Surface tension of the isotropic-nematic interface

We present the first calculations of the pressure tensor profile in the vicinity of the planar interface between isotropic liquid and nematic liquid crystal, using Onsager's density functional theory and computer simulation. When the liquid crystal director is aligned parallel to the interface, the situation of lowest free energy, there is a large tension on the nematic side of the interface and a small compressive region on the isotropic side. By contrast, for perpendicular alignment, the tension is on the isotropic side. There is excellent agreement between theory and simulation both in the forms of the pressure tensor profiles, and the values of the surface tension.Comment: Minor changes; to appear in Phys. Rev.

Virtual porous carbons: what they are and what they can be used for

We use the term “virtual porous carbon” (VPC) to describe computer-based molecular models of nanoporous carbons that go beyond the ubiquitous slit pore model and seek to engage with the geometric, topological and chemical heterogeneity that characterises almost every form of nanoporous carbon. A small number of these models have been developed and used since the early 1990s. These models and their use are reviewed. Included are three more detailed examples of the use of our VPC model. The first is concerned with the study of solid-like adsorbate in nanoporous carbons, the second with the absolute assessment of multi-isotherm based methods for determining the fractal dimension, and the final one is concerned with the fundamental study of diffusion in nanoporous carbons.M. J. Biggs and A. But