Single step synthesis and organization of gold colloids assisted by copolymer templates

Abstract

We report here an original single-step process for the synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared using polystyrene (PS)-polymethylmethacrylate copolymer and thiolated PS with propylene glycol methyl ether acetate as a solvent. The spin-coating and annealing of this solution then allows the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (Au NPs) per PS domain. For high concentrations of Au NPs in PS domains, the coupling between plasmonic NPs leads to the observation of a second peak in the optical extinction spectrum. Such a collective effect could be relevant for the development of optical strain sensors in the near future.

Surface plasmon resonance in metal nanospheres explained with LCR circuits

“…Simulation results of circuit shown in (d) shows the appearance of a second peak whose behavior is a mirror of the first. (e) The results of DDA calculations of collodial Au-Au in organic liquid shows the trend in peak position with proximity effect [46] and our simulation (f ) matches quite well with results.…”

“…as the inter-particle distance decreases, the peak shifts towards lower wavelengths. In other words, this new peak shows a blue-shift with increasing proximity [see fig4(d)].Experimentally, this second peak is usually a "minor" (in terms of absorption intensity) peak[46], [fig 4(e)]. Our simulations [fig 4(f)] replicated the results of fig 4(d), i.e.…”

“…Experimentally, this second peak is usually a “minor” (in terms of absorption intensity) peak 50 (Fig. 4(e)).…”

“…4(d)). Experimentally, this second peak is usually a ''minor'' (in terms of absorption intensity) peak 50 Clearly, the symmetry of curves seen in Fig. 4(c) is broken due to the weak interaction between two neighbouring metal grains where the interaction flux has to go through the surrounding media.…”

Dense Brushes of Tilted Metallic Nanorods Grown onto Stretchable Substrates for Optical Strain Sensing

“…The working principle of the first prototype, developed by Liz-Marzan and co-workers, was based on a drop of the light absorption when the substrate is stretched, and less NPs are illuminated . Very quickly, other groups (including ours) investigated color-changing stretchable films exploiting the variation of the plasmonic coupling between NPs when strains, applied to the substrates, lead to NP displacements. − Finally, by embedding free-standing nanorod arrays into an elastomeric thin film, it has been demonstrated that suitable excitation conditions (off-normal incidence) can induce both long and short axis plasmon oscillations and can also be exploited for strain sensing applications . These pioneering works lead to the emergence of a new field, which can be identified as “plasmomechanics,” and whose essence is based on both the use of mechanical stress to investigate plasmonic coupling and on plasmonic coupling monitoring to detect strains applied to the substrate …”