关键词: 超分子模板, 层状中孔结构氧化铝, 混合表面活性剂

Abstract: Lamellar mesostructured alumina was synthesized at room temperature by using alkyl sulfates as templates. The effects of the length of the surfactant alkyl chain and the ratio of mixed surfactants on the structural data of the obtained lamellar mesophases were investigated. It was revealed that when single surfactants were used as templates, the interlayer spacing(d) as well as the long-range order of the lamellar structure increases with increasing alkyl chain length. When the carbon number(n) of the alkyl chains varies from 8 to 12, the plot of d versus n is linear with a slope of 0.205 nm/carbon atom, which indicates that for n=8～12, the thickness of the inorganic layers keeps nearly constant and the alkyl chains are arranged as double layers between the inorganic layers with a tilt angle of ca. 53. If mixed surfactants C₈H₁₇SO₄Na-C₁₄H₂₉SO₄Na are used as mixed templates, when the molar fraction(x) of C₁₄H₂₉SO₄Na varies in the range of 0<x≤0.5, the int erlayer spacing remains essentially unchanged and approximates to the case of using a single surfactant with an average carbon number of 11 as template. On the other hand, when x>0.5, the interlayer spacing increases gradually with x. This result has been interpreted in terms of a proposed structure model for the molecular arrangement of mixed surfactants between the inorganic layers.

Key words: Supramolecular templates, Lamellar mesostructured alumina, Mixed surfactants