Malleable mesoatom reactions in tubular networks

Mesoatoms in soft-matter crystals consist of large groups of flexible molecules whose sub-unit-cell configurations couple strongly to supra-unit-scale symmetry and differ strongly from conventional hard matter atoms by their ability to deform easily into new shapes and sizes. Recently, twin boundary (TB) mirror defects have been quantified in the tubular double diamond (DD) and double gyroid (DG) network phases^1,2 and new types of mesoatoms identified by employing scanning electron microscopic tomography. Moreover, the order-order transition (OOT) between the DD and DG phases has also been investigated with new types of transitional mesoatom structures visualized. Such data allows extraction of mesoatom reactions occurring within these transition zones. Various nodes split and then recombine to achieve the structural changes. In terms of node functionality, the number of struts f connected to a node, the f = 4 DD nodes transform into pairs of f = 3 DG nodes in the DD-DG OOT. In the DD twin, one f = 3 node and one f = 4 node create a pair of f = 5 and f = 3 nodes at the grain boundary. Such 3D structural data motivates theoretical investigations of the role of malleable, self-assembled soft crystal mesoatoms in phase transitions and defect formation.