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Oxygen plasma etching has been performed to roughen the surface structure of an Al-doped ZnO (AZO) seed layer. The distribution of Ag nanoparticles was optimized to improve the characteristics of a film and facilitate its application as a touch sensing electrode. First, an intermittent procedure was performed to optimize the quality of the AZO seed layer. After the optimal parameters were obtained according to the figure-of-merit, the surface of the seed layer was roughened, and the depth of surface roughening was affected by adjusting the etching power of the oxygen plasma, and the surface roughness uniformity was affected by adjusting the etching time. Finally, by changing the etching oxygen flow rate, the width of the rough structure was further affected. The above three steps can optimize the surface roughness structure and effectively improve the uniform distribution of Ag nano-particles. To improve the sensitivity (SE) and stability (ST) of the film, the density of nano-Ag particles was modulated. The characteristics of film carriers were measured with a Hall effect analyzer. The surface morphology of the seed layer and the crystallinity change of the film were examined using electron microscopy, x-ray diffraction, ultraviolet–visible spectroscopy, and atomic force microscopy. The results revealed that a favorable film quality was achieved by performing three intermittent procedures. When the AZO seed layer surface was etched with a power of 50 W for 5 min, a 50-sccm etching oxygen flow and a 90-W nano-Ag deposition power were applied for 20 s, the density and distribution of the nano-Ag particles was favorable, and the SE and ST of the film were optimal. Under these conditions, the film's resistance was 3.21 × 10−3 Ω-cm, its SE was 45.04%–52.48%, and its ST error was within 7.44%. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the morphological changes and molecular structure changes on the surface of single-walled carbon nanotube (SWCNT) films during oxygen plasma (O2) etching of SWCNT surfaces formed by the spray method and analyzed their potential use as electrochemical electrodes. For this purpose, a SWCNT film was formed on the surface of a glass substrate using a self-made spray device using SWCNT powder prepared with DCB as a solvent, and SEM, AFM, and XPS analyses were performed as the SWCNT film was O2 plasma etched. SEM images and AFM measurements showed that the SWCNT film started etching after about 30 s under 50 W of O2 plasma irradiation and was completely etched after about 300 s. XPS analysis showed that as the O2 plasma etching of the SWCNT film progressed, the sp2 bonds representing the basic components of graphite decreased, the sp3 bonds representing defects increased, and the C–O, C=O, and COO peaks increased simultaneously. This result indicates that the SWCNT film was etched by the O2 plasma along with the oxygen species. In addition, electrochemical methods were used to verify the damage potential of the remaining SWCNTs after O2 plasma etching, including cyclic voltammetry, Randles plots, and EIS measurements. This resulted in a reversible response based on perfect diffusion control in the cyclic voltammetry, and an ideal linear curve in the Randles plot of the peak current versus square root scan rate curve. EIS measurements also confirmed that the charge transfer resistance of the remaining SWCNTs after O2 plasma etching is almost the same as before etching. These results indicate that the remaining SWCNTs after O2 plasma etching do not lose their unique electrochemical properties and can be utilized as electrodes for biosensors and electrochemical sensors. Our experimental results also indicate that the ionic conductivity enhancement by O2 plasma can be achieved additionally. [ABSTRACT FROM AUTHOR]

Oxygen plasma etching followed with spraying of hydrophobic suspension containing SiO2 nanoparticles were used to construct superhydrophobic cotton fabric, and the adhesion behavior of the superhydrophobic surface to deionized water, dye liquor, sterile defibrinated sheep blood, and simulated blood solutions was studied and evaluated in focus. Results of the present study showed the water contact and water slip angles of the superhydrophobic cotton fabric were 158.6° and 7.3° with 5 wt% of hexadecyltrimethoxysilane (HDTMS). The plasma etching imparted uniform strip grooves on the fiber, which together with the deposition of SiO2 nanoparticles constituted a dual-scale rough structure on the fabric surface. FTIR analysis showed the successful combination of HDTMS and SiO2 nanoparticles and covering on the cotton surface. This superhydrophobic surface possessed hydrophobic effect even after 35 times of abrasion and immersion in strong acid or alkali solutions for 8 h. The surface tension and viscosity of simulated blood and sterile defibrinated sheep blood (SDSB) were similar, with a contact angle of only 139.7° and a slip angle above 20°. And their adhesion forces were calculated by the Cassie-Baxter equation to be 30.93 and 37.88 μN. Moreover, the droplets placement of simulated blood and SDSB on the superhydrophobic surface for 2 h caused trace adhesion but no penetration. This indicated that the superhydrophobic surface had anti-adhesion performance to the liquids. In conclusion, it was evident that the superhydrophobic fabric has good application prospects in the field of textiles for daily life and medical protection. [ABSTRACT FROM AUTHOR]

