Dynamics of caged microemulsion droplets: a neutron spin echo and dynamic light scattering study

✍ Scribed by Geyer, Arnaud de; Molle, Boris; Lartigue, Colette; Guillermo, Armel; Farago, Bela

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 200 KB
• Volume: 350
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2004.04.026

✦ Synopsis

We report a neutron spin echo (NSE) and dynamic light scattering (DLS) study of droplet dynamics in a microemulsion at high droplet packing fraction (F droplet B62%). NSE measurements in range qrb1 allow to investigate the short-range Brownian motion of droplets trapped within the cages formed by their nearest neighbors. For a particular scattering contrast, NSE also reveals, for q values around qrBp; the shape fluctuations of the caged droplets. In range qr51; DLS correlation functions reveal two independent diffusive modes with well separated decay times. Comparing DLS results with NSE and pulsed-field gradient NMR measurements allows to associate both DLS modes with collective dynamics of 'transient-trapped' droplets, revealing strong similarity to the long-time and short-time diffusion modes observed by light scattering in concentrated colloidal suspensions below the glass transition.