Schematic mechanism of spiral formation. a m-Cresol droplets as templates for the nanospiral pattern. b The counterclockwise inward rotating spiral is made of self-assembled carboxylic acid dimers along the evaporating liquid/solid/vapor contact line. c Molecular orientation in the spiral on HOPG as represented by the unit cell structure of the B-form C18A crystal structure (viewed along the a axis). The height of the spiral is close to the unit cell dimension along the b axis.