Vertically aligned graphite substrate (VGS)-copper packaging was renowned for improving the robustness against the thermal gradient loading by using micro texturing. The micro-groove array with a line width of 50 μm and a pitch of 100 μm was formed into the VGS by controlling the line depth with the use of fast-rate oxygen plasma etching. Three micro-grooved VGS specimens were wet-plated to fill these microgrooves with copper deposits and to cover the VGS surfaces. The nearly full-deposited VGS-Copper specimens were subjected to a severe thermal transient loading test. The simply Cu-covered package and shallow rib-structured VGS-Cu packages were damaged to delaminate at their interfaces. The VGS-Cu package with the copper rib structure with a height of 50 μm experienced no delamination. This rib-structured VGS-copper package with high rib height had sufficient robustness against the severe thermal transients even with the proof of homogeneous thermal spreading capacity. [ABSTRACT FROM AUTHOR]

In this study, we analyzed the morphological changes and molecular structure changes on the surface of single-walled carbon nanotube (SWCNT) films during oxygen plasma (O2) etching of SWCNT surfaces formed by the spray method and analyzed their potential use as electrochemical electrodes. For this purpose, a SWCNT film was formed on the surface of a glass substrate using a self-made spray device using SWCNT powder prepared with DCB as a solvent, and SEM, AFM, and XPS analyses were performed as the SWCNT film was O2 plasma etched. SEM images and AFM measurements showed that the SWCNT film started etching after about 30 s under 50 W of O2 plasma irradiation and was completely etched after about 300 s. XPS analysis showed that as the O2 plasma etching of the SWCNT film progressed, the sp2 bonds representing the basic components of graphite decreased, the sp3 bonds representing defects increased, and the C–O, C=O, and COO peaks increased simultaneously. This result indicates that the SWCNT film was etched by the O2 plasma along with the oxygen species. In addition, electrochemical methods were used to verify the damage potential of the remaining SWCNTs after O2 plasma etching, including cyclic voltammetry, Randles plots, and EIS measurements. This resulted in a reversible response based on perfect diffusion control in the cyclic voltammetry, and an ideal linear curve in the Randles plot of the peak current versus square root scan rate curve. EIS measurements also confirmed that the charge transfer resistance of the remaining SWCNTs after O2 plasma etching is almost the same as before etching. These results indicate that the remaining SWCNTs after O2 plasma etching do not lose their unique electrochemical properties and can be utilized as electrodes for biosensors and electrochemical sensors. Our experimental results also indicate that the ionic conductivity enhancement by O2 plasma can be achieved additionally.

[Display omitted] • Chemical corrosion resistance mechanism of flexible fabric-like plasma nanostructures. • Formation law and mechanisms of fabric-like nanostructure arrays on the PDMS surface. • A novel fabrication method for acid and alkali resistant plasma sensors. The flexible plasmonic sensor has triggered tremendous efforts for on-demand, on-site, in-situ, and real-time monitoring applications due to its ideal conformal contact, excellent optical tunability, high mechanical stability, and sensing repeatability. However, the corrosion resistance of flexible plasmonic sensors is often overlooked and remains an intractable obstruction. Herein, flexible fabric-like plasmonic nanostructures were developed and investigated in detail as a promising platform to resist chemical corrosion. The underlying mechanism for the chemical corrosion resistance of this fabric-like plasma nanostructure stems from two aspects: firstly, X-ray photoelectron spectroscopy (XPS) results demonstrate that oxygen plasma etching fractures the Si-O-Si and Si-C bonds, generating abundant Si–OH and C-OH bonds on the surface of the flexible substrate, thereby promoting condensation reactions between the flexible substrate material and Au, resulting in stable Si-O-Cr and C-O-Cr bonds; secondly, comparative experimental results indicate that the anchoring effect of the nanostructure with noble metals hinders the penetration and corrosion of liquid molecules at the interface. As a result, this plasmonic sensor with a fabric-like nanostructure can remain stable for more than 36 h in acidic, alkaline, and neutral solutions, and accurately identify target molecules at ultra-low concentrations. This work highlights the importance of surface nanostructures in enhancing acid and alkali resistance of flexible substrates, providing a reference strategy for the design and fabrication of other corrosion-resistant flexible sensors. [ABSTRACT FROM AUTHOR]

