scholarly journals Polymeric Biomaterials with Complementary Role in the Articular Endoprosthesis I. Surface Characteristics

2019 ◽  
Vol 56 (2) ◽  
pp. 306-308
Author(s):  
Dana Nicoleta Mihai ◽  
Dan Mihailescu ◽  
Sorin Alexandru Ibanescu ◽  
Liliana Savin ◽  
Victor Grigorescu ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Surface Energy ◽  
Methyl Methacrylate ◽  
Surface Characteristics ◽  
Contact Angles ◽  
Cold Hardening ◽  
Partial Replacement ◽  
Bone Cements ◽  
Polymeric Biomaterials ◽  
Complementary Role

The change of the organic bone cements�composition (COO) determines the adjustment of some important properties for the behaviour as fixing material, such as the: superficial tension, polarity, surface energy, viscosity, contraction at polymerisation, porosity. In the present paper we monitored the influence of the composition�s changes for some acrylic cements upon their handling features. The samples were obtained via the partial replacement of the methyl methacrylate (MMA) in the liquid phase of some usual formulas with another acrylic monomer. For these, it was measured the contact angles as wettablility of the fixing material. Moreover, it was estimated the values of the hardening time, important parameter for the application phases of the cements with cold hardening and fixing of the articular endoprostheses.

scholarly journals Study on contact angles and surface energy of MXene films

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5512-5520
Author(s):  
Hang Zhou ◽  
Fuqiang Wang ◽  
Yuwei Wang ◽  
Changping Li ◽  
Changrui Shi ◽  
...  
Keyword(s):  
Surface Energy ◽  
Contact Angles ◽  
Time Dependent ◽  
Wetting Behaviors

This work sheds light on the process- and time-dependent wetting behaviors and surface energy of MXene films.

Frost Formation and its Density Behavior on Various Surfaces

2001 ◽  
Author(s):  
Cheolhwan Kim ◽  
Jongmin Shin ◽  
Alexei V. Tikhonov ◽  
Samchul Ha ◽  
Bongjun Choi
Keyword(s):  
Surface Energy ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Test Time ◽  
Test Results ◽  
Plate Temperature ◽  
Specific Test ◽  
Frost Formation ◽  
Frost Layer ◽  
Density Behavior

Abstract An experimental study has been conducted to investigate the effects of surface energy on frost formation. Test samples with three different surfaces of which Dynamic Contact Angles (DCA) are 23, 55 and 88 degrees are installed in a wind tunnel and exposed to a humid airflow. The thickness and the mass of frost layer are measured and used to calculate frost density while frost formation is visualized simultaneously with their measurements. Results show that frost density increases as time increases at specific test conditions. The air Reynolds number, the airflow humidity and the cold plate temperature are maintained at 12,000, 0.0042 kg/kg and −20 degrees Celsius, respectively. The surface with a lower DCA shows a higher frost density for a two-hour test, but no differences in frost density have been found after two hours of frost generation. Empirical correlations for thickness, mass and density are proposed as the functions of test time and surface energy. Visualization of frost generation was in good agreements with test results.

scholarly journals A Novel Synthetic UV-Curable Fluorinated Siloxane Resin for Low Surface Energy Coating

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 979 ◽  
Author(s):  
Chunfang Zhu ◽  
Haitao Yang ◽  
Hongbo Liang ◽  
Zhengyue Wang ◽  
Jun Dong ◽  
...  
Keyword(s):  
Surface Energy ◽  
Photoelectron Spectroscopy ◽  
Contact Angles ◽  
Proton Nuclear Magnetic Resonance ◽  
Energy Materials ◽  
Uv Curable ◽  
X Ray ◽  
Low Surface Energy ◽  
Low Concentrations ◽  
Siloxane Polymers

Low surface energy materials have attracted much attention due to their properties and various applications. In this work, we synthesized and characterized a series of ultraviolet (UV)-curable fluorinated siloxane polymers with various fluorinated acrylates—hexafluorobutyl acrylate, dodecafluoroheptyl acrylate, and trifluorooctyl methacrylate—grafted onto a hydrogen-containing poly(dimethylsiloxane) backbone. The structures of the fluorinated siloxane polymers were measured and confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. Then the polymers were used as surface modifiers of UV-curable commercial polyurethane (DR-U356) at different concentrations (1, 2, 3, 4, 5, and 10 wt %). Among three formulations of these fluorinated siloxane polymers modified with DR-U356, hydrophobic states (91°, 92°, and 98°) were obtained at low concentrations (1 wt %). The DR-U356 resin is only in the hydrophilic state at 59.41°. The fluorine and siloxane element contents were investigated by X-ray photoelectron spectroscopy and the results indicated that the fluorinated and siloxane elements were liable to migrate to the surface of resins. The results of the friction recovering assays showed that the recorded contact angles of the series of fluorinated siloxane resins were higher than the original values after the friction-annealing progressing.

scholarly journals Adhesion of Individual Attachment Setae of the Spider Cupiennius salei to Substrates With Different Roughness and Surface Energy

2021 ◽  
Vol 7 ◽  
Author(s):  
Bastian Poerschke ◽  
Stanislav N. Gorb ◽  
Clemens F. Schaber
Keyword(s):  
Surface Energy ◽  
Glass Substrate ◽  
Adhesion Force ◽  
Adhesive System ◽  
Adhesive Contact ◽  
Contact Angles ◽  
Individual Variability ◽  
Van Der Waals Interactions ◽  
Smooth Surfaces ◽  
Cupiennius Salei

