The effects of molecular weight, evaporation rate and polymer concentration on pillar formation in drying poly(ethylene oxide) droplets

Baldwin, Kyle A.; Fairhurst, David

doi:10.1016/j.colsurfa.2012.10.049

Cited by 20 publications

(40 citation statements)

References 26 publications

(35 reference statements)

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“…Even though we did not include the result of PEO solution, we observed similar Marangoni vortex for PEO, which was also observed in a previous study 31 . In fact, PEO has the same chemical structure as PEG but relatively large molecular weight (MW = 600,000, Sigma-Aldrich, USA).…”

Section: Discussionsupporting

confidence: 84%

Altering the coffee-ring effect by adding a surfactant-like viscous polymer solution

Seo

Jang

Chae

et al. 2017

Sci Rep

119

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A uniform deposition of the suspended particles in an evaporating droplet is necessary in many research fields. Such deposition is difficult to achieve, because the coffee-ring effect dominates the internal flow in a droplet. The present study adopts a biocompatible, surfactant-like polymer (Polyethylene glycol, PEG) to break the coffee-ring effect and obtain a relatively uniform deposition of the microparticles with yielding multi-ring pattern over a droplet area. Movements of the suspended particles in evaporating droplets and deposition patterns of them on a glass substrate were analyzed with microscopic images and video files. The PEG in the droplets successfully altered the coffee-ring effect because of the surface tension variation, which induced a centripetal Marangoni flow. Balancing these two phenomena apparently generated the Marangoni vortex. For PEG solution droplets, the pinning–depinning process during evaporation was periodically repeated and multiple rings were regularly formed. In conclusion, adding a surfactant-like viscous polymer in a droplet could provide a uniform coating of suspended particles, such as cells and various biomaterials, which would be essentially required for droplet assays of biomedical applications.

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Section: Discussionsupporting

confidence: 84%

Altering the coffee-ring effect by adding a surfactant-like viscous polymer solution

Seo

Jang

Chae

et al. 2017

Sci Rep

119

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show abstract

“…This behavior is reminiscent of the contraction stage seen in pillar formation in evaporating polymer droplets by Baldwin and Fairhurst (2014). 5.…”

Section: Creeping Salt Dropletsmentioning

confidence: 78%

Droplets of Ionic Solutions

Fairhurst

2015

Droplet Wetting and Evaporation

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“…They concluded that the drying behaviour of these droplets were defined by three critical factors; initial concentration, droplet geometry and evaporation rate. 29 In the latest work of Baldwin et al 30…”

Section: Besides Single Component Fluids and Colloidal Suspensions Dmentioning

confidence: 99%

Effect of Poly(ethylene oxide) Molecular Weight on the Pinning and Pillar Formation of Evaporating Sessile Droplets: The Role of the Interface

et al. 2015

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We report on the drying process of sessile droplets of aqueous poly(ethylene oxide) (PEO) solutions studied by contact angle analysis. Liquid samples were prepared with the same initial concentration of four different molecular weights, M w of PEO. Droplets with initial volumes between 1 µL and 5 µL were left to evaporate while temperature, pressure and relative humidity were kept constant. Residues were formed with either a disk-like puddle or a distinctive tall conical pillar shape. The latter occurred following a four-stage deposition process: pinned drying, during which the contact line is stationary; pseudodewetting, where the receding contact line is induced by precipitation; bootstrap building, during which the liquid droplet is lifted upon freshly-precipitated solid; and late drying. Contact angle analysis allowed us to monitor all stages during drying and consider transitions between stages for different molecular weights. We illustrate the mechanisms taking place during the crucial stages of pinning and depinning, revealing the effect of adhesion and contact line friction for high molecular weights and its influence on the final 2 morphology of the dried PEO solute. To this end, we performed PEO solution droplet evaporation on PEO and PTFE films demonstrating the importance of interfacial interaction phenomena. We show that the formation of disk-like puddles for high molecular weights on glass are associated with continuous droplet contact line pinning. This results from the strong adhesion due to the interdigitation of the loops and tails of a polymer layer (adsorbed on glass during evaporation) with the polymer gel network inside the droplet that forms as water evaporates.

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The effects of molecular weight, evaporation rate and polymer concentration on pillar formation in drying poly(ethylene oxide) droplets

Cited by 20 publications

References 26 publications

Altering the coffee-ring effect by adding a surfactant-like viscous polymer solution

Altering the coffee-ring effect by adding a surfactant-like viscous polymer solution

Droplets of Ionic Solutions

Effect of Poly(ethylene oxide) Molecular Weight on the Pinning and Pillar Formation of Evaporating Sessile Droplets: The Role of the Interface

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