Role of interfacial correlation in melting of Langmuir-Blodgett films

Abstract

Cadmium arachidate Langmuir-Blodgett (LB) films, exhibiting two different in-plane correlation, namely self-affine and logarithmic, were studied to understand the role of interfacial correlation in the melting process. X-ray specular reflectivity and diffuse scattering measurements were performed on these films at different temperatures starting from room temperature (20°C) upto 110°C. Systematic analysis of specular and transverse diffuse scattering data showed that the average bilayer spacing and the roughness correlation at room temperature is retained for both the films even up to 100°C. Our results suggest that melting of the LB films occurs predominantly through the lateral motion of molecules, irrespective of the type of correlation. Between 100°C and 110°C the film disorders completely leading to the breakdown of the ordered bilayer structure existing up to 100°C.