Thus, it is clearly demonstrated that hydrophilic PEG and higher amount of soft segments contributed significantly to the progress of enzymatic degradation since addition of PEG has been found to turn the copolymers to hydrophilic material . In support of observed surface erosion mechanism, studies reported in , on PBS-based copolymers have reported analogous surface features, including the formation of holes and cracks during enzymatic degradation. These findings are consistent with our SEM observations, where we observed the manifestation of cracks and pores after 20 days of enzymatic degradation. Moreover, Bai et al. reported the surface erosion of PBS where the first signs of enzymatic hydrolysis on polymer films were observed as cracks . These cracks evolved into holes, progressively deepening over prolonged erosion time, and gradually interconnecting with each other. The surface observed in our study after 20 days mirrors the presence of similar cracks and holes, wherein the copolymers with PEG are connected to each other, as illustrated in SEM images. This consistency of our results with other studies, further confirms the degradation mechanism as primarily driven by the surface erosion. Hydrophilic fragments facilitate enhanced water molecule accessibility into the structure when compared to hydrophobic sequences, which subsequently contributes to enhanced biodegradability . Additionally, copolymerization often increases the susceptibility of polyesters to biodegradation by reducing their crystallinity . Thus polymers with lower crystallinity exhibit higher hydrolysis rates as amorphous regions are more susceptible to biodegradation. The analysis of PBS-DLS-PEG degree of crystallinity calculated from DSC data (see segments content modified with PEG (60-40-5 wt.%) showed lower crystallinity, i.e., Xc=26.3% compared to copolymers containing 70-25-5 wt.% of PBS-DLS-PEG segments (Xc=42.2 %), thus indicating higher degradation (10% of mass loss) through the amorphous phase removal. During this process, the hydrophilic amorphous phase of PEG was the first to be degraded. Following this, the amorphous but hydrophobic DLS was degraded, albeit at a slower rate compared to PEG. In the crystalline regions, water diffusion is limited, leading to the selective removal of short segments from the end-chains.