Understanding the wettability of rough surfaces using simultaneous optical and electrochemical analysis of sessile droplets

Sow, Pradeep Kumar; Kung, Chun Haow; Mérida, Walter

doi:10.1016/j.jcis.2017.04.043

Cited by 28 publications

(26 citation statements)

References 78 publications

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“…The contact angles of the surface of CM-Chit gel and CAF nonwovens were illustrated in Figure 4D. For hydrophilic materials, the contact angle decreases with the increase of absorbency [48,49]. The contact angle of CM-Chit gel surface was smaller than that of CAF nonwovens surface, indicating that the CM-Chit gel possessed better hydrophilicity.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

2019

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As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay against Escherichia coli and Staphylococcus aureus indicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.

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Section: Resultsmentioning

confidence: 99%

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

2019

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“…The determination of the actual wetting area under a droplet is important to test Wenzel and Cassie equations in the wetting studies. An electrochemical approach was employed to calculate the true wetted area under a droplet in an experimental study, by using the proportionality between the electrochemically measured double layer capacitance and the solid-liquid interfacial area when a droplet of aqueous electrolyte was used on the hydrophilic glassy carbon disc surface [82]. Solutions of sodium sulfate in varying concentration were used to provide conductivity and the electric double layer formation.…”

Section: Direct Testing Of Wenzel and Cassie Equationsmentioning

confidence: 99%

Dependency of Contact Angles on Three-Phase Contact Line: A Review

Erbil

2021

Colloids and Interfaces

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The wetted area of a sessile droplet on a practical substrate is limited by the three-phase contact line and characterized by contact angle, contact radius and drop height. Although, contact angles of droplets have been studied for more than two hundred years, there are still some unanswered questions. In the last two decades, it was experimentally proven that the advancing and receding contact angles, and the contact angle hysteresis of rough and chemically heterogeneous surfaces, are determined by interactions of the liquid and the solid at the three-phase contact line alone, and the interfacial area within the contact perimeter is irrelevant. However, confusion and misunderstanding still exist in this field regarding the relationship between contact angle and surface roughness and chemical heterogeneity. An extensive review was published on the debate for the dependence of apparent contact angles on drop contact area or the three-phase contact line in 2014. Following this old review, several new articles were published on the same subject. This article presents a review of the novel articles (mostly published after 2014 to present) on the dependency of contact angles on the three-phase contact line, after a short summary is given for this long-lasting debate. Recently, some improvements have been made; for example, a relationship of the apparent contact angle with the properties of the three-phase line was obtained by replacing the solid–vapor interfacial tension term, γSV, with a string tension term containing the edge energy, γSLV, and curvature of the triple contact line, km, terms. In addition, a novel Gibbsian thermodynamics composite system was developed for a liquid drop resting on a heterogeneous multiphase and also on a homogeneous rough solid substrate at equilibrium conditions, and this approach led to the same conclusions given above. Moreover, some publications on the line energy concept along the three-phase contact line, and on the “modified” Cassie equations were also examined in this review.

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“…For accurate wettability analysis based on the capacitance measurement, the relative scale of roughness feature to the mass transport rate within the pore structures and DL thickness must be accounted for. The impact of these roughness‐induced phenomena on the interpretation of the interfacial area has been investigated by studying the effect of ion mobility and electrolyte concentration . A sufficiently low DL charging rate is needed to provide enough time for ion penetration into the entire electrode surface sites within the timeframe of the charging cycle.…”

Section: Definition Of Surface Wettability: Beyond General Classificamentioning

confidence: 99%

Assessment and Interpretation of Surface Wettability Based on Sessile Droplet Contact Angle Measurement: Challenges and Opportunities

Kung

Sow

Zahiri

et al. 2019

Adv Materials Inter

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131

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www.advmatinterfaces.de the sessile CA remains the favored method for quantifying wettability, mostly due to its conceptual and measurement simplicity. [9,31] However, the classification on the basis of the cut-off CA of 90° has attracted criticism. [32,33] The simplistic evaluation criteria of relative wettability are becoming inadequate in satisfying the needs of superwettability studies to classify different wetting phenomena. [34] Several works have questioned the accuracy of the sessile-droplet measurement as the CA value approaches the limits of 0° or 180°. [35,36] Yet, evaluation of surfaces in the superhydrophobic (CA > 150°) and superhydrophilic (CA < 10°) regimes is central in the development of enhanced wettabilities. Moreover, the interpretation of the CA results is often complicated by several factors, including surface smoothness, heterogeneity and cleanliness. [37] The Chun Haow Kung obtained his B.A.Sc. and M.A.Sc. in Chemical Engineering at the University of British Columbia (UBC). His graduate work with Prof. Mérida's group at UBC focused on the development and application of novel wetting characterization techniques, smart stimuli-responsive materials as well as electrochemical and hydrogen energy systems. He is currently a Research Scientist at Ballard Power Systems Inc. where he continues to pursue his interest in the polymer electrolyte membrane (PEM) fuel cell technology. Beniamin Zahiri is currently a researcher in the University of Illinois at Urbana-Champaign

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Understanding the wettability of rough surfaces using simultaneous optical and electrochemical analysis of sessile droplets

Cited by 28 publications

References 78 publications

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

Dependency of Contact Angles on Three-Phase Contact Line: A Review

Assessment and Interpretation of Surface Wettability Based on Sessile Droplet Contact Angle Measurement: Challenges and Opportunities

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