Needleless Electrospinning of nanofibers with a conical wire coil

In this article, we have demonstrated a novel needleless electrospinning of PVA nanofibers by using a conical metal wire-coil as spinneret. Multiple polymer jets were observed to generate on the coil surface. Up to 70 kV electric voltage can be applied to this needleless electrospinning nozzle without causing corona discharge. Compared with conventional needle electrospinning, this needleless electrospinning system produced finer nanofibers on a much larger scale, and the fiber processing ability showed a much greater dependence on the applied voltage. Finite element calculation indicates that the electric field intensity profiles for the two systems are also quite different. This novel concept of using wire coil as the electrospinning nozzle will contribute to the further development of new large-scale needleless electrospinning system for nanofiber production.

Wire coil needleless electrospinning of polymer nanofibers

Elcctrospinning is a very useful technique to produce polymeric nanofibers for diverse applications. The conventional needle-based electrospinning system has VCIY limited fiber productivity and a key challenge has been to develop electrospinning systems that can produce uniform nanofibcrs on a large scale l-3.
In this study, we have demonstrated that a rotating metal wire coil can be used as a nozzle to eiectrospin nanofibers on a large-scale. Without using any needles, the rotating wire coil, partially immersed in a polymer solution reservoir, can pick up a thin layer of charged polymer solution and generate a large number of nanofibers from the wire surface simultaneously. This arrangement significantly increases the nanofiber productivity.
The fiber productivity was found to be determined by the coil dimensions, such as wire diameter, coil radius and distance, and coil length. The effects of applied voltage, the distance bctv,lcen the coil nozzle and collector, and polymer concentration on the fiber
morphology were examined. The dependency of fiber diameter on the polymer concentration showed a similar trend to that for a conventional electrospinning system using a syringe needle nozzle, but the diameter distribution was narrower for the
coil electrospun fibers.
The profiles of electric fIeld strength in coil electrospinning was calculated and showed
concentrated electrical field intensity on the top wire surface. This novel concept of using wire coil as the electrospinning nozzle will contribute to the further development of new large-scale needleless electrospinning systems for nanofiber production.

Studying and evaluating anti-corrosion coatings and inhibitors using the wire beam electrode method in conjunction with electrochemical noise analysis

Purpose – To provide a summary of research work carried out mainly in the authors' group for evaluating various protective coatings including rustproofing oils, and also for studying corrosion inhibitors using the wire beam electrode (WBE) method.

Design/methodology/approach – A range of published papers published during the past 15 years was summarised and reviewed. Recent research work in the authors' group was also included, which involved the combined use of the WBE with electrochemical noise analysis and the scanning reference electrode technique.

Findings – The WBE method has been developed into a very useful tool of evaluating the performance of coatings and inhibitors. In particular, The WBE is uniquely applicable for determining the performance of coatings and inhibitors to control localised corrosion.

Research limitations/implications – Focusing mainly on recent research.

Practical implications – A useful source of information for researchers and graduate students working in the areas of organic coating and inhibitor research.

Originality/value – The first summary or review on this research topic.