Vesicle-Directed Generation of Gold Nanoflowers by Gemini Amphiphiles and the Spacer-Controlled Morphology and Optical Property

Abstract

In this article, we developed an effective approach to generate gold nanoflowers (AuNFs) by vesicles made from a series of gemini amphiphiles (G2-G10) with different spacer lengths. The gemini amphiphiles were found to form vesicles in aqueous solution. Upon mixing with vesicles in the presence of AgNO(3), HAuCl(4) could be reduced into gold nanoflowers by ascorbic acid. The vesicles directed the growth of the AuNFs, and the spacer length of the gemini amphiphiles showed obvious control of the morphology and optical properties of the formed AuNFs. At a lower HAuCl(4) concentration, the minimum-sized AuNFs were formed when vesicles from the amphiphile with a spacer length of 4 were applied. Upon increasing the spacer length, branched nanoflowers are predominantly produced. A seed-growth mechanism together with the conformational change of the spacer of the gemini amphiphiles was proposed according to the studies on reaction processes. In addition, the formed gold nanoflowers showed obvious surface-enhanced Raman scattering activity for R6G. The present method provided an efficient, controllable way to synthesize branched gold nanostructures.

Tailored synthesis of various Au nanoarchitectures with branched shapes

“…37 For instance, in comparison with simply bumped Au nanostructures, gold nanoflowers show drastically enhanced SERS activity. 38 Au itself has an inherently symmetric nature of face-centered cubic (fcc) structure. 39 For the formation of anisotropic branched structures from metals with highly symmetrical crystals in an isotropic aqueous medium, it is necessary to break the nature of the crystal symmetry.…”

Glycolic acid-g-chitosan-gold nanoflower nanocomposite scaffolds for drug delivery and tissue engineering

“…The electron diffraction pattern can be determined by face centred cubic (fcc) structure of gold. Morphologically nanoflowers are regarded as spheres and branch particles [30,31]. These gold nanoflowers possess more surface area due to the protrusion like tips and therefore, interaction of these nanoflower with the grafted chitosan biopolymer is more efficient in comparison to smooth surface gold nanoparticle.…”

Fabrication of Organic Solar Cells with Branched Cauliflower-Like Nano Structures as a Back Electrode Replicated from a Natural Template of Cicada Wing Patterns

“…In this regard, branched metal NS materials are of specific interest that arises from their unique surfacesensitive properties, large number of multiple surface edges and large surface-to-volume ratio [14][15][16][17] . It would be also feasible to tune the fascinating properties of branched structures such as their optical and electrical properties by size and shape modifications [18,19].…”