Adsorption of surfactant molecules at interface is an important aspect in surface science research directed at elucidating surface structures. Monomolecular films at the air-water interface or on the solid surface have been a considerable focus of recent model systems for biological membranes and two-dimensional pattern formation, photomechanical responses, and molecular recognition systems. A number of techniques have been employed to investigate the microscopic structure and morphological properties of insoluble monolayers on water and monolayers on solid substrates such as X-ray diffraction, nonlinear optical spectroscopy, Raman and infrared spectroscopy and Brewster angle microscopy. On the other hand, the application of these techniques to water-soluble surfactant monolayers adsorbed at the air-solution interface is still limited. This review presents the application of vibrational spectroscopy, which is a nondestructive and sensitive method of monitoring molecular conformation, to the characterization of surfactant monolayer.

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An emulsion film is formed when I apply emulsion cosmetics on skin. I tried to investigate the state of emulsion film, because this state affected the moisturizing and occlusive functions, feelings of emulsion cosmetics significantly. For emulsions used polyoxyethylene-type surfactant, droplets disappear after the film is formed, whereas used polyglycerin-type surfactants, the droplets shape is retained even. The moisturizing and occlusive functions show good results together. The stratum corneum is improved significantly after continuous use. Hydration gel film is formed in the upper side in the case of using alginic acid propylene glycol ester. Therefore I am able to get good feeling, no sticky even if oil content in emulsion is increased.

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In this article, the control methods and the characterization of specific sunscreen film structure are described. To development of high water-resistant sunscreen, it was important that the film formed the minute and periodic uneven structure (MPUS) like lotus leaf. The MPUS was able to form by two methods. One method was the water immersion method and the other was the solvent evaporation method. The formation mechanism was explained by the theory of dissipative structure. It was considered that diffusion ability of the pigments and the contraction property of film by evaporation of the solvents play important role in the formation process of this structure. MPUS showed superior function of water-resistant and UV-protect. Furthermore, MPUS also had unique tensile and optical properties.

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The friction properties of the molecularly thin films of a poly (dimethylsiloxane) (PDMS) melt (M_w ≈ 80000) were investigated using the surface forces apparatus (SFA). When a PDMS droplet was confined between mica surfaces by normal compression, PDMS molecules were squeezed out from between the surfaces and formed a confined hard-wall film. The measurements of the dynamic thickness and friction reveal that PDMS molecules form well-ordered layer structures in the hard-wall film, and the friction mechanisms involve the slippage between ordered PDMS layers. The film structures and resulting friction properties observed for confined PDMS are very different from those of most of the hydrocarbon-type polymeric lubricants, which generally have disordered film structures in confinement and exhibit rheological responses upon shearing. The SFA enables us to clarify the unique friction mechanisms of a confined PDMS melt at the molecular scale, which must be also useful to understand the macroscopic tribological phenomena on PDMS lubricated surfaces.

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Stability factors of surfactant foam film are determined by several physical conditions depending on the thickness. Major driving forces in the drainage process are gravity, capillary pressure and surface tension, and the equilibrium film thickness is observed with a balance between the capillary pressure and the disjoining pressure. For a thick foam film, drainage progresses according to the hydrodynamic properties of the solution. Thermal fluctuation would occur during the drainage process, and a black film is finally formed after vigorous fluctuation. For a thin foam film, effects of the disjoining pressure, which can be expressed as the sum of the electrostatic double-layer force and the van der Waals force, would determine the foam film thickness. An air bubble in water would be considered hydrophobic by virtue of its high interfacial tension, thus raising the possibility of bubble coalescence. At the low concentration of surfactant, hydrophobic force plays an important role in bubble coalescence, while film elasticity is important at higher concentrations. The aim of this article is to review the research of single foam films from hydrodynamic and equilibrium points of view with using both horizontal and perpendicular foam film techniques. The effects of additives for foam film stabilization are then described.

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The field of soft nanocapsules prepared via precision polymerization is briefly reviewed. The recent development of precision polymerization has provided us with versatile tools for synthesis of wide range of functional block copolymers with well-defined structure. The molecular dimensions influence the self-assembly and dictate their products such as nanoparticles and nanocapsules. In this review, general nanoparticles, which are classified 3 types such as homogeneous, core-shell, and hybrid-type, were first described briefly. In the next place, the recent development of shell cross-linked micelles, namely SCK micelles, including in our results are focused on as a typical example of the core-shell typed nanoparticles. This shell cross-linked design leads to numerous potential applications in encapsulation, drug delivery, templating, nanoreacter, and many other.

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