Morphological Control of Hydrothermal Ni(OH)2 in the Presence of Polymers and Surfactants: Nanocrystals, Mesocrystals, and Superstructures

• Published in: Crystal growth & design Vol. 8; no. 10; pp. 3847 - 3855
• Main Authors: Buscaglia, Maria Teresa, Buscaglia, Vincenzo, Bottino, Carlo, Viviani, Massimo, Fournier, Roxane, Sennour, Mohamed, Presto, Sabrina, Marazza, Rinaldo, Nanni, Paolo
• Format: Journal Article
• Language: English
• Published: Washington,DC American Chemical Society 01.10.2008
• Subjects: Condensed Matter; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials Science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Self-assembly; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Particle size; Morphological changes; Cellulose; Crystallization; PVP; Surfactants; Morphogenesis; Time dependence; Hexagonal lattices; Hollow sphere; Self-assembly; Hydrothermal synthesis; Ostwald ripening; Sodium; Polyacrylates; Morphology; Superstructure; Growth mechanism; Recrystallization; Nickel; Polymers; Nanostructured materials; Nanocrystal
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg800555x

Polymers with different hydrophilic groups [polyvinylpyrrolidone (PVP), ammonium polyacrylate (APA), and hydroxypropylmethyl cellulose (HPMC)] and surfactants [cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzensulfonate (SDBS)] were used as additives to modify the crystallization of β-Ni(OH)2 in hydrothermal conditions. Marked morphological changes in the β-Ni(OH)2 particles were observed depending on the additive concentration and on the duration of the hydrothermal treatment. The final morphology is the result of a complex, time-dependent self-assembly and growth process. 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 were easily obtained after a short time (2−24 h) aging at 150−200 °C. With PVP and CTAB, there is evidence of a growth process dominated by self-assembly of nanocrystals to produce mesocrystals. The formation of spherical superstructures (with SDBS, up to 70 μm in diameter) and hollow spheres (with PVP) is observed at long times (>24 h) as a result of solvent-mediated recrystallization processes, like Ostwald ripening. The overall results show that hydrothermal synthesis of β-Ni(OH)2 in the presence of polymers with hydrophilic groups and surfactants is a versatile tool for crystal morphogenesis.