Water nanodroplets confined in molecular nanobeakers

Thanks to the ability of an AFM to topographically image a surface and to apply forces perpendicular to it we have studied the case of nanometer-scale beakers, formed by dewetting of a dissolution of an organic material with its solvent, filled with water. The confinement of such water nanodroplets (WNDs) allows their imaging and the exploration of their mechanical behavior. Surprisingly to a certain extent, the WNDs mechanical response can be approximated by a hookean spring exhibiting force constants, closely related to the surface tension, significantly larger than the well-known value of 0.073 N m−1. We ascribe the larger values to the nanometric length scale involved.