For both i Pr and Et-substituted materials, the lamellar thickness increased as the BSE loading decreased (Figure , Table ). Notably, however, the nature of the Si substituents also affected the lamellar thickness; L ranged from 124-133 Å for i Pr-based samples and 133-145 Å for Et. This observation is consistent with the bulkier BSE functional groups being expelled from the crystalline HDPE-like regions (Figure ). Altogether, these results demonstrate that both the BSE loading and Si substituents of BSEs can be leveraged to tune and potentially optimize the crystallinity of PE mimics for future applications.