Visualizing the Inner Architecture of Poly(ϵ‐caprolactone)‐Based Biomaterials and Its Impact on Performance Optimization

Abstract

The performance of poly(ϵ-caprolactone) (PCL)-based biomaterials is defined by spatial distributions of PCL's amorphous and crystalline domains. Unfortunately, directly visualizing their inner architectures has been challenging. This study demonstrates, the superior degradation selectivity of Candida antarctica lipase B (CALB) enzyme; when used at low concentrations, it preferentially breaks down the amorphous chains prior to the crystalline chains. Top-down dissection using this enzyme is performed on several PCL-based systems. Self-assembled nanolamellae (e.g., thin films) or hierarchically nanostructured crystalline skeletons (e.g., fibers) are clearly captured. Thus, the spatial distribution of the amorphous compartments can be precisely mapped out, which otherwise cannot be achieved.

A Prerequisite of the Poly(ε‐Caprolactone) Self‐Induced Nanohybrid Shish–Kebab Structure Formation: An Ordered Crystal Lamellae Orientation Morphology of Fibers

“…Figure .) . The figure shows a very random orientation of the crystal lamellae in the fiber of R‐25, while a parallel orientation was observed in A‐25, which is perpendicular to the fiber axis.…”

“…Figure 8.). [7] The figure shows a very random orientation of the crystal lamellae in the fiber of R-25, while a parallel orientation was observed in A-25, which is perpendicular to the fiber axis. However, it seems that the collecting method did not have much effect on the orientation of PCL crystal lamellae in the R-14 and A-14 fibers, both of which showed a parallel orientation.…”

“…However, it seems that the collecting method did not have much effect on the orientation of PCL crystal lamellae in the R‐14 and A‐14 fibers, both of which showed a parallel orientation. A similar result was also reported in a previous study . The reason might be that for R‐25 fibers, the extension of the molecular chains is not as much as that of R‐14 due the lower fraction of solution and much more entanglement of the molecular chains in the solution concentration at 25 wt%, therefore the crystal lamellae show a random orientation in R‐25 fibers.…”

“…A similar result was also reported in a previous study. [7] The reason might be that for R-25 fibers, the extension of the molecular chains is not as much as that of R-14 due the lower fraction of solution and much more entanglement of the molecular chains in the solution concentration at 25 wt%, therefore the crystal lamellae show a random orientation in R-25 fibers. While for A-25 nanofiber, the extra extension force provided by the rotation drum in the electrospinning process further decreases the fiber diameter.…”

Fabrication of Electrospun Polymer Fibers with Nonspherical Cross‐Sections Using a Nanopressing Technique

“…[8][9][10] Recently, Li and co-workers also studied the morphology changes of electrospun poly(ε-caprolactone) fi bers by solvent vapor annealing and selective degradation using Candida antarctica lipase B enzyme. [ 11,12 ] Although different posttreatment techniques have been proved to be effective in controlling the sizes and morphologies of electrospun fi bers, these techniques usually affect the fi bers isotropically. Electrospun polymer The fabrication of electrospun polymer fi bers is demonstrated with anisotropic cross-sections by applying a simple pressing method.…”