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Objective The objective of this study is to propose a method for assessing the antiwear‐ability (AW) or surface scratch‐resistance (SR) efficacy of makeup products through in vitro experiments. Materials and method The method primarily involves measuring the change in weight as a means of evaluating the overall effectiveness. AW/SR effects are evaluated by applying a fixed amount of makeup product on artificial fake skin and comparing the weight difference after simulated friction/scratch. Results The in vitro results indicate that this method is easy to operate and yields repeatable data. It consistently reflects differences between samples when compared to clinical studies. Conclusions This method effectively compares the AW/SR effects of makeup products and demonstrates utility in evaluating product efficacy and difference. It holds great scientific and practical value.

Background: The aim of this study was to evaluate the influence of acidic beverages on the mechanical properties of various dental resin-based materials. Methods: A total number of 160 samples were prepared using four types of resin-based materials—Group A (n = 40): flowable composite, Group B (n = 40): heavy-flow composite, Group C (n = 40): resin-based sealant and Group D (n = 40): nano-hybrid composite. Then, the samples were distributed into four subgroups according to the submersion solution: a (n = 10): artificial saliva, b (n = 10): coffee, c (n = 10): cola and d (n = 10): red wine. The Vickers microhardness, Young’s modulus of elasticity and scratch resistance were assessed using a CETR UMT-2 tribometer. Results: The obtained results showed that 14-day submersion of the resin-based materials in coffee, cola and red wine solutions significantly (p < 0.05) decreased the microhardness values (VHN), Young’s modulus of elasticity and scratch resistance. Fourteen days of storage in coffee decreased the microhardness values of flow resin from 117.5 to 81.59 VHN (p < 0.001) whereas the values of the nanohybrid resin decreased from 125.5 to 89.4 (p < 0.001). The elasticity modulus of the heavy flow resin showed a decline from 15.57 to 10.50 GPa after 14 days’ submersion in coffee (p < 0.001), and from 21.29 to 13.10 GPa for the nanohybrid resin after immersion in cola (p < 0.001). For the scratch test, the resin-based sealant showed a significant decrease after 14 days of storage in coffee, from 0.34 to 0.02 units. Conclusions: The submersion of conventional nanohybrid, flowable, heavy-flow composite resins and resin-based sealants in coffee, cola and red wine solutions changes the mechanical properties (Young’s modulus of elasticity, Vickers microhardness and scratch resistance). The most resistant resin-based material to acid attack was the conventional nanohybrid composite resin, followed by heavy flow resin, flowable resin and resin-based sealant.

Ti6Al4V coatings were cold sprayed onto the same bulk alloy at standard conditions, using 800 °C as gas temperature, and a set of new conditions, using 1100°C as gas temperature, which improved coatings performance. Some of these coatings, processed with innovative parameters, were heat treated to promote adhesion and reduce porosity. Scratch tests were performed using a nanoindenter Agilent G200 and the effect of both normal load and scratch velocity were explored. The different mechanisms responsible of wear were evaluated, identifying ploughing and cutting as the main abrasion mechanisms. The wear rate measured in the standard coating was the highest, indicating that this material could not be used to repair the bulk component. However, the abrasion resistance measured in the coatings sprayed at 1100°C was similar to that found in the bulk substrate. Therefore, cold spray could be used for repairing using the new conditions evaluated in this work.

Numerical modeling and experimental work were performed to establish a correlation between the bulk mechanical properties and scratch-induced deformation features in polymers. Three-dimensional finite element method (FEM) parametric study was carried out to investigate the effect of asymmetric tension–compression constitutive behavior on scratch-induced deformation of polymers. The scratch depth and shoulder height of the groove formed during the scratch was analyzed by considering different hypothetical asymmetric tension–compression constitutive behaviors. Experimental work on a set of model polymers was also carried out to validate the FEM findings following the ASTM D7027-05 scratch testing protocol. The results indicate that the compressive behavior, not the tensile behavior, dominates the scratch depth and shoulder height formation. Implication of the present findings for designing scratch resistant polymers is discussed.

