Forces of exclusion are repulsive. Talking chemistry, it's called hydrophobia. Grease, for example, will not dissolve like salt does in the sea; instead it clots together, usually floating on top because it lacks the gravitas of water. And while grease is hydrophobic, it is lipophilic, a word that, like hydrophobia, also comes to us via Greek, rooted in the word lipos.
Lipids and water don't mingle. It's not that lipids are weak--they are very strong internally, giving us energy--they just lack enough polarity to part water like salt can. Salt ions actually direct water: cations attract the oxygen part of H2O and anions attract the hydrogen part. These are electrostatic forces. They are intermolecular forces meaning between atoms and molecules:
Notice the orientation of white to red (hydrogen to oxygen, plus to minus), H-bonding is an attractive force, not unique to water, but best exemplified by it. When a lipid or a hydrophobe enters the picture, the waters give up their ordered coziness and are forced to reorient around each hydrophobe to make what's called a cage--without enthalpic recompense as with a salt. Thus the exclusion is an entropic effect because it relates to physical law and order.