Adsorption And Morphologies Of Surfactants Under Confinement Of Nanomaterials

Surfactants are a kind of substances which have both hydrophilic groups and hydrophobic groups. Surfactants can apparently lower the surface tension/the interfacial tension of the liquid/interface, and also make themselves orientation on the surface/interface.In this thesis, a model called lattice Monte Carlo (Lattice Monte Carlo, LMC) simulation method was used to study the behaviors of surfactants in the confined space and at solid-liquid interface with high curvature. We would like to explain the behaviors of surfactant aggregation at the interface of mesoscopic scale which play an important rule in the theoretical studies and practical applications. The main conclusions are as follows:1. Lattice MC Simulation was used to study the morphologies and morphological transitions of surfactant-inorganic-solvent systems confined in spherical pores. In this part, we focus on the effects of the interaction energies between the head groups and tail groups of surfactants,εHT, and the interaction between tail groups of surfactants and water,εTW, on the morphological transitions. The simulation results indicate that when asεHT increases the self-assembled morphologies of the surfactants confined in spherical pores show three different configurations:an irregularly Y-junction structure, transition structure and regularly spiral structure. On the other hand, asεTW changes, the self-assembled morphologies show two different configurations: irregularly Y-junction structure and regularly spiral structure. The morphologies of these novel structures are also a function of the pore diameter D,εHT andε-TW.2. Lattice MC simulations method was used to study the curvature induced morphologies of surfactants adsorbed on the surface of the hydrophilic solid-liquid interface. We study the adsorption behaviors of surfactants on the surface of flat nanomaterials and on cylindrical nanomaterials. We found that the morphology of H3T4 surfactant adsorbed on the flat nanomaterials is worm-like structure. However, when H3T4 surfactant adsorbed on the cylindrical nanomaterials, the morphologies show different structures. When the cylinder radius R=5 and 13, the morphologies of H3T4 surfactant adsorbed on the surface of cylindrical nanomaterials are linear chain-like micelle structures. While as R=7,9,11, the morphologies of H3T4 surfactants on the surface of cylindrical nanomaterials are Y-junction structures. In general, the morphologies of these novel structures are significantly affected by the curvature of solid surface.