Adsorptions of sodium dodecylsulfate (SDS), dodecyltrimethylammonium bromide (DTAB) and octaethylene glycol monododecyl ether (C12E8) at the air/water interface in the presence of hydrocarbon and fluorocarbon surfactants (HCEP and FCEP) were investigated by molecular dynamics (MD) simulation. With the addition of HCEP or FCEP, the monolayer is more organized than in individual surfactant systems. Extremely expanded C12E8 chain in a smaller tilt angle is discovered in C12E8/HCEP system. In SDS or DTAB systems, relatively small tilt angle of surfactants is observed in the presence of FCEP. Their analog, a silicone surfactant DSEP shows a favorable effect on interfacial properties with DTAB. (C) 2012 Elsevier B.V. All rights reserved.