scholarly journals Experimental Investigation of the Wettability of Protective Glove Materials: A Biomimetic Perspective

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emilia Irzmańska ◽  
Aleksandra Jastrzębska ◽  
Łukasz Kaczmarek ◽  
Agnieszka Adamus-Włodarczyk
Keyword(s):  
Experimental Investigation ◽  
Free Energy ◽  
Surface Topography ◽  
Surface Free Energy ◽  
Work Of Adhesion ◽  
Textured Surface ◽  
Butadiene Rubber ◽  
Hydrophobic Properties ◽  
Nitrile Butadiene Rubber ◽  
Different Levels

Abstract The objective of the present work was to evaluate the surface wettability of commercially available polymeric protective gloves, as well as to determine the effects of their surface topography in conjunction with the glove material on the hydrophobic properties of the final products, together with surface free energy (SFE) and work of adhesion. The geometric structures imparted to the surface led to different levels of hydrophobicity and SFE. Most of the studied materials were characterized by good wettability properties. It was shown that a textured surface topography affects wettability. The highest SFE was found for nitrile butadiene rubber materials. All materials except for nitrile butadiene rubber exhibited good hydrophobic properties and relatively low work of adhesion.

Hydrophilic-Hydrophobic Characteristics of Wood-Polymer Composites Filled with Modified Wood Particles

2018 ◽  
Vol 762 ◽  
pp. 176-181
Author(s):  
Jevgenijs Jaunslavietis ◽  
Galia Shulga ◽  
Jurijs Ozolins ◽  
Brigita Neiberte ◽  
Anrijs Verovkins ◽  
...  
Keyword(s):  
Free Energy ◽  
Polymer Composites ◽  
Surface Free Energy ◽  
Moisture Sorption ◽  
Contact Angles ◽  
Work Of Adhesion ◽  
Wood Polymer ◽  
Wood Particles ◽  
Wood Polymer Composites ◽  
Modified Wood

In this study, hydrophobic-hydrophilic characteristics, including contact angle and moisture sorption of a modified wood filler and the wood-polymer composites (WPC) containing it was investigated. The wood filler obtained from aspen sawdust was modified by mild acid hydrolysis and by ammoxidation. Contact angles of the wood particles and the WPC samples were measured with Kruss K100M using the Washburn and Wilhelmy methods, respectively. Work of adhesion was calculated using Young-Dupre equation. Surface free energy as well as its dispersive and polar parts were found using Owens-Wendt-Rabel-Kaelble approach. It was found that the hydrolysis and the ammoxidation led to decrease of the hemicelluloses content in the lignocellulosic matrix. Beside this, the ammoxidation favours the formation of amide bonds in the ammoxidised particles. These changes enhanced the contact angles, decreased the work of adhesion, and decreased surface free energy of the WPC samples filled with the modified particles in comparison with the WPC sample that contained the unmodified ones. The treatment of the wood particles decreased the wettability towards water, but increased it towards recycled polypropylene. This positively effects mechanical properties of the samples.

scholarly journals Enhancement of Polyvinyl Acetate (PVAc) Adhesion Performance by SiO2 and TiO2 Nanoparticles

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 707 ◽  
Author(s):  
Gorana Petković ◽  
Marina Vukoje ◽  
Josip Bota ◽  
Suzana Pasanec Preprotić
Keyword(s):  
Free Energy ◽  
Tio2 Nanoparticles ◽  
Surface Free Energy ◽  
Polyvinyl Acetate ◽  
Adhesive Bonding ◽  
Sio2 Nanoparticles ◽  
Work Of Adhesion ◽  
Nanoparticles Concentration ◽  
Adhesion Performance ◽  
End Use

Post press processes include various types of bonding and adhesives, depending upon the nature of adherends, the end use performance requirements and the adhesive bonding processes. Polyvinyl acetate (PVAc) adhesive is a widely used adhesive in the graphic industry for paper, board, leather and cloth. In this study, the enhancement of PVAc adhesion performance by adding different concentrations (1%, 2% and 3%) of silica (SiO2) and titanium dioxide (TiO2) nanoparticles was investigated. The morphology of investigated paper-adhesive samples was analyzed by SEM microscopy and FTIR spectroscopy. In addition, the optimal adhesion at the interface of paper and adhesive was found according to calculated adhesion parameters by contact angle measurements (work of adhesion, surface free energy of interphase, wetting coefficient). According to obtained surface free energy (SFE) results, optimum nanoparticles concentration was 1%. The wettability of the paper-adhesive surface and low SFE of interphase turned out as a key for a good adhesion performance. The end use T-peel resistance test of adhesive joints confirmed enhancement of adhesion performance. The highest strength improvement was achieved with 1% of SiO2 nanoparticles in PVAc adhesive.

