© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

9.3.5.3.3 Sonication

Multiple acoustic pulses applied simultaneously to the surfaces of a crystal may elevate the interior mechanical stress above the failure strength of the material, causing it to fracture. Consider six diamond hammers of facial area L² and failure strength ~1 x 10¹¹ N/m² that simultaneously impact each of the six faces of a cubic diamond target of edge L, applying a non-self-fracturing peak pressure of 0.3 x 10¹¹ N/m² at each face. The peak pressure rises to 1.8 x 10¹¹ N/m² at the center of the cube where the plane waves converge, well exceeding the strength of diamond and shattering the target cube throughout its interior. Sonic pulverization is an analogous macroscale manufacturing process.

Single-walled fullerene nanotubes are cut by water-bath ultrasonication at 55 KHz,¹⁵²⁵ which is inferred to produce microscopic domains of high temperature¹⁵²³ following the collapse of cavitation bubbles, leading to localized sonochemistry that opens a hole in the tube side. Vigorous sonication of multiwalled fullerene nanotubes produces similar damage in a CH₂Cl₂ bath.¹⁵⁹⁰

Last updated on 21 February 2003