Study Of Monolayer Properties And The Cyclic Isotherms Of Langmuir Monolayers

To prepare advanced materials with multifunction, it is necessary to endure the materials with special structural architecture, such as monolayer, multilayer, nano-structure, supramolecular assembly and so on. LB teschnique is a proper method to fabricate multilayer in a molecular scale and with controllable. LB film has ultrathin thickness and ordered molecular packing, which is very favorable to its application in high-technological fields, such as semiconductor nonlinearopticsN bionics and so on.LB films have not gained mass industrial production at present due to the poor mechanical properties and stability. This is related to many basic problems, such as the condensed structure, intermolecular interaction, relaxation, etc. The mechanical properties and stability of Langmuir films have strong and direct effect on the deposition process of LB films.The effects of the monolayer-formation conditions on the monolayer behavior, including the phase structure (molecular packing), intermolecular interactions, stability, and so on, were discussed. Based on the theory model we study low molecule weight surfactant (behenic acid ) and phospholipid monolayer and the cyclic isotherms of their mono layers; Including the standard thermodynamic characteristics and aggregation of the cyclic isotherms.The main works are shown as the below: (1). Langmuir monolayer of behenic acid and DPPC surfactantsBehenic acid is a classical amphiphile, it has been applied to prepare functional LB films and quantum semiconducting particle films. Therefore, it is of essentialimportance to study behenic acid monolayer at the air /aqueous interface; At additional,in the different subphase(H2O CdCl2) conditions behaviors of behenic acidmonolayers have been studied; Moreover, we study DPPC monolayer at the aqueous subphase, stability of DPPC at the different surface pressures and speed rates.(2). The cyclic isotherms study of behenic acid and DPPC surfactantsWe investigate the cyclic isotherms of behenic acid and DPPC monolayer at different surface pressures, based on the existing theory, we discuss the standard free energy of the system on aggregation of the cyclic isotherms.