Morphological Characterization of Spherulites in Silk‐Polycaprolactone Mixtures: Implications for Textured Materials

ABSTRACT Incorporation of silk fibroin into polycaprolactone (PCL) matrices introduces significant alterations to the crystalline structure and surface morphology of blended polymeric materials, presenting opportunities for advanced biomaterial design. This study investigates fibroin‐PCL blends prepared either as films via solution casting or solvent‐based extrusion printing. Fibroin dispersed within the PCL matrix was found to modulate crystalline organization, inducing distinct morphological transformations. The structural and morphological changes were comprehensively characterized using wide‐angle X‐ray scattering (WAXS), atomic force microscopy (AFM), optical microscopy, and scanning electron microscopy (SEM). Low fibroin concentrations in the blends (<50% w/w) promoted the formation of ring‐banded PCL spherulites, whereas higher fibroin content (>50% w/w) resulted in the emergence of pits and porous surface topography. Despite the significant morphological changes on the blends’ surface, the type of PCL‐crystallinity remained unchanged, as shown by WAXS. Furthermore, the evaporation rate of the solvent during processing critically influences the texture patterns of the films and the printed grids. By leveraging the interplay between fibroin and PCL in the blended constructs, this work provides insights into the control of surface features in fibroin–PCL systems, with implications for the rational design of biomaterials.