scholarly journals Flowability, Tear Strength, and Hydrophilicity of Current Elastomers for Dental Impressions

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2994
Author(s):  
Fabian Huettig ◽  
Andrea Klink ◽  
Alexander Kohler ◽  
Moritz Mutschler ◽  
Frank Rupp
Keyword(s):  
Contact Angles ◽  
Strength Test ◽  
Tear Strength ◽  
Heavy Body ◽  
Static Contact ◽  
Water Drops

This study investigates 2 polyethers (PE), 2 polyvinylsiloxanethers (VXSE), and 10 polyvinylsiloxanes (PVS), seven of which had a corresponding light-body consistency and seven of which had a corresponding heavy-body consistency. Each light-body elastomer underwent a flowability test using the shark fin method 20, 50, and 80 s after mixing. The tear strength test DIN 53504 was used after setting the time (T0). Next, 24 h later (T1), hydrophilicity testing was used with static contact angles in water drops during polymerization (20, 50, and 80 s, as well as after 10 min). The heavy-body elastomers underwent shark fin testing with a corresponding light-body material at 50 and 80 s after mixing. The results of light-body testing were combined in a score to describe their performance. The highest differences were detected within flowability in shark fin heights between PE and a PVS (means of 15.89 and 6.85 mm) within the maximum tear strengths at T0 between a PVS and PE (3.72 and 0.75 MPa), as well as within hydrophilicity during setting between VXSE and a PVS (15.09° and 75.5°). The results indicate that VSXE and novel PVS materials can significantly compensate shortcomings in PE towards tear strength and hydrophilicity, but not flowability.

scholarly journals TEOS-Based Superhydrophobic Coating for the Protection of Stone-Built Cultural Heritage

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135
Author(s):  
Fotios G. Adamopoulos ◽  
Evangelia C. Vouvoudi ◽  
Eleni Pavlidou ◽  
Dimitris S. Achilias ◽  
Ioannis Karapanagiotis
Keyword(s):  
Cultural Heritage ◽  
Water Repellency ◽  
Contact Angles ◽  
Tetraethyl Orthosilicate ◽  
Superhydrophobic Coating ◽  
Water Penetration ◽  
Wetting Properties ◽  
Aesthetic Appearance ◽  
Static Contact ◽  
Water Drops

Tetraethyl orthosilicate (TEOS) is extensively used in the conservation of stone-built cultural heritage, which is often subjected to water-induced degradation processes. The goal of this study was to produce and study a TEOS-based material with the ability to repel liquid water. A sol solution of TEOS and 1H,1H,2H,2H-perfluorooctyl triethoxysilane (FAS) was prepared and deposited on marble. The static contact angles (CAs) of water drops on the coated marble surface were >170° and the sliding angles (SA) were <5°, suggesting that superhydrophobicity and water repellency were achieved on the surface of the synthesized TEOS-based coating. FTIR and SEM-EDS were employed to characterize the produced coating. The latter offered good protection against water penetration by capillarity, reducing the breathability of marble only by a small extent and with practically no effect on its aesthetic appearance. The durability of the coating was evaluated through various tests that provided very promising results. Finally, the versatility of the method was demonstrated as the TEOS-based coating was successfully deposited onto glass, brass, wood, silicon, paper and silk, which obtained extreme wetting properties.

scholarly journals Effect of sizing agent on interfacial properties of carbon fiber-reinforced PMMA composite

2021 ◽  
Vol 30 ◽  
pp. 2633366X2097865
Author(s):  
Li Jian
Keyword(s):  
Shear Strength ◽  
Surface Treatment ◽  
Photoelectron Spectroscopy ◽  
Resin Composite ◽  
Contact Angles ◽  
Static Contact ◽  
Before And After ◽  
C Value ◽  
Interlayer Shear Strength ◽  
Pmma Resin

The surface treatment of carbon fibers (CFs) was carried out using a self-synthesized sizing agent. The effects of sizing agent on the surface of CFs and the interface properties of CF/polymethyl methacrylate (PMMA) composites were mainly studied. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and static contact angle were used to compare and study the CFs before and after the surface treatment, including surface morphology, surface chemical element composition, and wettability of the surface. The influence of sizing agent on the mechanical properties of CF/PMMA resin composite interface was investigated. The results show that after sizing treatment, the CF surface O/C value increased by 35.1% and the contact angles of CF and resin decreased by 16.2%. The interfacial shear strength and interlayer shear strength increased by 12.6%.

