Nonionic Fluorinated Surfactant:Investigation of Phase Diagram and Preparaton of Ordered Mesopaorous Materials

摘要

The behavior of fluorinated surfactant F(CF_2)_8C_2H_4(OC_2H_4)_9OH in water solution was investigated,and the preparation of mesoporous molecular sieves was achieved.A direct micellar phase (L_1) and a hexagonal (H_1) liquid crystal were found.Small-angle X-ray scattering measurements proved that the hydrophobic chains are completely extendened and that the cross sectional area remains constant in H~1.At 80 deg C,materials with a hexagonal array of their channel are prepared via a copperative templating type mechanism in a wide range of surfant concentrations (5-20wt%).Decreasing the hydrothermal temperature leads to the formation of wormhole-like structure.In this case the channel arrangement is no longr governed by the surfactatn behavior but by teh silica condensation and polymerization.An increase of the mean pore diametr with heating temperature is noted.This result is assocaited with changes of aggregation mean pore diamtr with heating temperature is noted.This result is associated with changes o faggregation number with temperature.A comparison of the characteristics of the materials obtained with both hydrogenated and lfuorinated surfactants is also made.