Nanohybrid Shish-kebab Research Articles

Reprocessible nanohybrid shish-kebab superstructures of poly (lactic acid) crystallites evolving in quiescent melt: Soft epitaxy nucleation in correlation with mechanics

Poly (butylene terephthalate) (PBT) nanofibrils (NFs) were developed in-situ by implementing a rheologically tuned melt spinning process on poly (lactic acid) (PLA)/PBT blends. In the absence of any flow fields, melt crystallization of fabricated PLA/PBT in-situ nanofibrillar composites (NFCs) resulted in orthogonal patterning of PLA nanodomain crystallites around single or double PBT NFs. Geometric confinement (soft epitaxy) was the nucleation mechanism of PLA chains at the interface of isotropic distributed PBT NFs followed by the formation of reprocessible 2D nanohybrid shish-kebab (NHSK) superstructures. By increasing the PBT NFs content and their bundling, a fan-shaped transcrystalline structure was formed due to seeding or epitaxial nucleation on the bundle of PBT NFs owning a less curved interface. The nucleation and growth mechanism of crystallites structures which were influenced by temperature and PBT NF content have been discussed thermodynamically and kinetically by parallel investigations on microscopic observations and X-ray diffraction analysis. The evolution of different crystalline structures in quiescent melt in the forms of spherulites, NHSK, or fan-shaped transcrystallinity induces a local orientation in the isotropic NFCs. Mechanical propertie improvements of NFCs were compared in amorphous and crystalline states with tailored NHSK superstructures.

Stable 3D hierarchical scaffolds by origami approach: Effect of interfacial crosslinking by nanohybrid shish-kebab assemblies

3D highly porous architectures with tailored flexibility along with dimensional stability are currently an emerging area due to a wide range of technological applications. We have highlighted here the importance of mechanical and thermal stability of the building blocks and interfacial bonding for development of such scaffolds. 2D electrospun free-standing nanofibrous mats of polyethylene terephthalate (PET) with different molecular weights were used to study the properties of basic foundation units. The nanohybrid shish-kebab (NHSK) type polycaprolactone (PCL) crosslinked networks were grown between the stacked nanofibrous mat for better bindings among the layers. Carbon nanotubes were further introduced into PET nanofibers as well as in binder envelop layers in order to insight into the properties of thermal and structural stability. The presence of different confined 1D nucleating surface like nanotubes and nanofibers gives us the opportunity to study interpenetrating NHSK lamellae at different length scale. A range of crosslinked scaffold microstructures by origami route were investigated to highlight the importance of process design for fabrication of dimensionally robust porous geometries.

External flow-induced highly oriented and dense nanohybrid shish-kebabs: A strategy for achieving high performance in poly (lactic acid) composites

In situ nanofibrillation is regarded as an efficient and cost-effective technique to enhance polymeric materials' mechanical properties and crystallization behavior. Recently, a combination technique applying an intense external flow field and a polytetrafluoroethylene (PTFE) phase were shown to have the potential to enhance polymer properties. Using this approach, poly(lactic acid) (PLA)-based in situ nanofibrillar composites containing 1, 3, and 5 wt% PTFE were successfully prepared by a loop oscillatory push-pull molding (LOPPM) method in this study. The LOPPM approach applied a continuous intense dynamic oscillatory shear flow field during processing and in situ generation of well-aligned PTFE nanofibrils. Scanning electron microscopy (SEM) results showed that the in situ generation of nanofibrils served as the shish to induce the formation of highly oriented and dense nanohybrid shish-kebab superstructures in the composites. These superstructures were confirmed by two-dimensional (2D)-small-angle X-ray scattering (2D-SAXS) and 2D-wide-angle X-ray scattering (2D-WAXS) techniques. Benefiting from oriented and dense nanohybrid shish-kebab superstructures, the in situ nanofibrillar PLA/PTFE composites containing 3 wt% PTFE exhibited superior mechanical properties than pure PLA; the tensile strength, Young's modulus, and impact strength were 82.5 MPa, 4781.4 MPa, and 11.3 kJ/m2, respectively. Moreover, dynamic mechanical performance was significant improved as well. Overall, this work demonstrates a novel combination processing technique for the cost-effective, eco-friendly, and efficient design of PLA-based in situ nanofibrillar composites for engineering applications.

