Porphyrin Assemblies viaa Surfactant-Assisted Method:From Nanospheres to Nanofibers with Tunable Length.

In this paper, we report that a porphyrin, zinc 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine(ZnTPyP), could be organized to form one-dimensional (1D) nanofibersvia a surfactant-assisted self-assembly (SAS) method. We disclosethat when a chloroform solution of ZnTPyP is dropwise added into anaqueous solution of cetyltrimethylammonium bromide (CTAB), sphericalnanostructures are formed at the initial stage. The nanospheres arenaturally transformed into 1D nanostructures simply by aging underambient conditions. Interestingly, by adjusting the volume of theemployed ZnTPyP chloroform solution, the length of thus-produced 1Dnanoarchitectures could be efficiently controlled. It is disclosedthat longer nanofibers could be manufactured when a small volume ofchloroform solution of ZnTPyP is involved, while shorter 1D nanospeciescould be produced when a large volume of chloroform solution of ZnTPyPis employed. The 1D nanostructures are characterized by UV–visiblespectra, scanning electron microscopy, low-resolution transmissionelectron microscopy, high-resolution transmission electron microscopy,and fast Fourier transformation. A solubility experiment has beencarried out to disclose the dispersibility of our ZnTPyP in plainwater and in CTAB aqueous solution. On the basis of the experimentalfacts, an explanation is proposed for these interesting new findings.The investigation provides new opportunities for the controllableassembly of porphyrin-based 1D nanomaterials with tunable length,and it sheds new scientific insights on the molecular assembly processoccurring in the SAS system, wherein an oil/water system is used asthe assembly medium. [ABSTRACT FROM AUTHOR]