Nanofibers: Current Status and Role on Future of Technical Textiles Gajanan Bhat Professor MSE & Director, UTNRL University of Tennessee, Knoxville, TN, USA TECHNOTEX 2011, Mumbai, India August 26, 2011

Nanotechnology  “ The science, engineering and technology related to the understanding and control of matter at the scale length of approximately 1 to 100 nanometers. However, nanotechnology is not merely working with matter at the nanoscale, but also research and development of materials, devices and systems that have novel properties and functions due to their nanoscale dimensions and components” The National Nanotechnology initiative at Five years: Assessment and Recommendations of the National Nanotechnology Advisory Panel, Presidents Council of Advisors on Science and Technology, Washington, DC, May 2005, p7.

 Has not reached the state of application that draws public interest  Can be a big investment - a lot at stake  Lot of research and developmental activity in this area  In general technology lags behind science  Textiles – technology may be ahead of science Nanotechnology

 Relevance to Textiles  Nanofibers  Coating  Finishing  Modification  Characterization

Nanofibers  Diameter  High specific surface area  Higher filtration efficiency

Nanofiber Research Publications

Cotton Structure – Nanofibers?

Wool Structure – Nanofibers?

Production Techniques for Nanofibers  Splitting (IS)  Drawing  Electrospinning  Forcespinning  Modified Melt Blowing (MB)

Production Techniques for Nanofibers  Splitting of bi-/multi-component fibers  From multicomponent spinning and dissolution of some components  Hard to precisely control the fiber dimensions  Solvent

Electrospinning Process  Simple process at lab scale  Fine fibers possible  Scalability  Solvents  Dielectric requirements  Not suitable for PP

Forcespinning Fiberrio  By using Centrifugal Force  Both solutions and Melts  No high voltage, no hot air  New Process – many unknowns

Melt Blowing Process  Fiber Diameter (2-5 μ)  Air permeability/Hydrohead  Filtration efficiency  Porosity, pore size & Distribution  Mechanical Properties  Composite structures  Suitable for any thermoplastic polymer – No solvents

Nanofiber Melt Blowing Figure 6: Nanofiber Melt Blowing

Nanofiber Melt Blowing  Modular Dies  AGR/NTI  Hills

Melt Blown Nanofibers

20-inch Meltblowing Line

Melt blown Nano and Sub-Micron Fibers

Where are We?  Consistently produce NF MB webs from several thermoplastic polymers  Narrow fiber diameter distribution  Optimize Processing Conditions  Understand the Morphology Development  Evaluating Composite Structures

Applications of Melt Blown Nanofibers

 Scaffolds  Controlled Rate of Drug Delivery  Tissue engineering  Wound dressing

Applications of Melt Blown Nanofibers  Detoxification/Decontamination,  Enhanced reactivity of the Catalysts, Biocides,  Enhanced oxidative/ hydrolyzing activity of Catalysts (nano MgO,  -Cyclodextrin), biocides (N-Halamines), have against wide spectrum of of CBWA Polymer nanofiber membrane to capture chemical agents

Applications of Melt Blown Nanofibers Figure 10: Functionalized nanofibers for protective clothing

Applications of Melt Blown Nanofibers  Nanocomposites  Oil Adsorbents  Accidental oil spills  Fuel cell membranes, battery and fuel cell separators, catalysis

Applications of Melt Blown Nanofibers  Filtration Media  Lower pressure drop  Higher permeability  Higher particle capture efficiency  Quality factor Air & water purification filters, chemical filtration, HEPA filtration devices, face masks, filters for furnace

Applications of Melt Blown Nanofibers

Nanofiber Arrays Dramatically Boost Battery Energy Storage New method allows a dramatic boost in capacity for a given weight

Future Prospects of Melt Blown Nanofibers  Future Prospects  The global market should reach $176 million in 2012 and grow to $825 million by 2017  $1 trillion are market in textile  $100 billion market in electronic packaging  Scaffolds for the $10 billion tissue engineering by 2020  The mechanical/chemical sector is projected to account for 73.5% of total revenues in 2007

Nanofiber Market Projection BCC Research

Nanotechnology for Textiles  Nanocomposite fibers  CNT and nanoclay  Finishes  Water repellency  UV protection  Antibacterial  Wrinkle resistance  Reactivity  Functionality without sacrificing physical properties

Nanotechnology for Textiles BASF

Nanoparticle Application on Textiles  Continuous Spraying system  Sonication to achieve dispersion of nanoparticles  Uniform application on nonwovens and other textiles

Other Nonwoven Related Research Projects at UTNRL  Nanoparticle Reinforced Fibers, Webs and Films (Corp)  Nanoparticle Reinforced Composites (ONR)  Thermal Bonding Fundamentals  Melt Blowing –Processing, Polymers and Fundamentals  Nanofiber Composites  Biodegradable Nonwovens & Composites  Coating of textiles, webs and films  Multifunctional Composites –(NASA)  Flame Retardant Nonwovens – (USDA & Cotton Inc.)  High Temperature Polymeric Fibers – (Corp)  Fiber Formation Fundamentals – (corp)  Other Proprietary work – Various companies.

Future of Nanotechnology for Textiles in Indian Context  Availability of Science and Technology  Product Development  Value Addition  Marketing  Approach  Domestic and Global  Creativity and Engineering will lead to tremendous growth – where do you want to be?

Thank You