Topic:　Carbon Nanotubes with Temperature Invariant Viscoelasticity from -196 °C to 1000 °C

Speaker:　Dr. Ming XU

From:　National Institute of Advanced Industrial Science and Technology (AIST), JAPAN

Time:　14:00 p.m.,　June.　13,  2012

Venue:　Room 403,  Lihua Building

Abstract: Viscoelasticity describes the ability of a material to possess both elasticity and viscosity. Viscoelastic materials, such as rubbers, possess a limited operational temperature range. (e.g., for silicone rubber: 55 to 300 °C) above which the material breaks down and below which the material undergoes a glass transition and hardens. We created a viscoelastic material composed from a random network of long interconnected carbon nanotubes that exhibited an operational temperature range from -196 °C to 1000 °C. The storage and loss moduli, frequency stability, reversible deformation level, and fatigue resistance were invariant from -140 to 600 °C. We interpret that the thermal stability stems from energy dissipation through the zipping and unzipping of carbon nanotubes at contacts.