Fabricating porous poly(lactic acid) fibres via electrospinning

Abstract

In this paper, amorphous poly(lactic acid) (PLA), a biodegradable polymer with excellent biocompatibility, is successfully electrospun into micron-sized fibres with controlled surface and internal morphologies. By careful solvent selection, either surface porosity or internal porosity can be achieved through different mechanisms. Use of chloroform as the solvent gives rise to circular pores of 100 nm diameter confined to the surface. These are obtained in humid conditions by the so-called 'Breath Figure' mechanism. It is found that combining chloroform with a water-miscible non-solvent yields either surface porosity (wrinkled effect) using a low boiling point liquid, e.g. ethanol, or internal porosity using a high boiling point liquid, e.g. dimethyl sulphoxide (DMSO). Both these microstructures are obtained through a non-solvent induced phase separation (NIPS) mechanism. Finally, it is found possible to produce both surface and internal porosity using DMSO by a vapour induced phase separation (VIPS) mechanism. The porous electrospun PLA mats were shown to exhibit significantly increased oil absorption capacity compared with the non-porous fibre mats.

Electrospinning of Essential Oils

“…This includes control over the properties of the polymer solution (viscosity, molecular weight of the polymer, conductivity and boiling point of the solvent system, presence of additives), the applied voltage, the flow rate, the spinneret-collector distance, the environmental conditions (temperature and humidity), and the collector geometry. For example, solvent volatility is instrumental to engineer in-fibre porosity and generate fibres with high specific surface area [2,[34][35][36]. Binary and ternary polymer solutions prepared with an appropriate selection of solvents and non-solvents (low boiling point solvents) have been investigated to induce phase separation events prior or during the electrospinning process and hence generate pores.…”

Bifunctional polymer-of-intrinsic-microporosity membrane for flexible Li/Na–H2O2 batteries with hybrid electrolytes

“…S2 †). Note that our droplettemplating strategy is based on the reported "breath gure" mechanism, 31 where water droplets (in this work, the water droplets are produced by Li salts through adsorbing the vapour from the air) serve as templates for creating pores on the surface of an evaporating polymer solution. The aim of the second step is to convert a portion of the cyano (-CN) groups in PIM-1 into carboxyl (-COOH) groups (Fig.…”

Electrospun Functional Materials toward Food Packaging Applications: A Review

“…The formation mechanism of nanopores on the surface of fibers is solvent phase separation. Huang et al [137] further studied the effect of different solvents on the surface morphology and internal porous structure of electrospun PLA fibers. Both surface and internal pore can be achieved through different mechanisms.…”