Electro Fluid Dynamics: A Route to Design Polymers and Composites for Biomedical and Bio-Sustainable Applications

Abstract

In the last two decades, several processes have been explored for the development of micro and/or nanostructured substrates by sagely physically and/or chemically manipulating polymer materials. These processes have to be designed to overcome some of the limitations of the traditional ones in terms of feasibility, reproducibility, and sustainability. Herein, the primary aim of this work is to focus on the enormous potential of using a high voltage electric field to manipulate polymers from synthetic and/or natural sources for the fabrication of different devices based on elementary units, i.e., fibers or particles, with different characteristic sizes—from micro to nanoscale. Firstly, basic principles and working mechanisms will be introduced in order to correlate the effect of selected process parameters (i.e., an applied voltage) on the dimensional features of the structures. Secondly, a comprehensive overview of the recent trends and potential uses of these processes will be proposed for different biomedical and bio-sustainable application areas.

Tailoring the properties of epoxy/silicone blends for high-voltage capacitor applications

“…Materials with higher permittivity have charges that can be more easily displaced. Epoxy resin and silicone rubbers are considered for capacitor dielectrics in high-voltage applications [2]. The properties which make its use attractive are biocompatibility, environmentally friendly, flame resistance, and long shelf-life [3].…”

New Insights to Design Electrospun Fibers with Tunable Electrical Conductive–Semiconductive Properties

“…This involves dissolving the polymer in a suitable solvent or mix of solvents. The concentration of the polymer in the solution, as well as the choice of solvent, can affect the properties of the resulting fibers [ 30 , 31 , 32 ]. Parameters such as the viscosity [ 33 ], molecular weight [ 34 ], permittivity [ 35 ], and surface tension [ 36 ] will define the physical and chemical properties of the nanofibers.…”

Green Routes for Bio-Fabrication in Biomedical and Pharmaceutical Applications

“…Electro-fluid-dynamic techniques (EFDs) are emerging as highly flexible and low-cost processes to manipulate polymers and drugs in solution by applying electrostatic forces generated via high-voltage electric fields [ 75 , 76 ]. They include a pattern of “bottom-up” technologies such as electrospinning or spraying and their combinations, showing a high process versatility, not limiting the opportunity to control the characteristic size del carrier accurately—from micro- to sub-micrometric size scale—making them suitable for manufacturing of highly scalable devices in the form of particles or fibres or their assemblies, for research use or industrial processes [ 77 ].…”

“…Indeed, polymer droplet is interested in the antagonism of three different forces: columbic, viscoelastic, and surficial. By applying an increasing voltage, electric forces increase, until reaching the threshold value that allows it to overcome the other ones, thus promoting the ejection of a polymer jet and the formation of fibres [ 75 , 78 ]. In this context, a large range of factors over the voltage plays a relevant role in this mechanism, including operative parameters (i.e., flow rate, collector distance), polymer, solvent/co-solvent chemistry, or environmental conditions (i.e., humidity, temperature) [ 79 , 80 ].…”