Vertically aligned graphite substrate (VGS)-copper packaging was renowned for improving the robustness against the thermal gradient loading by using micro texturing. The micro-groove array with a line width of 50 μm and a pitch of 100 μm was formed into the VGS by controlling the line depth with the use of fast-rate oxygen plasma etching. Three micro-grooved VGS specimens were wet-plated to fill these microgrooves with copper deposits and to cover the VGS surfaces. The nearly full-deposited VGS-Copper specimens were subjected to a severe thermal transient loading test. The simply Cu-covered package and shallow rib-structured VGS-Cu packages were damaged to delaminate at their interfaces. The VGS-Cu package with the copper rib structure with a height of 50 μm experienced no delamination. This rib-structured VGS-copper package with high rib height had sufficient robustness against the severe thermal transients even with the proof of homogeneous thermal spreading capacity.

Metallization of a polystyrene-block-poly-(2-vinylpyridine) (PS-b-P2VP) block copolymer produced three-dimensional nanostructures consisting of Pt-infused P2VP cylinders in a PS matrix via a single-step process. The Pt is introduced from an aqueous chloride solution and penetrates through 100s of nm thickness of the microphase-separated PS-b-P2VP to form multilevel metallized nanostructures. The metallization process replicated the through-thickness transition from in-plane to out-of-plane oriented P2VP cylinders produced by solvent annealing. Oxygen plasma etching removed the PS majority block and promoted crystallization of the Pt into nanoparticles forming cylindrical nanocrystalline assemblies. [ABSTRACT FROM AUTHOR]

Abstract Fabrication of carbon micro/nanostructures by carbon microelectromechanical systems (carbon-MEMS) technique on conductive substrate stably is of great significance but difficulty, for the poor adhesive property and low -temperature resistance of the substrate. In this study, three-dimensional carbon micro/nanostructures are fabricated on stainless steel (SS) substrate for the first time by carbon-MEMS technique and oxygen plasma etching process without extra conductive layer fabrication process. The effects of oxygen plasma etching time and the height of photoresist array on the morphologies of carbon micro/nanostructures are investigated. The carbon micro/nanostructures were then electrodeposited with manganese dioxide (MnO 2) thin film as microelectrodes for supercapacitors, and the electrochemical performances of the microelectrodes were demonstrated. At the current density of 0.05 mA cm−2, the MnO 2 /carbon micro/nanostructures microelectrode deposited with 5 min show a large specific capacitance of 453.47 F g−1. It also shows excellent long-term cycling stability of ∼94% capacitance retention even after 6000 cycling tests. This study shows that the MnO 2 /carbon micro/nanostructures microelectrodes have great potential for supercapacitors as micro-energy storage devices, and the proposed approach of fabricating carbon hierarchical micro/nanostructures array on a conductive substrate is promising for large-scale micro/nanostructures manufacturing. [ABSTRACT FROM AUTHOR]

In this work, SiNx/a-Si/SiNx caps on conductive coplanar waveguides (CPWs) are proposed for thin film encapsulation of radio-frequency microelectromechanical systems (RF MEMS), in view of the application of these devices in fifth generation (5G) and modern telecommunication systems. Simplification and cost reduction of the fabrication process were obtained, using two etching processes in the same barrel chamber to create a matrix of holes through the capping layer and to remove the sacrificial layer under the cap. Encapsulating layers with etch holes of different size and density were fabricated to evaluate the removal of the sacrificial layer as a function of the percentage of the cap perforated area. Barrel etching process parameters also varied. Finally, a full three-dimensional finite element method-based simulation model was developed to predict the impact of fabricated thin film encapsulating caps on RF performance of CPWs.

This study was to investigate the effects of O2 plasma-etching of the 3D polycaprolactone (PCL) scaffold surface on preosteoblast cell proliferation and differentiation, and early new bone formation. The PCL scaffolds were fabricated by 3D printing technique. After O2 plasma treatment, surface characterizations were examined by scanning electron microscopy, atomic force microscopy, and contact angle. MTT assay was used to determine cell proliferation. To investigate the early new bone formation, rabbits were sacrificed at 2 weeks for histological analyses. As the O2 plasma etching time is increased, roughness and hydrophilicity of the PCL scaffold surface increased. The cell proliferation and differentiation on plasma-etched samples was significantly increased than on untreated samples. At 2 weeks, early new bone formation in O2 plasma-etched PCL scaffolds was the higher than that of untreated scaffolds. The O2 plasma-etched PCL scaffolds showed increased preosteoblast differentiation as well as increased new bone formation. [ABSTRACT FROM AUTHOR]

