D. Schwahn et al., CRITICAL NEUTRON-SCATTERING IN A POLYMER BLEND ABOVE AND BELOW THE CRITICAL-POINT OF DEMIXING - CRITICAL EXPONENTS AND AMPLITUDE RATIOS, Physical review letters, 73(10), 1994, pp. 1452-1455
The critical behavior of a polymer blend was measured by small-angle n
eutron scattering above and below the critical temperature T-c, i.e.,
outside and inside the unstable region. The critical exponents and the
amplitudes of the susceptibility and the correlation length were dete
rmined. For T > T-c the critical exponents gamma and nu are consistent
with the renormalization-group predictions. Below T-c, however, devia
tions from the expected values were observed. Also experimental critic
al amplitude ratios (20-30)% smaller than predicted were found.