Suppression of coffee ring: (Particle) size matters

Bansal, Lalit; Seth, Pranjal; Murugappan, Bhubesh; Basu, Saptarshi

doi:10.1063/1.5034119

Cited by 42 publications

(32 citation statements)

References 26 publications

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“…The effect of capillary flow on particles can be overcome by triggering a tension gradient (Marangoni flow) [30] in droplets [31][32][33][34][35], so a uniform and flat film without "coffee rings" can be obtained [36]. Sometimes, increasing the particle size or changing the particle shape can reduce the effect of capillary force and weaken the "coffee ring" effect [37][38][39]. The solute volume fraction can also be varied to adjust the degree of sparsity or density on deposition patterns [40,41].…”

Section: Type Of Qd Filter Array Operating Range Referencementioning

confidence: 99%

Influence of Ink Properties on the Morphology of Long-Wave Infrared HgSe Quantum Dot Films

Wang¹,

Zhang²,

Wang³

et al. 2022

Nanomaterials

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As the core device of the miniature quantum dot (QD) spectrometer, the morphology control of the filter film array cannot be ignored. We eliminated strong interference from additives on the spectrum of a long-wave infrared (LWIR) QD filter film by selecting volatile additives. This work is significant for detecting targets by spectroscopic methods. In this work, a filter film with characteristic spectral bands located in the LWIR was obtained by the natural evaporation of QD ink, which was prepared by mixing various volatile organic solvents with HgSe QD–toluene solution. The factors affecting the morphology of HgSe LWIR films, including ink surface tension, particle size, and solute volume fraction, were the main focus of the analysis. The experimental results suggested that the film slipped in the evaporation process, and the multilayer annular deposition formed when the surface tension of the ink was no more than 24.86 mN/m. The “coffee ring” and the multilayer annular deposition essentially disappeared when the solute particles were larger than 188.11 nm. QDs in the film were accumulated, and a “gully” morphology appeared when the solute volume fraction was greater than 0.1. In addition, both the increase rate of the film height and the decrease rate of the transmission slowed down. The relationship between film height and transmission was obtained by fitting, and the curve conformed to the Lambert–Beer law. Therefore, a uniform and flat film without “coffee rings” can be prepared by adjusting the surface tension, particle size, and volume fraction. This method could provide an empirical method for the preparation of LWIR QD filter film arrays.

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Section: Type Of Qd Filter Array Operating Range Referencementioning

confidence: 99%

Influence of Ink Properties on the Morphology of Long-Wave Infrared HgSe Quantum Dot Films

Wang¹,

Zhang²,

Wang³

et al. 2022

Nanomaterials

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“…For instance, coffee-ring effects are well-known phenomena by which colloidal particles tend to accumulate at triple-phase (solid, liquid, air) contact lines, leaving ring-like patterns during evaporation and thus disrupting formation of uniform deposit patterns 14 – 16 . Additionally, Marangoni flows 17 – 20 , wetting–dewetting transitions 21 – 24 , temperature variations 22 , 25 , 26 , and gravitational effects 26 – 31 can modify the physical phenomena that govern evaporation and deposition dynamics of colloidal fluids.…”

Section: Introductionmentioning

confidence: 99%

Evaporation and deposition of inclined colloidal droplets

Kim

Gonçalves

Jung

et al. 2021

Sci Rep

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Colloidal droplets on flat solid substrates commonly leave symmetric ring-like deposits due to coffee-ring flows during evaporation. On inclined substrates, droplet shapes may become asymmetric by gravity. On this basis, it is not clear how their evaporation dynamics and final deposits are changed depending on inclination. Here we explore evaporation and deposition dynamics of colloidal droplets on inclined substrates, mainly by controlling colloidal particle size, substrate inclination, and relative humidity, which are crucial to gravitational intervention and evaporation dynamics. We experimentally investigate two different flows with opposite directions: downward sedimentation flows by gravity ($$v_s$$ v s ) and upward capillary flows by evaporation ($$v_c$$ v c ). We find that the competition of two flows determines the formation of final deposits with a flow speed ratio of $$\alpha = v_s/v_c$$ α = v s / v c . Notably, for $$\alpha$$ α $$\ll$$ ≪ 1, evaporation-driven upward flows overwhelm sedimentation-driven downward flows, resulting in accentuated particle movement towards the top ring, which seems to defy gravitational intervention. We suggest a possible explanation for the flow speed dependence of final deposits in evaporating colloidal droplets. This study offers a framework to understand the intervention of inclination to the formation of final deposits and how to overcome the deposit pattern radial asymmetry, achieving symmetric deposit widths from inclined colloidal droplets.

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“…One of the most common phenomena related to the droplets is evaporation, that is, vaporization, which plays an essential role in various industrial fields. For example, the droplet evaporation has been classified into uniform, coffee-ring, and multi-ring patterns [1][2][3][4][5][6][7][8][9][10] for various uses, including ink-jet printing techniques [11][12][13] and fuel evaporation in a combustion engine [14][15][16][17]. Some researchers have also found applications for droplet evaporation in nano-chromatography [18,19], medical diagnosis, food quality assessment, and medicine manufacture [20,21].…”

Section: Introductionmentioning

confidence: 99%

Review of the binary mixture droplet evaporation studies

et al. 2021

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Understanding the evaporation characteristics of sessile binary mixture droplets (BMDs) is crucial in various industries, such as surface coating, ink-jet printing, evaporators, fuel combustion, and medical diagnosis. The underlying physics of BMDs has not yet been fully explored despite numerous prior studies. This paper reviews the recent studies on evaporating BMD and examines various studied and unaddressed issues. First, we introduce measurement techniques to estimate time-varying mixture concentrations of BMDs during evaporation. Next, the theoretical models that have been developed to predict selective evaporation dynamics of BMDs are reviewed and summarized. Finally, this paper reviews the recent studies that have examined the three distinct stages of the contact line motion and internal flows of BMDs.

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Suppression of coffee ring: (Particle) size matters

Cited by 42 publications

References 26 publications

Influence of Ink Properties on the Morphology of Long-Wave Infrared HgSe Quantum Dot Films

Influence of Ink Properties on the Morphology of Long-Wave Infrared HgSe Quantum Dot Films

Evaporation and deposition of inclined colloidal droplets

Review of the binary mixture droplet evaporation studies

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