Structure analysis of a buried interface between organic and porous inorganic layers using spin-contrast-variation neutron reflectivity

This work demonstrates the advantage of spin-contrast-variation neutron reflectivity (NR) for the structure analysis of a buried interface in a bilayer film comprising organic and inorganic layers of acrylic urethane resin and methylated silica (MePDS), derived from methyl-group-substituted perhydropolysilazane. As the proton polarization P-H changed from 0 to +/- 24%, the NR curve of the bilayer film varied significantly. These NR curves were not reproduced using global fitting with a standard bilayer model. The oscillation in the NR curve at P-H = -24% was shifted slightly and non-negligibly from the fitting curve using the best-fit structure parameters for the curve at P-H = 0%. It was found from the shift of the oscillation that the density of the MePDS layer decreased within several nanometres of the interface, but the resin did not permeate the low-density MePDS layer.

Automated summary

This work demonstrates the advantage of spin-contrast-variation neutron reflectivity (NR) in the structure analysis of a buried interface in a bilayer film. The study shows that as the proton polarization changes, the NR curve of the bilayer film varies significantly and cannot be reproduced using a standard bilayer model. By observing the shift in oscillation, it was found that the density of the organic layer decreased near the interface, but the resin did not permeate the low-density inorganic layer.