Search

Lanthanide-doped upconversion nanoparticles (Ln-UCNPs) are a new type of nanomaterials with excellent fluorescence properties, which are well applied in fluorescent biosensing. Herein we developed a multifunctional probe based on the surface engineering of core-shell structure UCNPs with polyacrylic acid (PAA). The developed PAA/UCNPs probe could be highly selective to detect and respond to Cu2+ at different pH. Cu2+ could easily combine with the carboxylate anion of PAA to quench the fluorescence of UCNPs. Therefore, we creatively proposed a fluorescent array sensor (PAA/UCNPs-Cu2+), in which the same material acted as the sensing element by coupled with pH regulation for pattern recognition of 5 thiols. It could also easily identify the chiral enantiomer of cystine (L-Cys and D-Cys), and distinguish their mixed samples with different concentrations, and more importantly, it could be combined with urine samples to detect actual level of homocysteine (Hcys) to provide a new solution for judging whether the human body suffers from homocystinuria.

Surface engineering of active materials to generate desired energy state is critical to fabricate high-performance heterogeneous catalysts. However, its realization in a controllable level remains challenging. Using oxygen evolution reaction (OER) as a model reaction, we report a surface-mediated Fe deposition strategy to electronically tailor surface energy states of porous Co3O4 (Fe-pCo3O4) for enhanced activity towards OER. The Fe-pCo3O4 exhibits a low overpotential of 280 mV to reach an OER current density of 100 mA cm−2, and a fast-kinetic behavior with a low Tafel slop of 58.2 mV dec−1, outperforming Co3O4-based OER catalysts recently reported and also the noble IrO2. The engineered material retains 100% of its original activity after operating at an overpotential of 350 mV for 100 h. A combination of theoretical calculations and experimental results finds out that the surface doped Fe promotes a high energy state and desired coordination environment in the near surface region, which enables optimized OER intermediates binding and favorably changes the rate-determining step.

The problem of managing the durability of products due to the creation of regions in materials with a given temporal and spatial non-locality is considered. A mathematical model of softening of materials under the action of external loads is proposed, allowing to take into account the special role in the formation of damaged places of exit of grain boundaries and their triple junctions on the outer surfaces of parts, as well as their interaction with stress concentrators formed after mechanical processing. The developed model representations are used to ensure the operational uniformity of structural elements with concentrators under stress by methods of surface engineering, in particular, when determining the role of changes in the quantitative parameters of the microstructure on the wear resistance of the surface layers of rolling stock parts of railway transport containing stressed concentrators. The optimal depth of the plasma hardening of the subsurface layers of the rims of wheel pairs of locomotives has been established, depending on the size, placement and geometric characteristics of the tension concentrators. It is shown that taking into account the dynamics of structural changes during the degradation of materials in the conditions of operation according to the proposed model ratios allows to achieve the specified life cycle of parts at minimal costs. Increasing the durability of products is achieved by optimizing technological modes of surface engineering, which ensure the formation of structures with a smaller gradient of properties., Розглянута проблема управління довговічністю виробів за рахунок створення в їх матеріалах областей із заданою часовою та просторовою нелокальністю. Запропоновано математичну модель знеміцнення матеріалів при дії зовнішніх навантажень, яка дозволяє враховувати особливу роль у формуванні пошкоджень місць виходу границь і потрійних стиків зерен на зовнішні поверхні деталей, а також їх взаємодію із концентраторами напружень, що утворені після механічної обробки. Розроблені модельні уявлення використані для забезпечення експлуатаційної рівноміцності елементів конструкцій з концентраторами напружень методами інженерії поверхні, зокрема при визначенні ролі зміни кількісних параметрів мікроструктури на зносотривкість поверхневих шарів деталей рухомого складу залізничного транспорту, що містять концентратори напружень. Встановлено оптимальну глибину плазмового зміцнення приповерхневих шарів бандажів колісних пар локомотивів в залежності від розмірів, розміщення і геометричних характеристик концентраторів напружень. Показано, що врахування динаміки структурних змін в часі при деградації матеріалів в умовах експлуатації згідно запропонованих співвідношень моделі дозволяє досягти заданого життєвого циклу деталей при мінімальних затратах. Підвищення довговічності виробів досягається при оптимізації технологічних режимів інженерії поверхні, які забезпечують формування структур із меншим градієнтом властивостей.

