Ionic self-assembly of porphyrin nanostructures on the surface of charge-altered track-etched membranes

Abstract

Track-etched polymer membranes are typically used as templates in the synthesis of various nanowires or nanotubes arrays. The unique advantages of track-etched membranes, such as uniform pore structure, excellent porosity, easily tailored pore sizes, and a well characterized surface chemistry, may find use in self-assembly strategies where colloidal nanostructures can be tethered to a suitable substrate to produce devices of interest. Meso-tetrakis(4-phenylsulfonicacid)porphyrin dihydrochloride and Sn(IV) tetrakis(4-pyridyl)porphyrin were used to synthesize ionic self-assembled porphyrin nanorods. The track-etched membranes surface charge was changed from negative to positive using polyethyleneimine. The porphyrin nanorods were either filtered through or self-assembled onto the surface of track-etched membranes. Comparisons were made with track-etched membranes modified with, and without, polyethyleneimine. Assembly of the porphyrin nanotubes only occurred on the surface of positively charged track-etched membranes, and filtration of the porphyrin nanorods produced a mesh-like structure on the surface of the membrane irrespective of the track-etched membrane pore diameter. In each case the characteristic absorbance profiles of the porphyrin nanorods was maintained. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and UV-vis spectroscopy were used to characterize the various systems.

A Systematic Approach toward Designing Functional Ionic Porphyrin Crystalline Materials

“…Synthesis of binary porphyrin (BP) based crystalline nanostructures by ionic self-assembly (ISA) was first introduced by Shelnutt and co-workers over a decade ago . ISA is the coupling of structurally different or structurally similar (or identical) ionic building blocks (charged tectons) by electrostatic interactions. ,, Since then, nano- to microsized crystalline assemblies fabricated from oppositely charged ionic free-base porphyrins and their metal derivatives have been reported. ,,,,,,,− These take the shape of rods, tubes, nanofibers, sheaves, sheets, spheres, or clovers. Binary porphyrin crystals can be built from monomers with strong electron acceptors (−NO 2 , −COOH, −SO 3 H, −OH, −CN, etc.)…”

Photoluminescence Quenching and Structure of Nanocomposite Based on Graphene Oxide Layers Decorated with Nanostructured Porphyrin

“…PN were synthesized via an ionic self-assembly technique by mixing aqueous solutions of two porphyrin precursors using the same procedures developed by Wang and al. [11,12] ) dichloride solution (3.5 µM) were mixed and left undisturbed in the dark for 72 hours at room temperature. Rod formation is very sensitive to solution conditions, especially pH, because it alters the charge balance; hence, the synthesis was conducted under acidic conditions of pH ~2.…”

“…PN were synthesized via an ionic self-assembly technique by mixing aqueous solutions of two porphyrin precursors using the same procedures developed by Wang and al. [11, 12]. Mesotetrakis (4-phenylsulphonicacid) porphyrin (H 2 TPPS 4 2− ) dihydrochloride and Sn(IV) tetrakis(4-pyridyl)porphyrin (SnTPyP 2+ ) dichloride were purchased from Frontier Scientific and used without further purification.…”

Porphyrin nanorods-polymer composites for solar radiation harvesting applications

“…We previously explored the self-assembly of porphyrin nanorods on the surface of modified track-etched membrane and this approach demonstrated how ionic interactions can induce porphyrin self-aggregation on a solid surface. This is of important value in regard to approaches of fabricating nanostructures on solid substrates [71].…”