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

scholarly journals Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

2011 ◽  
Vol 2 ◽  
pp. 152-161 ◽  
Author(s):  
Hans J Ensikat ◽  
Petra Ditsche-Kuru ◽  
Christoph Neinhuis ◽  
Wilhelm Barthlott
Keyword(s):  
Chemical Composition ◽  
Water Repellency ◽  
Contact Angles ◽  
Dense Layer ◽  
Lotus Effect ◽  
Nano Structure ◽  
Lotus Leaf ◽  
Water Drops ◽  
The Impact ◽  
Unique Chemical

Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.

The Surface Modification with Fluorocarbon Thin Films for the Prevention of Stiction in Mems

1998 ◽  
Vol 518 ◽  
Author(s):  
Sang-Ho Lee ◽  
Myong-Jong Kwon ◽  
Jin-Goo Park ◽  
Yong-Kweon Kim ◽  
Hyung-Jae Shin
Keyword(s):  
Contact Angle ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Fluorocarbon Films ◽  
Perfluorodecanoic Acid ◽  
Large Hysteresis ◽  
Static Contact ◽  
Receding Contact ◽  
Highly Hydrophobic ◽  
Receding Contact Angle

AbstractHighly hydrophobic fluorocarbon films were prepared by the vapor phase (VP) deposition method in a vacuum chamber using both liquid (3M's FC40, FC722) and solid sources (perfluorodecanoic acid (CF3(CF2)8COOH), perfluorododecane (C12F26)) on Al, Si and oxide coated wafers. The highest static contact angles of water were measured on films deposited on aluminum substrate. But relatively lower contact angles were obtained on the films on Si and oxide wafers. The advancing and receding contact angle analysis using a captive drop method showed a large contact angle hysteresis (ΔH) on the VP deposited fluorocarbon films. AFM study showed poor film coverage on the surface with large hysteresis. FTIR-ATR analysis positively revealed the stretching band of CF2 groups on the VP deposited substrates. The thermal stability of films was measured at 150°C in air and nitrogen atmospheres as a function of time. The rapid decrease of contact angles was observed on VP deposited FC and PFDA films in air. However, no decrease of contact angle on them was observed in N2.

Modeling of Transport During Droplet Deposition and Spreading on Smooth and Microstructured Superhydrophilic Surfaces

2016 ◽  
Author(s):  
Jordan P. Mizerak ◽  
Van P. Carey
Keyword(s):  
Contact Angle ◽  
Contact Angles ◽  
Ansys Fluent ◽  
Effective Contact ◽  
Microstructured Surfaces ◽  
Static Contact ◽  
Droplet Behavior ◽  
Contact Line Pinning ◽  
The Impact ◽  
Superhydrophilic Surfaces

The dynamic behavior of impinging water droplets is studied in the context of varying surface morphologies on smooth and microstructured superhydrophilic surfaces. The goal of this study is to evaluate the capability of contact angle wall adhesion models to accurately produce spreading phenomena seen on a variety of surface types. We analyze macroscale droplet behavior, specifically spreading extent and impinging regime, in situations of varying microscale wetting character and surface morphology. Axisymmetric, volume of fluid (VOF) simulations with static contact angle wall adhesion are conducted in ANSYS Fluent. Simulations are performed on water for low Weber numbers (We<20) on surfaces with features of length scale 5–10μm. Advanced microstructured surfaces consisting of unique wetting characteristics and lengths on each face are also tested. Results show that while the contact angle wall adhesion model shows fair agreement for conventional surfaces, the model underestimates spreading by over 60% for surfaces exhibiting estimated contact angles below approximately 0.5°. Microstructured surfaces adapt the wetting behavior of smooth surfaces with higher effective contact angles based on contact line pinning on morphology features. The propensity of the model to produce Wenzel and Cassie-Baxter states is linked to the spreading radius, introducing an interdependency of microscale wetting and macroscale spreading behavior. Conclusions describing the impact of results on evaporative cooling are also discussed.

scholarly journals Numerical Bifurcation Analysis of a Film Flowing over a Patterned Surface through Enhanced Lubrication Theory

