New Electrospinning Nozzle to Reduce Jet Instability and Its Application to Manufacture of Multi-layered Nanofibers

Abstract

A new nozzle system for the efficient production of multi-layered nanofibers through electrospinning is reported. Developed a decade ago, the commonly used coaxial nozzle system consisting of two concentric cylindrical needles has remained unchanged, despite recent advances in multi-layered, multi-functional nanofibers. Here, we demonstrate a core-cut nozzle system, in which the exit pipe of the core nozzle is removed such that the core fluid can form an envelope inside the shell solution. This configuration effectively improves the coaxial electrospinning behavior of two fluids and significantly reduces the jet instability, which was proved by finite element simulation. The proposed electrospinning nozzle system was then used to fabricate bi- and tri-layered carbon nanofibers.

The Electrospun Ceramic Hollow Nanofibers

“…Since the sheath and core solutions meet at the end of the nozzle, two physical phenomena take place simultaneously: the wrapping of the sheath solution around the core solution and the formation of the Taylor cone by the sheath solution to equilibrate the charge effect and the fluid surface tension [ 71 ]. Hence, for a successful electrospinning, two important relevant issues should be taken into account.…”

Facile method to improve initial reversible capacity of hollow carbon nanofiber anodes

“…In addition, the thermal decomposition of SAN occurs at about 400°C, which is high enough to sustain the stabilization process of PAN, thus offering large possibilities to form uniform hollow CNFs (HCNFs) during the carbonization process. N,N-dimethyl formamide (DMF) was used as a solvent for both PAN and SAN [21,22].…”

“…1(a)) [23]. A coaxial nozzle was designed to stabilize the electrospinning process by separating two physical phenomena, that is, the formation of both the core/shell fluid and the Taylor cone, at the end of the nozzle [22]. SAN and PAN were dissolved in DMF with concentrations of 30 and 20 wt%, respectively.…”

Desenvolvimento De Um Dispositivo De Eletrofiação Automatizado Para Testes De Precisão

“…O comportamento e a estabilidade do campo elétrico, a interação do fluido com o campo XII Congresso Brasileiro de Engenharia Química em Iniciação Científica UFSCar -São Carlos -SP 16 a 19 de Julho de 2017 elétrico, além de propriedades fluídicas como viscosidade e tensão superficial, vazão da solução para o capilar, distância entre a extremidade do capilar e a base coletora, e variáveis ambientais como temperatura, umidade e fluxo de ar através do jato (Doshi e Reneker, 1995). Apesar de cruciais, muitas das variáveis citadas não possuem controle apropriado nos equipamentos atuais e alguns procedimentos (como posicionamento do capilar) ainda são realizados manualmente, ainda que exista desenvolvimento na área de controle como modelos do efeito da uniformidade da distribuição do campo elétrico em eletrofiação (Yang et al, 2008), criação de novos tipos de capilares para redução de instabilidade do jato (Lee et al, 2014) e desenvolvimento de sistemas totalmente automatizados (Endler et al, 2015).…”