Dynamics of density fluctuations in colloidal gels

✍ Scribed by A.H. Krall; Z. Huang; D.A. Weitz

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 838 KB
• Volume: 235
• Category: Article
• ISSN: 0378-4371
• DOI: 10.1016/s0378-4371(96)00325-1

✦ Synopsis

We use dynamic light scattering to measure the dynamic structure factor of density fluctuations occurring in colloidal suspensions that have attained a quiescent state long after aggregation. We find a stretched-exponential decay to a finite plateau. Our interpretation of the arrested decay is that these systems are gels, i.e., systems possessing a finite elastic modulus G. We develop a theory for the internal elastic modes of a fractal cluster and use it to derive G and the arrested, stretched-exponential behavior of colloidal gel dynamics. Good agreement between experiment and theory is obtained.