Surface-induced phase behavior of polymer/nanoparticle blends with attractions

Area of Science:

• Soft Matter Physics
• Materials Science
• Physical Chemistry

Background:

• Athermal nanoparticle-homopolymer blends exhibit phase transitions near hard walls.
• Previous studies used density functional theory (DFT) at constant packing fraction.

Purpose of the Study:

• To investigate the robustness of nanoparticle segregation to a hard wall.
• To explore phase transitions under constant pressure conditions.

Main Methods:

• Density functional theory (DFT) calculations were performed.
• Systems studied included athermal blends with varying nanoparticle densities.
• Effects of nanoparticle-polymer and polymer-wall attractions were simulated.

Main Results:

• The first-order phase transition of nanoparticle monolayer formation at the wall was confirmed under constant pressure.
• Increasing nanoparticle-polymer attractions raised the transition density.
• Strong nanoparticle-polymer attractions suppressed the first-order transition, leading to a continuous layered state.
• Polymer-wall attractions delayed and suppressed the first-order transition but did not induce continuous transitions.

Conclusions:

• The nanoparticle segregation transition is robust and occurs under constant pressure conditions.
• Interactions between components significantly influence the nature and occurrence of the phase transition.
• Continuous layered states can emerge under specific attractive interaction conditions.