Cellulose, the most abundant natural polymer on earth, has recently gained attention for a large spectrum of applications. At a nanoscale, nanocelluloses (mainly involving cellulose nanocrystals or cellulose nanofibrils) possess many predominant features, such as highly thermal and mechanical stability, renewability, biodegradability and non-toxicity. More importantly, the surface modification of such nanocelluloses can be efficiently obtained based on the native surface hydroxyl groups, acting as metal ions chelators. Taking into account this fact, in the present work, the sequential process involving chemical hydrolysis of cellulose and autocatalytic esterification using thioglycolic acid was performed to obtain thiol-functionalized cellulose nanocrystals. The change in chemical compositions was attributed to thiol-functionalized groups and explored via the degree of substitution using a back titration method, X-ray powder diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis. Cellulose nanocrystals were spherical in shape and ca. 50 nm in diameter as observed via transmission electron microscopy. The adsorption behavior of such a nanomaterial toward divalent copper ions from an aqueous solution was also assessed via isotherm and kinetic studies, elucidating a chemisorption mechanism (ion exchange, metal chelation and electrostatic force) and processing its operational parameters. In contrast to an inactive configure of unmodified cellulose, the maximum adsorption capacity of thiol-functionalized cellulose nanocrystals toward divalent copper ions from an aqueous solution was 4.244 mg g−1 at a pH of 5 and at room temperature.

Surface plasmon resonance (SPR) based sensors play an important role in the biological and medical fields, and improving the sensitivity is a goal that has always been pursued. In this paper, a sensitivity enhancement scheme jointly employing MoS2 nanoflower (MNF) and nanodiamond (ND) to co-engineer the plasmonic surface was proposed and demonstrated. The scheme could be easily implemented via physically depositing MNF and ND overlayers on the gold surface of an SPR chip, and the overlayer could be flexibly adjusted by controlling the deposition times, thus approaching the optimal performance. The bulk RI sensitivity was enhanced from 9682 to 12,219 nm/RIU under the optimal condition that successively deposited MNF and ND 1 and 2 times. The proposed scheme was proved in an IgG immunoassay, where the sensitivity was twice enhanced compared to the traditional bare gold surface. Characterization and simulation results revealed that the improvement arose from the enhanced sensing field and increased antibody loading via the deposited MNF and ND overlayer. At the same time, the versatile surface property of NDs allowed a specifically-functionalized sensor using the standard method compatible with a gold surface. Besides, the application for pseudorabies virus detection in serum solution was also demonstrated.

Exosomes are small nanosized biovesicles that form when multivesicular bodies and the plasma membrane fuse and are released into the surrounding body fluids. They are best known for their multifunction in mediating intercellular communication by transferring various biomolecules, including DNA, RNAs, proteins, and lipids, in a short- and long-distance manner and have been identified as health and disease messengers. Importantly, exosomes are necessary for various physiological processes in health and disease. The generation of exosomes depends on the status of the disease, which usually exhibits opposite roles by inducing enhanced cellular stress and damage. Recently, exosome-based nanotechnologies have provided unprecedented opportunities to boost the developments of exosome-related biology, chemistry, pathology, and therapeutics in different diseases based on their unique structural/compositional/morphological characteristics for next-generation nanomedicines. Herein, we provide a comprehensive overview of the recent advances in exosome nanotechnology research, including their classification, isolation and preparation, constitution, biological function, and nanobiomedical applications in disease treatment and diagnosis. Furthermore, future prospects were also concluded. This review will provide more inspiration for promoting the development of exosome-based advanced theranostic nanoplatforms and nanotechnology.