The Influence of Mechanical and Mechanochemical Activation of Hardwood Wood Waste on Biocomposite Properties

2019 ◽  
Vol 800 ◽  
pp. 200-204
Author(s):  
Jevgenijs Jaunslavietis ◽  
Galia Shulga ◽  
Jurijs Ozolins ◽  
Brigita Neiberte ◽  
Anrijs Verovkins ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Mechanochemical Activation ◽  
Moisture Sorption ◽  
Wood Waste ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Aspen Wood ◽  
Wood Polymer ◽  
The Impact

As the demand for sustainable environment friendly materials increases, the biocomposites such as wood-polymer composite (WPC) have gained more attention in past years. Wood wastes and by-products like sawdust, chips, bark and wood residues as well as recycled polymers can serve as raw materials for production of WPC. However, there are still many issues obtaining WPCs, mainly a poor compatibility between a hydrophobic polymer matrix and a hydrophilic wood filler. In the present study, mechanical and mechanochemical activation of aspen wood waste were performed to increase their compatibility with recycled polypropylene matrix in the WPC, and the impact of both methods on the biocomposite properties were studied. It was found, that mechanochemical activation (MCA) of aspen wood particles leads to increased hydrophobicity of the obtained WPC compared to the WPC with mechanically activated (MA) particles. Work of adhesion with water was remarkably lower for the WPC modified by MCA which also correlates with moisture sorption results. Surface free energy of the WPC modified by MCA was lower compared to the WPC modified by MA, mostly due to decreased the polar component of surface free energy. The modulus of elasticity (MOE) were competitive for both the WPC formulations, however, MCA led to increased flexural strength of WPC compared to MA.

scholarly journals Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoe Hosoda ◽  
Mari Nakamoto ◽  
Tadatomo Suga ◽  
Stanislav N. Gorb
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Adhesion Force ◽  
Intermolecular Forces ◽  
Adhesive Force ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Adhesion Mechanism ◽  
Ladybird Beetle ◽  
Ladybird Beetles

AbstractWhy can beetles such as the ladybird beetle Coccinella septempunctata walk vertically or upside-down on a smooth glass plane? Intermolecular and/or capillary forces mediated by a secretion fluid on the hairy footpads have commonly been considered the predominant adhesion mechanism. However, the main contribution of physical phenomena to the resulting overall adhesive force has yet to be experimentally proved, because it is difficult to quantitatively analyse the pad secretion which directly affects the adhesion mechanism. We observed beetle secretion fluid by using inverted optical microscopy and cryo-scanning electron microscopy, which showed the fluid secretion layer and revealed that the contact fluid layer between the footpad and substrate was less than 10–20 nm thick, thus indicating the possibility of contribution of intermolecular forces. If intermolecular force is the main physical phenomenon of adhesion, the force will be proportional to the work of adhesion, which can be described by the sum of the square roots of dispersive and polar parts of surface free energy. We measured adhesion forces of ladybird beetle footpads to flat, smooth substrates with known surface free energies. The adhesive force was proportional to the square-root of the dispersive component of the substrate surface free energy and was not affected by the polar component. Therefore, intermolecular forces are the main adhesive component of the overall adhesion force of the ladybird beetle. The footpads adhere more strongly to surfaces with higher dispersive components, such as wax-covered plant leaves found in the natural habitat of ladybird beetles. Based on the present findings, we assume ladybird beetles have developed this improved performance as an adaptation to the variety of plant species in its habitat.

Surface chemical composition and roughness as factors affecting the wettability of thermo-mechanically modified oak (Quercus robur L.)

