Overview of Materials Used for the Basic Elements of Hydraulic Actuators and Sealing Systems and Their Surfaces Modification Methods.

Rare earth solution (RES) surface modification and air-oxidation methods were used to improve the interfacial adhesion of the carbon fiber reinforced polyimide (CF/PI) composite. The mechanical and tribological properties of the PI composites reinforced by the carbon fibers treated with different surface modification methods were comparatively investigated. Results showed that both the strength parameters (tensile and flexural) of the CF/PI composites improved remarkably due to RES treatment along with enhancement in friction and wear performance.

Metallization of polymer through a novel surface modification applying a photocatalytic reaction

Magnesium and its alloys are being paid much attention recently as temporary implants, such as orthopedic implants and cardiovascular stents. However, the rapid degradation of them in physiological environment is a major obstacle preventing their wide applications to date, which will result in rapid mechanical integrity loss or even collapse of magnesium-based implants before injured tissues heal. Moreover, rapid degradation of the magnesium-based implants will also cause some adverse effects to their surrounding environment, such as local gas cavity around the implant, local alkalization and magnesium ion enrichment, which will reduce the integration between implant and tissue. So, in order to obtain better performance of magnesium-based implants in clinical trials, special alloy designs and surface modifications are prerequisite. Actually, when a magnesium-based implant is inserted in vivo, corrosion firstly happens at the implant-tissue interface and the biological response to implant is also determined by the interaction at this interface. So the surface properties, such as corrosion resistance, hemocompatibility and cytocompatibility of the implant, are critical for their in vivo performance. Compared with alloy designs, surface modification is less costly, flexible to construct multi-functional surface and can prevent addition of toxic alloying elements. In this review, we would like to summarize the current investigations of surface modifications of magnesium and its alloys for biomedical application. The advantages/disadvantages of different surface modification methods are also discussed as a suggestion for their utilization.

Surface modification of crumb rubber and its influence on the mechanical properties of rubber-cement concrete

Glass surface modification is one of the processes which changes its physical properties. Changing optical property is a significant effect of surface modification. Among the surface modification methods, laser surface modification is attractive for researchers. Here, SiO2 glass target was irradiated by Q-switched Nd:YAG laser (1064 nm) in SF6 atmospheres as well as vacuum. In this process, an Nd:YAG laser beam was focused near the glass target while the target was inserted in a chamber containing SF6 atmosphere or at vacuum condition. The surface morphology changes were investigated by scanning electron microscopy (SEM). Noticeable surface changes were observed due to laser irradiation in SF6 atmosphere. Although the absorption lines of SF6 molecule are not near the Nd:YAG laser wavelength, laser-induced breakdown spectroscopy (LIBS) showed decomposition of SF6 molecules near a glass target. The ablated fragments from the target impacted on gas molecules and decomposed them. In this work, LIBS showed that there were several fluorine ions when the target was irradiated in an SF6 atmosphere. This demonstrates SF6 molecule decomposition near the glass target by laser irradiation. The plasma temperature was ~2000 K. This temperature is much less than metallic or other gaseous materials’ plasma temperatures.

Influence of Cu-, Fe-, Co-, and Mn-oxide nanoclusters on sensing behavior of SnO 2 films

Cellular adhesion on surface structures from PA 2200 made through Selective Laser Sintering (SLS) process can be improved by modifying the parts surface. In this paper, different methods for surface modification are presented. The PA 2200 samples were immersed in six different solvents. SEM images and surface roughness tests were performed in order to evaluate the surface modification both for the control group and for the tested groups. The obtained results clearly show that there is a significant difference between the roughness of the control (untreated) surface and each of the treated surfaces. Modifying by immersion, of the PA 2200 structures produced by Selective Laser Sintering process, brings original approaches concerning the use of those procedures in the increase of the surfaces quality.

Surface modification of polymers by plasma treatments for the enhancement of biocompatibility and controlled drug release

Corrosion-resistant and interfacial conductive AlTiVCrMo high-entropy alloy and (AlTiVCrMo)Nx high-entropy ceramics coatings for surface modification of bipolar plates in proton exchange membrane fuel cells

Surface modification with an antithrombin–heparin complex for anticoagulation: Studies on a model surface with gold as substrate

Flax straw and flax fibers are renewable resource and have potential for use in the manufacturing industry. In this study, flax fiber (including 58% flax shives by weight) was studied as a material to be added into polyethylene (high density polyethylene and linear low density polyethylene) in 10% by mass and processed through extrusion and injection molding to biocomposites. Five surface modification methods on flax fibers were carried out and scanning electronic micrographs were taken to analyze the surface characteristic. The biocomposite tensile strength increased and moisture absorption decreased to varying degrees after fiber surface modifications. Among those surface modification techniques, acrylic acid treatment showed a relatively good result in reducing moisture absorption and enhancing tensile properties of biocomposites. It was also found that with increased fiber content (from 10% to 30%), the tensile strength and moisture absorption of biocomposites increased.