A single-walled carbon nanotube (SWCNT)-silica composite thin film on a quartz glass was formed by ultraviolet irradiation (20–40 °C) onto a spin-coated precursor film. With 7.4 mass% SWCNTs, the electrical resistivity reached 7.7 × 10−3 Ω·cm after UV-irradiation. The transmittance was >80% at 178–2600 nm, and 79%–73% at 220–352 nm. Heat treatment increased the transparency and pencil hardness, without affecting the low electrical resistivity. Raman spectroscopy and microscopic analyses revealed the excellent film morphology with good SWCNT dispersal. The low refractive index (1.49) and haze value (<1.5%) are invaluable for transparent windows for novel optoelectronic devices.

Conductive and stretchable electrodes that can be printed directly on a stretchable substrate have drawn extensive attention for wearable electronics and electronic skins. Printable inks that contain liquid metal are strong candidates for these applications, but the insulating oxide skin that forms around the liquid metal particles limits their conductivity. This study reveals that hydrogen doping introduced by ultrasonication in the presence of aliphatic polymers makes the oxide skin highly conductive and deformable. X-ray photoelectron spectroscopy and atom probe tomography confirmed the hydrogen doping, and first-principles calculations were used to rationalize the obtained conductivity. The printed circuit lines show a metallic conductivity (25,000 S cm –1 ), excellent electromechanical decoupling at a 500% uniaxial stretching, mechanical resistance to scratches and long-term stability in wide ranges of temperature and humidity. The self-passivation of the printed lines allows the direct printing of three-dimensional circuit lines and double-layer planar coils that are used as stretchable inductive strain sensors. Hydrogen doping and polymer adsorption at the oxide surface of liquid metal microparticles increase the conductivity and viscoplastic behaviour of the oxide, leading to liquid-metal-based printed circuits with stable resistance up to 500% strain.

Highly transparent coatings with scratch-resistant properties have garnered significant attention in both scientific research and practical applications. In this study, a high-gloss, scratch-resistant, and hydrophobic polyurethane (PU) nanocomposite topcoat was fabricated. To achieve enhanced hydrophobicity, nanosilica (NS) particles were surface-functionalized using two cost-effective silane coupling agents (i.e., octyltriethoxysilane (OTES) and vinyltriethoxysilane (VTES)) with varying silane concentrations (1%, 5%, 10%, and 20% of stoichiometric content) to maximize grafting efficiency. The surface-modified nanoparticles were characterized using FTIR, TGA, and XRD. The water contact angle (WCA) measurements reveal a clear hydrophobicity trend where VTES-modified NS (1% optimal concentration, 135°) exhibits superior water-repellency compared to OTES-modified (5% optimal concentration, 107°) and unmodified NS (52°), demonstrating the effectiveness of vinyl-group functionalization in enhancing surface hydrophobicity. Both pristine and silanized nanoparticles were incorporated into the PU topcoat at 1, 3, and 5wt%, and their effects on gloss, mechanical properties (hardness and scratch resistance), and steel substrate adhesion were evaluated. Notably, the scratch resistance of the PU coating improved by 25% with 5wt% OTES-modified NS and 37.5% with 1 wt% VTES-modified NS, compared to coatings with unmodified NS. WCA measurements show that the pure PU surface has a contact angle of 34°, which decreases to 5° with NS, increases to 91° with OTES-modified NS, and reaches 111° with VTES-modified NS, highlighting the progressive enhancement of hydrophobicity. Nano-scratch testing further revealed that the modified coatings delayed crack initiation, enhancing metal surface durability. This approach also demonstrates scalability for industrial applications, as evidenced by the successful fabrication of automotive topcoat prototypes.

