Gold nanoparticles protected by mixed hydrogenated/fluorinated monolayers: controlling and exploring the surface features

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology Vol. 20; no. 6; pp. 1 - 15
• Main Authors: Şologan, Maria, Gentilini, Cristina, Bidoggia, Silvia, Boccalon, Mariangela, Pace, Alice, Pengo, Paolo, Pasquato, Lucia
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2018; Springer Nature B.V
• Subjects: 20th Anniversary Issue: From the editors; Characterization and Evaluation of Materials; Chemistry and Materials Science; Computer simulation; Diagnostic systems; Drug delivery; Drug delivery systems; Fabrication; Fluorination; Gold; Hydrogenation; Inorganic Chemistry; Lasers; Ligands; Materials Science; Molecular chains; Monolayers; Morphology; Nanoparticles; Nanotechnology; NMR; Nuclear magnetic resonance; Optical Devices; Optics; Organic solvents; Perspectives; Photonics; Physical Chemistry; Self-assembly; Fluorinated thiolates; Phase segregation; Janus nanoparticles; Gold nanoparticles; Monolayer morphology
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-018-4231-5

Harnessing the reciprocal phobicity of hydrogenated and fluorinated thiolates proved to be a valuable strategy in preparing gold nanoparticles displaying mixed monolayers with a well-defined and pre-determined morphology. Our studies display that the organisation of the fluorinated ligands in phase-separated domains takes place even when these represent a small fraction of the ligands grafted on the gold surface. Using simple model ligands and by combining
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F NMR or ESR spectroscopies, and multiscale molecular simulations, we could demonstrate how the monolayer morphology responds in a predictable manner to structural differences between the thiolates. This enables a straightforward preparation of gold nanoparticles with monolayers displaying stripe-like, Janus, patchy, and random morphologies. Additionally, solubility properties may be tuned as function of the nature of the ligands and of the monolayer morphology obtaining gold nanoparticles soluble in organic solvents or in aqueous solutions. Most importantly, this rich diversity can be achieved not by resorting to ad hoc developed fabrication techniques, but rather relying on the spontaneous self-sorting of the ligands upon assembly on the nanoparticle surface. Besides enabling control over the monolayer morphology, fluorinated ligands endow the nanoparticles with several properties that can be exploited in the development of novel materials with applications, for instance in drug delivery and diagnostic imaging.