Superior mechanical performance of in-situ nanofibrillar HDPE/PTFE composites with highly oriented and compacted nanohybrid shish-kebab structure

Hierarchical structures dominate the mechanical performance of polymer materials. In this work, in-situ nanofibrillar high-density polyethylene/polytetrafluoroethylene (HDPE/PTFE) composites with highly ordered and compacted nanohybrid shish-kebab (NHSK) structure were successfully fabricated using a self-made loop oscillating push-pull molding (LOPPM) equipment. Through the synergistic effect of the oscillatory push-pull shear flow field and PTFE, in-situ nanofibrillar HDPE/PTFE composites with superior strength and toughness were obtained. With the addition of 5 wt% PTFE in HDPE, the tensile strength, Young's modulus and impact strength of in-situ nanofibrillar composites reached 133.4 MPa, 4388.1 MPa and 69.1 kJ/m2, which was about 6.0, 6.0 and 3.1 times higher than that of neat HDPE, respectively. These superior improvements in mechanical performance were attributed to the oriented and compacted NHSK structure. Additionally, two-dimensional small-angle X-ray scattering (2D-SAXS), two-dimensional wide-angle X-ray scattering (2D-WAXS) and differential scanning calorimetry (DSC) results confirmed the synergistic enhancement effect of the flow field and PTFE on the degree of orientation, lamellar thickness, average length of shish and crystallization properties. Overall, it is believed that this proposed strategy can be extended to a wide range for the preparation of polymer materials with superior mechanical properties.

Rheological rationalization of in situ nanofibrillar structure development: Tailoring of nanohybrid shish-kebab superstructures of poly (lactic acid) crystalline phase

The key rheological parameters for in situ development of poly (butylene terephthalate) nanofibrils (PBT NFs) in poly (lactic acid) (PLA) matrix using a tuned melt spinning process were studied. Observation of ellipsoidal PBT domains oriented along a short die was attributed to a low interfacial tension between the blend constituents and fulfilled melt rheological criteria for fibrillation in a simple shear flow. The stability of the deformed droplets under the shear and elongational flows was studied by comparing the droplet breakup time and residence time in each flow field. It was demonstrated that the deformed droplets (ellipses) with an increased robust interface underwent coalescence through pinch-off in the subsequent elongational flow field, and transformed to the nanofibrils with an average diameter comparable to the gyration radius (Rg) of PLA chains. In the fabricated isotropic in situ nanofibrillar composites (NFCs), a random orientation of 2D nanohybrid shish-kebab (NHSK) superstructure was observed as a result of the orthogonal pattern of melt crystallized PLA nanodomains on the PBT NFs surface. The NHSK superstructure established in quiescent bulk through mechanism of geometric confinement (soft epitaxy) enabled us to tailor the crystalline morphology via annealing temperature. In a constant nanofibril content, increasing the isothermal temperature (Tiso) up to 114 °C led to an increase in the kebabs length and interlocking of the adjacent superstructures. A transition to spherulitic crystal morphology was observed due to further temperature increase (Tiso≥117 °C). The observed transition indicated that at higher Tiso, the fewer raw nuclei, which were initiated by soft epitaxy mechanism of PLA chain segments on the PBT NFs at the early stage of nucleation, could conduct self-nucleation and 3D lateral growth. The Avrami model was found to be applicable for interpreting variations of crystallite morphology, crystallization rate, and nucleation mechanisms with PBT NF content and isotherm temperature.

Crystallisation behaviour of composites of HDPE and MWCNTs: The effect of nanotube dispersion, orientation and polymer deformation

Multi-walled carbon nanotubes (MWCNTs) were readily dispersed and distributed in the high density polyethylene (HDPE) matrix and a very low (<0.3 wt%, 0.17 vol%) rheological percolation threshold obtained. The polymer is seen to coat the MWCNTs, which act as a nucleating agent and induce an oriented nanohybrid shish-kebab (NHSK) crystalline structure, in part an artefact of the injection moulding process. The elastic modulus and yield stress of HDPE increased on addition of MWCNTs, but the polymer strain at break increased sharply below percolation before decreasing again above percolation. Addition of MWCNTs, above the percolation threshold, hindered orientation of the polymer chains such that failure occurred before necking during tensile testing, the inclusion of MWCNTs altered the uniaxial deformation behaviour of HDPE. SAXS/WAXS studies on samples post uniaxial drawing revealed that the HDPE and composites of HDPE and MWCNTs developed a highly oriented sheared herringbone lamellar structure. The drawing process also caused surface cavitation and voiding in the composites.

