Self-assembly of well-defined block copolymers in solution has gained attention not only for
its scientific value but also for its potential application in nanotechnology. In this study, we present a comprehensive series of synthesized block copolymers that allows conclusions to be drawn how to design micelles by
ROMP with defined core−shell geometry and controlled size. We used a general route for the preparation of
well-defined block copolymers by ring opening metathesis polymerization (ROMP) with “Grubbs first generation
catalyst” RuCl2(PCy3)2(CHPh) (Cy = cyclohexyl). In a first step, we sequentially polymerized endo,exo[2.2.1]bicyclo-2-ene-5,6-dicarboxylic acid dimethylester with endo,exo[2.2.1]bicyclo-2-ene-5,6-dicarboxylic acid
di-tert-butyl ester, to obtain a high control of polymerization and complete characterization of the block copolymers. The polymers were characterized by 1H- and 13C NMR spectroscopy, FT-IR spectroscopy, by GPC,
and by DSC. By cleavage of the tert-butyl group, the polymer was transformed into an amphiphilic block
copolymer. In two series of polymers, we investigated the micelle formation in ethanol by dynamic light scattering
(DLS) and small-angle X-ray scattering (SAXS). In the first series, the influence of the block ratio on the size
of the micelle, the aggregation number, and the core−shell dimensions were investigated while the overall polymer
length was kept constant. In the second series, the block ratio was fixed to 1:1 and the overall polymer length
was varied, leading to direct proportionality of the micelle size to the polymer length, while the core-to-shell
ratio was constant.