Effects Of Metal Ions And Monomolecular Membrane Electrostatic Interaction Between Physical Factors

Langmuir-Blodgett membrane (hereinafter referred to as LB film) as a new kind of single molecule membrane technology, has been focused by all of the countries. LB membrane technique could manipulate at the molecular level of single molecule membrane, and the introduction of metal ions to LB film improves its potential application value.When the metal ions added to phase, metal ion will act with amphiphilic molecules hydrophilic head groups, and then change the interaction between the amphiphilic molecules hydrophilic head groups. Also the film strength, film ability, membrane structure and morphology can be affected, which was mainly caused by amphiphilic molecules hydrophilic head groups. The two ways of metal ions and amphiphilic molecules combination were first amphiphilic molecules and metal ion combined to form the metal surface active agent, second amphiphilic molecules spread directly in the phase of containing metal ions, and combined with metal ions. The properties of single molecule film was affected by the interface complex, which was formed from electrostatic, coordination or other object function between metal ions and amphiphilic molecules hydrophilic head groups; and single molecule membrane film quality can also be influenced by the change of outside environment factor, such as the change of phase temperature, the change of phase pH, the velocity of pressed film, membrane material amount, and the change of phase concentration, and so on.The unconcerned contents were studied by theoretical analysis and experiment research in this paper. A simplified model was created according to the structure characteristics of amphiphilic molecules. The polar head groups of amphiphilic molecules was simplified to the polarity electric dipole, the interaction between the molecules, the interaction between the ions, and the interaction between the amphiphilic molecules and the interaction between were analyzed according to classical electromagnetism, and the force between ions was discussed in the membrane-forming process. The effect of experimental conditions to film was analyzed by the control variable method, including the five factors such as the film quality including temperature change of the phase, the pH value change, film speed, membrane material addition, and the phase concentration. It is found that the above-mentioned experimental conditions could affect film quality, besides the phase temperature, pH value, and membrane material addition could affect more, temperature is too high or too low will destroy the membrane performance, the membrane will has some damage effects when pH partial acid or alkali, the addition amount of film-forming material are too little or too much all cannot get a better molecular film. While the phase concentration and film speed have little influence. So a complete π-A curve can be obtained in PE-chloroform solution at the conditions of0.32mg/ml, pH value of6.8, temperature of21.8℃to28.0℃, and film speed of10mN/m-25mN/m in15min. In order to verify the results, the effect of phase temperature and pH value to the film from metal ions and phospholipids was investigated, too high or low temperature could affect the single molecule film; when the pH value was neutral, a better quality of single molecule membrane could be obtained, which was agreed with the theoretical analysis, and thus the conclusion of theoretical analysis was further proved.