The phenomenon of liquid-liquid phase separation (LLPS) gives rise to the formation of polymer condensates (a.k.a. "membraneless organelles''), which are highly dense phases (typically ≳30%) of polymers that coexist with a dilute phase (typically ≲10%). We aim to study these condensates' formation mechanisms, specifically their surface tension and chain conformations. We will develop a theory for the thermodynamics of these structures and test it using molecular dynamics simulations.