Structural modification of water in the confined layer of a lamellar liquid crystal

Neutron diffraction measurements have been made on water confined in the lamellar phase (Lα) of the amphiphile tetraethylene glycol n-dodecyl ether (C12E4). Using a first-order difference procedure, the structure factor for a planar water layer of 58 Å thickness confined between surfactant sheets has been obtained. Comparison with bulk water at the same temperature shows that there is enhanced hydrogen-bonding in the water layer and modification of the inter-molecular structure over the intermediate range (2.5–8 Å). These results suggest that the connectivity of the H-bonded network is influenced by the geometrical confinement imposed by the surfactant interface.