Pervaded volume is a measure of the size of a polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 chain in space. In particular, it is "the volume

Volume

Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....

 of solution spanned by the polymer chain".

Scaling

The pervaded volume V scales as the cube of the chain size



R is some length scale describing the chain conformation such as the radius of gyration

Radius of gyration

Radius of gyration or gyradius is the name of several related measures of the size of an object, a surface, or an ensemble of points. It is calculated as the root mean square distance of the objects' parts from either its center of gravity or an axis....

 or root-mean-square end-to-end distance of the chain. Typically the pervaded volume is very large relative to the space actually occupied by the chain as most of the pervaded volume is usually filled with solvent

Solvent

A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

 or other chains.

Applications

Chain pervaded volume is relevant in the morphology and rheology

Rheology

Rheology is the study of the flow of matter, primarily in the liquid state, but also as 'soft solids' or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force....

of melt and bulk polymers through its relation to quantities such as the interchain entanglement density, the number of entanglements between different chains per volume .