Self-organised aggregates

Analysis of the fluorescence decay curves in water indicated that the intracoil process is static and that anthryl aggregation induces non-exponentiality in the fluorescence decay associated with a dynamic equilibrium between the singlet diphenyl-anthracene and a non-fluorescent dimer state. Further evidence was also presented to show that these polymers self-organise into hydrophobic and hydrophilic regions Energy migration in alternative and random copolymers of 2-vinylnaphthalene and methyl methacrylat methacrylic acid... 

Experiments towards growing ribosomal crystals in vitro were stimulated by the observations that ribosomes may self-organise into ordered aggregates in the living cell two-dimensional arrays have been found under special conditions, such as hibernation or lack of oxygen (e.g. Byers (1967) Unwin (1977) Milligan and Unwin (1986)). However, the complex structure, the enormous size and the flexibility of ribosomal particles render their crystallisation in vitro extremely difficult. Therefore, only a few successful efforts to produce three-dimensional crystals have been reported (e.g. Yonath et al (1980) Trakhanov et al (1987) Yonath and Wittmann (1988)). 

Figure 2.6 Scheme of the mechanism for the formation of mesoporous silica. Silica polymers formed initially from silica monomers, and associated with surfactant monomers, which form composite self-organised primary particles which can either continue to grow via monomer addition (path 1) or themselves aggregate in a directional fashion (path 2) to form the final mesophase composite. Nondirectional aggregation would cause formation of disordered pore structures. Reprinted with permission from Nooney, R.I. Thirunavukkarasu, D. Chen, Y. Josephs, R. Ostafin, A.E., Synthesis of Nanoscale Mesoporous Silica Spheres with Controlled Particle Size, Chem. Mater., 14, 4721—4728. Copyright (2002) American Chemical Society... 

This Chapter outlines some of the nature, delicacy and specificity of molecular forces, and how it is that these forces conspire with the geometry of molecules to organise self-assembled molecular aggregates. The shapes and topologies that set the physico-chemical environments for biochemistry are the subject of following chapters. The references provide a sufficient guide to the literature for the reader interested in exploring further complex technical issues. 

In addition to the function of ordered hydrogen bonded arrays in the biological cell [42], the design of new materials is closely connected with the organised self-assembly of supramolecular structures [43]. The physical and chemical properties of molecular aggregates depend on the nature of the constituent molecules as well as on the manner in which the molecules assemble in the solid state. This is because the properties and architectural features of the supramole-... 

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