Our parametrization is based on matching properties of compounds such as pentadecane, which have the same or similar number of carbons as the tails of DPPC. Furthermore, although n-alkanes such as pentadecane are known to condense into ordered bulk phases at low temperatures, the thin nanometer sized monolayer film is at different conditions compared to the bulk phase. So, we first get an estimate of the repulsion parameters by matching the bulk properties of relevant alkanes such as density and water -octanol partition coefficients (log 𝑃 𝑂𝑊 ) and then further refinement of the parameters is done to reproduce the monolayer phase behavior quantitively at temperature 293K. The C/E bead repulsion parameter 𝑎 𝐶𝐶 = 𝑎 𝐶𝐸 = 𝑎 𝐸𝐸 is initially estimated by matching pentadecane density at 293K with 𝑇 𝐷𝑃𝐷 = 0.65. Then the parameter 𝑎 𝑊𝐶 = 𝑎 𝑊𝐸 is obtained by matching log 𝑃 𝑂𝑊 of water and octanol. The parameters involving the hydrophilic head groups are estimated initially by a pragmatic mean-field approach following Anderson et al , 𝑎 𝐼𝐽 = 25/𝑅 𝐼𝐽 . All parameters are further refined by matching monolayer 𝑃 -𝐴 isotherms at 293K. The obtained DPD repulsion parameters are given in Table . provided in Table . Ideally, one should calculate bond lengths and angles by matching distributions from atomistic simulations. However, such bond distributions between atom groups corresponding to the CG beads, may depend on the temperature as well.