As one of the emerging surface treatment technologies, ultrasonic nanocrystal surface modification (UNSM) tends to generate a plastic hardening layer to modify the mechanical and tribological properties of the workpiece near the surface. Among other surface modification methods, the lifting of mechanical performance near-surface region is mainly attributed to the presence of severe plastic deformation (SP2D). Thus, a more gradient distribution of residual stress is also introduced along the working process. The most notable advantage of UNSM technology is to make the surface optimization results precisely controllable through input parameters adjusting. Although the process and optimization results of UNSM on metals have been extensively studied experimentally, there are few studies on the effect of parameters on surface modification characteristics. This is due to the difficulty of conducting experiments to investigate the influence mechanism of the parameters and the procedure is costly and time-consuming. Nevertheless, this greatly limits the specific application studies of UNSM-treated specimens, such as accurate modeling before wear and fatigue testing, etc. In this work, a dynamic process of UNSM is built based on the finite element method (FEM). A displacement-controlled tip ball is modeled to simulate ultrasonic striking behaviors and a single-way process extracted from UNSM has been parametrically investigated carefully. The experimental data is used to verify and corroborate the FE results and it shows a good agreement. The depth and maximum value of residual stress are measured in the post-processing stage. As a result, the numerical results show that the UNSM-treated specimen exhibits a higher gradient of residual stress and plastic strain than its substrate.

Polymers are commonly used materials for microfluidic chip fabrication, because they are standardized in fabrication and low in cost. However, most polymeric materials that are readily fabricated on the industrial scale are hydrophobic, which is inconvenient for the injection and flow of the aqueous solution, resulting in poor analytical performance for biochemical assays. In this work, we present a straightforward and ultrastable surface modification process for polymeric chips. A one-step modification by using norepinephrine bitartrate monohydrate as a modification reagent is completed at room temperature. The hydrophilicity of the polymeric surfaces increases dramatically. Surface modification is stable for at least 2.5 years, allowing for autoinjection of aqueous solution into the channels. The chips are applied in the immunoassay of alpha-fetoprotein (AFP). The low nonspecific adsorption after modification results in significantly decreased background noise, optimized signal-to-noise ratios (SNR), and dramatically enhanced reproducibility of the immunoassay. Thirty clinical human serum samples are analyzed; these results strongly correlated with the values obtained using commercial test kits. We anticipate that this surface modification method can be used for immunoassay devices in analytical and biosensing technology.

The modern textile fibre treatments aim to obtain the required level of beneficial effect while attempting to confine the modification to the fibre surface. Recently, much attention has been focused on different physical methods of fibre surface modification, cold plasma treatment being considered as very useful. Moreover, there are efficient chemical methods available, such as peroxide, biopolymer and enzyme treatment. Some interesting combinations of these physical and chemical surface modification methods as means to modify fibre surface topography and thus controlling the surface-related properties of the fibre are presented in this paper. The properties obtained are discussed on the basis of the physico-chemical changes in the surface layer of the fibre, being assessed by wettability and contact angle measurements, as well as by FTIR-ATR and XPS analysis. The SEM and AFM technique are used to assess the changes in the fibre surface topography and to correlate these changes to the effectiveness, uniformity and severity of the textile fibre surface modification treatments.

A novel surface modification method was proposed to improve the tribological property of Si. Multilayers were grown on Si(100) substrate by self-assembling monolayer (SAMs) method and filtered catholic vacuum arc (FCVA) technique. The film composition and structure were characterized by using x-ray photoelectron spectroscope (XPS) and Raman spectroscopy (Raman). Surface morphology and the roughness were also analyzed by an atomic force microscope (AFM) and a scanning electron microscopy (SEM). The frictional behaviors of the films were evaluated by a UMT tester. Results showed that elastomeric nanocomposite monolayer prepared by SAM was uniformly distributed and isotropy, and the diamond-like carbon (DLC) film was successfully deposited by the FCVA technique. The friction coefficients of the prepared samples were in the range of 0.108–0.188. Furthermore, the friction coefficient slightly increased but the surface quality of the wear trace was improved after adding the copolymer elastomeric macromolecules SEBS on aminopropyl-triethoxysilane (APS) layer due to the inherent long chain of SEBS which abated the immediate impulsion at the interface and changed the kinetic energy into elastic potential energy, and stored it in SEBS.