Why is there a greater degree of separation in a dipole-dipole interaction?
Like I answered my other question, this is in some ways very similar. Since electrostatic attractions are so strong, it is decreases less at a longer distances. The $+$ &amp; $-$ are attracted together so strongly. 

Dipole-dipole attractions aren't strong attractions, electrostatic attractions are stronger, since they are created by ionic bonding. Dipole-dipole occur in covalent bonding. Thus dipole-dipole attractions decrease with increasing distance faster.

This is just a piece of the whole picture.



Check the refs: 1, 2, 3. They provide more in depth detail to the entire picture.