Drawing in poly(ϵ-caprolactone) fibers: Tuning mechanics, fiber dimensions and surface-modification density

Uniaxial drawing of melt-coextruded poly(ϵ-caprolactone) (PCL) microfibers was investigated to understand impact on topological, mechanical, and chemical properties of the fibrous scaffolds. Fibers were uniaxially elongated up to 7-fold to observe polymer chain orientation and crystal structure. Crystallinity and orientation of crystal domains were investigated by DSC and X-ray scattering. Polymer physical properties were directly correlated to bulk fiber properties. Furthermore, the drawn fibers were modified photochemically with functionalized benzophenones. The results of these studies allowed for comparison between fiber dimension/surface area, mechanical properties, and photochemical reaction yield for surface modification. As drawing increased, the modulus and tensile strength of the fibers increased as did the surface area of the scaffolds. By contrast, increased drawing led to a decrease in the ability to undergo photochemical reaction at the polymer surface. This fundamental investigation provides a predictive framework to understand how post-processing impacts three critical parameters for coextruded fibrous biomaterial scaffolds.