We explore how walls can be introduced into chemically specific dissipative particle dynamics models such that the surface energies can be chosen to obtain a desired contact angle on a given substrate, for example, for an oil/water interface. We certify the methodology for determining the surface energy, which can be positive or negative, such that the Young equation is automatically satisfied. We validate the approach against direct numerical simulation of cylindrical droplets of dodecane in water on the surface and test it against an experimental model of a water droplet in dodecane on a surface-adsorbed monolayer on silica.