{{unreferenced, date=April 2017
A micellar cubic phase is a
lyotropic liquid crystal
A liquid crystalline mesophase is called lyotropic (a portmanteau of lyo- "dissolve" and -tropic "change" ) if formed by dissolving an amphiphilic mesogen in a suitable solvent, under appropriate conditions of concentration, temperature and pr ...
phase formed when the concentration of
micelles
A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloid, colloidal suspension (also known as associat ...
dispersed in a solvent (usually water) is sufficiently high that they are forced to pack into a structure having long-ranged positional (translational) order. For example, spherical micelles a subic packing of a body-centred cubic lattice.
Normal topology Normal(s) or The Normal(s) may refer to:
Film and television
* ''Normal'' (2003 film), starring Jessica Lange and Tom Wilkinson
* ''Normal'' (2007 film), starring Carrie-Anne Moss, Kevin Zegers, Callum Keith Rennie, and Andrew Airlie
* ''Norma ...
micellar cubic phases, denoted by the symbol I
1, are the first lyotropic liquid crystalline phases that are formed by
type I amphiphiles. The amphiphiles' hydrocarbon tails are contained on the inside of the micelle and hence the polar-apolar interface of the aggregates has a positive
mean curvature In mathematics, the mean curvature H of a surface S is an ''extrinsic'' measure of curvature that comes from differential geometry and that locally describes the curvature of an embedded surface in some ambient space such as Euclidean space.
The ...
, by definition (it curves away from the polar phase).
Inverse topology
Inverse or invert may refer to:
Science and mathematics
* Inverse (logic), a type of conditional sentence which is an immediate inference made from another conditional sentence
* Additive inverse (negation), the inverse of a number that, when a ...
micellar cubic phases (such as the Fd3m phase) are observed for some
type II amphiphiles at very high amphiphile concentrations. These aggregates, in which water is the minority phase, have a polar-apolar interface with a negative
mean curvature In mathematics, the mean curvature H of a surface S is an ''extrinsic'' measure of curvature that comes from differential geometry and that locally describes the curvature of an embedded surface in some ambient space such as Euclidean space.
The ...
. The structures of the normal topology micellar cubic phases that are formed by some types of amphiphiles (e.g. the oligoethyleneoxide monoalkyl ether series of
non-ionic surfactants
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
are the subject of debate. Micellar cubic phases are isotropic phases, but are distinguished from
micellar solutions
A micellar solution consists of a dispersion of micelles in a solvent (most usually water). Micelles consist of aggregated amphiphiles, and in a micellar solution these are in equilibrium with free, unaggregated amphiphiles. Micellar solutions fo ...
by their very high viscosity. When thin film samples of micellar cubic phases are viewed under a polarising microscope they appear dark and featureless. Small air bubbles trapped in these preparations tend to appear highly distorted and occasionally have faceted surfaces.
Phases of matter
Liquid crystals