This work presents a multiscale computational approach to probe the behavior of polymer/ clay nanocomposites based on poly(ethylene oxide) (PEO)/montmorillonite (MMT)as obtained from water intercalation In details, Our modeling recipe is based on four sequential steps (a) atomistic Molecular dynamics simulations to derive interaction energy values among all system components, (b) mapping of these values onto mesoscale dissipative particle dynamics parameters, (c) mesoscopic simulations to determine system density distributions and morphologies (i.e., intercalated vs exfoliated), (d) simulations at finite element levels to calculate the relative macroscopic properties The entire computational procedure has been applied to four PEO/MMT systerns with PEO chains of different molecular weight (750, 1100, 2000, and 5000), and thermal and electrical characteristics were predicted in excellent aggreement with the available experimental data importantly. our methodology constitutes;I truly integrated multiscale modeling approach, in which no "learning against experiment" has been performed in any step of the computational recipe.