Generation of Fractal Silicas by Negative Pressure Rupturing of Si02 Glass

John Kieffer, Charles Angell

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Stimulated by the finding that SiO2 aggregates (e.g. SiO2 “smokes” or “snow”) assembled under highly non-equilibrium conditions have fractal geometries and dynamics - and retain them under annealing densification almost until the density of silica glass is reached - we have examined the consequences of an inverse procedure. Using the power of molecular dynamics to perform otherwise difficult experiments we have subjected normal density vitreous SiO2 at 300 K to isotropic expansions (which generate negative pressures) to and well beyond the tensile limit at - 70 kbar. As the tensile limit is exceeded, void-containing structures are produced which indeed prove to be fractal in character, and the pressure trends towards zero. The fractal dimension is determined concordantly from two different density correlation relationships and is found to change smoothly with density from 3.0 at the tensile limit down to 1.7 at the limiting density of 0.1 g/cm3 set by our system size. Our study suggests that the path of least resistance to the rupturing of an initially stable structure may be the path to fractal geometries.

Original languageEnglish (US)
Pages (from-to)137-154
Number of pages18
JournalMolecular Simulation
Volume3
Issue number1-3
DOIs
StatePublished - May 1 1989
Externally publishedYes

Keywords

  • fractal
  • isotropic expansion
  • rupture
  • Silica

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Information Systems
  • Materials Science(all)
  • Modeling and Simulation
  • Condensed Matter Physics
  • Chemistry(all)

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