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

Abstract

The shish–kebab structure has been extensively applied in many fields; however, the formation mechanism is still an open question. In this study, different electrospun poly(ε‐caprolactone) (PCL) fibers are applied as the shish material in a self‐induced crystallization process, and two different self‐induced crystal structures are obtained. The PCL fibers with an ordered crystalline morphology lead to an induced crystalline structure with the crystal lamellae perpendicular to the fiber axis. However, the PCL fibers with a disordered structure induce a complicated (less ordered) crystalline lamellae morphology. Investigation of the surface crystalline structure reveals that the self‐induced nanohybrid shish–kebab (SINSK) structure follows a lattice matching and epitaxial growth mechanism. The internal crystalline structure of PCL nanofibers plays a dominant role in the formation of the SINSK structure. This study may prove helpful in screening materials for formation of the SINSK structure.

Biomimetic Mineralization of Hierarchical Nanofiber Shish-Kebabs in a Concentrated Apatite-Forming Solution

“…It has been previously demonstrated that for PCL kebabs the kebab size and period increase as incubation time increases. , However, BCP crystal growth could be quite different from PCL homopolymer, and desired crystalline morphology can only be formed when crystallization instead of BCP phase separation dominates the structure formation process. − For PCL- b -PAA BCP kebabs, incubation times ranging from 0.5 to 10 min were tested for their effect on NFSK morphology, as seen in Figure . PCL electrospun nanofibers had an average diameter of 351 ± 177 nm (Figure a).…”

Core–Shell Nanofibers with a Shish-Kebab Structure Simulating Collagen Fibrils for Bone Tissue Engineering

“…The kebabs competed to grow in a limited space, which would cause distortion. Wang et al found that ordered PCL nanofibers formed a regular SK structure, while disordered nanofibers led to a complex crystal layer morphology …”

“…26−28 When nanofibers and the polymer matrix are similar in geometry, such as lattice parameters, orientation, or some crystal plane spacing, polymer chains can form a kebab or coating on the surface of nanofibers. 29,30 Yu et al confirmed that the crystallization behavior of polymers significantly increased the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 cells. 31 Chen et al found that the SK structure improved the mechanical properties of nanofibrous membranes.…”

“…The shish-kebab (SK) structure is a special interface crystal structure in semicrystalline polymers, which consists of straight-chain crystals and folded-chain crystals. Electrospun nanofibers can be used as a straight-chain crystal, which induces the periodic growth of polymers perpendicular to its surface at a certain temperature to form lamellae. − When nanofibers and the polymer matrix are similar in geometry, such as lattice parameters, orientation, or some crystal plane spacing, polymer chains can form a kebab or coating on the surface of nanofibers. , Yu et al confirmed that the crystallization behavior of polymers significantly increased the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 cells . Chen et al found that the SK structure improved the mechanical properties of nanofibrous membranes …”

A review on the processing–morphology–property relationship in biodegradable polymer composites containing carbon nanotubes and nanofibers

“…The shish-kebab crystal morphology was reported for PCL/CNT electrospun nanocomposite systems. [105,106] Arras et al [106] firstly demonstrated the formation of NHSK in electrospun PCL/MWCNT composite. The MWCNT, which is shish in their case, is overgrown by lamellae polymer crystals (kebabs).…”