This paper determines the optimal settings for the deposition of ZrWN nitride films using reactive direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS), with pure Zr and W metal targets and Ar plasma and N 2 reactive gases. The materials tested as buffer layers are metal tungsten (W) and tungsten nitride (WN) thin films. Using a Taguchi method, this study determines the effect of deposition parameters for the buffer layer (W DC power, substrate bias, N 2 /(N 2 +Ar) flow rate and substrate temperature) on the structural and mechanical properties, and the dry machining performance of cutting-tools for multilayer ZrWN/W and ZrWN/WN/substrates. In the confirmation runs using grey Taguchi analysis, there is an improvement of 32.31% and 13.38% in surface roughness and flank wear, respectively. The films are characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (FEI-TEM) and a nanoindenter. The TEM pattern for the ZrWN films shown corresponds to the (111), (200) and (220) planes of the face-center-cubic phase. Pretreatment of a tungsten carbide tool uses oxygen plasma etching to enhance the adhesion of the multilayer ZrWN/WN coating. Compared with coatings that are deposited using DCMS, the samples that are deposited using HIPIMS exhibit a higher film density and a smoother surface. In the HIPIMS mode, the XRD diffraction peaks of the films are sharper and more intense, which indicates an improvement in crystallinity. [ABSTRACT FROM AUTHOR]

In this work, the effect of pulse current and pulse duration in die-sinking electrical discharge machining (EDM) on the machining characteristics of Ti-6Al-4Valloy is studied. The EDM characteristics, including the electrode wear ratio (EWR), the material removal rate (MRR), and the surface roughness (SR), are used to measure the effect of machining. An increase in the intensity of the pulse current from 2.5 to 5 A produces a slow increase in EWR, MRR, and SR. An increase in the intensity of the pulse current from 5 to 7 A produces a rapid increase in EWR, MRR, and SR. Control charts are basic and powerful tools for controlling statistical processes and are widely used to monitor manufacturing processes and ensure good EDM quality. EWR, MRR, and SR are normal distributions, and the regression curves for the data are straight lines. All of the data points vary randomly around the centerline, which follows the Shewhart criteria and shows that the EDM process and product performance are under control and stable over time. After EDM, the surface exhibits an irregular fused structure, with pinholes, micro voids, globule debris, and many damaged surfaces. Oxygen plasma etching and surface modification after EDM reduce these surface defects, so finer and flatter surfaces can be achieved. Moreover, fatigue life can be enhanced. [ABSTRACT FROM AUTHOR]

Fe-doped Ni (oxy)hydroxide shows intriguing activity toward oxygen evolution reaction (OER) in alkaline solution, yet it remains challenging to further boost its performance. In this work, a ferric/molybdate (Fe 3+ /MoO 4 ) co-doping strategy is reported to promote the OER activity of Ni oxyhydroxide. The reinforced Fe/Mo-doped Ni oxyhydroxide catalyst supported by nickel foam (p-NiFeMo/NF) is synthesized via a unique oxygen plasma etching-electrochemical doping route, in which precursor Ni(OH) 2- ) co-doping strategy is reported to promote the OER activity of Ni oxyhydroxide. The reinforced Fe/Mo-doped Ni oxyhydroxide catalyst supported by nickel foam (p-NiFeMo/NF) is synthesized via a unique oxygen plasma etching-electrochemical doping route, in which precursor Ni(OH) 2 nanosheets are first etched by oxygen plasma to form defect-rich amorphous nanosheets, followed by electrochemical cycling to trigger simultaneously Fe 3+ /MoO 4 2- co-doping and phase transition. This p-NiFeMo/NF catalyst requires an overpotential of only 274 mV to reach 100 mA cm -2 in alkaline media, exhibiting significantly enhanced OER activity compared to NiFe layered double hydroxide (LDH) catalyst and other analogs. Its activity does not fade even after 72 h uninterrupted operation. In situ Raman analysis reveals that the intercalation of MoO 4 2- is able to prevent the over-oxidation of NiOOH matrix from β to γ phase, thus keeping the Fe-doped NiOOH at the most active state., (© 2023 Wiley-VCH GmbH.)

