Zweischicht

Zweischicht is a German term meaning “two-layer” and is used as a descriptive label in several disciplines for a structure that consists of two distinct layers. The exact interpretation depends on context: one layer may be a substrate while the other is a functional, protective, or decorative layer; the two layers may be continuous or separated by an interface.

In materials science and engineering, Zweischichtsysteme refer to coatings and films composed of two layers, such as a base substrate and an upper protective or functional layer. Common goals include improving wear resistance, corrosion protection, optical properties, or barrier performance. The interface between the layers influences adhesion, mechanical strength, and diffusion across the boundary.

In biology and medicine, the term can describe bilayer membranes (lipid bilayers) or stratified tissues where two cellular layers exist, for example, in epithelia. In these contexts the two layers may have different cell types and functions.

In earth and environmental sciences, Zweischicht-Systeme may describe two-layer soils, atmospheres, or water bodies, where distinct physical or chemical properties are found in the upper and lower layer. The term is generally used descriptively rather than as a strict technical designation.

Because Zweischicht is a generic term, its precise meaning must be inferred from the field and the accompanying description.