Solid Surface Structure Affects Liquid Order at the Polystyrene/SAM Interface

TL;DR

This study investigates how the solid surface structure influences the molecular arrangement of polystyrene at the interface with silanized surfaces, linking microscopic structure to polymer flow properties.

Contribution

It provides detailed molecular-level insights into the PS/silanized surface interface, highlighting the impact of surface structure on polymer conformation and slip behavior.

Findings

Differences in molecular tilt of OTS and DTS are reflected in PS conformation.

Molecular conformation correlates with slip velocity differences.

Interfacial structure influences polymer dynamics.

Abstract

We present a combined x-ray and neutron reflectivity study characterizing the interface between polystyrene (PS) and silanized surfaces. Motivated by the large difference in slip velocity of PS on top of dodecyl-trichlorosilane (DTS) and octadecyl-trichlorosilane (OTS) found in previous studies, these two systems were chosen for the present investigation. The results reveal the molecular conformation of PS on silanized silicon. Differences in the molecular tilt of OTS and DTS are replicated by the adjacent phenyl rings of the PS. We discuss our findings in terms of a potential link between the microscopic interfacial structure and dynamic properties of polymeric liquids at interfaces.