Abstract
Native biological tissues are viscoelastic materials that undergo time-dependent loading in vivo. It is therefore crucial to ensure that biomedical materials have a suitable viscoelastic response for a given application. In this study, the viscoelastic properties of electrospun poly(vinyl alcohol) are investigated using tensile load relaxation testing. A five-parameter generalised Maxwell constitutive model is found to characterise the experimental response. The effect of polymer concentration and electrospinning voltage on model parameters is investigated in detail. The stiffness coefficients for the relaxation process appear to be dependent on the electrospinning conditions used whereas the time constants remain relatively unchanged. It is also observed that the stiffness parameters are linearly correlated with the equilibrium modulus, indicating that a single underlying material property dictates the relaxation moduli. Lastly, it is found that the viscoelastic model parameters are not predicted by the fibre diameter. These results provide an important understanding in designing electrospun mats with desired time-dependent properties.
Highlights
Ensuring the mechanical integrity of biomedical materials is critical for their success in applications such as tissue engineering (Mauck et al, 2009), wound healing (Zhong et al, 2010) and drug delivery (Sill and von Recum, 2008)
Biomedical materials are required to mimic the mechanical properties of native biological tissues e.g. for use as tissue engineering scaffolds (Mauck et al, 2009; Sill and von Recum, 2008)
The applied voltage does not appear to have a consistent effect on the average fibre diameter whereas increasing solution concentration leads to an overall increase in the fibre size, consistent with previous studies (Supaphol and Chuangchote, 2008)
Summary
Ensuring the mechanical integrity of biomedical materials is critical for their success in applications such as tissue engineering (Mauck et al, 2009), wound healing (Zhong et al, 2010) and drug delivery (Sill and von Recum, 2008). Biomedical materials are required to mimic the mechanical properties of native biological tissues e.g. for use as tissue engineering scaffolds (Mauck et al, 2009; Sill and von Recum, 2008). Electrospinning provides a relatively simple, cost effective and versatile technique to create non-woven fibrous materials with fibre diameters in the nanoand micrometer range, making it suitable to mimic the structure of native extracellular matrix (Sill and von Recum, 2008). While there has been some focus on the effect of these processing parameters on the resulting Young's modulus and strength of the samples (Huang et al, 2004; Lee and Deng, 2011; Butcher et al, 2017), their influence on the viscoelastic response remains to be investigated thoroughly
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