Altering Glass Transition in Polymer Films through Vibrational Strong Coupling

Vibrational strong coupling (VSC) is emerging as a tool for influencing material properties by harnessing quantum fluctuations. In this study, we demonstrate that VSC can modify the glass transition temperature (<i>T</i>_g), a key parameter describing the thermal behavior of polymeric films, using polyvinyl acetate (PVAc) and polystyrene (PS) as model systems. PVAc and PS films exhibit significant reductions in <i>T</i>_g of 7 and 10 K, respectively, under VSC conditions. Excitingly, the extent of <i>T</i>_g modification depends on the selective coupling of a specific vibrational mode in the polymer. These results suggest that the presence of vibro-polaritonic states in materials modifies structural relaxation, thereby altering their thermal response. Our findings highlight the potential of VSC to modulate intermolecular forces and their macroscopic consequences, such as <i>T</i>_g, an aspect that should be carefully considered in technological applications.