Досліджено ефективність поєднання холодного пластичногодеформування та фрикційно-механічного методу нанесенняантифрикційних покриттів при обробці деталей тертя. У результаті проведених досліджень запропоновано комбінованутехнологію відновлення гільз циліндрів двигунів внутрішнього згорання з використанням деформуючого протягування та фінішної антифрикційної безабразивної обробки. The purpose of the work is to develop a technological process that combines the deforming drawing operation and the finishing operation of applying anti-friction coatings.

Late in-stent thrombus and restenosis still represent two major challenges in stents’ design. Surface treatment of stent is attracting attention due to the increasing importance of stenting intervention for coronary artery diseases. Several surface engineering techniques have been utilised to improve the biological response in vivo on a wide range of biomedical devices. As a tailorable, precise, and ultra-fast process, laser surface engineering offers the potential to treat stent materials and fabricate various 3D textures, including grooves, pillars, nanowires, porous and freeform structures, while also modifying surface chemistry through nitridation, oxidation and coatings. Laser-based processes can reduce the biodegradable materials' degradation rate, offering many advantages to improve stents’ performance, such as increased endothelialisation rate, prohibition of SMC proliferation, reduced platelet adhesion and controlled corrosion and degradation. Nowadays, adequate research has been conducted on laser surface texturing and surface chemistry modification. Laser texturing on commercial stents has been also investigated and a promotion of performance of laser-textured stents has been proved. In this critical review, the influence of surface texture and surface chemistry on stents performance is firstly reviewed to understand the surface characteristics of stents required to facilitate cellular response. This is followed by the explicit illustration of laser surface engineering of stents and/or related materials. Laser induced periodic surface structure (LIPSS) on stent materials is then explored, and finally the application of laser surface modification techniques on latest generation of stent devices is highlighted to provide future trends and research direction on laser surface engineering of stents., Graphical abstract Image 1, Highlights • Compared conventional surface engineering with laser-based methods for biomedical devices. • Explained the influence of texture geometry and surface chemistry on stents biological response. • Reviewed state of the art in laser surface engineering of stents for improved biological response. • Reviewed state of the art in laser surface engineering to control degradation of bioresorbable stents. • Highlighted novel laser surface engineering designs for improved stents'performance.

The influences of bulk diffusion and surface exchange on oxygen transport of (La0.6Ca0.4)(Co0.8Fe0.2)O3-δ (LCCF) hollow fiber membranes were investigated. As an outcome, two strategies for increasing the oxygen permeation were pursued. First, porous LCCF hollow fibers as support were coated with a 22 μm dense LCCF separation layer through dip coating and co-sintering. The oxygen permeation of the porous fiber with dense layer reached up to 5.10 mL min−1 cm-2 at 1000 °C in a 50 % CO2 atmosphere. Second, surface etching of dense LCCF hollow fibers with H2SO4 was applied. The surface etching of both inner and outer surfaces leads to a permeation improvement up to 86.0 %. This finding implies that the surface exchange reaction plays a key role in oxygen transport through LCCF hollow fibers. A good long-term (>250 h) stability of the asymmetric hollow fiber in a 50 % CO2 atmosphere was found at 900 °C.

