The problem of instability in halide perovskite nanocrystals (NCs) remains a major deterrent towards their rational development in different applications. This instability can be largely attributed to the dynamic nature of both the organic ligands and the inorganic core of the NCs. Thus, the search for a better stabilizing ligand has generated a lot of interest among different researchers. For example, quaternary alkylammonium ligands such as didodecyldimethylammonium bromide (DDAB) have been used in attempts to stabilize the surface of CsPbBr₃ nanocrystals but often with contradictory results reported in literature. While some researchers have reported improvement in colloidal stability, quantum yield, and optoelectronic properties of CsPbBr₃ NCs using DDAB,¹ others have reported it to cause a phase transformation to poorly fluorescent 2D CsPb₂Br₅.² Thus, the impact of quaternary alkylammonium ligands on the surface of CsPbBr₃ NCs and its role in driving phase transformation have remained unclear. Here, we investigated the thermodynamics of ligand exchange and subsequent processes as DDAB is introduced to CsPbBr3 NCs coated with oleate/oleylammonium native ligands. Using isothermal titration calorimetry (ITC) combined with complementary spectroscopy analysis, we were able to resolve the processes that occur upon introduction of DDAB to natively capped CsPbBr₃ nanocrystals. The first step, involving ligand exchange proceeds readily at low DDAB concentration and is endothermic (𝜟H ~30 kJ/mol) with an exchange equilibrium constant K_ex >100 indicating that the ligand exchange is entropically driven. On the other hand, larger equivalencies of DDAB bring about a second, exothermic process which corresponds to the displacement of PbBr_x complexes from the NCs surface. This process ultimately leads to the formation of 2D phases. Resolving these processes through direct thermal measurements helps to reconcile contradictory reports in prior studies of the surface passivation with quaternary ammonium ligands and also showed that ITC could be a viable technique in understanding the dynamics of the surface ligands on perovskite NCs that can be geared towards a better understanding of the passivation process for improved stability. In addition to this, we compared the ITC profile of DDAB exchange with other analogous ion pairs such as tetraoctylammonium bromide (TOAB), tetraoctylammonium hexafluorophosphate (TOA-PF₆), and didodecyldimethylammonium hexafluorophosphate (DDA-PF₆), revealing the ability of DDA cation to occupy Cs vacancy sites promoting strong interaction of the ligand with NC surface.