Self-assembly into temperature dependent micro-/nano-aggregates of 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin

Various nanostructures of 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H2TCPP) can be easily synthesized by a surfactant-assisted self-assembly (SAS) method at different temperatures. When the DMF solution of porphyrin monomer was injected into cetyltimethylammonium bromide (CTAB) aqueous solution by a syringe, diverse H2TCPP nanostructures dependent on the different temperatures, including hollow nanospheres, solid nanospheres and nanospheres with holes, were successfully obtained. As a result, the suitable concentration of the CTAB aqueous solution used to form nanostructues of porphyrin ranges from 0.15 to 0.2 mM. The various morphologies of porphyrin nanostructures were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). UV–vis adsorption spectra showed that the micro-/nano-aggregate properties of porphyrin transformed from H-aggretates to J-aggregates during the process of self-assembly of porphyrin at different temperatures. Fluorescence spectra revealed a greater fluorescence quenching of various micro-/nano-aggregatess of porphyrin formed at different temperatures in aqueous solution, compared to the DMF solution of porphyrin monomer.