Experimental Determinations of the Excluded-Volume Exponent in Different Environments

The excluded-volume exponent $\ensuremath{\nu}$ is determined from a neutron scattering experiment by polystyrene chains, in the "intermediate" momentum-transfer range. The chains were successively dispersed in a good solvent, in a $\ensuremath{\Theta}$ solvent, and in the bulk material. The new result is the value of $\ensuremath{\nu}$ for the bulk material, which is discussed below.