Elucidation of Structural Changes through Drying Process for Polyether Modified Silicone Vesicle Systems by Using Rheo-SANS & NR

Abstract

Polyethyleneglycol 12 mol / polydimethylsiloxane co-polymer (PEG-12 dimethicone) is a type of polyether modified silicone (PEMS), which can form a lamellar liquid crystalline phase, and is widely used in cosmetics. The structural changes of PEG-12 dimethicone caused by water evaporation as well as shear flow were evaluated using simultaneous measurements of rheology and small angle neutron scattering (Rheo-SANS) and neutron reflectometry (NR). In bulk, a reorientation of plate-like lamellar structures were observed and the neutral orientation was the most favorable at high PEG-12 dimethicone concentrations (≥ 36 wt%). However, lamella-to-vesicle transitions were hardly observed. It is also important to understand the static and dynamic adsorption processes of surfactants on a substrate and the structure of the adsorbed dried film, as that are key factors that control function and properties of the formed film. PEG-12 dimethicone turned out to form a bi-layer on a hydrophilized Si-wafer in a similar manner to that in bulk though the structure had a certain level of roughness.

graphical abstract