scholarly journals Research and Prediction of Wettability of Irregular Square Column Structure on Polymethyl Methacrylate (PMMA) Surface Prepared by Femtosecond Laser

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 529
Author(s):  
Bangfu Wang ◽  
Juan Song
Keyword(s):  
Contact Angle ◽  
Femtosecond Laser ◽  
Prediction Model ◽  
Polymethyl Methacrylate ◽  
Groove Width ◽  
Complete Wetting ◽  
Column Structure ◽  
Pmma Surface ◽  
Incomplete Wetting ◽  
Wetting Model

Based on the contact angle prediction model of a traditional square column structure, the prediction models for wettability of a parallelogram square column structure (PSCS) on polymethyl methacrylate (PMMA) surface prepared by femtosecond laser were established. An experiment was conducted to analyze the rationality of the established complete wetting model and incomplete wetting model. It was found that the incomplete wetting prediction model of the square column structure was more in line with the actual situation. For PSCS, the length of both the long and short sides of the boss and the width of the groove exerted an impact on the contact angle prediction results. Under the condition that the length of the long and short sides of the boss remained unchanged and the groove width increased, the contact angle increased under complete wetting and incomplete wetting. In contrast, under the condition that the long side length of the boss and the groove width remained unchanged and the short side length of the boss increased, the contact angle increased under complete wetting but decreased under incomplete wetting. The maximum contact angle reached 135.65°, indicating that PSCS on PMMA surface enhanced the surface hydrophobicity of the material.

scholarly journals Investigation and Prediction on Regulation of Hydrophobicity of Polymethyl Methacrylate (PMMA) Surface by Femtosecond Laser Irradiation

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 386
Author(s):  
Bangfu Wang ◽  
Yongkang Zhang ◽  
Juan Song ◽  
Zhongwang Wang
Keyword(s):  
Contact Angle ◽  
Femtosecond Laser ◽  
Prediction Model ◽  
Laser Irradiation ◽  
Structural Parameters ◽  
Edge Length ◽  
Contact Angles ◽  
Groove Structure ◽  
Incomplete Wetting ◽  
Wetting Model

This study presents the contact angle prediction model of a trapezoidal groove structure based on the laser irradiation on polymethyl methacrylate (PMMA). The trapezoidal groove structure was designed and proposed according to the characteristics of a femtosecond laser. First, the complete wetting model and incomplete wetting model which were compatible with the characteristics of the laser mechanism were constructed based on the Gibbs free energy and the structural parameters of the trapezoidal groove structure. Then, based on the contact angle prediction models constructed, the samples were divided into two groups according to the designed structural parameters, and the experimental investigations were carried out. The result demonstrated that the incomplete wetting prediction model was more in line with the actual situation. The convex width and the top edge length of spacing of the trapezoidal groove structure both affected the contact angle prediction results. From both the experimental contact angles and the contact angles predicted by the incomplete wetting model, it could be known that the contact angle reached 138.09° when the ratio of the convex width to the top edge length of spacing was 0.25, indicating that the smaller the ratio of the convex width to the top edge length of spacing, the better the hydrophobicity of PMMA.

Siliconic and Acrylic Resins Dispersed in Water as Protectives for Stone Surface

1992 ◽  
Vol 267 ◽  
Author(s):  
Guido Biscontin ◽  
P. Maravelaki ◽  
E. Zendri ◽  
A. Glisenti
Keyword(s):  
Contact Angle ◽  
Protective Effect ◽  
Water Absorption ◽  
Water Repellency ◽  
Point Of View ◽  
General Effect ◽  
Pore Filling ◽  
Complete Wetting ◽  
Vapour Permeability ◽  
Acrylic Resins

