mikrofazy

Mikrofazy is a term used in materials science to describe nanoscale phase-separated domains that form within certain polymer systems, notably block copolymers, when chemically dissimilar segments segregate while remaining covalently connected.

The driving force is incompatibility between blocks, quantified by the Flory-Huggins chi parameter. The product χN (N total degree of polymerization) must exceed a critical value for microphase separation to occur, leading to a periodic arrangement with domain sizes typically 5–50 nanometers. The phenomenon reflects a balance between the enthalpic penalty of mixing and the configurational entropy of the chains, and it features an order-disorder transition as conditions such as temperature change.

Morphologies depend on the volume fraction f of a block; common structures include lamellae (f around 0.5), hexagonal cylinders, body-centered cubic spheres, and gyroid networks. Domain spacing increases with molecular weight and with the degree of segregation between blocks.

Characterization methods commonly used to study mikrofazy structures include small-angle X-ray scattering, transmission electron microscopy, and atomic force microscopy. These microphase-separated morphologies have applications in nanolithography, templating for porous materials, membranes, and functional surfaces, where nanoscale periodicity and domain architecture are exploited.

The term mikrofazy is used in several languages to translate microphase, and in English literature the concept is usually described as microphase or microphase-separated structure within block copolymers.