Effect of Surfactant on the Drying Patterns of Graphite Nanofluid Droplets

Crivoi, Alexandru; Duan, Fei

doi:10.1021/jp401751z

Cited by 49 publications

(56 citation statements)

References 35 publications

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“…[21][22][23][24][25][26][27] More specifically, Still et al 22 achieved a uniform deposition of colloidal particles on glass by adding Sodium dodecyl sulfate (SDS) to the drop dispersion.…”

Section: -12mentioning

confidence: 99%

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Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

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We consider the flow dynamics of a thin evaporating droplet in the presence of an insoluble surfactant and non-interacting particles in the bulk. Based on lubrication theory, we derive a set of evolution equations for the film height, the interfacial surfactant and bulk particle concentrations, taking into account the dependence of the liquid viscosity on the local particle concentration. An important ingredient of our model is that it takes into account the fact that the surfactant adsorbed at the interface hinders evaporation. We perform a parametric study to investigate how the presence of surfactants affects the evaporation process as well as the flow dynamics with and without the presence of particles in the bulk. Our numerical calculations show that the droplet life-time is affected significantly by the balance between the ability of surfactant to * To whom correspondence should be addressed † Department of Chemical Engineering, University of Patras, Patras 26500, Greece ‡ Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 285, Telangana, India ¶ Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK 1 enhance spreading suppressing the effect of thermal Marangoni stresses-induced motion and to hinder the evaporation flux through the reduction of effective interfacial are of evaporation, which tend to accelerate and decelerate the evaporation process, respectively. For particle-laden droplets and in the case of dilute solutions, the droplet life-time is found to be weakly-dependent on the initial particle concentration. We also show that the particle deposition patterns are influenced strongly by the direct effect of surfactant on the evaporative flux; in certain cases, the "coffee stain" effect is enhanced significantly. A discussion of the delicate interplay between the effects of capillary pressure, solutal and thermal Marangoni stresses, which drive the liquid flow inside the evaporating droplet giving rise to the observed results is provided herein.

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“…[21][22][23][24][25][26][27] More specifically, Still et al 22 achieved a uniform deposition of colloidal particles on glass by adding Sodium dodecyl sulfate (SDS) to the drop dispersion.…”

Section: -12mentioning

confidence: 99%

“…However, Crivoi and Duan 25,26 have shown that the formation of coffee ring of graphite nanoparticles is enhanced with the addition of Cetyltrimethyl Ammonium Bromide (CTAB)…”

Section: Sempels Et Almentioning

confidence: 99%

Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants

2016

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“…Among these patterns, the formation of "coffee ring" patterns is due to the "coffee ring" effect (explained in Section 2.4.1), the multi-ring patterns are related to the "stick-slip" motion of the contact line of the droplet during drying (mentioned in Section 2.3), the uniformdeposition patterns are the result of the inhibition of the "coffee ring" effect caused by the wide . Desiccation patterns of sessile drops of nanofluids: (a) "coffee ring" patterns in the suspension of single-walled carbon nanotube [57]; (b) multi-ring patterns in the suspension of titanium dioxide nanoparticles in ethanol [5]; (c) uniform-deposition patterns in the suspension of graphite nanoparticles [58]; (d) cracking patterns in the suspension of silica nanoparticles [43].…”

Section: Sessile Drops Of Nanofliudsmentioning

confidence: 99%

Wetting and Drying of Colloidal Droplets: Physics and Pattern Formation

Chen¹,

Zhang²,

Zang³

et al. 2016

Advances in Colloid Science

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When a colloidal droplet is deposited on a solid substrate at ambient condition, it will experience the processes of wetting and drying spontaneously. These ostensibly simple and ubiquitous processes involve numerous physics: droplet spreading and wetting, three-phase contact line motion, flow fields inside droplets, and mass transportation within droplets during drying. Meanwhile, the continuous evaporation of liquid produces inter-and/or intra-molecular interactions among suspended materials and builds up the internal stress within droplets. After drying, interesting and complex desiccation patterns form in the dried droplets. These desiccation patterns are believed to have wide applications, e.g., medical diagnosis. However, many potential applications are limited by the current understanding of wetting and drying of colloidal droplets. This chapter focuses on the complex physics associated with these processes and the pattern formation in the dried colloidal droplets. Moreover, potential applications of these desiccation patterns and prospective works of wetting and drying of the colloidal droplets are outlined in this chapter.

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“…The particles get convected along with the fluid and deposited at the edge forming coffee ring pattern [15]. Pattern deposition depends on many factors like particle size [17,18], droplet size [18], nature of substrate surface [19,20], particle shapes [21,22], flow pattern inside droplet [15,23,24], presence of surfactant 15 and additives [25,26], substrate temperature [22], droplet composition [27] etc.…”

Section: Introductionmentioning

confidence: 99%

“…Evaporation condition from the droplet surface affects the flow pattern leading to different deposition pattern [29,24]. For edge enhanced evaporation, fluid flows towards the center forming ring like deposits 25 and for center enhanced evaporation, fluid flows towards the top of the droplet leading to uniform deposits [24]. Internal flow generated inside the droplet by electrowetting can suppress the coffee ring forming uniform deposits [30].…”

Section: Introductionmentioning

confidence: 99%