Wed, 20 Aug 2008 22:09:43 BST CiteULike: dchen Kegel http://www.citeulike.org/user/dchen/author/Kegel CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/3089337 <i>Faraday Disc., Vol. 123 (2003), pp. 27-35.</i><br /><br />In concentrated suspensions of fluorescent colloidal hard spheres (close to and above the glass transition density), we bleached part of the system in cube shaped regions using high intensity laser light. Recovery of these bleached cubes was followed in real space using confocal scanning laser microscopy (CSLM). This method provides mean squared particle displacements up to timescales that are three orders of magnitude beyond those available by present experimental techniques. We show that, above the (hard sphere) glass transition density, particles move over distances of the order of their own diameter on timescales of 106 to 108 Brownian times. Moreover, the mean squared displacement, [left angle bracket]x2[right angle bracket], shows power-law behavior over seven time ([small tau]) decades: [left angle bracket]x2[right angle bracket][is proportional to][small tau](0.30+/-0.05). This behavior is different from earlier observations by dynamic light scattering. It is argued that these differences are caused by gravity effects, as the only difference between the systems is the buoyant mass of the colloids. Real-space fluorescence recovery after photo-bleaching of concentrated suspensions of hard colloidal spheres Nikoleta Simeonova Willem Kegel doi:10.1039/b204406d Faraday Disc., Vol. 123 (2003), pp. 27-35. 2008-08-05T19:04:20-00:00 2003 Faraday Disc. 123 27 35 The Royal Society of Chemistry colloids diffusion experiment utrecht http://www.citeulike.org/user/dchen/article/1304875 <i>Science, Vol. 287, No. 5451. (14 January 2000), pp. 290-293.</i><br /><br />10.1126/science.287.5451.290 Direct Observation of Dynamical Heterogeneities in Colloidal Hard-Sphere Suspensions Willem Kegel And van Blaaderen doi:10.1126/science.287.5451.290 Science, Vol. 287, No. 5451. (14 January 2000), pp. 290-293. 2007-05-18T06:58:01-00:00 2000 Science 287 5451 290 293 blaaderen heterogeneity science utrecht http://www.citeulike.org/user/dchen/article/2553406 <i>Physical Review Letters, Vol. 98, No. 15. (2007)</i><br /><br />We show that under appropriate conditions, mixtures of oil, water, and nanoparticles form thermodynamically stable oil-in-water emulsions with monodisperse droplet diameters in the range of 30–150 nm. This observation challenges current wisdom that so-called Pickering emulsions are at most metastable and points to a new class of mesoscopic equilibrium structures. Thermodynamic stability is demonstrated by the spontaneous evolution of binary droplet mixtures towards one intermediate size distribution. Equilibrium interfacial curvature due to an asymmetric charge distribution induced by adsorbed colloids explains the growth of emulsion droplets upon salt addition. Moreover, the existence of a minimal radius of curvature with a concomitant expulsion of excess oil is in close analogy with microemulsions. Thermodynamically Stable Pickering Emulsions S Sacanna WK Kegel AP Philipse doi:10.1103/PhysRevLett.98.158301 Physical Review Letters, Vol. 98, No. 15. (2007) 2008-03-19T01:12:04-00:00 2007 Physical Review Letters 98 15 APS 2007 emulsion experiment technique http://www.citeulike.org/user/dchen/article/2453702 <i>Science</i> Direct Observation of Dynamical Heterogeneities in Colloidal Hard-Sphere Suspensions Willem Kegel Alfons van Blaaderen Science 2008-03-01T20:33:48-00:00 Science experiment heterogeneity