Nanoparticle Induced Morphology Modulation in Spin Coated PS/PMMA Blend Thin Films.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Polystyrene/poly(methyl methacrylate) (PS/PMMA) immiscible blends are widely used in thin film applications.
• Understanding thin film morphology is crucial for controlling material properties.
• The effect of nanoparticle addition on blend thin film morphology is not fully understood.

Purpose of the Study:

• To investigate the influence of gold nanoparticles (AuNPs) on the as-cast morphology of PS/PMMA thin films.
• To explore the impact of film thickness, composition, and nanoparticle concentration on morphology.
• To understand the role of AuNPs in film stabilization and dewetting.

Main Methods:

• Spin coating of PS/PMMA blend thin films with varying thickness and composition.
• Addition of thiol-capped gold nanoparticles (AuNPs) at different concentrations.
• Characterization of film morphology using X-ray photoelectron spectroscopy and X-ray reflectivity.

Main Results:

• In particle-free films, morphology is largely independent of thickness for PS/PMMA ratios of 3:1 and 1:3, but shows thickness dependence for a 1:1 ratio.
• AuNP addition minimally affects films with a 3:1 PS/PMMA ratio.
• AuNPs significantly influence the morphology of 1:1 and 1:3 PS/PMMA films, particularly at high concentrations (≈10.0%).
• AuNPs migrate to the free surface through the PS phase, stabilizing the film against dewetting.

Conclusions:

• Nanoparticle addition can significantly alter the morphology of PS/PMMA blend thin films.
• The extent of morphological change depends on blend composition and nanoparticle concentration.
• AuNPs play a role in stabilizing thin films against dewetting, with implications for future studies on nanoparticle dynamics.