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Vacuum ultraviolet (VUV) transmission spectra show a clear polarization effect in pi electronic transition in spin coated atactic polystyrene (aPS) films of thickness below 4Rg, where Rg (~20.4nm) is the radius of gyration of the polymer. This transition associated with pendant benzene rings in polystyrene. The polarization effect clearly indicates pendant benzene ring alignment on a macroscopic scale. Study of core electron (1s) transition through near edge x-ray absorption fine structure (NEXAFS) spectroscopy confirms the ordering and shows that the rings are oriented towards out-of-plane direction with a tilt angle ~63 degree with the sample plane, which is consistent with the observed in-plane (sample surface) VUV polarization. These results indicate the transition of a common polymer, like polystyrene, inherently disordered in the bulk, to an orientationally ordered phase under a certain degree of confinement.
We simulate a strongly size-disperse hard-sphere fluid confined between two parallel, hard walls. We find that confinement induces crystallization into n-layered hexagonal lattices and a novel honeycomb-shaped structure, facilitated by fractionation.
When systems that can undergo phase separation between two coexisting phases in the bulk are confined in thin film geometry between parallel walls, the phase behavior can be profoundly modified. These phenomena shall be described and exemplified by c
The rheological properties of highly concentrated suspensions of hard-sphere particles are studied with particular reference to the rheological response of shear induced crystals. Using practically monodisperse hard spheres, we prepare shear induced
Liquid water can become metastable with respect to its vapor in hydrophobic confinement. The resulting dewetting transitions are often impeded by large kinetic barriers. According to macroscopic theory, such barriers arise from the free energy requir
We study equilibrium shapes and shape transformations of a confined semiflexible chain inside a soft lipid tubule using simulations and continuum theories. The deformed tubular shapes and chain conformations depend on the relative magnitude of their