9523440 Pershan This project is concerned with the development of techniques and methods that will allow measurement of previously unobserved phenomena at the surfaces of both bulk liquids and thin liquid films. Some of the phenomena to be studied include: (i) The relation between microscopic structure and thermodynamic properties of two-dimensional (2D) order of Langmuir monolayers (LM). One particularly interesting such system will be LM of periodic amphipillic polypeptides prepared by bacterial expression of artificial genes. (ii) The 2D in plane order of Langmuir monolayers of fullerene chemical derivatives on the surface of water. (iii) The effects of chemical variations on the in-plane structure of self assembled Langmuir monolayers of thiols on the surface of liquid mercury and possibly gallium. (iv) The compositional structure along the surface normal of wetting layers of complex systems, such as binary liquids and polymer brushes. These experiments can increase knowledge of the properties of liquid surfaces dramatically, and have potential commercial applications in the US and elsewhere. %%% The principal objective of this research program is to explore the microscopic structure and associated statistical properties of liquid surfaces. The project is concerned with the development of techniques and methods that will allow measurement of previously unobserved phenomena at the surfaces of both bulk liquids and thin liquid films. In contrast with the relatively comprehensive understanding of the solid phases of matter, including their surfaces, knowledge of the liquid phase is relatively modest. One reason that this is true in spite of the vast literature on liquid phases is that the lack of long-range order in bulk liquids obviates much of the measurable phenomena that contributed to the current understanding of the microscopic structure of solids. ***