Plasma technology is an eco‐friendly way to modify or fabricate carbon‐based materials (CBMs) due to plasmas’ distinctive abilities in tuning the surface physicochemical properties by implanting ...functional groups or incorporating heteroatoms into the surface without changing the bulk structure. However, the mechanisms of functional groups formation on the carbon surface are still not clearly explained because of the variety of different discharge conditions and the complexity of plasma chemistry. Consequently, this paper contains a comprehensive review of plasma‐treated carbon‐based materials and their applications in environmental, materials, and energy fields. Plasma‐treated CBMs used in these fields have been significantly enhanced in recent years because these related materials possess unique features after plasma treatment, such as higher adsorption capacity, enhanced wettability, improved electrocatalytic activity, etc. Meanwhile, this paper also summarizes possible reaction routes for the generation of functional groups on CBMs. The outlook for future research is summarized, with suggestions that plasma technology research and development shall attempt to achieve precise control of plasmas to synthesize or to modify CBMs at the atomic level.
Plasma treatment for carbon‐based materials (CBMs) has great merits in that plasma technology can alter the surface physicochemical properties by implanting functional groups or incorporating heteroatoms without changing the bulk structure. CBMs in different plasma treatment atmospheres can obtain tailored surface physicochemical properties, thus the different CBMs modified or fabricated can be used in environmental abatement, materials science, and energy storage.
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•A simple method to synthesize phytic acid surface-modified biochar/MoS2 (BDC/MoS2-PO4).•The adsorption of U(VI) on adsorbent was a monolayer chemisorption process, which was a ...spontaneous endothermic reaction.•Sulfur vacancies increased after H2 plasma treatment of BDC/MoS2-PO4, favoring the adsorption of U(VI).•The S vacancies, S, C-O and P-O of BDC/MoS2-PO4 were bonded to U(VI) in solution.
Using a low-cost, pollution-free and efficient adsorbents to adsorb uranium in radioactive wastewater is of great significance to protect the environment. In this study, bamboo powder-derived biomass charcoal (BDC) was first composited with MoS2, and then the composites were surface-modified with phytic acid to obtain BDC/MoS2-PO4. The microstructure of the adsorbents was analyzed by various characterization techniques. The adsorption kinetics results showed that the U(VI) adsorption by BDC/MoS2-PO4 was more in line with the pseudo-second-order kinetic model, suggesting that the process is mainly chemical adsorption. The adsorption isotherm model confirmed that the U(VI) adsorption by BDC/MoS2-PO4 conformed to the Langmuir isotherm model, which was mainly surface monolayer adsorption with a maximum adsorption capacity of 161.29 mg/g. Furthermore, the adsorption performance of the adsorbent for U(VI) was significantly enhanced after H2 plasma treatment (204.08 mg/g), indicating that the increase in sulfur vacancies favors the U(VI) adsorption. The EPR, XPS and FT-IR results suggested that the interaction mechanism could be explained in that the S vacancies, S, C-O and P-O of the BDC/MoS2-PO4 were bonded to O = U = O2+ in the solution. This study provides a theoretical and experimental basis for the design and synthesis of biochar-based materials, and also provides a reference for radioactive wastewater treatment.
Atmospheric plasma activation and plasma coating with 3-aminopropyltriethoxysilane (APTES) were used to investigate the effect of a modified interface on the creep behaviour of flax fibre reinforced ...polyoxymethylene composite. The wetting parameters and the interfacial shear strength indicate that using air-based plasma activation is superior to plasma coating with APTES when improvement of interface and mechanical properties are concerned. Hygrothermal creep tests within the linear viscoelastic region reveal that the creep resistance of air plasma treated composites is significantly enhanced, evidenced by reduced instantaneous strain and slower viscoelastic flow when compared to the untreated composites. However, creep rupture (run to failure) tests demonstrate that the air plasma treatment extends the creep lifespan only under standard conditions (50 % RH and 23 °C). Under severe conditions (85 % RH and 23 °C), plasma-treated composites exhibit a somewhat shorter lifespan, possibly because some damage induced by the plasma treatment is exacerbated at high humidity.
•Polydimethylsiloxane (PDMS) surface treatment was carried out using C4F8/O2/Ar plasma.•The Surface energy control of PDMS for direct transfer of graphene to various thin films.•Mechanism behind the ...changes in the surface energy of PDMS was investigated using plasma diagnosis, surface energy analysis, and XPS.
