1 research outputs found
Scattering Properties of Individual Hedgehog Particles
“Hedgehog”
particles (HPs) possess a micrometer-sized
dielectric spherical core which is densely coated with nanoscale metal
oxide spikes. This unique surface topography, resembling the appearance
of a hedgehog, provides the particles with the exclusive physiochemical
property to stably disperse in both polar and nonpolar solvents without
the necessity of changing the surface chemistry. Optical extinction
measurements of HP ensembles in aqueous solution indicate a broad
spectral response in the visible range. However, there remains a dearth
of fundamental knowledge about the cause of the broad optical resonance,
as it can be a consequence of shape polydispersity in the many-particle
system or intrinsic to each individual HP. In this paper, we present
the first experimental study of the dark-field scattering of individual
hydrophilic and hydrophobic HPs. Our measurements disclose that the
expansive optical response in the visible spectral range is truly
characteristic for the far-field scattering of a single HP. Our results
also uncover how intrinsic particle features, such as spike length,
as well as environmental changes affect the scattering of individual
HPs. In particular, by changing the atmosphere around a hydrophilic
HP from air to nitrogen and by completely immersing in water by employing
a 3D optical trap, we discovered that the scattering from a hydrophilic
HP is strongly modulated by excess water in its interstitial shell