Structural origin of dynamical arrest in gels and glasses

Colloidal dispersions enter in an arrested state when a certain concentration is reached and depending on inter-particle interactions a gel or glass is formed. Recent results indicate the presence of peculiar intermediate range structures that appear to be correlated with the glass formation process. Whether or not these, or similar, structures exist also in the gel phase is not clear. If found also in gels they can hint the existence of a new universal feature for all arrested systems.