Incommensurate modulation in phase separating binary paraffin mixtures

Small-angle neutron and X-ray scattering (SANS and SAXS) has been measured on C28–C36 mixtures quenched from the melt for compositions varying from 15.6:1 to 1:5. Satellite peaks are observed in the SAXS whose offset in Q (where Q is the scattering vector), relative to Bragg diffraction peaks associated with the average lamellar structure, are composition dependent. The offset is close to the position of the most intense peak observed in the SANS. A model for the phase separated structure is suggested based on correlated positional and substitutional disorder.