Enhancement of contact line mobility by means of infrared laser illumination. I. Experiments

Abstract

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The shape of a droplet moving on a solid substrate is largely determined by the mobility of its contact line. Above a certain critical velocity, the droplet typically disintegrates and leaves residual liquid behind. We studied experimentally how localized infrared laser illumination can stabilize it against the progressive loss of liquid. We systematically varied the substrate velocity, the laser power, and the laser spot position and found that the critical velocity of the droplet can be substantially increased. These results are potentially important for increasing throughput in immersion lithography systems. V C 2016 AIP Publishing LLC.

Interfacial Flows and Interfacial Shape Modulation Controlled by the Thermal Action of Light Energy

“…In addition, they determined the range of beam powers and substrate rotation speed in which the thermocapillary film rupture and the subsequent dewetting process occur without residual droplets. In [27] the thermal action of the IR laser beam on the receding contact line of a droplet, which represents a liquid bridge between the needle tip and the rotating substrate, was studied. It was shown that the generation of the thermocapillary flows on the receding part of the droplet leads to an increase in the mobility of the contact line, prevents fragmentation and formation of residual droplets.…”

“…Today, optical radiation (light) is widely used as a high-precision and efficient tool for controlling the fluid flow, the shape of the liquid-liquid or liquid-air interfaces, and manipulating small objects suspended in the bulk liquid phase or located on the interfaces. Using light makes it possible to solve a wide range of problems in various applications, including biological research [1][2][3][4], liquid diagnostics [5][6][7][8][9][10][11][12][13][14][15], non-destructive evaluation of solids [16][17][18][19][20], methods for studying properties of soft interfaces [21][22][23][24], electronic industry [25][26][27][28][29][30][31], technologies of tunable and biomimetic optics [8,[32][33][34], image recording systems [35][36][37][38], and non-linear optics [39,40].…”

Enhancement of contact line mobility by means of infrared laser illumination. II. Numerical simulations

“…45,46 In this manuscript, we study the increase of mobility of a stationary contact line on a moving, partially wetting substrate by means of localized infrared (IR) laser irradiation. In Paper I, 69 we presented corresponding experimental results. In the following, we present two coupled numerical models that allow us to identify the dominant mechanism of the mobility enhancement and to detail the influence of both thermocapillary shear stresses and viscosity reduction.…”