Sat, 26 Jul 2008 08:38:06 BST CiteULike: dchen Dufresne http://www.citeulike.org/user/dchen/author/Dufresne CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2747059 <i>Review of Scientific Instruments, Vol. 69, No. 5. (1998), pp. 1974-1977.</i> Optical tweezer arrays and optical substrates created with diffractive optics Eric Dufresne David Grier Review of Scientific Instruments, Vol. 69, No. 5. (1998), pp. 1974-1977. 2008-05-02T20:52:54-00:00 1998 Review of Scientific Instruments 69 5 1974 1977 AIP grier opticaltweezer http://www.citeulike.org/user/dchen/article/2713887 <i>Physical Review Letters, Vol. 91, No. 22. (24 November 2003), 224501.</i> Flow and Fracture in Drying Nanoparticle Suspensions ER Dufresne EI Corwin NA Greenblatt J Ashmore DY Wang AD Dinsmore JX Cheng XS Xie JW Hutchinson DA Weitz doi:10.1103/PhysRevLett.91.224501 Physical Review Letters, Vol. 91, No. 22. (24 November 2003), 224501. 2008-04-24T18:38:32-00:00 2003 Physical Review Letters 91 22 224501 American Physical Society dinsmore drying weitz http://www.citeulike.org/user/dchen/article/2710298 <i>Physical Review Letters, Vol. 94, No. 1. (2005)</i><br /><br />Minute concentrations of suspended particles can dramatically alter the behavior of a drying droplet. After a period of isotropic shrinkage, similar to droplets of a pure liquid, these droplets suddenly buckle like an elastic shell. While linear elasticity is able to describe the morphology of the buckled droplets, it fails to predict the onset of buckling. Instead, we find that buckling is coincident with a stress-induced fluid to solid transition in a shell of particles at a droplet's surface, occurring when attractive capillary forces overcome stabilizing electrostatic forces between particles. Onset of Buckling in Drying Droplets of Colloidal Suspensions N Tsapis ER Dufresne SS Sinha CS Riera JW Hutchinson L Mahadevan DA Weitz doi:10.1103/PhysRevLett.94.018302 Physical Review Letters, Vol. 94, No. 1. (2005) 2008-04-23T21:45:07-00:00 2005 Physical Review Letters 94 1 APS colloids drying weitz http://www.citeulike.org/user/dchen/article/2710262 <i>Langmuir, Vol. 21, No. 11. (24 May 2005), pp. 4881-4887.</i><br /><br />Abstract: While the important role of electrostatic interactions in aqueous colloidal suspensions is widely known and reasonably well-understood, their relevance to nonpolar suspensions remains mysterious. We measure the interaction potentials of colloidal particles in a nonpolar solvent with reverse micelles. We find surprisingly strong electrostatic interactions characterized by surface potentials, e, from 2.0 to 4.4 kBT and screening lengths, -1, from 0.2 to 1.4 m. Interactions depend on the concentration of reverse micelles and the degree of confinement. Furthermore, when the particles are weakly confined, the values of e and extracted from interaction measurements are consistent with bulk measurements of conductivity and electrophoretic mobility. A simple thermodynamic model, relating the structure of the micelles to the equilibrium ionic strength, is in good agreement with both conductivity and interaction measurements. Since dissociated ions are solubilized by reverse micelles, the entropic incentive to charge a particle surface is qualitatively changed from aqueous systems, and surface entropy plays an important role. Charge Stabilization in Nonpolar Solvents MF Hsu ER Dufresne DA Weitz doi:10.1021/la046751m Langmuir, Vol. 21, No. 11. (24 May 2005), pp. 4881-4887. 2008-04-23T21:21:25-00:00 2005 Langmuir 21 11 4881 4887 micelle weitz http://www.citeulike.org/user/dchen/article/2709642 <i>Langmuir, Vol. 22, No. 17. (15 August 2006), pp. 7144-7147.</i><br /><br />Abstract: We investigate the dynamics of fracture in drying films of colloidal silica. Water loss quenches the nanoparticle dispersions to form a liquid-saturated elastic network of particles that relieves drying-induced strain by cracking. These cracks display intriguing intermittent motion originating from the deformation of arrested crack tips and aging of the elastic network. The dynamics of a single crack exhibits a universal evolution, described by a balance of the driving elastic power with the sum of interfacial power and the viscous dissipation rate of flowing interstitial fluid. Dynamics of Fracture in Drying Suspensions ER Dufresne DJ Stark NA Greenblatt JX Cheng JW Hutchinson L Mahadevan DA Weitz doi:10.1021/la061251+ Langmuir, Vol. 22, No. 17. (15 August 2006), pp. 7144-7147. 2008-04-23T17:48:29-00:00 2006 Langmuir 22 17 7144 7147 drying dynamics film weitz