Influence of Tacticity on the Glass-Transition Dynamics of Poly(methyl methacrylate) (PMMA) under Elevated Pressure and Geometrical Nanoconfinement

The physicochemical properties of polymers can be modified by spatial configuration. Here, dielectric spectroscopy (DS) was employed to investigate the effect tacticity on glass-transition dynamics confined polymer films. We have also carried out relaxation studies at ambient and elevated pressure conditions. High-pressure measurements provide information sensitivity density changes, which helpful better understand confinement effect. For our study, we chosen a glass-forming polymer, poly(methyl methacrylate) (PMMA), with two different tacticities (isotactic syndiotactic) an approximately equal molecular weight. shown that segmental for bulk syndiotactic PMMA is observed higher temperature range compared isotactic PMMA. experimental data analysis has revealed order influences behavior under increased pressure. more sensitive pressure/density changes than Finally, demonstrated significant impact Syndiotactic stronger interaction substrate PMMA, indicated amount irreversibly adsorbed chains. this reason, s-PMMA thin films follows behavior. In contrast, i-PMMA, effects are pronounced, accelerate reduction thickness