Synthesis of montmorillonite/Fe3O4-OTAB composite capable of using as anisotropic nanoparticles

•Magnetic MMTs were synthesized via in situ growth method by using OTAB as intercalating agent and Fe3O4 as magnetic nanoparticles.•Fe3O4-MMT-OTAB prepared in deionized water has more Fe3O4 nanoparticles on MMT surface than that prepared in ethanol.•Fe3O4-MMT-OTAB possessed higher hydrophobicity and higher magnetic response than OTAB-MMT-Fe3O4.•Magnetic MMTs will become a promising new candidate of orientable nanomaterials used in polymers.