Predicting the temporal wetting of porous, surfactant-added polydimethylsiloxane (PDMS)

Nam, Gyungmok; Yoon, Sang‐Hee

doi:10.1016/j.jcis.2019.08.081

Cited by 10 publications

(7 citation statements)

References 55 publications

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“…Previously, the model had only been utilized to model the surfactant Silwet L-77's effect on PDMS wetting, and at lower concentrations (0.5−1.0 wt %), some data deviated significantly from the model. 11 Alternatively, the power law dependence of the Hua−Rosen model allows more generalizable data analysis. Figure 3 shows a comparison of the two models' fits to experimental data using three popular surfactants, Triton X-100, PDMS-b-PEO, and Silwet L-77.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the Starov model’s exponential dependence, it is unable to account for the long induction times found in dilute PDMS–surfactant systems. Previously, the model had only been utilized to model the surfactant Silwet L-77’s effect on PDMS wetting, and at lower concentrations (0.5–1.0 wt %), some data deviated significantly from the model . Alternatively, the power law dependence of the Hua–Rosen model allows more generalizable data analysis.…”

Section: Resultsmentioning

confidence: 99%

“…Despite the many applications of DST, surfactant diffusion and adsorption kinetics in silicones are not well studied compared to the kinetics of aqueous solutions of surfactant. Recently, Starov’s theory of surfactant adsorption was adopted to model the wetting of porous, surfactant-laden PDMS. , However, this investigation was limited to a single trisiloxane ethoxylate surfactant (Silwet L-77), and the model is not applicable for describing dilute mixtures. In this paper, we instead adapt Hua and Rosen’s DST model, which was derived empirically and improves upon Starov’s model in its compatibility with the longer time scales of surfactant diffusion in silicones.…”

Section: Introductionmentioning

confidence: 99%

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Modeling Dynamic Surface Tension on Surfactant-Enhanced Polydimethylsiloxane

O'Brien

Paranjape

2021

Langmuir

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Surfactants are often added to aqueous solutions to induce spreading on otherwise unwettable hydrophobic surfaces. Alternatively, they can be introduced directly into solid hydrophobic materialssuch as the soft elastomer, polydimethylsiloxaneto induce autonomous wetting without requiring additional surface or liquid modifications. Given the similarity between mechanisms of these two approaches, models that describe wetting by aqueous surfactant solutions should also characterize wetting on surfactant–solid systems. To investigate this theory, multiple surfactants of varying size and chemical composition were added to prepolymerized PDMS samples. After cross-linking, water droplets were placed on the surfaces at set time points, and their contact angles were recorded to track the temporal evolution of the interfacial tension. Multiple nonlinear models were fitted to this data, their parameters were analyzed, and each goodness of fit was compared. An empirical model of dynamic surface tension was found to describe the wetting process better than the single established model found in the literature. The proposed model adapted better to the longer time scales induced by slow molecular diffusivity in PDMS. Siloxane ethoxylate surfactants induced faster and more complete wetting of PDMS by water than oxyoctylphenol ethoxylates did. The generalizability of this model for characterizing nonionic surfactants of a wide range of physiochemical properties was demonstrated.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling Dynamic Surface Tension on Surfactant-Enhanced Polydimethylsiloxane

O'Brien

Paranjape

2021

Langmuir

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“…This result is consistent with that of the previous studies. 34,45 After the experiments, the results of EDS showed that the carbon, oxygen, and silicon ratios were 33.39, 24.65, and 41.96, respectively, and the oxygen/silicone ratio was 0.587. It can be seen that this is significantly reduced compared to the oxygen/ silicon ratio (≥0.650) of the 0.5 wt % Silwet L-77-added PDMS (Table S1).…”

Section: Resultsmentioning

confidence: 99%

“…Second, this phenomenon is explained by surfactant diffusion. The superhydrophilic tube contains Silwet L-77, a kind of surfactant, which causes surfactant diffusion on the tube surface when wetted with water. ,,− The surfactant is diffused from the PDMS surface to water. When the surfactant diffuses in water, the surface tension of water decreases.…”

Section: Resultsmentioning

confidence: 99%

Air-Stable Aerophobic Polydimethylsiloxane Tube with Efficient Self-Removal of Air Bubbles

et al. 2019

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The adherence of underwater air bubbles to surfaces is a serious cause of malfunction in applications such as microfluidics, transport, and space devices. However, realizing spontaneous and additional unpowered transport of underwater air bubbles inside tubes remains challenging. Although superhydrophilic polydimethylsiloxane (PDMS) tubes are attracting attention as air bubble repellents, superhydrophilic PDMS, which is fabricated via oxygen plasma treatment, has a disadvantage in that it is weak against aging. Here, we present a tube with the ability to self-remove air bubbles, which overcomes the drawback of rapid aging. PDMS containing Silwet L-77 with a hierarchical nano–microstructure exhibiting subaqueous aerophobicity was fabricated. We conducted adherence and saturation experiments of air bubbles using the fabricated PDMS tube with Silwet L-77 to investigate the mechanism of bubbles adhering to and separating from the fabricated tube surface. The developed PDMS with Silwet L-77 exhibits a strong self-removal effect with an air bubble removal of 97.7%. The adherence and saturation experiments suggest that the transparent superhydrophilic–underwater aerophobic PDMS is a potentially exceptional tool for spontaneously separating air bubbles attached to tube surfaces.

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