Uniaxial tensile deformation of microinjection molded PCL/SWCNTs nanocomposites: Effect of interfacial “soft epitaxy” on the structural evolution as studied by synchrotron SAXS and WAXD techniques

In this study, the uniaxial tensile deformation of microinjection molded poly(ε-caprolactone)/single walled carbon nanotubes (PCL/SWCNTs) nanocomposites was explored by in-situ synchrotron SAXS and WAXD methods with simultaneous stress-strain curves, and the effect of interfacial “soft epitaxy” on the structural evolution of the nanocomposites was examined as a function of SWCNTs’ content by coupling with the ex-situ DSC and density measurements. The combination of SAXS and WAXD data implies that oriented nanohybrid shish-kebab (NHSK) structures that consist of rigid SWCNTs shish surrounded by “soft epitaxy” PCL lamellar crystals were formed in injection molded PCL/SWCNTs. Similar to PCL, PCL/SWCNTs nanocomposites again present the representative stress-strain behavior of semicrystalline polymers, i.e., the structural evolution upon stretching essentially follows the same melting-recrystallization mechanism, but the evolution proceeding of PCL/SWCNTs nanocomposites is obviously depressed with the incorporation and increase of SWCNTs. This should be attributed to that the “soft epitaxy” of PCL crystallized at the surfaces of rigid SWCNTs induces the formation of the more stable NHSK crystals that are difficult to be destroyed or melted upon uniaxial deformation and therefore act as the physical crosslinks to improve the mechanical properties of the PCL/SWCNTs nanocomposites. The present findings can improve the understanding of structural evolution behavior during the tensile deformation of PCL/SWCNTs nanocomposites, and especially enhance dramatically our understanding about the underlying reinforcing mechanism of the “soft epitaxy” of semicrystalline polymers at the surfaces of CNTs on the mechanical properties of polymer/CNTs nanocomposites.

The mobility of PEG chains versus micellar stability towards the formation of PE‐b‐PEG nanohybrid shish‐kebab on carbon nanotubes

A comparative study of the effect of copolymer composition on nanohybrid shish‐kebab (NHSK) architecture on carbon nanotubes (CNTs) is presented. A semi‐crystalline amphiphilic di‐block copolymer, polyethylene‐b‐polyethylene glycol (PE‐b‐PEG) was used in this study. Copolymer composition was varied on the basis of the molecular weight of individual copolymers and the ratio between PE and PEG. NHSK structure was characterized using a combination of scanning and transmission electron microscopy. The mobility of PEG, which is determined by its chain length was found to have a significant impact on the periodic decoration of the copolymer on CNTs. With higher chain length or molecular weight, PEG chains provided better stability to micelles formed by the copolymer. Further, PEG assisted micellar stability to create a foundation for PE chains to interact and orient along the tube axis of CNTs as a function of the copolymer composition. It was found that the stability of NHSK architecture can also be changed over time at the same crystallization temperature. This work offers novel and fundamental insights towards the mobility of PEG in the copolymer and its disk‐shaped crystal's formation and micellar stability during crystallization with CNTs. This study provides a better understanding of a mechanically tunable NHSK where the architecture of copolymer crystals can be modified by adjusting the molecular weight of PEG.

The Effect of Grafting Density on the Crystallization Behaviors of Polymer Chains Grafted onto One-Dimensional Nanorod

The crystallization behaviors of five polymer chain systems grafted on a nanorod and the corresponding effect of grafting density were investigated by dynamic Monte Carlo simulations. The segment density near the interfacial regions, the number of crystallites, and the mean square radius of gyration (&lt;Rg2&gt;) increase with increasing grafting density, which are beneficial to the enhancement of crystallizability. Meanwhile, the crystalline morphology is greatly influenced by grafting density and polymer-nanorod interaction. For the grafted system with 52 chains, a nanohybrid shish-kebab (NHSK) structure is formed, when the polymer-nanorod interaction (Eb/Ec) is -0.4. For the system with 128 chains, a NHSK structure is formed, when Eb/Ec is -1.0. For the system with 252 chains, NHSK structure cannot be formed. The findings in this work can supply important theoretical reference for the design, preparation, and application of polymer nanocomposites.

