Narendiran Vitchuli

PhD, Fiber Polymer Science, 2011
North Carolina State University, North Carolina

M.S., Fiber Polymer Science, 2008
India Institute of Technology Delhi, India

B.S., Textile Technology, 2006
Alagappa College of Technology, Anna University, India

Curriculum Vitae

Research Focus: Technology Transfer Project of Liquid Shear Nanofabrication Process

1. Liquid shear nanofabrication of polymer nanofibers

Liquid shear nanofabrication process is a novel method to prepare nanofibers by subjecting polymer solution droplets to simultaneous shear and anti-solvent induced precipitation in viscous liquid media. The typical lab scale process involves creation of laminar shear in viscous media (glycerol + antisolvent) using a shear impeller and injection of polymer solution droplets into it. During shear process, the low interfacial tension between major component of viscous media i.e. glycerol and polymer solution, leads to infinite stretching of polymer droplets into proto fibers and simultaneous precipitation by anti-solvent component in viscous media gives rise to solidified fibers of very thin diameter in the range 300-500 nanometers. This novel process is capable to fabricate nanofibers from almost all polymers that are soluble in a solvent. The method is also capable to fabricate variety of functional nanofibers.

Figure 1: Liquid shear nanofiber fabrication process

The current objective of research is to investigate and model the fiber formation, optimize the process parameters of shear, polymer injection geometry, and polymer feed rate to scale up the nanofiber production. The recycling process of benign shear medium i.e. glycerol and anti-solvent and removal of residual polymer solvent are critical topic of research interest to minimize the production cost.

2. Technology transfer and process optimization

Xanofi Inc. adopted the liquid shear technology and designed a proto type commercial scale XanoShearTM machine which is a continuous process to produce polymer nanofibers at bulk volume at extra ordinary production rate. The XanoShearTM process optimization was carried out to reduce the average fiber diameter from 300 nm to 130 nm and maintaining significant high production rate.

Figure 2: Polystyrene polymer nanofiber fabricated using XanoShearTM machine at Xanofi Inc.

3. Product development:

The liquid shear nanofabrication process is capable to fabricate variety of functional materials including nanofibers, functional composite fibers, submicron flat ribbons and micro sheets. The liquid shear nanofibers and microstructures have application in filtration, automotive, food product, biomedical, energy and technical textiles.

Figure 3: SEM images of XanoShearTM nanofibers fabricated using different polymers

Figure 4: Liquid Sheared functional nanofibers

[1] Alargova, R. G.; Paunov, V. N.; Velev, O. D. Formation of polymer microrods in shear flow by emulsification – Solvent attrition mechanism. Langmuir 2006, 22, 765–774.

[2] Alargova, R. G.; Bhatt, K. H.; Paunov, V. N.; Velev, O. D. Scalable synthesis of a new class of polymer microrods by a liquid-liquid dispersion technique. Advanced Materials 2004, 16, 1653-1657.