Synthesis and characterization of alternated (humic acid/Fe3 +)n multilayer film on alumina fiber

By using layer-by-layer self-assembly technology, multilayered films consisting of alternated humic acid and Fe3 + ions ((HA/Fe3 +)n, n = 10,20,40) were fabricated on alumina fiber (AF) substrate for the first time. FTIR and FESEM results show that the (HA/Fe3 +)n thin films were effectively immobilized on the AF surface. The average thickness of a single bi-layer HA/Fe3 + is not sensitive to the total layers. On the contrary, the concentration of Fe3 + ions significantly influences this mean thickness. A loose and amorphous structure with some irregular pores was detected from the as-prepared specimens, while relatively smooth surface and denser structure were observed after carbonized at 1000 °C. The large BET surface areas and excellent absorbability of the as-prepared and carbonized samples were found. Moreover, at room temperature, a ferromagnetic property of these samples was revealed by magnetism testing. Due to the adjustable number of layers, the ferromagnetic property is controllable. Therefore, these produces possess potential application as the support material in catalytic and target drug delivery areas.