Compressible Viscoelastic Liquid Effects Generated by the Breathing Modes of Isolated Metal Nanowires

Abstract

Transient absorption microscopy is used to examine the breathing modes of single gold nanowires in highly viscous liquids. By performing measurements on the same wire in air and liquid, the damping contribution from the liquid can be separated from the intrinsic damping of the nanowire. The results show that viscous liquids strongly reduce the vibrational lifetimes but not to the extent predicted by standard models for nanomaterial-liquid interactions. To explain these results a general theory for compressible viscoelastic fluid-structure interactions is developed. The theory results are in good agreement with experiment, which confirms that compressible non-Newtonian flow phenomena are important for vibrating nanostructures. This is the first theoretical study and experimental measurement of the compressible viscoelastic properties of simple liquids.

Breathing mode vibrations and elastic properties of single-crystal and penta-twinned gold nanorods

“…It is worth mentioning that these two breathing modes have also been observed in a recent experiment on the vibrations of single gold nanorods with an average width of B45 nm. 24 In view of the results in Fig. 2 and 3, it is pointed out that the breathing periods of single gold nanorods in either the single-crystal or penta-twinned structure could be well described using the macroscopic elastic model, together with the bulk material elastic constants.…”

“…The effects of nanoscale solid-fluid interactions on the vibrational period and damping of nanorods and on the non-Newtonian viscoelastic behaviors of high-viscosity liquids would be of particular interest. [22][23][24]49…”

Strong vibrational coupling in room temperature plasmonic resonators

“…3. Previous experiments on Au nanowires have measured quality factors for damping by the surfactant layer of 19,39 , which implies that the intrinsic damping for the chemically synthesized thin Au nanoplates in this study must be very small 17 . This also means that it may be possible to further improve the quality factor by fully removing the surface-capping layer.…”

“…5. Previously, trenches were used to isolate metal nanostructures from the substrate to improve the vibrational quality factors 37–39 . This design produced moderate quality factors of 40–60 for the breathing modes of Au nanowires, and ~30 for Au nanoplates with thicknesses of several hundred nanometers 28 .…”

“…In general, the total quality factor for a given vibrational mode can be expressed as , where is the intrinsic damping quality factor, and corresponds to the environment damping. Normally intrinsic damping of chemically synthesized nanoparticles is relatively small 17,39 , although it may become dominant with lithographically fabricated plasmonic nanostructures where the crystal defects were abundant 18 . The measured quality factor for Au nanoplates on Lacey carbon films is remarkable, especially considering that molecular capping ligands were presented, as can be seen from the TEM measurements in Supplementary Fig.…”