Pervaporation is considered to have great potential for application in the field of organic-solvent dehydration. In this study, a type of keto-enamine-linked covalent organic framework TpPa (synthesized using the Schiff-base reaction of 1,3,5-triformylphloroglucinol [Tp] with p -phenylenediamine [Pa]), was fabricated on commercial polyacrylonitrile (PAN) ultrafiltration membranes through an oxygen-plasma assisted contra-diffusion self-assembly strategy for organic-solvent dehydration. The PAN membranes with a glycerol exhibited a better separation factor for dehydration of organic solvents than those without a glycerol layer. The influence of oxygen plasma and glycerol on the formation of the TpPa membrane was investigated. The best plasma treatment condition and optimum glycerol impregnation concentration were determined as a device power of 60 W and 30 wt%, respectively. Defect-free TpPa membrane formation took only 24 h. The as-prepared TpPa membrane exhibited a separation factor of 1491 and a high permeation flux of 2530 g m−2 h−1 for a 90 wt% isopropanol–water mixture. The separation performance of the TpPa membrane was stable for >100 h, exhibiting great potential in organic-solvent dehydration. [Display omitted] • Oxygen plasma assisted contra-diffusion method was used to prepare TpPa membrane. • Formation of TpPa membrane was accelerated by oxygen plasma treatment. • Glycerol in the substrate provide more hydrogen bonds to form dense TpPa membrane. • The TpPa membrane was prepared in 24 h at room temperature. • The TpPa membrane exhibited excellent organic solvent dehydration performance. [ABSTRACT FROM AUTHOR]

Macrophages are innate immune cells that have a central role in combating infection and maintaining tissue homeostasis. They exhibit remarkable plasticity in response to environmental cues. At either end of a broad activation spectrum are pro-inflammatory (M1) and anti-inflammatory (M2) macrophages with distinct functional and phenotypical characteristics. Macrophages also play a crucial role in orchestrating immune responses to biomaterials used in the fabrication of implantable devices and drug delivery systems. To assess the impact of different surface chemistries on macrophage polarisation, human monocytes were cultured for 6 days on untreated hydrophobic polystyrene (PS) and hydrophilic O 2 plasma-etched polystyrene (O 2 -PS40) surfaces. Our data clearly show that monocytes cultured on the hydrophilic O 2 -PS40 surface are polarised towards an M1-like phenotype, as evidenced by significantly higher expression of the pro-inflammatory transcription factors STAT1 and IRF5. By comparison, monocytes cultured on the hydrophobic PS surface exhibited an M2-like phenotype with high expression of mannose receptor (MR) and production of the anti-inflammatory cytokines IL-10 and CCL18. While the molecular basis of such different patterns of cell differentiation is yet to be fully elucidated, we hypothesise that it is due to the adsorption of different biomolecules on these surface chemistries. Indeed our surface characterisation data show quantitative and qualitative differences between the protein layers on the O 2 -PS40 surface compared to PS surface which could be responsible for the observed differential macrophage polarisation on each surface. [ABSTRACT FROM AUTHOR]

An oxygen plasma etching technique was introduced for improving the tribological properties of the graphene sheets embedded carbon (GSEC) film in electron cyclotron resonance plasma processing system. The nanostructural changing in the film caused by oxygen plasma etching was examined by transmission electron microscope, Raman spectroscopy and X-ray photoelectron spectroscopy, showing that the 3 nm thick top surface layer was restructured with smaller graphene nanocrystallite size as well as higher sp 3 bond fraction. The surface roughness, mechanical behavior and tribological properties of the original GSEC and oxygen plasma treated GSEC films were compared. The results indicated that after the oxygen plasma treatment, the average roughness decreased from 20.8 ± 1.1 nm to 1.9 ± 0.1 nm, the hardness increased from 2.3 ± 0.1 GPa to 2.9 ± 0.1 GPa, the nanoscratch depth decreased from 64.5 ± 5.4 nm to 9.9 ± 0.9 nm, and the wear life increased from 930 ± 390 cycles to more than 15,000 frictional cycles. The origin of the improved tribological behavior was ascribed to the 3 nm thick graphene nanocrystallite film. This finding can be expected for wide applications in nanoscale surface engineering. [ABSTRACT FROM AUTHOR]

A hybrid triple-layered nanocomposite structure of plasmonic gold (Au), polymethylmethacrylate ( PMMA), and lead selenide ( PbSe) quantum dot ( QD) on quartz substrate was developed. The fabricated nanocomposite exhibited well-established triple-layered morphology (Au- PMMA-QD on quartz), but had different coupling distances between Au, on the bottom, and PbSe QD, on the top. Control of the coupling distances in terms of different thicknesses of a PMMA spacer layer was examined by etching for different durations, from 7 to 30 min. The corresponding thicknesses of the PMMA layer ranged from ~3.8 to ~88 nm at an etching rate of 2 nm/min. Atomic force microscopy measurements showed that the well-established triple-layered hybrid nanocomposite structure had the heights of ~15 nm (Au) and ~4 nm ( PbSe QD). X-ray photoelectron spectroscopy results revealed the characteristic peaks assigned to each nanoparticle and polymer layer. The results illustrated the triple-layered structures with different PMMA spacer layers, with no cross interference between the layers. [ABSTRACT FROM AUTHOR]

