Small-angle neutron scattering from aqueous micellar solutions of a nonionic surfactant as a function of temperature

Solutions of 0.029 M n-dodecyl hexa(oxyethylene glycol) monoether (C/sub 12/E/sub 6/) in D/sub 2/O have been investigated by small-angle neutron scattering at a series of temperatures from 14.3 to 47.3/sup 0/C. The sample displays a lower consolute temperature of 47.4 +- 0.05/sup 0/C. The scattering curves are fit best by assuming that (1) spherical micelles are present at all temperatures investigated and (2) the observed increases in the scattered intensity with increasing temperature in the low-angle region are due to critical concentration fluctuations. The angular dependence in this region can be approximated by the Ornstein-Zernike relation, with the correlation lengths obtained following a power law dependence on the reduced temperature (T/sub c/ - T)/T/sub c/. 5 figures, 2 tables.