Strategies to control the morphology and the growth of Ni(OH)2 films from aqueous solution.

The crystallization of Ni(OH)2 in hydrothermal conditions and the growth of nanostructured films and arrays of micro/nanocrystals on different substrates was realised under different conditions, on different substrates and with the addition of various polymers and surfactants. Marked morphological changes were observed: well-defined particles with sizes from submicrometer range to a few micrometers corresponding to hexagonal lamellae, hexagonal tabular mesocrystals, rosette- and flowerlike aggregates of lamellae, hexagonal prismatic mesocrystals and acicular nanocrystals. The films thickness, continuity and the adherence depended also strongly on substrates properties. The final morphology is the result of a complex, time-dependent self- assembly and growth process.The overall results show that hydrothermal synthesis of Ni(OH)2 in the presence of polymers with hydrophilic groups and surfactants is a versatile tool for crystal morphogenesis and growth of films.