In this study, a hybrid structure of inversely truncated pyramid-shaped diamond nanopits infilled with gold nanoparticle (Au NP) has been fabricated from a Au film coated single crystal diamond by oxygen plasma etching. Surface enhanced Raman scattering (SERS) performances based on the Au-NP/diamond-pit, using 4-Mercaptopyridine as the probe molecule, show that the hybrid structure could realize a larger SERS enhancement factor compared to the conventional isolated Au NPs. This is attributed to the increased concentration of incident light field on the Au NPs due to the special geometric feature, and the coupling of localized surface plasmon resonance from Au NPs. Taking into account the unique properties of diamond, the diamond-related hybrid structure could be used as a kind of high performance SERS substrate. [ABSTRACT FROM AUTHOR]

Oxygen plasma etching was used to treat silk fibroin (SF). The plasma exposure removed a significant amount of SF but left behind most surface properties close to their original state. However, nano-indenter measurements revealed a substantial increase in surface modulus of swollen SF from 62 to 500 kPa. This allowed oxygen plasma etching as a potential tool to investigate the impact of surface stiffness on cell-substrate interaction. Mouse fibroblasts (L929) and human mesenchymal stem cells (hMSC) were employed as distinct model cases. In vitro results revealed that the increased stiffness of plasma-treated SF affected only L929 adhesion, not hMSC. L929 cell attachment and spreading were better on the stiffer surface than the untreated surface, while hMSC could spread well on all SF surfaces. [ABSTRACT FROM AUTHOR]

Abstract: Vertically aligned carbon nanotubes/graphene oxide nanocomposite (VACNT-GO) has been prepared and applied as electrode material. First, dense packets of VACNT were prepared in microwave chemical vapor deposition reactor, and then functionalized by oxygen plasma etching. We observed that oxygen plasma could exfoliate carbon nanotubes tips and provide oxygen group attachment on its surface, changing its wettability as well. This change in wettability of the VACNT is crucial for its electrochemical application, since as-grown VACNT is super-hydrophobic. After exfoliation and functionalization, the electrochemical tests were performed using potassium ferrocyanide. The cyclic voltammetry (CV) and impedance spectroscopy revealed fast electron transfer kinetics on this new material. The CV peak potential separation was 59mV, suggesting ideal reversibility at the electrode. The Nyquist and Bode plots were well-fitted as modified Randles equivalent electrical circuits with non-charge transfer impedance. This new highly porous nanostructures have been intensively characterized by scanning electron microscopy, Brunauer–Emmett–Teller surface area, surface wettability, Raman and X-ray photoemission spectroscopy. Our results suggest this new material has a relevant potential for future applications in electrocatalysis and (bio)sensors. [Copyright &y& Elsevier]

Abstract: Diamond-like carbon (DLC) coating via PVD/CVD on the SKD11 substrate was employed to make micro-texturing by using high density oxygen plasma etching. Original pattern by metal chromium was first line-drawn on the surface of DLC coating; then, it was subjected to oxygen plasma etching. Even without any hazardous etchants such as CF4, high etching rate was attained only by using oxygen gas; i.e. 5μm/H. Plasma diagnosis by spectroscopy proved that this etching process should be controlled by activated oxygen atom flux of {O, O*}. Direct chemical reaction by C (in DLC)+O→CO, or, C (in DLC)+O*→Cthis etching process. Detection of CO peaks in the wave length range from 200 to 300nm also proved that this oxygen plasma etching should be advanced by chemical reactions. This etching behavior was insensitive to line width (WG) and pitch width (PG) for 2μm

A Pt thin film catalyst was prepared by a novel green method of micro drop dispersion–oxygen plasma etching (MD-OPE) method with Pt(acac)2 as starting material and silicon wafer as substrate. The catalytic activity of the film catalyst was evaluated by methanol combustion at room temperature, and its surface properties were characterized by SEM and XPS techniques. The results indicated that Pt(acac)2 can be decomposed and reduced to PtO and Pt0 with small size by oxygen plasma, which is the reason for the improved catalytic activity of as-prepared Pt film compared with the Pt film catalysts prepared by the micro drop dispersion (MD) method. [ABSTRACT FROM PUBLISHER]

