Engineered Conductivity in Polymer Nanocomposites

Mr. Max D. Alexander, Ms. Heather Dowty, and Mr. Brandon Black
Materials and Manufacturing Directorate
Air Force Research Laboratory
WPAFB , OH 45433-7750
Phone:  937-255-9135 / Fax:  937-255-9157
Email:  Max.Alexander@wpafb.af.mil  

Abstract:  This research explores the use of a variety of nanoparticles to impart conductivity to polymer matrices. We have chosen three highly promising families of nanomaterials : multiwall carbon nanofibers, metal coated mutliwall carbon nanofibers, and metal nanostrands for use as fillers. These materials were dispersed in a variety of polymer systems including thermoplastic high elongation elastomers, space durable polyimides, PEEK, polycarbonate, and polystyrene. The aspect ratio of the nanomaterials ranged from 40 to 800 which lead to percolation thresholds below 0.5 volume percent with ultimate conductivities on the order of 4000 S/cm.  The polymer nanocomposites systems retained the mechanical robustness of the original systems in contrast to traditional highly loaded macroscopically filled systems. The end products can be solution cast, dip coated, extruded or sprayed using conventional processing techniques. Examples of these systems, methods of fabrications, electrical percolation, mechanical properties and potential uses will be discussed.

Examples of materials examined are shown in the figures below.


(a) Carbon Nanofibers in polymer matrix

(b) Metal Coated Carbon Nanofibers

(c) Nickel Naostrands