Rheology is science of flow, of deformation of liquids and solids, and of the in-between viscoelastic materials, such as asphalt, glass, dough or plastics (polymers). The properties of the materials are described by the constitutive equation (rheological equation of state) which may an include other then mechanical quantities, such as magnetic or electrical fields. Constitutive equation describes the memory of materials, effects of thermal and stress history and effects such as hysteresis.
Rheology is an interdisciplinary field which draws on mathematics and differential geometry, chemistry, thermodynamics, polymer science and mechanics of continua. It includes as special cases hydrodynamics and theory of elasticity while studying more general cases of viscoelastic materials and of non-linear and complex fluids.

Derivation of the constitutive equation from the microscopic properties, the structure-property relationship of materials or ''structural rheology'' generalises methods of statistical mechanics from study of N-particle systems to more complex ensembles, e.g. to three-dimensional networks of polymer chains to derive equations of rubber elasticity.

Journals devoted to mechanical properties of polymers and other complex materials
see above
Learned societies devoted to studies of rheology, complex liquids and polymers.
Please note that university departments, consultant firms and research centers have a different subcategory