We conducted plasma treatment on polydimethylsiloxane (PDMS) films using inductively coupled C4F8/O2/Ar gas mixture plasma to modify their surface properties. We investigated the relationship between plasma characteristics and the changes in PDMS surfaces in order to understand the surface modification mechanism. The surface characteristics of PDMS films were evaluated in detail by surface energy measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Using contact angle measurements, it was confirmed that the surface, polar, and dispersive energies of the plasma-treated PDMS films increased as the O2 gas ratio increased. AFM analysis showed that the roughness of plasma-treated PDMS surfaces increased when the O2 gas ratio increased. XPS analysis confirmed the presence of a functional group CFx (X=1, 2, and 3) in C4F8-rich plasma and a functional group OH in O2-rich plasma. It was confirmed that the surface energy of the PDMS films could be controlled by controlling the C4F8/O2/Ar plasma treatment parameters which should be required for applying the direct transfer technique in each material having different surface energy.
As a sustainable pathway for energy storage and to close the carbon cycle, CO2 electroreduction has recently gained significant interest. We report here the role of the electrolyte, in particular of ...halide ions, on CO2 electroreduction over plasma-oxidized polycrystalline Cu foils. It was observed that halide ions such as I– can induce significant nanostructuring of the oxidized Cu surface, even at open circuit potential, including the formation of Cu crystals with well-defined shapes. Furthermore, the presence of Cl–, Br–, and I– was found to lower the overpotential and to increase the CO2 electroreduction rate on plasma-activated preoxidized Cu catalyst in the order Cl– < Br– < I–, without sacrificing their intrinsically high C2–C3 product selectivity (∼65% total Faradaic efficiency at −1.0 V vs RHE). This enhancement in catalytic performance is mainly attributed to the specific adsorption of halides with a higher coverage on our oxidized Cu surface during the reaction, which have been previously reported to facilitate the formation and stabilization of the carboxyl (*COOH) intermediate by partial charge donation from the halide ions to CO2.
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•Combine effect of NH3 and NF3 plasma treatments on spray coated ZnO is studied by analyzing Hall Effect, UV-Vis, PL , AFM , XRD , XPS and SIMS.•It is concluded that NH3 plasma ...contributes to control Vth by forming Vo-H complex and N incorporation and that NF3 plasma improves the mobility and stability of ZnO TFT.
We investigate the effects of NH3 and NF3 post plasma-treatment on the performance of spray-coated ZnO thin film transistors (TFTs). Both NH3 and NF3 plasma treatment are varied from 10 to 40 s. The properties of plasma treated ZnO were studied by Hall Effect measurements, UV–visible spectroscopy, photoluminescence, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. NF3 plasma treatment causes n-type doping and generates carriers by F incorporation. While, NH3 plasma can cause not only n-type doping by Hydrogen incorporation but also creates acceptor-like states by the formation of Vo–H complex and inducing Nitrogen in ZnO. Owing to the N incorporation, the threshold voltage can be controlled by NH3 plasma treatment. The appropriate NH3 and NF3 plasma treatments for 10 s each greatly enhance theperformance of ZnO TFTs, exhibiting the saturation mobility and subthreshold swing of 20.65 cm2 V−1 s−1 and 0.18 V dec–1, respectively. Therefore, it is concluded that NH3 and NF3 plasma-treatment can be a useful technique to enhance the device performance and to improve the stability of solution-processed metal-oxide TFTs.
What affects the biocompatibility of polymers? Jurak, Małgorzata; Wiącek, Agnieszka Ewa; Ładniak, Agata ...
Advances in colloid and interface science,
August 2021, 2021-08-00, 20210801, Volume:
294
Journal Article
Peer reviewed
In recent decades synthetic polymers have gained increasing popularity, and nowadays they are an integral part of people’s daily lives. In addition, owing to their competitive advantage and being ...susceptible to modification, polymers have stimulated the fast development of innovative technologies in many areas of science. Biopolymers are of particular interest in various branches of medicine, such as implantology of bones, cartilage and skin tissues as well as blood vessels. Biomaterials with such specific applications must have appropriate mechanical and strength characteristics and above all they must be compatible with the surrounding tissues, human blood and its components, i.e. exhibit high hemo- and biocompatibility, low or no thrombo- and carcinogenicity, foreign body response (host response), appropriate osteoconduction, osteoinduction and mineralization. For biocompatibility improvement many surface treatment techniques have been utilized leading to fabricate the polymer biomaterials of required properties, also at nanoscale. This review paper discusses the most important physicochemical and biological factors that affect the biocompatibility, thus the reaction of the living organism after insertion of the polymer-based biomaterials, i.e. surface modification and/or degradation, surface composition (functional groups and charge), size and shapes, hydrophilic-hydrophobic character, wettability and surface free energy, topography (roughness, stiffness), crystalline and amorphous structure, nanostructure, cell adhesion and proliferation, cellular uptake. Particularly, the application of polysaccharides (chitosan, cellulose, starch) in the tissue engineering is emphasized.
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•The review outlines a general scheme for creating bio- and hemocompatible polymer materials.•Biomaterials of proper mechanical characteristics and of positive host-response are required.•Biocompatibility is determined by the graft surface physicochemical properties.•Properly selected surface features of polymer provide the conditions for the tissue repair.•Knowledge of processes inducing the host response is a way to find the suitable implant.
