Creation of a nanovascular network by electrospun sacrificial nanofibers for self-healing applications and its effect on the flexural properties of the bulk material

Abstract

Composites, increasingly significant due to their excellent properties, are prone to failure over time. Self-healing materials are being developed to extend their lifetime. Despite continuous progress, the effect of introducing such healing feature on the mechanical properties of the neat material is mainly overlooked. Therefore, we created a nanocomposite and a nanovascular network by pullulan sacrificial nanofibers, and analysed the flexural properties in comparison to the neat matrix. A parameter analysis of the electrospinning process allowed production of tailored pullulan nanofibers. Their introduction showed no effect on the strength and modulus of the epoxy matrix. On removal of the pullulan nanofibers, the properties of the resultant nanovascularized epoxy were somewhat reduced relative to the neat epoxy depending on volume fraction and diameter of the nanochannels. Interestingly, the decrease of mechanical properties of the nanovascular epoxy is lower than by introducing microcapsules, M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTand opens potential for a more appropriate introduction of self-healing systems in polymeric matrices.

Pullulan for Advanced Sustainable Body- and Skin-Contact Applications

“…The concentration of the polymer solution-used as the main parameter to control the fiber diameter-is critical and needs to be controlled in order to obtain spun fibers, and also because it modulates viscosity and surface tension of the final solution. Regarding PUL manufacturing, it has already been electrospun with success from an aqueous solution, and parameter mapping including environmental parameters such as humidity and temperature allows for reproducible electrospun mats with tuned fiber diameters [67]. Sun et al [68] obtained pullulan nanofibers with a diameter of 100-700 nm using redistilled water as the solvent through electrospinning technology.…”

Fabrication Techniques for Vascular and Vascularized Tissue Engineering

“…Subsequent dissolution of the fibers in water results in the formation of a perfusable microchannel network, which can be used as a microvasculature that supplies oxygen and nutrients to nearby cells populating the scaffold. For example, water‐soluble fibers, composed of the polysaccharide pullulan, were produced by electrospinning and embedded in a molded epoxy matrix . Perfusable channels were formed by curing the epoxy matrix and then dissolving the pullulan fibers in a water bath.…”

“…The recent development of sophisticated 3D printing techniques has led to the potential for cell‐encapsulated patient‐specific vascular graft fabrication . For prevascularized tissue‐engineered constructs, interconnected meso‐ and microchannels have been fabricated using techniques such as electrospinning, molding, 3D printing, and laser degradation of scaffold materials . Other approaches have focused on improving vascular network formation by promoting EC vasculogenesis and angiogenesis through cell sheet stacking, coculture of cells, and in vivo scaffold culture .…”

Selection of healing agents for a vascular self-healing application

“…The polysaccharide fibres were dissolved by immersing the composite pieces in water under stirring, leaving a network of interconnected submicron channels behind ( Figure 1). More details can be found in [30].The samples discussed in this paper contained 9 vol% of channels that were 830 ± 130 nm wide. Samples of virgin (non-vascularized) epoxy thermoset were prepared using the same curing conditions and cut to the required size.…”