Parameter that provides a mathematical description of the fractal structure of a polymer network, an aggregated particulate sol, or of the particles that comprise them.
- in which is the mass contained within a radius, , measured from any site or bond within a fractal structure.
- For a Euclidean object of constant density, , but for a fractal object, , such that its density decreases as the object gets larger.
- For the surface area of a fractal object, in which is the surface area contained within a radius, , measured from any site or bond and is termed the surface fractal dimension.
PAC, 2007, 79, 1801 (Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)) on page 1811