Epitaxial orientation and localized microphase separation prior to formation of nanohybrid shish-kebabs induced by one-dimensional nanofiller in miscible diblock copolymers with selective interaction

The incorporation of nanofillers can result in the changes of crystallization behaviors of block copolymers. We performed dynamic Monte Carlo simulations to investigate the crystallization behaviors induced by one-dimensional nanofiller in miscible diblock copolymers with selective interaction. The addition of nanofiller significantly improves the crystallizability of block copolymers by inducing heterogeneous nucleation on its surface. In addition, the presence of nanofiller leads to the formation of a novel nanohybrid epitaxial brush structure, which consists of a central nanofiller and surrounding “bristles” formed by lamellar crystals of crystallizable blocks with random coils of non-crystallizable blocks. During the formation of this hierarchical structure, the orientation of local crystallizable segments along the long axis of the nanofiller, as well as the local microphase separation between crystallizable and non-crystallizable blocks, both occur prior to crystallization.

Formation of stretched fibrils and nanohybrid shish-kebabs in isotactic polypropylene-based nanocomposites by application of a dynamic oscillatory shear

The hierarchical structures from micro- to nano-scale in polymeric materials can dramatically affect their physical properties. Controlling the formation of hierarchical structures in polymers through processing remains a challenge. We present here a green and convenient polymer processing approach to prepare isotactic polypropylene (iPP)/polytetrafluoroethylene (PTFE) nanocomposites with hierarchical superstructures via recently developed loop oscillating push-pull molding (LOPPM) method. By taking full advantage of intense oscillatory shear, the in situ generated PTFE fibrils are refined into nanoscale and well aligned, serving as the central shish to induce the formation of nanohybrid shish-kebab (NHSK) superstructure with iPP crystalline lamellae (kebabs). The structure evolution of NHSK superstructures was further examined using molecular dynamics simulations. The stretched fibrils can promote the kebabs growing into large domains with a more compact and ordered molecular chain configuration, compared to that in systems without fibrils or with flexible fibrils. The well-aligned fibrils and NHSK superstructure play a crucial role in enhancing properties. The prepared iPP/PTFE nanocomposites containing 3 wt% PTFE achieved 197.9% and 36.0% improvement in impact and flexural strength, respectively, as compared with the conventional injection-molded composites. Meanwhile, the LOPPM iPP/PTFE nanocomposites exhibits excellent resistance to thermal deformation under harsh environment (over 150 °C) while fabricates a hydrophobic surface. These findings provide a facile strategy to produce high-performance polymers from judiciously controlled sample preparations.

Fabrication of Dielectrically Sensitive Carbon Nanotube/Polyethylene Nanohybrid Shish-Kebab Structure for Potential Tissue Engineering Applications

Carbon nanotube (CNT)/polymer nanohybrid shish-kebab (NHSK) structure is a unique approach to functionalize CNTs and mimic the hierarchical architecture of native collagen fibrils in the extracellular matrix (ECM), owing to their favorable geometric similarity. This study thus aimed at combining the unique NHSK architecture of CNTs with their favorable dielectric properties to fabricate a collagen-like, dielectrically sensitive and biocompatible material. The NHSK structure was fabricated with CNTs and polyethylene (PE) by means of a solution crystallization technique. Configuration of PE in terms of molecular weight and structure was found to be one of the important factors that determined the morphology of the NHSK. Moreover, the material was exposed to dielectrophoresis (DEP) to guide the deposition of CNT/PE NHSK into the directional pattern. The PE-decorated CNTs exhibited enhanced dielectrophoretic sensitivity and controllable structural alignment, while the neat CNTs did not. Human osteoblast-like MG-63 cells were cultured on the scaffolds to examine their biocompatibility and results indicated that the nanotopography of the kebab crystals on the CNTs facilitated cell adhesion and proliferation while the DEP-patterned NHSK structure further boosted cell attachment and viability, thus suggesting that the CNT/polymer nanohybrid shish kebab structure has potential applications in tissue engineering.

