Dynamically controlled deposition of colloidal nanoparticle suspension in evaporating drops using laser radiation12. Issue 20 (20th April 2016)

• Record Type: Journal Article
• Authors: Ta, V. D.; Carter, R. M.; Esenturk, E.; Connaughton, C.; Wasley, T. J.; Li, J.; Kay, R. W.; Stringer, J.; Smith, P. J.; Shephard, J. D.
• Is Part Of: Soft matter. Volume 12:Issue 20(2016)
• Page Start: 4530
• Page End: 4536
• Publication Date: 2016-04-20
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c6sm00465b
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Particle deposition in a homogeneous or arbitrary distribution can be obtained by direct exposure to an infrared laser beam. Abstract : Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates.