A coefficient connecting the intrinsic viscosity, the radius of gyration and the molar mass of a chain macromolecule, according to the equation: $$\text{[}\eta \text{]}=\frac{\mathit{\Phi }{6}^{3/2}(<s^2>{)}^{3/2}}{M}$$ where $\text{[}\eta \text{]}$ is the intrinsic viscosity, $s$ is the radius of gyration and $M$ is the molar mass. The viscosity function is often referred to as the Flory constant.