Investigation of the thermal and structural properties of single-molecule magnet/polymer nanocomposite films

The inclusion of manganese-based single-molecule magnets (SMMs) into solvent cast films of poly(methyl methacrylate) (PMMA) or polycarbonate (PC) was found to influence the thermal stability of these polymers. Examination of the thermal decomposition profiles of PMMA films by thermo-gravimetric analysis (TGA) established that increasing weight % of SMM results in both enhancement of the rate of decomposition initiated at “head-to-head” linkages along with suppression of the rate of decomposition initiated at vinylidene chain ends. In the case of PC films, the temperature at which the primary thermal decomposition occurs decreases with increasing weight % of SMM. The extent of these decomposition trends is correlated to the degree of SMM dispersal, as studied by transmission electron microscopy (TEM). Favourable interactions between the ligands coordinated to the SMMs and the polymer or solvent used in film preparation dictated the degree of SMM dispersal, with the ligand–polymer interactions being dominant on the nano-length scale (1–100 nm) and ligand–solvent interactions being dominant on the micro-length scale (>100 nm).