Correlating diameter, mechanical and structural properties of poly(L-lactide) fibres from needleless electrospinning
Urundolil Kumaran, V.
Ramakrishna, Shivaprakash N.
Ferguson, Stephen John
Rossi, René Michel
Ehret, Alexander E.
- Journal Article
The development and application of nanofibres requires a thorough understanding of the mechanical properties on a single fibre level including respective modelling tools for precise fibre analysis. This work presents a mechanical and morphological study of poly-l-lactide nanofibres developed by needleless electrospinning. Atomic force microscopy (AFM) and micromechanical testing (MMT) were used to characterise the mechanical response of the fibres within a diameter range of 200–1400 nm. Young’s moduli E determined by means of both methods are in sound agreement and show a strong increase for thinner fibres below a critical diameter of 800 nm. Similar increasing trends for yield stress and hardening modulus were measured by MMT. Finite element analyses show that the common practice of modelling three-point bending tests with either double supported or double clamped beams is prone to significant bias in the determined elastic properties, and that the latter is a good approximation only for small diameters. Therefore, an analytical formula based on intermediate boundary conditions is proposed that is valid for the whole tested range of fibre diameters, providing a consistently low error in axial Young’s modulus below 10%. The analysis of fibre morphology by differential scanning calorimetry and 2D wide-angle X-ray scattering revealed increasing polymer chains alignment in the amorphous phase and higher crystallinity of fibres for decreasing diameter. The combination of these observations with the mechanical characterisation suggests a linear relationship between Young’s modulus and both crystallinity and molecular orientation in the amorphous phase. Show more
Journal / seriesActa Biomaterialia
Pages / Article No.
SubjectNeedleless electrospinning; Mechanical properties; Inverse ﬁnite element simulations; Boundary conditions; Internal ﬁbre structure
Organisational unit03389 - Spencer, Nicholas / Spencer, Nicholas
03605 - Mazza, Edoardo / Mazza, Edoardo
03915 - Ferguson, Stephen / Ferguson, Stephen
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