Glycerol–water sessile drop elongation on PTFE inclines in relation to biochemical applications

Zahidi, Alifa Afiah Ahmad; Cheong, Brandon Huey-Ping; Huynh, So Hung; Vuong, Thach; Liew, Oi Wah; Ng, Tuck Wah

doi:10.1016/j.colsurfa.2015.09.007

Cited by 5 publications

(5 citation statements)

References 37 publications

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“…This is aided to some extent by the ability of AL but not RL to breach initially, similar to situations that were reported previously. 14−16 With evaporation, this contact angle disparity reduces and AL gradually restores back toward its condition before breaching. From the quantitative plots of advancing and receding angles with time (Figure 13A), it can be seen that the rate with which the advancing contact angle reduces is somewhat similar to the rate at which the receding contact angle increases.…”

Section: Resultsmentioning

confidence: 99%

“…The SH plate was placed on a modified optomechanical rotary stage (Edmund Optics, 52-572) previously described. 16 The stage has a 1° resolution and permitted a drop to be located on the SH plate substrate at the gimbal position. This circumvents the need to move the camera when different degrees of tilt are applied and also allows the substrate to be tilted over a large angular range.…”

Section: Methodsmentioning

confidence: 99%

“…The SH plate was placed on a modified optomechanical rotary stage (Edmund Optics, 52-572) previously described . The stage has a 1° resolution and permitted a drop to be located on the SH plate substrate at the gimbal position.…”

Section: Methodsmentioning

confidence: 99%

“…It has been shown that with onset of tilt the advancing contact line breaches first, leaving the receding contact line to determine the drop’s ability to detach. 14−16 This then allows the ability of the drop to resist movement to be enhanced 17−19 or for the shape to be altered 20,21 (if the surface is hydrophilic) by providing additional pinning modes at the locale of the receding contact line.…”

Section: Introductionmentioning

confidence: 99%

“…With increasing tilt, the drop’s ability to accommodate contact angle hysteresis will eventually be exceeded by gravitational force, resulting in its detachment and movement on the surface. It has been shown that with onset of tilt the advancing contact line breaches first, leaving the receding contact line to determine the drop’s ability to detach. − This then allows the ability of the drop to resist movement to be enhanced − or for the shape to be altered , (if the surface is hydrophilic) by providing additional pinning modes at the locale of the receding contact line.…”

Section: Introductionmentioning

confidence: 99%

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Drops on a Superhydrophobic Hole Hanging On under Evaporation

Chung¹,

Huynh²,

Katariya³

et al. 2017

ACS Omega

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Drops with larger volumes placed over a superhydrophobic (SH) surface with a hole do not fall through unless they are evaporated to a size that is small enough. This feature offers the ability to preconcentrate samples for biochemical analysis. In this work, the influence of pinning on the behavior of drops placed on a 0.1 mm thick SH substrate with a 2 mm diameter hole as they evaporated was investigated. With 16 μL of water dispensed, the sessile drop component volume was initially higher than that of the overhanging drop component and maintained this until the later stages where almost identical shapes were attained and full evaporation was achieved without falling off the hole. With 15 μL of water dispensed, the volume of the sessile drop was initially higher than that of the overhanging drop component but the liquid body was able to squeeze through the hole after 180 s due to the contact line not having sufficient pinning strength when it encountered the edge of the hole. This resulted in the liquid body either falling through the hole or remaining pinned with an oval-like shape. When it did not fall-off, the liquid body had volume and contact angle characteristics for the sessile drop and overhanging drop components that were reversed. In the later stages, however, nearly identical shapes were again attained and full evaporation was achieved without falling off the hole. The effects of pinning, despite the substrate being SH, offer another path toward achieving practical outcomes with liquid bodies without the need for chemical surface functionalization. Similarities and differences could be seen in the behavior of a sessile drop on a SH plate that was inclined at 30° to the horizontal and evaporated.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Drops on a Superhydrophobic Hole Hanging On under Evaporation

Chung¹,

Huynh²,

Katariya³

et al. 2017

ACS Omega

Self Cite

View full text Add to dashboard Cite

show abstract

Behaviour of sessile drops revealed in ‘car crash’ like impact

Zahidi

Salleh

Samarasinghe

et al. 2019

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Versatile wetting measurement of microplate wells

Cheong

et al. 2016

Review of Scientific Instruments

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A method to measure the contact angle, which is indicative of wetting, using small liquid volumes dispensed directly on microplate wells is described and demonstrated. Experiments with enhanced green protein samples of volumes 4.4-6 μl showed no measured variance in the contact angle. Experiments with phosphate buffer solution with varied concentrations of a non-ionic detergent (Tween 20) dissolved, however, revealed smaller contact angles with increased detergent concentration. It is experimentally shown that drops can be located up to 7° from the lowest position of the well without affecting the accuracy of contact angle measurements. Numerical simulations confirm the ability of the drops to manifest the correct contact angle despite the lack of axis-symmetry in their shape while residing on a circular surface. This method offers a convenient means to determine the wetting characteristics of different liquid samples in different microplates.

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Glycerol–water sessile drop elongation on PTFE inclines in relation to biochemical applications

Cited by 5 publications

References 37 publications

Drops on a Superhydrophobic Hole Hanging On under Evaporation

Drops on a Superhydrophobic Hole Hanging On under Evaporation

Behaviour of sessile drops revealed in ‘car crash’ like impact

Versatile wetting measurement of microplate wells

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