Harnessing nanoparticle vibrations to probe surface mobility and glass transition

Advances in polymer nanoparticle synthesis and assembly techniques have enabled new applications, from drug delivery carriers to novel coatings. However, the polymer dynamics, especially at the particle surfaces of architected colloids, must be understood in order to realize their potential. Brillouin light spectroscopy as a direct probe of the particle surface mobility via nanoparticle vibrations, reveal the correlation between the glass transition behavior and surface dynamics and the presence of a low frequency mode extremely sensitive to particle-particle interactions. These are enabled by the surface mobility which can be engineered by different shell architecture layers. We demonstrate that a thin shell layer is able to eliminate the effect of enhanced particle surface mobility and drastically modify the structure of nanoparticle assembly. Surface mobility is strongly affected by the application of pressure modifies enabling a facile soldering of the colloidal film.