Stimulus-Responsive Shrinkage in Electrospun Membranes: Fundamentals and Control

Abstract

Shrinkage is observed in many electrospun membranes. The stretched conformation of the macromolecular chains has been proposed as the possible cause. However, so far, our understanding of the fundamentals is still qualitative and cannot provide much help in the shrinkage control. In this paper, based on the crimped fibers after stimulus-induced shrinkage, a clear evidence of buckling, the gradient pre-strain field in the cross-section of the electrospun fibers, which is the result of a gradient solidification field and a tensile force in the fibers during electrospinning, is identified as the underlying mechanism for the stimulus-induced shrinkage. Subsequently, two buckling conditions are derived. Subsequently, a series of experiments are carried out to reveal the influence of four typical processing parameters (namely, the applied voltage, solution concentration, distance between electrodes, and rotation speed of collector), which are highly relevant to the formation of the gradient pre-strain field. It is concluded that there are some different ways to achieve the required shrinkage ratios in two in-plane directions (i.e., the rotational and transverse directions of the roller collector). Some of the combinations of these parameters are more effective at achieving high uniformity than others. Hence, it is possible to optimize the processing parameters to produce high-quality membranes with well-controlled shrinkage in both in-plane directions.

3D Polycaprolactone/Gelatin-Oriented Electrospun Scaffolds Promote Periodontal Regeneration

“…Fang has interpreted this phenomenon figuratively as a kind of straightening effect when the fibers are collected on the roller. 39 We also observed fibers with smaller diameters in the aligned samples, consistent with Eslamian's research. 13 We thought that the decrease in diameter could be attributed to variational viscoelastic properties of the raw electrospun solution according to high rotation speeds.…”

“…Consequently, tight fiber deposition and highly ordered interfiber arrangement could be displayed, as shown intuitively in our SEM images. Fang has interpreted this phenomenon figuratively as a kind of straightening effect when the fibers are collected on the roller . We also observed fibers with smaller diameters in the aligned samples, consistent with Eslamian’s research .…”

Influence of Electrospinning Setup Parameters on Properties of Polymer-Perovskite Nanofibers

“…The maximum shrinkage values are found at 500–750 rpm. This can be explained by the higher stress caused by the improved orientation and straightening of nanofibers [ 58 , 59 , 60 ]. The shrinkage is associated with the stress created in nanofibers during electrospinning.…”

Nanocomposite electrospun fibers of poly(ε-caprolactone)/bioactive glass with shape memory properties

“…The specimens were cut into rectangular strips (gauge length: 8 mm; width: 5 mm, thickness: in the range 0.1–0.2 mm) and were preliminarily subjected to a thermal treatment consisting of heating the specimen at 85 °C, where the samples were allowed to shrink until a constant length was obtained. This treatment was necessary to gain samples with dimensional stability [ 25 , 52 ]. A thermo-mechanical loading-unloading cycle was then applied to assess shape memory properties, consisting in: (i) heating the specimen up to 80 °C, i.e.…”