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New well‐defined macrodiols were prepared by ring‐opening copolymerization of lactones and cyclic diesters with a low molecular weight diol. Suitable monomers are diglycolide, L,L‐dilactide, ε‐caprolactone, and rac‐β‐butyrolactone. With exception of rac‐β‐butyrolactone, the reaction can be performed with or without a catalyst. The use of a catalyst influences the sequence structure of the telechelics. Copolyesterdiols from ε‐caprolactone, diglycolide, and ethylene glycol with random, blocky, and intermediate structure were synthesized and characterized. The analogous copolyesterdiols from L,L‐dilactide, ε‐caprolactone, and ethylene glycol were also prepared. The sequence structure of the random chains with diglycolide corresponds to a random distribution of glycolate units, that of the corresponding chains with L,L‐dilactide exhibit a random distribution of L,L‐dilactate units.

Nanocomposites of gelatine and gold were prepared by reduction of AuC1,H in a gelatine solution, followeu' by a spin coating process and a brief washing. The thickness of the films thus obtained was typically 200-400 nm. The surface of the nanocomposites was investigated by scanning electron microscopy (SEM) and surface profilometry. The size of the gold particles is in the range of ca. 2-10 nm, as elucidated by transmission electron microscopy (TEM). Refractive indices were measured by ellips o m e t y at wavelengths of 632.8 and 1300 nm. The refractive index depends linearly on the volume fraction of gold, at least at 1300 nm. The lowest refractive indices measured are 1.008_+0.060 at 1300 nm and 0.963 f 0.062 at 632.8 nm (limits are 95% confidence interval). These values are, to our best knowledge, the lowest reported for a polymer or polymer composite.