The aim of the present work is to compare the protective effect of solvent and water dispersed products on marble, Lecce and Istria stones. This choice is justified by the need of products effective also from the ecological and toxicological point of view. To obtain these informations two tests have been chosen: contact angle and water absorption. The contact angle may, in theory, be considered a measure of the water repellency, since complete wetting implies a contact angle of 0° and absolutely no wetting an angle of 180°. This does not apply to the water absorption by capillarity test because the absorption variation may be caused by either the water repellency action of the treatments or by the pore filling. However this test may give practical information about the general effect of the treatments. Moreover, the effect of treatments on permeability was investigated by vapour permeability test. Protective effect was studied after application of the products and at various stages of artificial weathering.

scholarly journals Femtosecond Laser Micro-/Nano-Texturing of Stainless Steels for Surface Property Control

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 512 ◽  
Author(s):  
Aizawa ◽  
Inohara ◽  
Wasa
Keyword(s):  
Contact Angle ◽  
Fractal Dimension ◽  
Femtosecond Laser ◽  
Surface Properties ◽  
Stainless Steels ◽  
Surface Property ◽  
Textured Surface ◽  
Surface Geometry ◽  
Static Contact ◽  
Property Control

Surface geometry has had an influence on the surface property, in addition to the intrinsic surface energy, of materials. Many physical surface modification methods had been proposed to control the solid surface geometry for modification of surface properties. Recently, short-pulse lasers were utilized to perform nano-texturing onto metallic and polymer substrates for the improvement of surface properties. Most of the papers reported that the hydrophilic metallic surface was modified to have a higher contact angle than 120–150°. Little studies explained the relationship between surface geometry and surface properties. In the present study, the laser micro-/nano-texturing was developed to describe this surface-geometric effect on the static contact angles for pure water. Micropatterns with multi spatial frequencies are designed and synthesized into a microtexture. This tailored microtexture was utilized to prepare for computer aided machining (CAM) data to control the femtosecond laser beams. The nano-length ripples by laser induced periodic surface structuring (LIPSS) supposed onto this microtexture to form the micro-/nano-texture on the AISI304 substrate surface. Computational geometry was employed to describe this geometric profile. The fractal dimension became nearly constant by 2.26 and insensitive to increase of static contact angle (θ) for θ > 150°. Under this defined self-similarity, the micro-/nano-textured surface state was controlled to be super-hydrophobic by increasing the ratio of the highest spatial frequency in microtextures to the lowest one. This controllability of surface property on the stainless steels was supported by tailoring the wavelength and pitch of microtextures. Exposure testing was also used to evaluate the engineering durability of this micro-/nano-textured surface. Little change of the measured fractal dimension during the testing proved that this physically modified AISI304 surface had sufficient stability for its long-term usage in air.

Interfacial and Wetting Behavior of Cationic, Anionic and Nonionic Surfactants in the Absence and Presence of Lysozyme

2016 ◽  
Vol 10 (2) ◽  
pp. 179-185
Author(s):  
Rajan Patel ◽  
◽  
Neeraj Dohare ◽  
Abbul Bashar Khan ◽  
◽  
...  
Keyword(s):  
Contact Angle ◽  
Physicochemical Properties ◽  
Nonionic Surfactants ◽  
Surface Excess ◽  
Minimum Area ◽  
Opposite Trend ◽  
Different Temperatures ◽  
Pmma Surface ◽  
Presence And Absence ◽  
Contact Angle Analysis

Herein, we discuss various physicochemical properties of cationic (CTAB), anionic (SDBS) and nonionic (TX-100) surfactants in the presence and absence of lysozyme, at different temperatures by using tensiometery. The surface excess (Γmax) decreases with the increase in temperature for all three kinds of surfactants in the presence and absence of lysozyme, but the most prominent decrease is to be observed for SDBS as compared to CTAB and TX-100 in the presence of lysozyme. The minimum area per molecule (Amin) follows the opposite trend as expected. In addition, contact angle analysis was also done to observe the wettability of poly(methyl methacrylate) (PMMA) surface by these surfactants in the presence and absence of lysozyme.