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

AbstractThe 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.

Periodic Functionalization of Graphene‐Layered Alumina Nanofibers with Aromatic Thermosetting Copolyester via Epitaxial Step‐Growth Polymerization

AbstractIn situ epitaxial step‐growth polymerization driven interfacial functionalization of aromatic thermosetting copolyester (ATSP) with multilayered graphene wrapped alumina nanofiber surface is reported. During a thermal condensation polymerization, ATSP dip‐coated fiber strands develop a nanohybrid shish–kebab structure with periodically assembled and off‐surface grown micrometer‐scale lamella ATSP domains. A mechanism combining the Plateau–Rayleigh instability, the Marangoni effect, and the epitaxial growth phenomena is proposed to elucidate controlling parameters in the process. X‐ray diffraction measurements clearly demonstrate the formation of a mesomorphic lamella phase not present within either the neat ATSP or pristine fiber samples. Results of solid‐state nuclear magnetic resonance and thermogravimetric analysis reveal the development of an interfacial coupling between the graphene‐coated ceramic nanofibers and the ATSP matrix.

Controllability of Polymer Crystal Orientation Using Heterogeneous Nucleation of Deformed Polymer Loops Grafted on Two-Dimensional Nanofiller.

Nowadays, it is a research hotspot to realize the controllability of polymer crystal structure in polymer nanocomposites. However, polymer crystals induced by two-dimensional filler always exhibit random orientation, which somewhat limit the improvement of physical properties of polymer materials. In the current paper, dynamic Monte Carlo simulations were performed to explore the methods preparing crystals with uniform orientation. Heterogeneous nucleation of deformed polymer loops grafted on two-dimensional filler can induce the appearance of a special nanohybrid shish-kebab (NHSK) structure, in which the two-dimensional filler acts as "shish" and induces the formation of crystals with uniform orientation. The grafted deformed chains are first heterogeneously nucleated on filler surface, and then free chains participate in crystallization, resulting in the formation of the NHSK structure. The NHSK structure can only be formed in the systems with high interfacial interactions at high temperatures or moderate interfacial interactions at moderate temperatures or low interfacial interactions at low temperatures. The method proposed here can be used to achieve the controllability of polymer crystal orientation in experiments.

Nanohybrid shish-kebab supramolecular structure of single-walled carbon nanotubes/N,N′-dioctyl perylene tetracarboxylic diimide

In the present work, carbon nanotubes (CNTs)-induced solution crystallization of N, N′-dioctyl perylene tetracarboxylic diimide (PTCDI-C8) in o-dichlorobenzene was studied. It is found that the nanohybrid shish-kebab (NHSK) supramolecular structure, wherein the single-walled carbon nanotubes (SWCNTs) serve as the shish and PTCDI-C8 crystals are the kebabs, with regular arrangement of the kebabs can be formed. UV–vis, photoluminescence spectroscopy and XPS studies reveal that there exist strong π-π interaction between PTCDI-C8 and SWCNTs, and some PTCDI-C8 molecules are already adsorbed on SWCNTs surface prior to crystallization. This is the first example of NHSK structure formed by CNTs and organic small molecules. Nevertheless, multi-walled carbon nanotubes (MWCNTs) cannot induce PTCDI-C8 to form NHSK structure under the same conditions. This indicates that geometric confinement may be the predominant factor affecting the orientation of the pre-adsorbed PTCDI-C8 molecules and epitaxial growth of the crystals.

