39nm_fullwrap_topview
A circular polystyrene sheet wrapping a water drop immersed in silicone oil. The sheet is 39 nm thick and 3.0 mm in diameter.

“Optimal wrapping of liquid droplets with ultrathin sheets” appeared in Nature Materials (link)This work explains the wide variety of shapes that can form when a very thin elastic sheet wraps itself around a liquid drop. Although the mechanics of thin sheets are plagued by complicating features such as wrinkles, crumples, and folds, we established a geometrical principle that ignores these features and predicts the overall wrapping shape. In the end, the wrapper finds the three-dimensional shape that contains the most liquid filling within a fixed area of sheet, much like a stuffed calzone or empanada that is packed with filling inside a folded piece of dough.

Optimal wrapping of liquid droplets with ultrathin sheets. J. D. Paulsen, V. Démery, C. D. Santangelo, T. P. Russell, B. Davidovitch, and N. Menon, Nat. Mater. doi: 10.1038/nmat4397 (2015).  pdf  link  bibtex

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