Understanding the Thin Film Confinement Impact on the Glass Transition and Dynamic Fragility of Unentangled Atactic, <i>Cis</i> Poly(Methylene‐1,3‐Cyclohexane)

ABSTRACT Understanding the influences of thin film confinement on supported films, which are reflected in changes of glass transition temperature ( T g ) and dynamic fragility, is important as they can inform the implementation of polymers in nanotechnology. Here, two molecular weights (MWs) of atactic, cis poly(methylene‐1,3‐cyclohexane) (PMCH), 5.5 kDa (PMCH‐5.5) and 12.1 kDa (PMCH‐12.1), were studied to elucidate how their key physical properties are impacted under nanoconfinement. We note both polymers are below the critical MW ( M c ) as confirmed by rheological measurement. Specifically, the MW of unentangled PMCH has a large effect on both the bulk and confinement behaviors of the polymers, where PMCH‐5.5 had a lower T g and was less fragile than PMCH‐12.1. It was also found that decreasing the MW of PMCH could suppress confinement effects. These results not only elucidate the impact of nanoconfinement on the properties of PMCH, compared to other well‐studied polymers including polystyrene, but also can inform their use for emerging applications.