Effect of Annealing on Optical Structures Fabricated by Femtosecond Laser Irradiation Inside Polymethyl Methacrylate

2017 ◽  
Vol 54 (5) ◽  
pp. 051403
Author(s):  
庞博 Pang Bo ◽  
Patricia Scully Patricia Scully ◽  
Anca Taranu Anca Taranu ◽  
Alisdair Macpherson Alisdair Macpherson
Keyword(s):  
Femtosecond Laser ◽  
Laser Irradiation ◽  
Polymethyl Methacrylate ◽  
Femtosecond Laser Irradiation

Precise surface modification of polymethyl-methacrylate with near-infrared femtosecond laser

2015 ◽  
Vol 336 ◽  
pp. 170-175 ◽  
Author(s):  
F. Caballero-Lucas ◽  
C. Florian ◽  
J.M. Fernández-Pradas ◽  
J.L. Morenza ◽  
P. Serra
Keyword(s):  
Surface Modification ◽  
Femtosecond Laser ◽  
Polymethyl Methacrylate ◽  
Near Infrared

scholarly journals Ultrahydrophobic Textiles Using Nanoparticles: Lotus Approach

2008 ◽  
Vol 3 (4) ◽  
pp. 155892500800300 ◽  
Author(s):  
Karthik Ramaratnam ◽  
Swaminatha K. Iyer ◽  
Mark K. Kinnan ◽  
George Chumanov ◽  
Phillip J. Brown ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Contact Angle Hysteresis ◽  
Water Repellency ◽  
Textile Material ◽  
Water Repellent ◽  
Complete Wetting ◽  
Water Contact ◽  
Lotus Effect ◽  
Textile Materials

It is well established that the water wettability of materials is governed by both the chemical composition and the geometrical microstructure of the surface.1 Traditional textile wet processing treatments do indeed rely fundamentally upon complete wetting out of a textile structure to achieve satisfactory performance.2 However, the complexities introduced through the heterogeneous nature of the fiber surfaces, the nature of the fiber composition and the actual construction of the textile material create difficulties in attempting to predict the exact wettability of a particular textile material. For many applications the ability of a finished fabric to exhibit water repellency (in other words low wettability) is essential2 and potential applications of highly water repellent textile materials include rainwear, upholstery, protective clothing, sportswear, and automobile interior fabrics. Recent research indicates that such applications may benefit from a new generation of water repellent materials that make use of the “lotus effect” to provide ultrahydrophobic textile materials.3,4 Ultrahydrophobic surfaces are typically termed as the surfaces that show a water contact angle greater than 150°C with very low contact angle hysteresis.4 In the case of textile materials, the level of hydrophobicity is often determined by measuring the static water contact angle only, since it is difficult to measure the contact angle hysteresis on a textile fabric because of the high levels of roughness inherent in textile structures.

Pseudopartial Grain Boundary Wetting: Key to the Thin Intergranular Layers

2013 ◽  
Vol 333 ◽  
pp. 175-192 ◽  
Author(s):  
Boris B. Straumal ◽  
Alexey Rodin ◽  
A.E. Shotanov ◽  
Alexander B. Straumal ◽  
Olga A. Kogtenkova ◽  
...  
Keyword(s):  
Contact Angle ◽  
Phase Transitions ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Thin Layers ◽  
Second Phase ◽  
Triple Junctions ◽  
Complete Wetting ◽  
Grain Boundary Wetting

The thin layers of a second phase (also called complexions) in grain boundaries (GB) and triple junctions (TJs) are more and more frequently observed in polycrystals. The prewetting (or premelting) phase transitions were the first phenomena proposed to explain their existence. The deficit of the wetting phase in case of complete wetting can also lead to the formation of thin GB and TJ phases. However, only the phenomenon of pseudopartial (or pseudoincomplete, or constrained complete) wetting permitted to explain, how the thin GB film can exist in the equilibrium with GB lenses of a second phase with non-zero contact angle.

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