Critical droplet volume for spontaneous capillary wrapping

In this work, we show that an elastic thin sheet can be folded up by the surface tensions at the contact line when it is in contact with a droplet of sufficient volume. The critical volumes of different droplets for the wrapping of square and triangular polydimethylsiloxane sheets are measured. A dimensionless number involving the droplet volume is proposed and it is found that the critical dimensionless number, for which spontaneous capillary wrapping takes place, scales with the characteristic length of the sheet exponentially. (C) 2010 American Institute of Physics. [doi:10.1063/1.3492834]