We use Partical Mesh Ewald electrostatics with a direct space cutoff of 1.0 nm and a grid spacing of 0.12 nm. For nonbonded van der Waals interactions, a 1.0 nm cutoff is used. Pressure of the system is 1 bar and we have fixed the pressure of systems using the Berendsen barostat. We have maintained the geometry of water, urea and TMAO molecules during the simulations by using the LINCS algorithm. The temperature of the system is 298 K and it was kept constant using the velocity rescaling thermostat. Two different TMAO force-fields are considered for understanding the force-fields dependencies of hydrophobic association. One model was developed by Garcia and coworkers that is called as Garcia force-fields in our manuscript. The second one was developed by Netz and coworkers that is named as Netz force-fields. TIP3P and SPC/E 41 water models are considered along with Garcia and Netz force fields for TMAO respectively as this combination was used in the simulation studies of Ganguly et al. Kirkwood buff force field for urea and gromos54a7 force fields for neopentane are used. The force fields used here for neopentane is an united atom model.