as a template to create utrasmall cells when they get embedded in a polymer resin and to obtain well-defined cavities with particular chemical groups at their walls if the endgroups remain attached to the matrix. In a first approach cascade: (13-oxa-1-methylsilaundecenylidene): undecene was synthesised by the polyaddition reaction of methyl-di-undecenoxysilane as basic repeat unit. A multimodal weight distribution was found which appeared to be selfcontrolled to a limited molecular weight. Degradation was done with dry methanol and methanol with aqueous hydrochloric acid. In the case of dry methanol, the degradation products yielded only low molecular weight compounds while siloxane bonds were formed in the case the degradation was performed with methanol and aqueous hydrochloric acid. In order to create films with nanocavities, the degradable dendritic macromolecules were embedded in a methacrylate resin. Hole formation was illustrated by transmission electron microscopy for the case of 0.5 wt.-%, 5 wt.-% and 30 wt.-% of dendrimer content. However, aggregation of the dendritic molecules during the curing of the methacrylate resin could not be avoided. In order to suppress aggregation, cascade: (1-methylsilapropylidene): propene with methacrylate endgroups have been prepared which can be covalently linked to the embedding resin molecules. In a first approach the compatibility with the methacrylate resin was indicated by the optical transparency, while microscopy techniques were not capable to resolve the fine structure.