Significant size change during bacterial cellulose capsule drying

Use of engineered powders, whether by manufacturers or consumers, often requires rapid hydration but is hindered if hydration rates exceed dispersion rates, leading to “fish eyes”. More work is needed to understand how powder could be engineered to actively contribute to its own dispersion while minimizing the use of additional materials and additives. A recently developed bacterial cellulose microcapsule matrix, with good mechanical integrity but minimal mass usage, exhibits remarkable deformability owing to its fibrous shell structure. When dried into powder, the cellulose microcapsules experience significant deformation of their fibrous shells, changing their diameter by orders of magnitude. We demonstrate a capsule shape recovery mechanism by coating the cellulose fibers, which damps fiber interactions. The results demonstrate that drying microfibrous cellulose microcapsules can expand the range of encapsulation modes available and greatly reduce the mass needed to provide efficient powder rehydration. • Drying of microcapsules with sparse fiber mesh walls is studied. • Significant shrinkage via capillary stresses collapses the minimal mass capsules. • The fiber mesh shells can completely recover from huge deformation if rehydrated.