The ability to regulate and apply surface wettability has attracted much attention in the surface engineering field. In this study, a simple chemical etching method was used to construct a rough micro/nano structure on 304 stainless steel mesh; this rough surface was subsequently decorated with fatty acids of varying chain length to regulate wettability. The wettability, composition, and morphology of the surface were characterized and analyzed by measuring contact angles, and by atomic force microscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy . The superhydrophobic and superoleophilic properties of the mesh modified with long-chain fatty acids were examined for oil-water separation performance and reusability. The surface had a micro/nano hierarchical morphology with ordered carbon chains, and the hydrophilic-to-superhydrophobic transformation was achieved by adjusting the chain length of the fatty acid to deliver contact angles in the range of 30–154°. The oil contact angle was always 0°, irrespective of the chain length fatty acid, and oil drops quickly penetrated the mesh surface. A fatty acid with a longer chain afforded a more hydrophobic and oleophilic mesh surface and better oil–water separation efficiency (up to 96%), which still exceeded 85% after 50 cycles of oil–water separation testing. Consequently, the prepared surface with controllable wettability has excellent prospects for use in intelligent response interfaces and oil–water separation applications.

LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials can operate at extremely high voltages and have exceptional energy density. However, their use is limited by inherent structure instability during charge/discharge and exceptionally oxidizing Ni4+ at the surface. Herein, we have developed a citrate-assisted deposition concept to achieve a uniform lithium-conductive LiNbO3 coating layer on the NCM523 surface that avoids self-nucleation of Nb-contained compounds in solution reaction. The electrode–electrolyte interface is therefore stabilized by physically blocking the detrimental parasitic reactions and Ni4+ dissolution whilst still maintaining high Li+ conductivity. Consequently, the modified NCM523 exhibits an encouraging Li-storage specific capacity of 207.4 mAh g−1 at 0.2C and 128.9 mAh g−1 at 10C over the range 3.0–4.5 V. Additionally, a 92% capacity retention was obtained after 100 cycles at 1C, much higher than that of the pristine NCM523 (73%). This surface engineering strategy can be extended to modify other Ni-rich cathode materials with durable electrochemical performances.

Cr(VI)-based compounds pollution have attracted global concern due to serious harm to humans and environment. Hence, it is crucial to exploit an effective technique to eliminate Cr(VI) in water. Herein, we in-situ grown BiOI on graphitic carbon nitride to prepare the BiOI/g-C3N4 (BCN) direct Z-scheme heterojunction by solid phase engineering method at room temperature. Experimental result shown the photocatalytic activity of pure BiOI were obviously enhanced by constructing Z-scheme BCN heterostructure, and BCN-3 heterostructure exhibited the optimal photocatalytic degradation of RhB with 98% yield for 2.5 h and reduction of Cr(VI) with more than 99% yield for 1.5 h at pH = 2. Stability test shows BCN-3 still kept more than 98% reduction efficiency after 6 cycles. In addition, we also studied the reduction mechanism that shown the ·O2− radicals essentially helped to reduce the Cr(VI) in aqueous solution under illumination, verified the direct Z-scheme charge transfer path by X-ray photoelectron spectroscopy (XPS) and the free radical trapping experiment. The work open a new way for rationally designing photocatalyst heterostructure to reduce Cr(VI) to Cr(III).

Poor water stability is the main problem of commercialized Mn4+-doped fluorides for white light emitting diode (WLED) application. This work proposes a surface engineering strategy to rebuild a Mn4+-free fluoride shell on fluorides to effectively resist the destruction from water molecules. By simple processing using glyoxylic acid (GA) solution, the moisture resistance of the red-emitting fluorides can be significantly improved. The photoluminescence (PL) quantum efficiency (QE) of the surface-engineered K2SiF6:Mn4+ (KSFM-GA) still maintain 98.43% after water immersion for 360 h, in sharp contrary to the untreated one (its PLQE decreases to 59.79%). Additionally, PL intensity of the hydrolysed KSFM can be recovered to 99.1% through the treatment of the reducing GA solution. By using the high-stability KSFM-GA red phosphor, the as-fabricated high-performance warm-WLED device can still maintain 84.6% in luminous efficacy, higher than that (79.6%) with the untreated KSFM, after 500 hours of aging in a high temperature (85 oC) and high humidity (85%) environment.

