Singlet oxygen generation properties of Fe-OCAP and its influence on the antibacterial and mechanical properties of Fe-OCAP/PU blends

In this paper, the singlet oxygen generation properties of Fe-octacarboxyl acid phthalocyanine (Fe-OCAP)/polyurethane (PU) blends were investigated by ultraviolet–visible spectra. 1,3-diphenylisobenzofuran was used as the reaction substrate to detect the yields of the singlet oxygen of the samples. It was found that Fe-OCAP showed a high efficiency in generating singlet oxygen when it was dissolved in dimethylacetamide (DMAc), while no singlet oxygen was generated when it was in ethanol. The singlet oxygen generation properties of Fe-OCAP/PU blends were also investigated. It was found that with increasing Fe-OCAP content, Fe-OCAP/PU blends showed increased efficiency in generating singlet oxygen. The influence of wavelength of light on the singlet oxygen generation of Fe-OCAP/PU was studied. Compared with orange light, Fe-OCAP/PU had a higher efficiency in generating singlet oxygen under the illumination of red light. The generated singlet oxygen by Fe-OCAP/PU blends had a high efficiency in cell inactivation. As a result, the percentage bacterial reduction of the samples increased with increasing Fe-OCAP content. The influence of the generated singlet oxygen on the mechanical properties of PU was also investigated. The generated singlet oxygen could initiate the oxidation of PU chain and cause the degradation of PU. Therefore, after illuminated by white light, the tensile strength of the samples containing Fe-OCAP decreased, but still was higher than that of pure PU.