Atmospheric Pressure Non-Equilibrium Plasma Treatment to Improve the Electrospinnability of Poly(L -Lactic Acid) Polymeric Solution

Abstract

This work is focused on the use of non-thermal plasma to improve the electrospinnability of poly(L-lactic acid) (PLLA). The use of toxic high boiling point solvents is minimized to produce high quality solvent free nanofibrous scaffolds for biomedical applications. PLLA polymeric solutions dissolved in pure dichloromethane are exposed to the plasma plume of a jet developed by some of the authors and driven by high voltage pulses with rise rate of several kV ns À1 . The effects of peak voltage, pulse repetition frequency, volume of the solution and treatment time on the morphology of electrospun fibers are investigated by means of scanning electron microscope. Electrospinning is performed at different time lapses after the plasma treatment to study the durability of the induced effects. Figure 10. Spatially resolved optical emission spectrum of the plasma jet, operating conditions: PV ¼ 20 kV, PRF ¼ 330 Hz, Ar flow rate ¼ 1 slpm. V. Colombo et al.

Fabrication of PEOT/PBT Nanofibers by Atmospheric Pressure Plasma Jet Treatment of Electrospinning Solutions for Tissue Engineering

“…Colombo et al. followed a similar strategy, using an atmospheric pressure plasma jet (APPJ) to treat polylactic acid dissolved in dichloromethane and observed 100% bead‐free fibers . In our research group, an extensive study on the effects of NTP exposure on a solution of PCL or PLLA in CHCl 3 and DMF was recently performed .…”

“…Without the addition of HFIP to chloroform, independent of the used electrospinning parameters, it has not been possible so far to obtain continuous bead‐free nanofibers. Driven by the need to find more effective, eco‐friendly, and biomedically benign strategies to improve the electrospinning process, several research groups have been investigating the potential of using atmospheric pressure plasma to improve polymer solution properties prior to electrospinning . The exposure of solids to non‐thermal plasma (NTP) is well described and has found a widespread use in many disciplines .…”

“…However, the use of NTP to alter the properties of polymeric solutions (for electrospinning) is a field of research that has barely been touched upon. So far, to the best of the author's knowledge, only five research papers have been published that deal with this subject . Shi et al.…”

The Influence of Pre‐Electrospinning Plasma Treatment on Physicochemical Characteristics of PLA Nanofibers

“…For example, Shi et al have treated polyethylene oxide (PEO) and polyacrylonitrile (PAN) solutions and observed the creation of finer and smoother nanofibers after electrospinning. In another study by Colombo et al, plasma treatment was also found to promote the electrospinnability of poly‐ l ‐lactic acid (PLLA) solutions in dichloromethane resulting in the generation of nicely elongated smooth PLLA nanofibers. Inspired by the above‐mentioned works, our research group started to investigate the plasma treatment of poly‐ε‐caprolactone (PCL) solutions in a mixture of chloroform (CHL) and N , N ‐dimethylformamide (DMF) and also observed a significantly improved PCL nanofiber morphology as a result of PEPT .…”

“…Taking this into account, pre‐electrospinning plasma treatment (PEPT) of polymer solutions has already been investigated by several research groups, including ours, as an innovative and environmentally friendly method to change polymer solution properties in an effort to increase the electrospinnability of these solutions . For example, Shi et al have treated polyethylene oxide (PEO) and polyacrylonitrile (PAN) solutions and observed the creation of finer and smoother nanofibers after electrospinning.…”