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 405
Author(s):  
Nicola Suzzi ◽  
Giulio Croce
Keyword(s):  
Contact Angle ◽  
Bifurcation Analysis ◽  
Dynamic Contact Angle ◽  
Flow Characteristics ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Inclined Plate ◽  
Lubrication Equation ◽  
Static Contact ◽  
Numerical Bifurcation

The bifurcation analysis of a film falling down an hybrid surface is conducted via the numerical solution of the governing lubrication equation. Instability phenomena, that lead to film breakage and growth of fingers, are induced by multiple contamination spots. Contact angles up to 75∘ are investigated due to the full implementation of the free surface curvature, which replaces the small slope approximation, accurate for film slope lower than 30∘. The dynamic contact angle is first verified with the Hoffman–Voinov–Tanner law in case of a stable film down an inclined plate with uniform surface wettability. Then, contamination spots, characterized by an increased value of the static contact angle, are considered in order to induce film instability and several parametric computations are run, with different film patterns observed. The effects of the flow characteristics and of the hybrid pattern geometry are investigated and the corresponding bifurcation diagram with the number of observed rivulets is built. The long term evolution of induced film instabilities shows a complex behavior: different flow regimes can be observed at the same flow characteristics under slightly different hybrid configurations. This suggest the possibility of controlling the rivulet/film transition via a proper design of the surfaces, thus opening the way for relevant practical application.

Wetting Behavior and Drainage of Water Droplets on Microgrooved Brass Surface

2011 ◽  
Author(s):  
M. A. Rahman ◽  
A. M. Jacobi
Keyword(s):  
Aspect Ratio ◽  
End Milling ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Milling Process ◽  
Water Droplets ◽  
Sliding Angle ◽  
Flat Surfaces ◽  
Micro End Milling ◽  
Water Drops

In the present study, we report the contact angle hysteresis and drainage behavior of water drops on a number of brass surfaces with parallel microgrooves and compare them to the flat baseline surfaces. Parallel micro-grooves with different groove dimensions are fabricated by micro end-milling process without any modification of the surface chemistry. Advancing and receding contact angles in both parallel and perpendicular direction of the grooves and also the drainage behavior of water droplets on the microgrooved surfaces is found to be considerably affected by change in groove geometry parameters. Very high hysteresis is observed for both low (< 0.2) and high aspect ratio (> 0.7) of grooves and also for surfaces with lower groove spacing due to the droplets being in a Wenzel state. For intermediate aspect ratio (0.25–0.70) and larger spacing of the grooves, droplets remain in a Cassie state and the hysteresis is lower in both directions than that on the flat surfaces. Variation of critical sliding angle (angle at the point of incipient sliding of water droplets due to gravity) with groove geometry is investigated for a range of water droplet volume of 15 to 75 μl. Droplets of all volumes are found to slide much more readily on grooved surfaces than when placed on the flat baseline surfaces. Height and spacing of the grooves are also found to have significant influence on the sliding of the water droplets, as critical inclination angle decreased with groove height and increased with groove spacing. The results from this study may be useful in a broad range of applications where water retention plays an important role.

scholarly journals PENGARUH PENYAMAKAN ZIRKONIUM TERHADAP UJI KEKUATAN TARIK, UJI KEKUATAN SOBEK, UJI KEMULURAN DAN UJI SUHU KERUT PADA BERBAGAI JENIS KULIT IKAN (The Effect of Zirconium Tanning Against Tensile Strength Test, Strength Test of Tear, Glide Test, and Wrinkle Temperature Test on Different Fish Types)

2018 ◽  
Vol 13 (2) ◽  
pp. 105
Author(s):  
Rokhmah Hergiyani ◽  
Y. S. Darmanto ◽  
Lukita Purnamayati
Keyword(s):  
Tensile Strength ◽  
Negative Impact ◽  
Strength Test ◽  
Collagen Fibers ◽  
Raw Material ◽  
Tear Strength ◽  
Complex Processes ◽  
Materials Used ◽  
The One ◽  
Physical Changes

