Increased surface area on nanoparticles Why Nanocomposites? Size does matter       Increased surface area on nanoparticles                 Microparticles Nanoparticles

Why Nanocomposites?  Multi-functionality Small filler size: High surface to volume ratio Small distance between fillers  bulk interfacial material Mechanical Properties Increased ductility with no decrease of strength, Scratching resistance Optical properties Light transmission characteristics particle size dependent

Nanocomposite as a Multiscale System Macroscale composite structures Clustering of nanoparticles - micron scale Interface - affected zones - several to tens of nanometers - gradient of properties Polymer chain immobilization at particle surface is controlled by electronic and atomic level structure 1 s - 1h 10 -9 - 1 s 10 -12 s

The Glass transition temperature of nanocomposite thin films Background: The glass transition temperature of polymer thin films Influence of i) single walled carbon nanotubes, (ii) C60 fullerenes (“buckyballs”) and (iii) mica-type layered silicate inorganic clays on the Tg of thin polymer films in the nanometer thickness range from mmptdpublic.jsc.nasa.gov/jscnano/ 20-50 nm P. F. Green et al, U Texas Polymer coil Rg~2-20 nm

The Glass transition of Polymer thin film nanocomposites C60, and carbon nanotubes have a similar effect PS: b=9 Nanocomposite: b=4 Decrease in b reflects the increase in fraction of the slowly relaxing domains The effect of nanoparticles is to increase the effective fraction of slowly relaxing domains in the sample P. F. Green et al, U Texas