Temperature-induced structural transitions in self-assembling magnetic nanocolloids

• Autor(a) principal: Kantorovich, Sofia S.
• Data de Publicação: 2015
• Outros Autores: Ivanov, Alexey O., Rovigatti, Lorenzo, Tavares, Jose, SCIORTINO, Francesco
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.21/5921
• topic: Dipolar hard-spheres; Monte-Carlo; Nanoparticles; Colloids; Ferrofluids; Particles; Fluid; Polymers; Phase; Field

With the help of a unique combination of density functional theory and computer simulations, we discover two possible scenarios, depending on concentration, for the hierarchical self-assembly of magnetic nanoparticles on cooling. We show that typically considered low temperature clusters, i.e. defect-free chains and rings, merge into more complex branched structures through only three types of defects: four-way X junctions, three-way Y junctions and two-way Z junctions. Our accurate calculations reveal the predominance of weakly magnetically responsive rings cross-linked by X defects at the lowest temperatures. We thus provide a strategy to fine-tune magnetic and thermodynamic responses of magnetic nanocolloids to be used in medical and microfluidics applications.