Kulit ikan merupakan limbah perikanan yang dapat memberikan dampak negatif pada lingkungan. Salah satu cara untuk menanggulangi limbah tersebut adalah dengan proses penyamakan kulit. Penyamakan kulit adalah rangkaian proses yang sangat kompleks terjadi banyak perubahan fisik dan kimia di satu sisi, bagian yang tidak berguna dihilangkan dari kulit mentah untuk mendapatkan serat kolagen murni dan membuka struktur serat kolagen. Proses penyamakan yang tidak baik mengakibatkan kulit menjadi rusak, lemas, dan kebusukan, sehingga penanganannya dapat dengan cara menambah bahan penyamak untuk menguatkan dan menghindari kebusukan. Bahan penyamak yang digunakan yaitu zirconium. Tujuan penelitian ini adalah untuk mengetahui pengaruh penyamakan zirkonium terhadap uji kekuatan tarik, uji kekuatan sobek, uji kemuluran dan uji suhu kerut pada berbagai jenis ikan. Bahan baku yang digunakan adalah kulit ikan nila, kakap dan bandeng. Metode penelitian yang digunakan adalah experimental laboratories menggunakan Rancangan Acak Lengkap (RAL) dengan tiga kali ulangan dan  menggunakan analisa ragam ANOVA. Hasil uji menunjukan penggunaan zirkonium 7,5% terhadap kulit ikan nila, kakap, dan bandeng berpengaruh nyata (p<0,05) pada kekuatan tarik, kekuatan sobek, kemuluran dan suhu kerut pada karakteristik penyamakan. Penggunaan bahan penyamak zirkonium 7,5% terbaik dihasilkan oleh kulit ikan kakap pada uji kekuatan tarik 1675,84 N/cm2, kekuatan sobek 163,92 N/cm2 dan uji suhu kerut 103,45˚C sedangkan kemuluran untuk hasil terbaik pada kulit bandeng sebesar 28,74%, jadi setiap ikan mempunyai ciri kulit tersendiri pada setiap parameter uji. The skin of the fish waste is a fishery that can give a negative impact on the environment. One way of tackling the waste is by the process of tanning leather. Tanning is a very complex processes occur many chemical and physical changes on the one hand, the useless removed from rawhide to get pure collagen fibers and the open structure of the collagen fibers. The process of tanning is not a good result in the skin becomes broken, buckled, and corruption, so that responses can be with how to add ingredients to strengthen Tanner and avoid corruption. On the research of materials used i.e. Tanners used are zirconium.. The purpose of this research is to know the influence of zirconium tanning against test tensile strength, tear strength test, test and test temperature wrinkle elongation on various types of fish. The raw material used is leather fish tilapia, milkfish and snapper. Research methods used are experimental laboratories using Complete Random Design (RAL) with three-time repeats and a range of analysis using ANOVA. Test results showed the use of zirconium 7.5% against the skin of the fish, snapper, tilapia and milkfish influential real (p < 0.05) on the tensile strength, tear strength, elongation and wrinkle on temperature characteristics of tanning. The use of zirconium Tanner 7.5% best produced by skin test on a snapper 1675.84 tensile strength N/cm2, the strength of RIP 163.92 N/cm2 and test the temperature of the wrinkle 103,45 ˚ C while elongation for the best results on the skin of the banding of 28.74%, so each fish has its own skin characteristics on each test parameter.

scholarly journals Superhydrophobic Fabrics with Mechanical Durability Prepared by a Two-Step Plasma Processing Method

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 351 ◽  
Author(s):  
Kosmas Ellinas ◽  
Angeliki Tserepi ◽  
Evangelos Gogolides
Keyword(s):  
Surface Energy ◽  
Plasma Deposition ◽  
Contact Angle Hysteresis ◽  
Plasma Processing ◽  
High Water ◽  
Contact Angles ◽  
Processing Method ◽  
Static Contact ◽  
Mechanical Durability ◽  
Fabric Surface

Most studies on superhydrophobic fabrics focus on their realization using additive manufacturing (bottom-up) techniques. Here we present the direct modification of three different fabrics using a plasma-based method to obtain anti-adhesive and self-cleaning properties. A two-step plasma processing method is used: (a) for the creation of micro-nanoscale features on the fabric surface (plasma texturing step) and (b) the minimization of the fabric surface energy (by a short plasma deposition step of a very thin, low surface energy layer). The entire process takes only 14 min and all fabrics after processing exhibit high water static contact angles (WSCA > 150°), low contact angle hysteresis (CAH < 7°) and advantageous mechanical durability against hand-rumpling. The method is simple and generic, and it can be therefore expanded to other polymeric fabrics (i.e., acrylic) in addition to polyester, without any limitation rising from the weaving characteristics of the fabric or the starting nature of the material (i.e., hydrophobic or hydrophilic).

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