Evolution of Nanoflowers and Nanospheres of Zinc Bisporphyrinate Tweezers at the Air/Water Interface

Abstract

Although the sophisticated Langmuir and Langmuir-Blodgett (LB) techniques facilitate the fabrication of uniform ultrathin monolayer and films, they are also revealed as powerful tools for the bottom-up construction of the nanostructures through the air/water interface. In this paper, unique nanoflowers or nanospheres were constructed based on the synthesized m-phthalic diamide-linked zinc bisporphyrinate tweezers using the Langmuir and LB techniques. It was found that the two tweezer-type zinc bisporphyrinates could form stable two-dimensional spreading films at the air/water interface, which could be subsequently transferred onto solid substrates using the vertical lifting method. Atomic force microscopy (AFM) revealed that at the initial spreading stage, the compound formed flat disklike domains and then hierarchically evolved into nanoflowers or nanospheres upon compressing the floating film. Such nanostructures have not been reported before and cannot be fabricated using the other self-assembly methods.

Self-Assembly of Porphyrin Nanostructures at the Interface between Two Immiscible Liquids

“…7,8 By contrast, the grain boundaries, step defects and edge sites always present at solid|liquid interfaces can impede diffusion of adsorbed molecules, trapping them in local energy minima as molecules stick to defect sites. 9,10 The uniform templating of adsorbed molecules at liquid|air or immiscible liquid|liquid interfaces has been exploited to create a variety of porphyrin assemblies, [11][12][13][14][15][16] yet a facile and robust route to create highly-ordered porphyrin nanostructures remains challenging.…”

“…Molecular self-assemblies at “soft” liquid|air or immiscible liquid|liquid interfaces can exhibit the required macroscale long-range order . These soft interfaces are exceptionally smooth and have no inherent defects, leading to an unrivalled macroscale uniformity in molecule–interface interactions. , In contrast, the grain boundaries, step defects, and edge sites always present at the solid|liquid interfaces can impede diffusion of adsorbed molecules, trapping them in local energy minima as molecules stick to defect sites. , The uniform templating of adsorbed molecules at liquid|air or immiscible liquid|liquid interfaces has been exploited to create a variety of porphyrin assemblies, − yet a facile and robust route to create highly ordered porphyrin nanostructures remains challenging.…”

Self-Assembled Composite Langmuir Films via Fluorine-Containing Bola-Type Derivative with Metal Ions

“…The fabrications of spreading Langmuir films were prepared using a KSV-NIMA Mini-trough LB system [39][40][41]. The trough was thoroughly cleaned using solvents such as chloroform and ethanol, and then filled with pure water or metal ion solutions (0.50 mM) as subphases.…”

Thin Films of Lanthanide Stearates as Modifiers of the Q-Sense Device Sensor for Studying Insulin Adsorption

“… 8 , 9 The techniques often used to obtain these structures are not standard and have only been studied for a small number of trivalent cations. 10 − 14 Despite the fact that yttrium is formally trivalent, the formation of films proceeded with ease, as with films containing ordinary divalent cations. Yttrium stearate was studied in ref ( 15 ), where it was shown that the ion fraction form of the yttrium content in the film depends on the pH of the subphase.…”

“…At the same time, ions of trivalent cations tend to hydrolysis and complexation more than divalent metals in an overwhelming number of cases; therefore, this problem is more relevant for trivalent ions. In this regard, works on these lanthanide salts were published much later, in spite of the fact that the production of such films was described in literature and results of the preparation multilayer LBF from acids and trivalent metals were reported. , The techniques often used to obtain these structures are not standard and have only been studied for a small number of trivalent cations. − Despite the fact that yttrium is formally trivalent, the formation of films proceeded with ease, as with films containing ordinary divalent cations. Yttrium stearate was studied in ref , where it was shown that the ion fraction form of the yttrium content in the film depends on the pH of the subphase.…”