Understanding the adsorption behaviour of polymer/surfactant mixtures at the air-water interface is of fundamental importance and has direct relevance to a variety of practical applications, e.g. consumer goods products, and paper and oil industries. In recent years, studies using surface-sensitive experimental techniques such as X-ray and neutron reflectivity have considerably advanced our understanding on interfacial behaviours of polymer/surfactant mixtures. In this proposal, the focus is on two neutral comb co-polymers with a hydrophilic PEG backbone and a varying length and density of hydrophobic PVAc grafts, particularly when they are with a non-ionic surfactant C12E5 (bearing similar molecular structure to the PEG backbone). We are motivated by their conjectured effective roles in stabilizing foams and removing grease in P&G household products. Comb co-polymers can be thought of as a very sparsely grafted polymer brushes, and therefore, some interesting interfacial properties are expected following their self-assembly with surfactant at the air-water interface.