Dynamic adhesion is a key ability for animals to climb smooth surfaces. Spiders evolved, convergent to geckos, a dry adhesive system made of setae branching into smaller microtrichia ending as spatulae. Several previous studies concentrated either on the whole adhesive claw tuft on the spider´s foot that consists of attachment setae or on the single adhesive contact elements, the microtrichia with spatula-shaped tips. Here, the adhesion of single setae of the spider Cupiennius salei was examined and the morphology of the pretarsus and the fine structure of the setae were studied in further detail. Using individual setae fixed to force sensing cantilevers, their adhesion at different contact angles with a glass substrate was measured as well as their adhesive performance on substrates with different roughness and on smooth surfaces with different surface energies. The results show an individual variability of the adhesive forces corresponding to the seta morphology and especially to the seta tip shape. The tip shapes of the setae vary largely even in neighboring setae of the pretarsal claw tuft that comprises approximately 2,400 setae. Regarding surface energy of the substrate, the adhesion force on hydrophobic polytetrafluoroethylene was 30% of that on a hydrophilic glass substrate, which points to the importance of both van der Waals interactions and hydrogen bonds in spider adhesion.

The pH-Dependent Properties of the Biphasic Calcium Phosphate for Bone Cements

2014 ◽  
Vol 21 ◽  
pp. 3-16 ◽  
Author(s):  
Nuan La Ong Srakaew ◽  
Sirirat Tubsungnoen Rattanachan
Keyword(s):  
Compressive Strength ◽  
Liquid Phase ◽  
Calcium Phosphate ◽  
Phase Analysis ◽  
Calcium Phosphate Cement ◽  
Biphasic Calcium Phosphate ◽  
Setting Time ◽  
Bone Cements ◽  
Apatite Formation ◽  
Apatite Cement

Self-setting calcium phosphate cement (CPC) has been used in bone repair and substitution due to their excellent biocompatibility, bioactive as well as simplicity of preparation and use. The inherent brittleness and slow degradation are the major disadvantages for the use of calcium phosphate cements. To improve the degradation for the traditional CPC, the apatite cement formula incorporated with β-tricalcium phosphate (β-TCP) with varying concentration were studied and the effect of the pH value of liquid phase on the properties of this new calcium phosphate cement formula was evaluated. The apatite cements containing β-TCP for 10 and 40 wt.% were mixed into the aqueous solution with different pH values and then aging in absolute humidity at 37°C for 7 days. The setting time and phase analysis of the biphasic calcium phosphate were determined as compared to the apatite cement. For proper medical application, the compressive strength, the phase analysis and the degradation of the CPC samples at pH 7.0 and 7.4 were evaluated after soaking in the simulated body fluid (SBF) at 37°C for 7 days. The results indicated that the properties of the samples such as the setting time, the compressive strength related to the phase analysis of the set cements. The high degradation of the CPC was found in the cement with increasing β-TCP addition due to the phase after setting. Apatite formation with oriented plate-like morphology was also found to be denser on the surface of the biphasic bone cements after soaking in SBF for 7 days. The obtained results indicated that the cement containing β-TCP mixed with the liquid phase at pH 7.4 could be considered as a highly biodegradable and bioactive bone cement, as compared to the traditional CPC.

Comparative Study of Surface Energies of Native Oxides of Si(100) and Si(111) via Three Liquid Contact Angle Analysis

MRS Advances ◽  
2018 ◽  
Vol 3 (57-58) ◽  
pp. 3379-3390 ◽  
Author(s):  
Saaketh R. Narayan ◽  
Jack M. Day ◽  
Harshini L. Thinakaran ◽  
Nicole Herbots ◽  
Michelle E. Bertram ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Sessile Drop ◽  
Surface Composition ◽  
Ion Beam ◽  
Contact Angles ◽  
Van Der Waals Interactions ◽  
Native Oxides ◽  
Relative Errors ◽  
Contact Angle Analysis

ABSTRACTThe effects of crystal orientation and doping on the surface energy, γT, of native oxides of Si(100) and Si(111) are measured via Three Liquid Contact Angle Analysis (3LCAA) to extract γT, while Ion Beam Analysis (IBA) is used to detect Oxygen. During 3LCAA, contact angles for three liquids are measured with photographs via the “Drop and Reflection Operative Program (DROP™). DROP™ removes subjectivity in image analysis, and yields reproducible contact angles within < ±1°. Unlike to the Sessile Drop Method, DROP can yield relative errors < 3% on sets of 20-30 drops. Native oxides on 5 x 1013 B/cm3 p- doped Si(100) wafers, as received in sealed, 25 wafer teflon boats continuously stored in Class 100/ISO 5 conditions at 24.5°C in 25% controlled humidity, are found to be hydrophilic. Their γT, 52.5 ± 1.5 mJ/m2, is reproducible between four boats from three sources, and 9% greater than γT of native oxides on n- doped Si(111), which averages 48.1 ± 1.6 mJ/m2 on four 4” Si(111) wafers. IBA combining 16O nuclear resonance with channeling detects 30% more oxygen on native oxides of Si(111) than Si(100). While γT should increase on thinner, more defective oxides, Lifshitz-Van der Waals interactions γLW on native oxides of Si(100) remain at 36 ± 0.4 mJ/m2, equal to γLW on Si(111), 36 ± 0.6 mJ/m2, since γLW arises from the same SiO2 molecules. Native oxides on 4.5 x 1018 B/cm3 p+ doped Si(100) yield a γT of 39 ± 1 mJ/m2, as they are thicker per IBA. In summary, 3LCAA and IBA can detect reproducibly and accurately, within a few %, changes in the surface energy of native oxides due to thickness and surface composition arising from doping or crystal structure, if conducted in well controlled clean room conditions for measurements and storage.

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