Heterogeneous systems structurally

On a microscopic scale, a microemulsion is a heterogeneous system and, depending on the relative amounts of the constituents, three main types of structures can be distinguished [69] oil in water (OAV, direct micellar structure), water in oil (W/O, reverse micellar structure) and a bicontinuous structure (B) (Figure 6.1). By adding oil in water, OAV dispersion evolves smoothly to a W/O dispersion via bicontinuous phases. 

The situation becomes quite different in heterogeneous systems, such as a fluid filling a porous medium. Restrictions by pore walls and the pore space microstructure become relevant if the root mean squared displacement approaches the pore dimension. The fact that spatial restrictions affect the echo attenuation curves permits one to derive structural information about the pore space [18]. This was demonstrated in the form of diffraction-like patterns in samples with micrometer pores [19]. Moreover, subdiffusive mean squared displacement laws [20], (r2) oc tY with y < 1, can be expected in random percolation clusters in the so-called scaling window,... 

An understanding of specific and general solvent effects can provide a basis for interpreting the emission spectra of fluorophores that are bound to macromolecules or, in general, are located in different sites of structurally heterogeneous system. 

Key Words Structurally and/or dynamically heterogeneous systems, Hydrogels, Protein fibrils, Membrane proteins, Dynamic aspects... 

STRUCTURALLY HETEROGENEOUS SYSTEMS NETWORK STRUCTURES AND DYNAMICS OF HYDROGELS... 

Structural as well as dynamical studies of membrane proteins, constituting an estimated 30% of all proteins, are very important in view of their crucial biological importance. These membrane proteins are obviously dynamically heterogeneous systems, even though they are structurally homogeneous without any cross-links or aggregation so far discussed. 

---