Neutron Reflectivity Study on the Adsorption Layer of Polyethylene Grown on Si Substrate

Area of Science:

• Materials Science
• Polymer Science
• Surface Science

Background:

• Understanding polymer-substrate interfaces is key for advanced materials.
• Polyethylene films are widely used in various applications.
• Previous studies suggested amorphous polymer adsorption layers.

Purpose of the Study:

• To investigate the interfacial structure of polyethylene films on silicon substrates.
• To elucidate the growth mechanism of polyethylene adsorption layers.
• To assess the impact of annealing on interfacial properties.

Main Methods:

• Neutron reflectivity (NR) measurements on deuterated polyethylene (dPE) thin films.
• Utilizing silicon substrates for film deposition.
• Employing hot p-xylene leaching to analyze remaining layers.

Main Results:

• Water accumulation was observed at the polyethylene/silicon interface under ambient conditions.
• Annealing dPE films promoted the growth of a two-layer adsorption structure.
• An inner layer (3.7 nm, bulk density) and an outer layer (several nm, insufficient growth) were identified.

Conclusions:

• The study clarifies polyethylene adsorption layer growth at inorganic interfaces.
• The findings are valuable for enhancing polymer/inorganic filler nanocomposites.
• Crystalline polyolefins' utility in nanocomposites can be improved by understanding interfacial behavior.