Polarization-Multiplexed Dynamic Light Scattering: Characterizing Rotational Diffusion and Shape of Optically...

Rotational diffusion and shape analysis of optically anisotropic particles, such as the length and aspect ratio, is widely considered to be beyond the capabilities of standard batch-mode single-angle dynamic light scattering, which, unlike polarized and depolarized dynamic light scattering, does not benefit from multiangle and polarization-selective detection. Most desktop instruments lack these features; therefore, they are considered incapable of providing information about rotational diffusion and particle shape. Here we demonstrate that one can characterize rotational diffusion and the shape of particles with optical anisotropy without the use of any polarization filters, even at a single angle. By using a conventional desktop instrument with forward scattering low-angle detection, we demonstrate our approach by characterizing the principal dimensions and aspect ratios of gold nanostars, gold nanorods, and hematite spindles. Our approach opens up new possibilities that were previously inaccessible to users of standard dynamic light scattering.