Effect of fiber diameter on tensile properties of electrospun poly(ɛ-caprolactone)

Wong, Shing Chung Josh; Baji, Avinash; Leng, Siwei

doi:10.1016/j.polymer.2008.08.022

Cited by 478 publications

(351 citation statements)

References 23 publications

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“…2 of 8 Electrospinning is a widely accepted technique used to prepare polymer nanofibers, where ultrafine fibers in nanoscale can be collected after an emission of the polymer solution is ejected in an electrical field with high voltage [25,26].…”

Section: Introductionmentioning

confidence: 99%

Properties of Electrospun Nanofibers of Multi-Block Copolymers of [Poly-ε-caprolactone-b-poly(tetrahydrofuran-co-ε-caprolactone)]m Synthesized by Janus Polymerization

Shah

Yang

et al. 2017

Polymers

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Abstract:Novel biodegradable multiblock copolymers of [PCL-b-P(THF-co-CL)] m with PCL fractions of 53.3 and 88.4 wt % were prepared by Janus polymerization of ε-caprolactone (CL) and tetrahydrofuran (THF). Their electrospun mats were obtained with optimized parameters containing bead-free nanofibers whose diameters were between 290 and 520 nm. The mechanical properties of the nanofiber scaffolds were measured showing the tensile strength and strain at break of 8-10 MPa and 123-161%, respectively. Annealing improved their mechanical properties and their tensile strength and strain at break of the samples increased to 10-13 MPa and 267-338%, respectively. Due to the porous structure and crystallization in nanoscale confinement, the mechanical properties of the nanofiber scaffolds appeared as plastics, rather than as the elastomers observed in bulk thermal-molded film.

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Section: Introductionmentioning

confidence: 99%

Properties of Electrospun Nanofibers of Multi-Block Copolymers of [Poly-ε-caprolactone-b-poly(tetrahydrofuran-co-ε-caprolactone)]m Synthesized by Janus Polymerization

Shah

Yang

et al. 2017

Polymers

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“…In one study of PCL nanofibers, crystallinity and molecular orientation were found to increase with decreasing fiber diameter, based on wide-angle X-ray scattering experiments and draw ratio calculations, which was correlated in turn with the increase in stiffness of PCL nanofibers with decreasing radius. 12 In contrast, Arinstein et al reported that crystallinity and orientation in nylon-6,6 nanofibers showed only a modest, monotonic increase 16 that could not be correlated with the dramatic increase in Young's modulus observed with decreasing fiber diameter; the authors concluded that confinement on a supramolecular length scale must be responsible for this increase. 16 In the case of amorphous PS fibers in the range 410 nm<d < 4 μm, the increase in shear elastic modulus was attributed to molecular chain alignment arising from the extensional flow of the electrospinning process itself; 17 as mentioned earlier, our simulated nanofibers do not exhibit any significant molecular level orientation.…”

Section: Resultsmentioning

confidence: 94%

“…11 Recently, Wong et al reported an abrupt increase in tensile strength and stiffness of these PCL fibers below fiber diameter of 1.4 μm and attributed this to improved crystallinity and molecular orientation in fibers of smaller diameter. 12 Young's moduli of electrospun nylon-6 nanofibers were found to increase from 20 to 80 GPa as the fiber diameter decreased from 120 to 70 nm. 13 In separate tensile studies on electrospun nylon-6,6 nanofibers, E was reported to increase 3-fold for fibers with diameters <500 nm.…”

Section: Introductionmentioning

confidence: 93%

Mechanical Properties of Glassy Polyethylene Nanofibers via Molecular Dynamics Simulations

2009

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The extent to which the intrinsic mechanical properties of polymer fibers depend on physical size has been a matter of dispute that is relevant to most nanofiber applications. Here, we report the elastic and plastic properties determined from molecular dynamics simulations of amorphous, glassy polymer nanofibers with diameter ranging from 3.7 to 17.7 nm. We find that, for a given temperature, the Young's elastic modulus E decreases with fiber radius and can be as much as 52% lower than that of the corresponding bulk material. Poisson's ratio ν of the polymer comprising these nanofibers was found to decrease from a value of 0.3 to 0.1 with decreasing fiber radius. Our findings also indicate that a small but finite stress exists on the simulated nanofibers prior to elongation, attributable to surface tension. When strained uniaxially up to a tensile strain of ε = 0.2 over the range of strain rates and temperatures considered, the nanofibers exhibit a yield stress σ y between 40 and 72 MPa, which is not strongly dependent on fiber radius; this yield stress is approximately half that of the same polyethylene simulated in the amorphous bulk.

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“…25,26 For all the above examples, the portion of ''surface material'' is comparable with the bulk, due to extremely small object size, therefore, the ansatz claiming ''nano-object ¼ bulk þ surface'' seems relevant for such systems from a physical point of view. However, in certain experimental systems, 27,28 the size-dependent behavior of nanofibers bearing considerably higher transversal size ($500 nm) refute the size-dependence ansatz and require additional expressions to explain their behavior.…”

mentioning

confidence: 99%

Electrospun polymer nanofibers: Mechanical and thermodynamic perspectives

Arinstein

Zussman

2011

J Polym Sci B Polym Phys

138

103

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This article reviews and discusses some open problems concerning polymer materials of reduced sizes and dimensions. Such objects exhibit exceptional physical properties when compared with their macroscopic counterparts. More specifically, abrupt increases in polymer nanofiber elastic modulus have been observed when diameters drop below a certain value. In addition, temperature dependence of elastic modulus is highly influenced by fiber diameter. Mechanical (macroscopic) analyses have failed to provide satisfactory explanations for the mechanisms ruling such features, calling for detailed microscopic examination of the systems in question. A hypothesis bridging the current knowledge gaps is presented. The key element of this hypothesis is based on confinement of the supermolecular microstructure of polymer nanofibers and its dominant role in the deformation process. This suggestion challenges the commonly held view suggesting that surface effects are the most significant parameters impacting mechanical and thermodynamic nanofiber behaviors. The review will focus on the mechanical and thermodynamic properties of electrospun polymer nanofibers, selected as representatives of nanoscale polymer objects.

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Effect of fiber diameter on tensile properties of electrospun poly(ɛ-caprolactone)

Cited by 478 publications

References 23 publications

Properties of Electrospun Nanofibers of Multi-Block Copolymers of [Poly-ε-caprolactone-b-poly(tetrahydrofuran-co-ε-caprolactone)]m Synthesized by Janus Polymerization

Properties of Electrospun Nanofibers of Multi-Block Copolymers of [Poly-ε-caprolactone-b-poly(tetrahydrofuran-co-ε-caprolactone)]m Synthesized by Janus Polymerization

Mechanical Properties of Glassy Polyethylene Nanofibers via Molecular Dynamics Simulations

Electrospun polymer nanofibers: Mechanical and thermodynamic perspectives

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