Recently we have developed a coarse-grained model which exhibits antiplasticization. Antiplasticization occurs when a low molecular weight solvent increases the density and elastic constants of a polymer glass, while decreasing the glass transition temperature; this is in contrast to the more widely-studied behavior of a plasticizer, which decreases the glass transition temperature, density, and elastic constants. In this work, we have studied in detail the effects of antiplasticization on the potential energy landscape in both bulk and thin film geometries. We find that the energy barriers that impede relaxation are reduced upon antiplasticization in the bulk glasses. However, upon confinement, the antiplasticized glass shows little changes in its energy landscape, while the pure polymer glass shows significant confinement effects. This observation agrees well with previous experimental and simulation results, where it was found that confinement had little effect on the glass transition temperature of an antiplasticized melt. In addition, we characterize the response of our glasses to deformations and find that strain can reduce the magnitude of the energy barriers on the potential energy landscape; however, this finding depends on the type of strain applied to the system. Finally, we study the local mechanical properties in our system, and relate these properties to the anomalous boson peak, a ubiquitous, yet poorly understood, feature of glass-forming materials.

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