Hydroxylated surfactants as growth-driving agents for the syntesis of anisotropic gold nanoparticles

• Autor(a) principal: Silva, Monique Gabriella Angelo da
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal de Alagoas (UFAL)
• Texto Completo: http://www.repositorio.ufal.br/handle/riufal/1943
• topic: Agentes ativos de superfície; Nanopartículas de ouro; Surfactantes; Growth-driving agents; Anisotropic gold nanoparticles; Surfactants; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA

The gold nanorods (AuNRs) have attracted considerable interest due to their special optical properties, strongly dependent on the size and aspect ratio (thickness/length), and thus, their potential applications in optics and medicine (therapy, cancer diagnosis...). In this context, the development of new strategies for the synthesis of anisotropic nanorods with high yields and selectivities remains a challenge towards an effective control of the size and morphology. Among the different preparation routes, the seed mediated method is most commonly used, especially in the presence of cetyltrimethylammonium bromide (CTABr) as a growth-driving agent. To our knowledge, few works have reported in the literature this system in presence of other growth driving agents. In this context, we have developed a novel family of growth driving agents, N,N-dimethyl-N-cetyl-N-hydroxyalkylammonium salts (HAAX), producing gold nanorods with high yields and selectivities in water. These surfactants have good solubility in water and are easily synthesized in good yields in presence of different structural parameters that can be modulated such as: i) the length of the lipophilic chain (C12 , C16 , C18), ii ) the nature of the counter ions by metathesis (X= F-, Cl-, Br-, I-, HCO3- e BF4-), and an original way, iii) hydroxylated polar head. The gold nanoparticles obtained by the seed mediated method were characterized by UV -vis spectroscopy and transmission electron microscopy, showing the influence of the surfactant on the morphology and on the size (aspect ratio) of the gold nanoparticles. Thus, the modulation of this family of ammonium salts allows the access to different shapes and sizes of gold nanoparticles according to the desired application. The growth process control generated by the polar head groups allows the modulation of the structural parameters of gold nanorods and opens interesting perspectives in terms of applications.