ELASTIC BEHAVIOR OF NANOPARTICLE CHAIN AGGREGATES

Nanoparticle chain aggregates (NCA) possess elastomeric properties inc luding stretch under tension, and contraction when the tension is rela xed. Individual chain aggregates of 7 nm titania particles a few hundr ed nm long were observed in the electron microscope. The NCA were stre tched across expanding holes in the carbon film on an electron microgr aph grid. After stretching up to 90%, the NCA broke loose at one end a nd contracted to a tightly folded chain. This pattern was observed in repeated tests. Mechanisms for this behavior and reasons for its gener ality are proposed. Implications are discussed for the ductility of na noparticle ceramics, and the increased tensile strength and elastic mo dulus of rubber due to nanoparticle additives. (C) 1998 American Insti tute of Physics.