Holzforschung ◽  
2018 ◽  
Vol 72 (11) ◽  
pp. 993-1000 ◽  
Author(s):  
Agnieszka Laskowska ◽  
Janusz W. Sobczak
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Glassy Polymers ◽  
Work Of Adhesion ◽  
Densified Wood ◽  
Factors Affecting ◽  
X Ray ◽  
Densification Temperature

AbstractEuropean oak wood (W) was thermo-mechanically modified (TM) via densifying at 100 and 150°C and the surface properties of the TMW were investigated. The contact angle (CA) of the wood with the reference liquids water and diiodomethane was determined using the sessile drop method. The surface free energy of the TMW on tangential sections within the first 60 s after applying a drop was analyzed. The roughness parameters Ra and Rz parallel (‖) and perpendicular (⊥) to the grain were investigated. The wettability analysis showed that densified wood had a higher CA and lower work of adhesion and surface free energy than non-densified wood. An X-ray photoelectron spectroscopy [XPS or electron spectroscopy for chemical analysis (ESCA)] analysis showed that the oxygen to carbon atoms ratio (O/C ratio) of densified wood surface was lower than that of non-densified wood. The carbon C1-C2 atoms ratio (C1/C2 ratio) increased with increasing TM temperature. The results were interpreted as being that extractives migrate to the surface and amorphous and glassy polymers, i.e. lignin and hemicelluloses, in wood are rearranged. Increasing densification temperature makes TMW surfaces more hydrophobic.

scholarly journals Surface Free Energy Utilization to Evaluate Wettability of Hydrocolloid Suspension on Different Vegetable Epicarps

Coatings ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 16 ◽  
Author(s):  
Fernando Osorio ◽  
Gonzalo Valdés ◽  
Olivier Skurtys ◽  
Ricardo Andrade ◽  
Ricardo Villalobos-Carvajal ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Hydroxypropyl Methylcellulose ◽  
Energy Utilization ◽  
Work Of Adhesion ◽  
Edible Coatings ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
The Difference

Surface free energy is an essential physicochemical property of a solid and it greatly influences the interactions between vegetable epicarps and coating suspensions. Wettability is the property of a solid surface to reduce the surface tension of a liquid in contact with it such that it spreads over the surface and wets it, resulting from intermolecular interactions when the two are brought together. The degree of wetting (wettability) is determined by an energy balance between adhesive and cohesive work. The spreading coefficient (Scf/food) is the difference between the work of adhesion and the work of cohesion. Surface wettability is measured by the contact angle, which is formed when a droplet of a liquid is placed on a surface. The objective of this work was to determine the effect of hydroxypropyl methylcellulose (HPMC), κ-carrageenan, glycerol, and cellulose nanofiber (CNF) concentrations on the wettability of edible coatings on banana and eggplant epicarps. Coating suspension wettability on both epicarps were evaluated by contact angle measurements. For the (Scf/food) values obtained, it can be concluded that the surfaces were partially wet by the suspensions. Scf/food on banana surface was influenced mainly by κ-carrageenan concentration, HPMC-glycerol, κ-carrageenan-CNF, and glycerol-CNF interactions. Thus, increasing κ-carrageenan concentrations within the working range led to a 17.7% decrease in Scf/banana values. Furthermore, a HPMC concentration of 3 g/100 g produced a 10.4% increase of the Scf/banana values. Finally, Scf/fruit values for banana epicarps were higher (~10%) than those obtained for eggplant epicarp, indicating that suspensions wetted more the banana than the eggplant surface.

Interaction at interfaces and induction of surface free energy components

1987 ◽  
Vol 52 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Organic Liquid ◽  
Interaction Mechanism ◽  
Work Of Adhesion ◽  
Polar Component ◽  
Published Data ◽  
Free Energies ◽  
Dispersion Component ◽  
Mechanism Of Interaction

A set of published data on surface free energy (γ1, γ2) and interfacial energy (γ12) for interfaces mercury-organic liquid, mercury-water, and water-organic liquid (125 pairs altogether) has been critically evaluated. It has been found that the Antonow rule does not hold, that the Neumann equation is suitable for determining the work of adhesion, if γ1 and γ2 are not too different, and that the Fowkes equation can be used to assess the type of interaction at the interface. A hypothesis has been suggested which states that, besides the interaction between dispersion components of the surface free energies of the adjoining phases and the interaction between the non-dispersion components of the same type in bulk, a non-dispersion component of one phase may interact by inducing a component of the same type in the other phase near the interface. Relations concerning the mechanism of interaction at the interface have been derived. Also, the relation between the Girifalco-Good, Neumann and complemented Fowkes equation has been evaluated. For the particular liquids the dispersion portion of their surface free energies and the interaction mechanism at their interface with water and mercury have been estimated. For water, e.g. the polar component of the surface free energy (14.7 mJ m-2) and the hydrogen-bond component (36.3 mJ m-2) have been determined. The introduction of the induced component of the surface free energy is shown, as an example, for water-aromatic hydrocarbons and water-alcohols systems.

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