) : The temperature where a polymer transitions from a hard, brittle "glassy" state to a soft, flexible "rubbery" state.
: The simplest model (like a Random Walk ) assumes monomers have no volume and do not interact except through their immediate neighbors.
: Unlike small molecules, polymers rarely form perfect crystals. They are typically semi-crystalline , containing both ordered (crystalline) and disordered (amorphous) regions. Polymer Physics
) : The straight-line distance between the first and last monomer, useful for linear chains. Radius of Gyration ( Rgcap R sub g
: Polymers exhibit both viscous (liquid-like) and elastic (solid-like) properties. Their response to stress depends on time and temperature. ) : The temperature where a polymer transitions
) : A more universal measure of the chain's size relative to its center of mass, used for all architectures (branched, star, etc.). 2. Physical States and Phase Transitions
: Above a certain molecular weight, chains become physically interlaced, creating a temporary network that resists motion. Their response to stress depends on time and temperature
Polymer physics is the field that applies statistical mechanics and physical chemistry to understand the behavior of macromolecules—long, chain-like molecules made of repeating units called monomers. Because these chains are so large and complex, they are typically described using statistical models rather than deterministic ones. 1. Fundamental Models of a Single Chain