Polar steric interactions for V-shaped molecules

We consider the effect of shape polarity in the excluded-volume interaction between V-shaped polar particles in orientationally ordered phases. We show that the polar component of the steric interaction between these polar particles, large enough in two space dimensions, can also become important in three space dimensions. Unexpectedly, polar steric interactions, up to now neglected, favor an "antiparallel" pair binding, which may be the building block of orientationally ordered phases for polar particles. An antiferromorphic smectic ordering, which is also antiferroelectric, could further be attained at high enough density by the same mechanism.