In situ laser‐induced formation of α‐Fe2O3 from Fe3+ ions in a cylindrical core‐shell polymer brush

The Raman spectrum of a cylindrical core‐shell polymer brush containing Fe3+ ions was measured in a confocal spectrometer equipped with an He–Ne laser. During irradiation, the polymer matrix decomposed, and carbonaceous compounds containing sp2 and sp3 hybridized carbon were formed. Simultaneously, the strong and narrow Raman lines of crystalline α‐Fe2O3 (hematite) began to show up in the spectrum. After prolonged irradiation, the carbon signals decreased, whereas the hematite peaks remained strong. Similar experiments with the same polymer containing Cu2+ ions resulted only in very weak formation of cupric oxide.