Abstract: Diamond-like carbon (DLC) films have been use in numerous industrial applications due to its mechanical properties such as low friction coefficient, high hardness, and high adherence on different substrate materials. It has been demonstrated that the DLC surface can be modified with oxygen plasma treatment. The purpose of this paper is to study two kinds of surface treatments (atmospheric and low pressures) using oxygen gas for different etching exposure times in DLC films. Plasma durability along the time was also evaluated. DLC films were deposited using plasma enhanced chemical vapor deposition technique. The properties of DLC treated for both techniques in different exposure times were investigated through Raman, AFM and contact angle measurements. D band position slightly shifts toward lower wave numbers after oxygen plasma etching treatment whilst the surface becomes rougher, although the roughness values are still lower. A conventional wetting contact angle method was used to study the surface properties of DLC films with different treatments. The wetting contact angle reduced significantly due to the increase of carbon–oxygen sites on the surface. [Copyright &y& Elsevier]

In this work, the first example of fabricating feature sizes less than 10 nm by using block copolymer lithography on an organic-inorganic hybrid block copolymer material is described. A unique class of well-defined block copolymers which contain polyhedral oligomeric silsesquioxane (POSS) was used for this achievement. Two POSS containing block copolymers (BCPs) with high a degree of polymerization of POSS and a narrow polydispersity index (PDI) were synthesized by living anionic polymerization of styrene (PS-b-PMAPOSS) or methyl methacrylate and methacrylate functionalized POSS (PMMA-b-PMAPOSS). Both BCPs indicate well-defined lamellar or cylinder microphase-separated domains. The excellent self-assembly characteristics of these BCPs in thin-films combined with the outstanding high contrast in etching resistance and etch selectivity between PS or PMMA and PMAPOSS blocks leads to well-ordered line or hexagonally packed hole structures with a hole diameter of 9 rim. A one step oxygen plasma exposure converts the soft mask into a hard mask. The synthetic flexibility and the simplicity and ease of the self-assembly and etching process make these materials very attractive for creating small feature sizes. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we demonstrate fabrication of random columnar/filamented-like, low and high-aspect ratio micro or nano-structures based on O2 plasma-induced roughening (nano-texturing) of poly(methyl methacrylate) (PMMA). Plasma etching duration and conditions ensured absolute control of the topography height (37–2400nm) and surface chemistry. The effect of topography and ageing on surface wettability and protein adsorption capacity was investigated. Conditions (plasma treatment and ageing) are sought for maximum and uniform protein adsorption on nanotextured PMMA surfaces. Specifically, adsorption of biotinylated-BSA was found to increase with plasma duration. A 2–4 times (depending on the protein concentration) increase was observed on aged surfaces prepared following 5–60min O2 plasma treatment compared to untreated PMMA surfaces. Highly homogeneous protein microspots on such optimized plasma-nanostructured surfaces are also shown. [Copyright &y& Elsevier]

[Display omitted] • Perforated graphene (pGr) layers were fabricated by oxygen plasma etching of CVD-grown graphene. • The pGr layers were applied in quarter-wavelength nanocavity absorbers for enhancing the optical absorption. • The feature dependence of the nanocavity on incident angle and electrical/magnetical portion of light irradiation were examined. Aperiodic perforated graphene layers were synthesized and used in fabrication of optical nanocavity absorbers. Chemical vapor deposition-grown graphene (Gr) layers were exposed to oxygen plasma etching to obtain the perforated graphene (pGr). The fabricated pGr/SiO 2 (68 nm)/Ag (150 nm) nanocavity could present significant higher optical absorption, especially at around 530 nm wavelength region, as compared to a benchmark Gr/SiO 2 (68 nm)/Ag (150 nm) sample. The effect of pore size of the pGr layer on the absorption property of the nanocavity has been studied by both experimental and numerical methods. The dependence of the absorption property of the nanocavity on the incident angles of unpolarized light and also the electrical/magnetical portion of transverse polarized light have been examined. The electrical interaction between the nanopores of the pGr and the incident light was found as the main reason for the absorption. The proposed graphene-based nanocavity resonator can further excite designing high efficient electromagnetic wave absorbers highly demanding two-dimensional coatings with effective optical absorption features. [ABSTRACT FROM AUTHOR]

