DOMAIN-WALL FLUCTUATIONS AND INSTABILITIES IN MONOMOLECULAR FILMS

Static and dynamic aspects of domain wall fluctuations and instabilities are investigated in a monomolecular film confined to an air-water interface and composed of a phospholipid and cholesterol. Spectral analysis, based on techniques of digital image processing and optical character recognition, provides a quantitative description of domain shapes and their excitations. This methodology has permitted us to identify an elliptic instability, followed by a branching instability in the course of isothermal film compression. The latter event signals the emergence of a "melted" stripe phase in the vicinity of the consolute point. An intermediate regime is characterized by equipartition between serveral active, quasi-capillary domain wall excitations and by diffusive fluctuation dynamics. © 1990.