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1

Surface Energy of Solids: Selection of Effective Substrates for Bioadhesion in Aqueous Media

Boniewicz-Szmyt Katarzyna, Pogorzelski Stanisław

Scientific Journal of Gdynia Maritime University

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2019

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nr 112

7--22

EN

Surface wettability of model solids of different hydrophobicity (from hydrophilic to hydrophobic) in contact with an aqueous medium was determined by measuring the dynamic contact angles (CA) using common techniques: sessile drop, inclined plate and captive bubble. The surface wettability energetics parameters: contact angle hysteresis (CAH), 2D adhesive layer pressure, surface free energy (SFE) and work values of cohesion, adhesion and spreading were determined using the formalism proposed by Chibowski [2003]. CA values depended on the technique used and experimental conditions (flow numbers, spatial heterogeneity and roughness of the sample). The most effective substrates for testing bioadhesion on solids submerged in aqueous media were hydrophilic surfaces (SFE ~ 40–58 mJ m-2; CAH ~ 16–20 mN m-1).

2

Theoretical Model of the Influence of Textile Structure on Wetting Hysteresis

Bachurová M., Wiener J.

Fibres & Textiles in Eastern Europe

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2013

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Vol. 21, no. 2 (98)

80--83

EN

In our work we theoretically analysed the influence of textile structure on the hysteresis of wetting. The situation with current fabrics is complicated and the properties of fibers, yarns, and geometric arrangement also influence their wetting. The basis of the theoretical model is a simple plain weave fabric made from monofilaments. From this model we determined the real contact angle and apparent contact angle, and later we compared these values with results from the experimental measurement.

PL

W pracy przeanalizowano pod względem teoretycznym wpływ struktury tkaniny na histerezę zwilżania. Właściwości włókien, przędz i układ geometryczny mają wpływ na zwilżanie tkanin. Podstawą modelu teoretycznego jest tkanina o splocie prostym wykonana z monofilamentów. Wyznaczono rzeczywisty i pozorny kąt zwilżania, a następnie porównano otrzymane wartości z wynikami pomiarów eksperymentalnych.

3

Determination of surface free energy of polyamide, polypropylene and polyethyleneterephtalate surfaces from contact angle hysteresis

Bachurová M., Wiener J.

Autex Research Journal

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2011

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Vol. 11, no. 3

84--88

EN

Contact angle measurement is a method of surface characterisation of solid materials. The basis of this measurement is to determine the surface energy of solids and thus obtain information on the behaviour of the surface: if it, for example, applies a thin layer on the surface of another material. The surface energy can be determined using contact angle hysteresis, which was used this work.

4

Adsorption of natural surfactants present in sea waters at surfaces of minerals: contact angle measurements

Mazurek A., Pogorzelski S.J., Boniewicz-Szmyt K.

Oceanologia

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2009

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No. 51 (3)

377-403

EN

The wetting properties of solid mineral samples (by contact angles) in original surfactant-containing sea water (Gulf of Gdańsk, Baltic) were characterised under laboratory conditions on a large set (31 samples) of well-classified stones of diverse hydrophobicity using the sessile drop (ADSA-P approach), captive bubble and inclined plate methods. An experimental relation between the static contact angle θ_eq and stone density ρ was obtained in the form θ_eq = B-ρ+ C, where B = 12.23 š 0.92, C = - (19.17 š 0.77), and r2 = 0.92. The histogram of ?eq distribution for polished stone plates exhibited a multimodal feature indicating that the most abundant solid materials (hydrophilic in nature) have contact angles θ_eq = 7.2, 10.7, 15.7 and 19.2^(o), which appear to be applicable to unspecified field stones as well. The contact angle, a pH-dependent quantity, appears to be a sensitive measure of stone grain size, e.g. granite. The captive bubble method gives reproducible results in studies of porous and highly hydrophilic surfaces such as stones and wood. The authors consider the adsorption of natural sea water surfactants on stone surfaces to be the process responsible for contact angle hysteresis. In the model, an equation was derived for determining the solid surface free energy from the liquid's surface tension γ_LV it also enabled the advancing θ_A and receding θ_R contact angles of this liquid to be calculated. Measurements of contact angle hysteresis Δθ(=θ_A - θ_R) with surfactant-containing sea water and distilled water (reference) on the same stone surfaces allowed the film pressure ΔΠ (1.22 to 8.80 mJ m-2), solid surface free energy ??S (-17.03 to -23.61 mJ m-2) and work done by spreading ΔWS (-1.23 to -11.52 mJ m-2) to be determined. The variability in these parameters is attributed to autophobing, an effect operative on a solid surface covered with an adsorptive layer of surfactants. The wetting behaviour of solid particles is of great importance in numerous technological processes including froth flotation, demulgation, anti-foaming procedures and the coal industries. It is believed that the approach presented here and the examples of its application to common sea water/solid mineral systems could be successfully adapted to optimise several surfactant-mediated adsorption processes (see below) of practical value in natural water ecology.