A series of four trimethylsilyl group containing copolymers were synthesized using the solution free-radical copolymerization with azobisisobutyronitrile (AIBN) in 1,4-dioxane at 60 °C. The photoresists were prepared by dissolving copolymer, one of two kind photosensitizer (dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate) and Michler''s ketone in tetrahydrofuran (THF). The cyclic maleimide group was responsible for the high thermal stabilities. After irradiation by a deep-ultraviolet light and development with mixed solvent (methyl isobutyl ketone:2-propanol=1:3), the developed patterns showed negative images and exhibited good adhesion to the silicon wafer without using any adhesion promoter. The resolution of the resists was at least 1.75 μm and the oxygen plasma etching rate was 1/6 of hard-baked HPR-204, which can be also used as the top-imaging layer of a bilayer resist for microlithographic application. These photoresists can be stripped by week alkaline solution such as sodium carbonate solution (0.01 wt.%) after exposure. [Copyright &y& Elsevier]

[Display omitted] The boron-doped diamond (BDD) electrode, having ultra-high oxygen evolution potential and anodic stability, is potentially considered the ideal candidate for the next-generation ozone generator despite the relatively low current efficiency. In this work, we first report using a microporous BDD electrode etched by oxygen plasma, denoted as p-BDD, to improve the performance of electrochemical ozone generation. Two parameters, including O 2 plasma etching temperature and time, are experimentally optimized. We demonstrated that the electrochemically active surface area (ECSA) of the optimal p-BDD is 2.51 times that of the bare BDD, and this p-BDD shows about one-quarter lower charge transfer resistance than the latter. Under the same unit energy consumption, the p-BDD has 3.76 times the ozone generation capacity compared to the latter. The p-BDD shows excellent long-term stability, only having 4.2% of the decrease in the current density up to 40 h of consecutive water electrolysis under the steady-state period, and it also remains a 100% recovery rate in its capability of electrochemical performance after mild treatment by cycling at a diluted sulfuric acid solution for 200 s • A microporous BDD electrode etched by O 2 plasma (p-BDD) is fabricated. • We first report the use of p-BDD to carry out electrochemical ozone generation. • p-BDD has 3.76 times the capacity of ozone generation compared to the bare BDD. • p-BDD shows excellent stability with only 4.2% of current decrease within 40 h test. • p-BDD remains a 100% recovery rate in electrochemical performance after mild treatment. [ABSTRACT FROM AUTHOR]

Oxygen-doped carbon coatings were deposited by ion-irradiation-assisted growth using an electron cyclotron resonance plasma processing system, and the effects of the O 2 content on the coating's structure and tribological behavior were studied. During the coating deposition, O+, O 2 +, and Ar+ ions in the oxygen plasma were attracted to irradiate the growing coating surface, realizing oxygen plasma during-etching. X-ray photoelectron spectroscopy characterization showed that the O 2 addition incorporated some oxygen atoms into the carbon coating, and the sp 3/ sp 2 ratio of the entire coating increased. Such structural changes made the carbon coating present higher nanoscratch resistance and longer wear life that increased from 990 cycles to more than 5000 cycles. Finally, the reason why the oxygen doping can induce the sp 3/ sp 2 ratio to increase was suggested to be ion-irradiation-induced chemical recombination energy release, which could only occur when the O 2 introduction reduced the atom displacement threshold energy. • Oxygen-doped carbon coatings were deposited by ion-irradiation-assisted growth. • Plasma during-etching was realized by attracting O+, O 2 +, and Ar+ ions to irradiate the growing coating. • After doping, the wear life increased due to the increase in sp 3/ sp 2 of the entire coating. • The increase in sp 3/ sp 2 was caused by ion-irradiation-induced chemical recombination energy release. [ABSTRACT FROM AUTHOR]

In this work, SiNx/a-Si/SiNx caps on conductive coplanar waveguides (CPWs) are proposed for thin film encapsulation of radio-frequency microelectromechanical systems (RF MEMS), in view of the application of these devices in fifth generation (5G) and modern telecommunication systems. Simplification and cost reduction of the fabrication process were obtained, using two etching processes in the same barrel chamber to create a matrix of holes through the capping layer and to remove the sacrificial layer under the cap. Encapsulating layers with etch holes of different size and density were fabricated to evaluate the removal of the sacrificial layer as a function of the percentage of the cap perforated area. Barrel etching process parameters also varied. Finally, a full three-dimensional finite element method-based simulation model was developed to predict the impact of fabricated thin film encapsulating caps on RF performance of CPWs. [ABSTRACT FROM AUTHOR]