Membrane adoption mechanism

Adopting Eq. (16) as representative of the system, ion transfer reactions and adsorptions of respective ions participating in the oscillation were investigated individually at two aqueous-membrane interfaces in the system of Eq. (16) by use of VITIES, and as a result the mechanism of the oscillation was elucidated almost quantitatively. The mechanism can be summarized as follows [39]. 

The mere preparation of porous membranes is accompanied with a noticeable decrease of permselectivity 11, which is undesirable for reverse osmosis and ultrafiltration, A thin dense layer should be adopted to attain a high permeability with — out the decrease of permselectivity, but this necessarily decreases the mechanical strength. This conflict is largely resolved by the construction of asymmetric or composite membranes as described also in the present review. 

Artificial membranes are used to study the influence of drug structure and of membrane composition on drug-membrane interactions. Artificial membranes that simulate mammalian membranes can easily be prepared because of the readiness of phospholipids to form lipid bilayers spontaneously. They have a strong tendency to self-associate in water. The macroscopic structure of dispersions of phospholipids depends on the type of lipids and on the water content. The structure and properties of self-assembled phospholipids in excess water have been described [74], and the mechanism of vesicle (synonym for liposome) formation has been reviewed [75]. While the individual components of membranes, proteins and lipids, are made up of atoms and covalent bonds, their association with each other to produce membrane structures is governed largely by hydrophobic effects. The hydrophobic effect is derived from the structure of water and the interaction of other components with the water structure. Because of their enormous hydrogen-bonding capacity, water molecules adopt a structure in both the liquid and solid state. 

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