Self-organization of molecules

In the chemical sciences, progressive integration with chemical biology and also with nanotechnology is underway. Self-organization of molecules and modules into supramolecular and supramodular functional units plays a prominent role in both fields of development, as is clear from research and... 

By controlling the electrode potential, a delicate balance of various interactions can be achieved, resulting in the self-organization of molecules on the surface [57-59]. 

The key to inducing self-organization onto water-solid substrate interfaces is to achieve mild adsorption under controlled conditions. If adsorbate-substrate interactions are too strong, molecules cannot move around on the substrate surface. On the other hand, when adsorbate-substrate interactions are too weak, molecules desorb from surfaces. Relatively mild adsorption conditions between these extreme states leads to induction of 2D self-organization of molecules via rapid surface diffusion and acceleration of the adsorption/desorption equilibrium. Electrochemical potential management would be convenient for AISO, because it allows for precise control of adsorption strength in units of mV [11,13, 14]. 

The most well-known example of a self-organized system is provided by proteins that fold in aqueous solution into a eompact native structure where most of the hydro-phobic residues tend to reside in the core (popularly called the hydrophobic core ) while the hydrophilic residues are mostly on the surface. Such a self-organization is possible because of the simultaneous presence of hydrophilic and hydrophobic amino acid residues along the linear peptide chain. In fact, such self-organization of molecules is fairly common in nature. In this chapter, we shall discuss how water leads to the formations of exotic structures known as micelles, reverse micelles, and microemulsions. These structures are formed by molecules known as surficants, which are long-chain molecules and amphiphilic in nature, meaning that they contain two distinct individual parts that like water (because the part is polar) and dislike water (as it consists of hydrocarbons). These two opposite parts are usually located at the two ends of the surfactant molecule, named head and tail . 

Adsorption phenomena can be used for the investigation of the self-organization of molecules on the surface which are governed by stochastic laws. A typical example of monitoring the double-layer capacity as a function of time is given in Fig. 4, from which information on nucleation rate and growth mechanism can be obtained [9-11]. 

Kandjani, S.A., Barille, R., Dabos-Seignon, S., Nunzi, J.M., Ortyl, E., Kucharski, S. Incoherent light-induced self-organization of molecules. Opt. Lett. 30(23), 3177-3179 (2005)... 

The most commonly used and studied is the p-type semiconductor poly 3-hexylthiophene (P3HT) polymer that has a unique property of self-organization of molecules. Optimising the choice of solvent has also been proved to be a tedious work and thus, many studies have been conducted on the same. Experiments were conducted by Sirringhaus et al. [43] on a hydrophobic substrate and a 70-100 nm thick polymer film was spin-coated and also drop casted at 2000 rpm. It was observed that the amount of charge mobility was more in the case of drop casted... 

Fullerenes can be considered as a molecular full stop to organic synthesis highly complex and possibly very useful molecules are formed by self-organization of carbon atoms in the vapor phase. Sometimes synthetic chemists are not needed. 

It will be clear that L-B films are intrinsically linked to self-assembly of molecules, and this has been recognised in the title of a recent overview book (Ulman 1991), An Introduction to Ultra thin Organic Films from Langnmir-Blodgett to Self-Assembly An Overview. 

Recently, new ordered mesoporous silicas have also been synthesized by using self-organization of amphiphilic molecules, surfactants and polymers either in acidic or basic condition. A schematic phase diagram of water-surfactant is shown in the figure. 

Self-assembly is the spontaneous organization of molecules into stable, well-defined structures with the driving forces being noncovalent associations. The final structure is normally near or at the thermodynamic equilibrium arrangement allowing it to form spontaneously. Such formations can be done under conditions where defects are either minimized or eliminated. In nature, self-assembly is common as in the folding of proteins, formation of the DNA double helix, etc. 

Self-assembled monolayers (SAMs) are the most widely studied nonnatural self-assembly systems. They are generally spontaneously formed from chemisorption and self-organization of organic molecules onto appropriate surfaces. 

A further example of the influence of the solvent on the organization of the SAM is given by the self-organization of steroid-bridged thiophenes (Vollmer et al., 1999). MLs of aparticular complex molecule in phenyloctane on HOPG sub-... 

Lecommandoux S, Klok H-A, Sayar M, Stupp SI. Synthesis and self-organization of rod-dendron and dendron rod dendron molecules. J Polym Sci Part A Pol3mi Chem 2003 41 3501-3518. 

The organized structures give to the aqueous phases new macroscopic properties like iridescent colors, viscoelasticity, gel character, a yield stress, and, between crossed polarizers, beautifully colored patterns that make the order in the samples visible. The self-organization of the surfactant molecules is simply a result of the hydrophobic and electrostatic interaction between the individual molecules and the micellar structures. The size of the micellar structures, as in the case of small imUamellar vesicles, can be extremely monodisperse, even though one vesicle consists of hrmdreds of surfactant molecules. 

Self-organization of simpler molecular systems Detergent molecule... 

---