Fluid Synkinetic Membranes

Fluid synkinetic membranes are formed by self-organization of water-insoluble amphiphiles (see Sec. 1,5) They are characterized by extensive hydration of the amphiphile s headgroups and a loosely organized hydrophobic interior, which serves as good solvent for water-insoluble substances. If one considers an am-phiphile as a solvent molecule, its solubilization power in fluid membranes is comparable to chloroform, one of the best organic solvents. 

Biomembranes are not only the only organic solvents in nature. They also allow the construction of vectorial reaction systems. It is relatively easy, for example, to localize a photoactive electron donor (e.g., chlorophyll) on one side of a membrane and an acceptor (e.g., a quinone) on the other side. Visible light may then ecxcite the chlorophyll molecule to produce an energy-rich electron, which may travel in nanoseconds to the quinone. The back-reaction between the formed cation and anion radicals through the membrane may, under circum- 

A large variety of totally artificial membranes accessible by synkinesis have structures unknown to biological systems. One may, for example, prepare membranes as thin as 2 nm containing photoactive groups in various positions, and they may show a totally unsymmetrical distribution of two different head-groups on both surfaces of a curved membrane (see Sec. 2.5.3). Natural membranes, on the other hand, are incredibly functional. They perform the complex energy conversion and reproduction processes of life with unsurpassed efficiency and reliability. 

In the following we describe simple chemical models that can be analyzed on an atomic level and that have been developed to perform single, useful tasks in daily life and in the lab. 

One single property of micelles is more important than any other they solubilize organic compounds in water. A single sodium dodecyl sulfate (SDS) micelle, for example, dissolves up to 40 benzene molecules or a single porphyrin molecule or one hydrophobized AT pair (Fig. 2.5.4). Very often micelles made of long-chain sulfonates are chosen as solubilizers instead of the natural carboxy-lates, because carboxylates tend to precipitate with bivalent metal and ammonium counterions. Sulfonate micelles are much more hydrated and remain, for 

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The great diversity of concepts and synkinetic structures which have been realized within the last decade and which is partly represented in this volume, suggests that all kinds of membranes are accessible asymmetric, as thin as 2.0 nm, helical, porous, fluid or solid, chiral on the surface or in the centre, photoreactive etc. etc. This diversity will inevitably grow. A few obvious unsolved problems which need immediate attention can also be detailed e.g. synkinesis of solid micelles and vesicles from concave molecules with at least four hydrogen bonding sites, co-crystallization of porphyrins with solid membrane structures, and evaluation of nanopores as catalytic sites. Many more such target assemblies will undoubtedly be envisioned and successfully syn-kinetized. 

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