Molecular dynamics study of the poly(oxyethylene) surfactant C12E2 and water

Constant pressure and temperature (NPT) molecular dynamics (MD) simulations have been carried out to investigate the properties of a binary mixture of the poly(oxyethylene) surfactant C12E2 and water in its liquid crystalline lamellar phase (L-alpha). The calculated interlamellar spacing and the are a per surfactant were found to be in reasonable agreement with X-ray diffra ction results. The water molecules were observed to form hydrogen bonded br idged structures linking the oxygen atoms of the same surfactant chain. Thi s interaction leads to a strong preference for the C-C bonds in the headgro up to attain a gauche conformation.