Ultrathin film composite (TFC) membranes with selective layers less than 100 nm thick are highly desired to maximize the permeance of gas separation membranes for high energy efficiency. For ...membranes with ultrathin selective layers, a gutter layer is usually required to prevent pore penetration in the selective layers. Also, according to a recent model, the introduction of a gutter layer strongly improves TFC membrane performance by increasing the overall membrane performance up to an order of magnitude. Unfortunately, this improvement comes with an undesired decrease in selectivity unless the gutter layer is properly designed. This study found that the gutter layer permeability should be five- to tenfold that of the selective layer to minimize the decrease in selectivity. However, the most commonly used material for the gutter layer, polydimethylsiloxane, does not meet the requirements for high-performance membrane materials. Thus, here we report a gutter material with CO2 permeance sixfold that of polydimethylsiloxane, and prepare a TFC membrane with ultrathin gutter (75 nm) and selective layers (70 nm) for CO2/N2 separation. This work represents a guideline for developing next-generation TFC membranes and provides a comprehensive understanding of the impact of the gutter layer.
•A gutter layer with over sixfold enhanced CO2 permeance was prepared.•Inductively coupled plasma was used for hydrophilic treatment with minimized damage.•Ultrathin (< 100 nm) selective layer was successfully coated on the gutter layer.•The as-prepared membrane exhibited 1455 GPU of CO2 permeance with CO2/N2 68.•Long-term stability was confirmed upon 10,000 min operation.
In this work, the optical, morphological, and structural improvements of vertically aligned, hydrothermally grown ZnO submicrowires (SMWs) treated with a 250 W, 250 V RF argon plasma (Ar) during ...different exposure times were investigated by scanning and transmission electrons microscopy, X-ray diffraction, and micro-Raman and photoluminescence (PL) spectroscopies. In two steps, the SMWs were synthesized in an aqueous medium at low temperatures. The plasma-treated samples showed significantly improved room-temperature PL compared to untreated samples. All the treated samples exhibited a substantial increase of the near band edge UV emission intensity and a decrease of the deep level emission in the visible. The samples treated for 4 minutes presented the best UV/vis intensity ratio of ∼ 1568 (an increase of ⁓174-fold with respect to the untreated sample). The analysis of the UV band in terms of the first and second phonon replica of the excitonic emission indicated that the Ar plasma treatment favors the multiple phonon-exciton coupling, with partial correlation with the observed overall increase of the UV/visible intensity ratio. From the PL measurements at low temperatures, the presence of excitons bound to H donors in the ZnO structure was inferred. The possible reasons for the Ar plasma-induced enhancement of the UV emission from the treated SMWs are discussed in terms of previous work, the observed morphology and changes expected to occur at the SMW surfaces due to Ar ion impacts from the plasma.
•ZnO submicrowires were treated with Ar plasma at different exposure times.•Samples treated for 4 minutes presented the best UV/vis intensity ratio of ∼1568.•Ar plasma treatment favors the multiple phonon-exciton coupling.•Plasma-treated samples showed nanostructure on their surface.•These results are very relevant for developing optical-chemical sensors.
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•The OVs concentration in N-TiO2-x is enhanced via photoinduced strategy.•Plasma pre-treatment enhances oxygen vacancy formation on TiO2 surfaces.•Highly efficient photocatalytic ...trace CH4 conversion is achieved by N-TiO2-x.•The synergistic mechanism of N and OVs doping is revealed.
Photocatalysis employing cost-effective commercial titanium dioxide offers an ideal solution for eliminating trace methane emissions from livestock and poultry farming. However, significant challenges such as the rapid recombination of photogenerated carriers, a limited light absorption spectrum, and weak adsorption capabilities considerably hinder the effectiveness of titanium dioxide in the photocatalytic treatment of trace methane. This study proposes a novel approach to activate plasma pre-treated N-doped commercial anatase TiO2 into dual-defect TiO2 (N-doped TiO2-x) featuring stable and controllable oxygen vacancies (OV) through photoinduced defect engineering. Characterizations of the photocatalyst confirm the successful creation of surface defects, further evaluated through solar-light-driven CH4 (ppm level) removal investigations. The yield of this N-doped TiO2-x in converting CH4 is 4.84 μmol h−1, 44 times greater than that of unmodified TiO2, significantly outperforming previous studies. UV–Vis diffuse reflection spectra, and photoluminescence indicate that the modified commercial anatase TiO2 possesses a narrower band gap, efficient photogenerated carrier separation, and enhanced charge transfer. Furthermore, density functional theory (DFT) calculations demonstrate that the synergistic effects of oxygen vacancies and N doping enhance the adsorption and activation of both O2 and CH4 in the rate-determining step of the reaction. This innovative strategy holds considerable promise for modifying various materials for more efficient photocatalytic applications.