The formation of a nanohybrid shish-kebab (NHSK) structure in melt-processed composites of poly(ethylene terephthalate) (PET) and multi-walled carbon nanotubes (MWCNTs)

The combination of synchrotron Small- and Wide-Angle X-ray scattering (SAXS/WAXS), and thermal analysis was used to follow the evolution of crystalline morphology and crystallization kinetics in a series of melt-processed composites of poly(ethylene terephthalate) (PET) and multiwall carbon nanotubes (MWCNT). The as-extruded PET-MWCNT composites underwent both hot and cold isothermal crystallizations where a final oriented nanohybrid shish-kebab (NHSK) crystalline structure was observed. An oriented NHSK structure was seen to persist even after melting and recrystallization of the composites. From the scattering data, we propose a model whereby the oriented MWCNTs act as heterogeneous nucleation surfaces (shish) and the polymer chains wrap around them and the crystallites (kebabs) grow epitaxially outwards during crystallization. However, depending on crystallization temperature, unoriented crystallites also grow in the polymer matrix, resulting in a combination of a NHSK and lamellar morphology. In contrast, the neat PET homopolymer showed the sporadic nucleation of a classic unoriented lamellar structure under the same isothermal crystallization conditions. These results provide a valuable insight into the distinctive modification of the crystalline morphology of melt-processed polymer-MWCNT composites prior to any secondary processing, having a significant impact on the use of MWCNTs as fillers in the processing and modification of the physical and mechanical properties of engineering polymers.

Nanocellulose-PE-b-PEG copolymer nanohybrid shish-kebab structure via interfacial crystallization

We report a novel nanohybrid shish-kebab (NHSK) architecture of cellulose nanofibers (CNFs) and a block copolymer, (polyethylene-b-polyethylene glycol) (PE-b-PEG). Cellulose microfibers were ultrasonically dispersed to generate cellulose nanofibers in the size range of 50±10nm in diameter, while the block copolymer was crystallized using a solution crystallization approach to prepare NHSK. This unique approach allows the flocculated NHSK product to transfer quickly from toluene to ethanol, in order to shorten the preparation time. Morphological analysis reveals, for the first time, that nanocellulose can be used to induce crystallization of a block copolymer to generate NHSK and trans-crystalline structure. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results reveals the crystal morphology and crystallinity changes by virtue of crystallization. The ordered periodic growth and alignment of polymer crystals is recognized as the virtue of molecular origin of extended polymer chains. The proposed hypothesis affords elucidation of NHSK architecture and promotes the designing of novel nanohybrids with controllable functionality.

Confirmation of a nanohybrid shish‐kebab (NHSK) structure in composites of PET and MWCNTs

ABSTRACTHere, the confirmation of an oriented nanohybrid shish‐kebab (NHSK) crystalline structure in a series of composites of poly(ethylene terephthalate) (PET) and multiwall carbon nanotubes (MWCNTs) is reported. The combined use of small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) and thermal analysis has been used to investigate the morphology development in PET‐MWCNT nanocomposites under hot isothermal crystallization conditions. The MWCNTs act as both heterogeneous nucleating agents and surfaces (oriented shish structures) for the epitaxial growth of PET crystallites (kebabs) giving an oriented crystalline morphology. In contrast, the PET homopolymer does not show any residual oriented crystalline morphology during isothermal crystallization but gave a sporadic nucleation of a classic unoriented lamellar structure with slower crystallization kinetics. The results provide a valuable insight into the role of MWCNTs as nanoparticulate fillers in the morphology development and subsequent modification of physical properties in engineering polymers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 132–137

In Situ Formation of Nanohybrid Shish-Kebabs during Electrospinning for the Creation of Hierarchical Shish-Kebab Structures

We successfully tested the hypothesis that the nanohybrid shish-kebab (NHSK) structure, i.e., polymer kebabs on a CNT shish, can be created in situ during electrospinning. In addition, the resulting nanofibers containing the NHSKs were used to create a hierarchical structure by introducing a second level of shish-kebabs: the nanofiber shish-kebab (NFSK), i.e., polymer kebabs on the nanofiber shish. A multiwalled CNT/poly(e-caprolactone) (MWCNT)/(PCL) solution was electrospun to form nanofibers of O ≈ 100 nm. The MWCNTs aligned in fiber direction within the MWCNT/PCL nanofibers. The first time creation of the NHSK during electrospinning was confirmed by bright field diffraction contrast in the transmission electron microscope. The NFSK was created by incubating the NHSK containing nanofibers in a supersaturated PCL solution. A simple model explaining the in situ NHSK formation is presented. The hierarchical structure based on the shish-kebab morphology is proposed as a high-performing building block in fut...