Similarity of wet granular packing to gels

• Published in: Nature communications Vol. 5; no. 1; p. 5014
• Main Authors: Li, Jindong, Cao, Yixin, Xia, Chengjie, Kou, Binquan, Xiao, Xianghui, Fezzaa, Kamel, Wang, Yujie
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23-09-2014; Nature Publishing Group
• Subjects: 639/301; 639/301/923/1027; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6014

To date, there is still no general consensus on the fundamental principle that governs glass transition. Colloidal suspensions are ordinarily utilized as model systems to study the dynamical arrest mechanisms in glass or gels. Here, we tackle the problem using athermal granular particles. Slow dynamics and structural evolution of granular packing upon tapping are monitored by fast X-ray tomography. When the packing are wet and short-range attractive interactions exist, we find a large amount of locally favoured structures with fivefold symmetry, which bear great structural similarity to colloidal gels. In addition, these structures are almost absent in dry packing with similar packing fractions. The study leads strong support for the geometrical frustration mechanism for dynamic arrest in both thermal and athermal systems with attractive interactions. It also suggests nontrivial structural mechanism, if exists, for dynamic arrest in systems with purely repulsive interactions.
Colloidal suspensions are used as the model systems to study the gelation dynamics because colloidal particles are large and thermal. Here, Li
et al.
show an alternative system, wet granular packing, whose local structures exhibit fivefold symmetries similar to those observed in colloidal gels.