Organized assemblies, solution/interface

Keywords Fluorescence probing Hemimicelle Micellar fluidity Micelle Organized assemblies in solution and interfaces Polarity parameter Pyrene... 

Organizational characteristics of surface-active molecules have been studied by several researchers due to their applications in many areas such as personal care, polymerization, catalysis, drug delivery, separation and purification, enhanced oil recovery and lubrication. The structure of supramolecular organized assemblies formed in different solvents, when a critical concentration is exceeded, determines their properties such as solubilization [1-3], catalysis [1,4-6], adsorption [7-11] and flocculation [12,13]. As such, many techniques have been used to determine their structural properties. In this paper, the results obtained using fluorescence probing for properties of assemblies in solution and at solid-liquid interfaces are discussed in detail after a brief review of relevant assemblies formed by them. 

During the last decade the field of electrochemistry has witnessed a very fast progress on the modification of electrode surfaces. From the predominant use of random polymeric structures, prevalent in the electrode modification efforts of the late 70s and early 80s, electrochemists have learnt to control the molecular architecture of the electrode-solution interface to a degree that was clearly out of reach a decade ago. Many electrode modification methods developed recently rely on the use of thiolate self-assembled monolayers (SAMs) [1-3]. These systems offer unparalleled ease of preparation and levels of molecular organization close to those that can be reached with Langmuir-Blodgett film methods. Therefore, electrodes derivatized with unfunctionalized or functionalized alkanethiolate monolayers have been the subject of extensive research work during the last few years [4, 5]. 

The use of metal-ligand coordination in preparing supramolecular assemblies represents one of the major themes of materials chemistry over recent years. Notable achievements have been made in both the assembly of discrete clusters in solution and extended coordination polymers in the solid state,including metal organic frameworks (MOFs). The assembly of coordination polymers on surfaces is far less studied and, it would appear, more synthetically challenging. However, some notable studies have been reported both at the solid-solution interface and under UHV conditions. 

Abstract Self-assembly phenomena in block copolymer systems are attracting considerable interest from the scientific community and industry alike. Particularly interesting is the behavior of amphiphilic copolymers, which can self-organize into nanoscale-sized objects such as micelles, vesicles, or tubes in solution, and which form well-defined assemblies at interfaces such as air-liquid, air-solid, or liquid-solid. Depending on the polymer chemistry and architecture, various types of organization at interfaces can be expected, and further exploited for applications in nanotechnology, electronics, and biomedical sciences. 

Microporous inorganic solids, such as zeolites, clays, and layered oxide semiconductors offer several advantages as organizing media for molecular electron transport assemblies. Because these materials are microcrystalline, their internal pore spaces have well-defined size and shape. This property can be exploited to cause self-assembly, by virtue of size exclusion effects, ion exchange equilibria, and specific adsorption, of photosensitizers, electron donors, and electron acceptors at the solid/solution interface. 

The advantage of the LB technique is that it allows systematic studies of 2-D organization, both before and after transfer from the air—water interface onto a soHd substrate. However, the coupling of 3-D self-organization of macromolecules in solution with organization at a soHd surface may best be achieved using the self-assembly technique. 

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