STRUCTURAL MODIFICATION OF WATER IN THE CONFINED LAYER OF A LAMELLAR LIQUID-CRYSTAL

Neutron diffraction measurements have been made on water confined in t he lamellar phase (L(alpha)) of the amphiphile tetraethylene glycol n- dodecyl ether (C(12)E(4)) Using a first-order difference procedure, th e structure factor for a planar water layer of 58 Angstrom thickness c onfined between surfactant sheets has been obtained. Comparison with b ulk water at the same temperature shows that there is enhanced hydroge n-bonding in the water layer and modification of the inter-molecular s tructure over the intermediate range (2.5-8 Angstrom). These results s uggest that the connectivity of the H-bonded network is influenced by the geometrical confinement imposed by the surfactant interface.