Facile fabrication and wettability of nestlike microstructure maintained mixed metal oxides films from layered double hydroxide films precursors

Mixed metal oxide (MMO) films containing Ni2+ and Al3+ have been fabricated by a simple process involving calcination of layered double hydroxide (LDH) film precursors at 300-600 degrees C for 4 h in air. Scanning electron microscopy (SEM) reveals that the resulting Ni/Al-O thin films maintain the original nestlike morphology of the precursor films without any deformation of the microstructure during the thermal decomposition process. After surface treatment with an aqueous solution of sodium laurate, the wettability of the NiAl-LDH and Ni/Al-O thin film surfaces changes from hydrophilic to hydrophobic. Moreover, whereas the NiAl-LDH film exhibits a low adhesion for water (Cassie-Baxter behavior) after surface modification, the Ni/Al-O films exhibit a high adhesion for water (Wenzel behavior). A possible explanation for this phenomenon has been suggested.