DEGRADABLE DENDRITIC POLYMERS - A TEMPLATE FOR FUNCTIONAL PORES AND NANOCAVITIES

Degradable dendrimers are prepared as a template to create utrasmall c ells when they get embedded in a polymer resin and to obtain well-defi ned cavities with particular chemical groups at their walls if the end groups remain attached to the matrix. In a first approach cascade: (13 -oxa-1-methylsilaundecenylidene): undecene was synthesised by the poly addition reaction of methyl-di-undecenoxysilane as basic repeat unit. A multimodal weight distribution was found which appeared to be selfco ntrolled to a limited molecular weight. Degradation was done with dry methanol and methanol with aqueous hydrochloric acid. In the case of d ry methanol the degradation products yielded only low molecular weight compounds while siloxane bonds were formed in the case the degradatio n was performed with methanol and aqueous hydrochloric acid. In order to create films with nanocavities, the degradable dendritic macromolec ules were embedded in a methacrylate resin. Hole formation was illustr ated by transmission electron microscopy for the case of 0.5 wt.-%, 5 wt.-% and 30 wt.-% of dendrimer content, However, aggregation of the d endritic molecules during the curing of the methacrylate resin could n ot be avoided. In order to sup press aggregation, cascade: (1-methylsi lapropylidene): 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 indi cated by the optical transparency, while microscopy techniques were no t capable to resolve the fine structure.