Biosurfactant-mediated one-step synthesis of hydrophobic functional imogolite nanotubes

摘要: Imogolites are aluminosilicate nanotubes that attract a particular interest due to their insulating properties, surface reactivity and shape-selective properties in catalysis. Although being available nature, synthetic protocols have been developed since the 70's obtain large amounts of this mineral without purification processes. In particular, functionalized imogolites currently studied for application as dispersant hydrophobic matrixes like polymers. With respect known processes, natural imogolite is produced by using either milli- or deci-molar aluminium salts solution while systematically prepared two steps: synthesis followed functionalization mainly phosphonic acids. Here, we propose new one-step involving cheap, widely-used, non-toxic surfactant, glycerol α-monolaurate (MG) centimolar concentrations. presence Al3+ cations, MG forms an emulsion, subsequent addition tetraethoxysilane leads formation within 3 days at neutral pH under hydrothermal conditions. An interesting, new, lamellar long-range order can then be achieved after 10 days. Under similar conditions, blank tests performed on MG-free systems result proto-imogolite. Based combination highly selective 29Si, 27Al 1H solid-state NMR experiments additional lauric acid (LA) glycerol, mechanism proposed based dissociation LA binding outside nanotubes. As result, our process provides with unprecedented offer perspectives these materials nanoscale fillers in, e.g., polymeric media.