I'm assuming that IMF stands for Intermolecular Force (I wouldn't recommend using this acronym in future, it is unnecessary and unclear). read more
The dominant intermolecular force in both cases is the hydrogen bonding through the OH group, this is taken to be of similar strength for both ethanol and methanol as it is localised to the hydroxyl. Methanol, being the smaller molecule, therefore has a larger proportion of its mass (over 50%) in the hydroxyl group and is more polar. read more