  We study the formation of wrinkles in graphene upon wet transfer onto a
target substrate, whereby draining of water appears to play an important role.
We are able to control the orientation of the wrinkles by tuning the surface
morphology. Wrinkles are absent in flakes transferred to strongly hydrophobic
substrates, a further indication of the role of the interaction of water with
the substrate in wrinkle formation. The electrical and structural integrity of
the graphene is not affected by the wrinkles, as inferred from Raman
measurements and electrical conductivity measurements.
