𝑎 𝐵𝑗 and 𝑏 𝐵𝑗 are parameters specific to the beads. The exponential force in Eq. ( ) increases steeply when particles come into contact, effectively creating a 'hard core' interaction (Figure ). This reprodcues interfacial properties, particularly between water and vapor, more effectively than the linearly increasing standard DPD conservative force (Figure ). The B particles themselves, however, interact via the standard linear conservative force.