Nanocomposites of polycarbonate (PC) reinforced with nanosized silica particles were prepared by a melt mixing technique in an internal mixer. Two kinds of commercial hydrophilic fumed silicas differing in their specific surface area were added in amounts up to 5% by volume, and their reinforcing action was compared to that of organically modified silica, loaded in the same amounts. Particle–matrix interactions were investigated by means of rheological and dynamic-mechanical thermal analysis, demonstrating the important role played by the organic modification in the interactions with the polymer matrix, and showing an optimal nanoparticle loading around 2 vol%. The scratch resistance of the nanocomposites obtained from hydrophilic silicas was investigated, and a remarkable enhancement in the indenter’s penetration resistance was observed for all the compositions with respect to pristine PC. The same behaviour was observed for the Shore D hardness and for the impact resistance of the nanocomposites that also significantly improved with the maximum load shifting from a minimum value of 521 N for pristine PC up to values grater than 1330 N for the nanocomposites, demonstrating the activation of effective mechanisms of energy dissipation due to the presence of the nanofillers.

Epoxy resins as important organic matrices, thanks to their chemical structure and the possibility of modification, have unique properties, which contribute to the fact that these materials have been used in many composite industries for many years. Epoxy resins are repeatedly used in exacting applications due to their exquisite mechanical properties, thermal stability, scratch resistance, and chemical resistance. Moreover, epoxy materials also have really strong resistance to solvents, chemical attacks, and climatic aging. The presented features confirm the fact that there is a constant interest of scientists in the modification of resins and understanding its mechanisms, as well as in the development of these materials to obtain systems with the required properties. Most of the recent studies in the literature are focused on green fillers such as post-agricultural waste powder (cashew nuts powder, coconut shell powder, rice husks, date seed), grass fiber (bamboo fibers), bast/leaf fiber (hemp fibers, banana bark fibers, pineapple leaf), and other natural fibers (waste tea fibers, palm ash) as reinforcement for epoxy resins rather than traditional non-biodegradable fillers due to their sustainability, low cost, wide availability, and the use of waste, which is environmentally friendly. Furthermore, the advantages of natural fillers over traditional fillers are acceptable specific strength and modulus, lightweight, and good biodegradability, which is very desirable nowadays. Therefore, the development and progress of “green products” based on epoxy resin and natural fillers as reinforcements have been increasing. Many uses of natural plant-derived fillers include many plant wastes, such as banana bark, coconut shell, and waste peanut shell, can be found in the literature. Partially biodegradable polymers obtained by using natural fillers and epoxy polymers can successfully reduce the undesirable epoxy and synthetic fiber waste. Additionally, partially biopolymers based on epoxy resins, which will be presented in the paper, are more useful than commercial polymers due to the low cost and improved good thermomechanical properties.

Refractory high-entropy alloys (RHEAs) were first developed a decade ago for aerospace applications, with the goal of manufacturing high-strength materials having higher structural performance than high-nickel superalloys. Herein, RHEAs were investigated as protective coatings that can provide increased erosion and corrosion resistance for high-temperature components. This is a step to demonstrate their use as a viable, cost-effective solution for both aerospace and energy industry needs. Two nearly equiatomic-composition RHEAs based on HfNbTaZr and MoNbTaVW are examined. A methodology for RHEA coating composition selection, manufacturing, and characterization is presented. It is shown that HfNbTaZr is suitable for harsh environments that do not include nuclear reactor radiation, while MoNbTaVW is suitable for harsh environments that include radiation. The air plasma spray (APS) and high-velocity oxygen-fuel (HVOF) thermal spray coating process is used to deposit 50 to 200-µm thick functional coatings on stainless steel (SS) 321 and Inconel 718 substrates. Contact force-dependent friction and wear rates, as well as depth- and strain rate-dependent hardness, were obtained using spheroconical scratch-based and nanoindentation methods. The data show excellent adhesive properties, high strength, and reasonable homogeneity.