Nickel oxyhydroxide (NiOOH) is regarded as one of the promising cocatalysts to enhance the catalytic performance of photoanodes but suffers from serious interfacial charge-carrier recombination at the photoanode||NiOOH interface. In this work, surface-engineered BiVO4 photoanodes are fabricated by sandwiching an oxygen vacancy (Ovac) interlayer between BiVO4 and NiOOH. The surface Ovac interlayer is introduced on BiVO4 by a chemical reduction treatment using a mild reducing agent, sodium hypophosphite. The induced Ovac can alleviate the interfacial charge-carrier recombination at the BiVO4||NiOOH junction, resulting in efficient charge separation and transfer efficiencies, while an outer NiOOH layer is coated to prevent the Ovac layer from degradation. As a result, the as-prepared NiOOH-P-BiVO4 photoanode exhibits a high photocurrent density of 3.2 mA cm−2 at 1.23 V vs. RHE under the irradiation of 100 mW/cm2 AM 1.5G simulated sunlight, in comparison to those of bare BiVO4, P-BiVO4, and NiOOH-BiVO4 photoanodes (1.1, 2.1 and 2.3 mA cm−2, respectively). In addition to the superior photoactivity, the 5-h amperometric measurements illustrate improved stability of the surface-engineered NiOOH-P-BiVO4 photoanode. Our work showcases the feasibility of combining cocatalysts with Ovac, for improved photoactivity and stability of photoelectrodes.

A peerless inexpensive electrochemical engineering of spherical Pt nanoparticles (nano-Pt: ca. 100 nm in average diameter) was achieved with intersected ferric oxyhydroxide nanotubes (α-FeOOH (goethite): ca. 20 nm in average diameter). The FeOOH@Pt catalyst exhibited ca. 2.5 and 1.94-times increases in the catalytic activity and poisoning tolerance, respectively, of the formic acid electro−oxidation (FAO) – the anodic reaction in the direct formic acid fuel cells (DFAFCs). Surprisingly, with a post-activation of the FeOOH@Pt catalyst at 0.48 V vs. reversible hydrogen electrode (RHE) in 0.2 mol L−1 NaOH, a favorable Fe2+/Fe3+ transformation succeeded to eliminate the permanent CO poisoning of Pt that impaired the catalytic performance of DFAFCs. This was synchronized (relatively to nano-Pt) with a four-fold increase in the catalytic efficiency, ca. −174 mV shift in the onset potential, and eightfold enhancement in the catalyst's durability for FAO. The activated FeOOH@Pt catalyst also showed a mass activity of 296 mA mg−1Pt (at 0.8 V), which was ca. nine times higher than that (34 mA mg−1Pt) of the commercial Pt/C catalyst. The ascertained improvement in the electron transfer at the FeOOH@Pt surface foresees quick industrialization for DFAFCs.

A major part of the electric power is generated in coal operated thermal power plants which is operated by low rank fuel. During the operation of boilers with the high temperature combustion of low ranked fuel, few salt films are produced due to the presence of ash and abrasive minerals. This action produces the serious corrosion on the surface of boiler plates which is recognised as hot corrosion. A surface engineering method is used to encounter such problem in order to avoid repair and damage or economic loss such as high velocity oxy-fuel [HVOF] sprayed coatings. Various surface coating methods are being adopted for this purpose. Moreover, post heat treatment processes are also added in terms to retain the long period of surface coating.

Biomimetic nanoengineering presents great potential in biomedical research by integrating cell membrane (CM) with functional nanoparticles. However, preparation of CM biomimetic nanomaterials for custom applications that can avoid the aggregation of nanocarriers while maintaining the biological activity of CM remains a challenge. Herein, a high-performance CM biomimetic graphene nanodecoy was fabricated via purposeful surface engineering, where polyethylene glycol (PEG) was used to modifying magnetic graphene oxide (MGO) to improve its stability in physiological solution, so as to improve the screening efficiency to active components of traditional Chinese medicine (TCM). With this strategy, the constructed PEGylated MGO (PMGO) could keep stable at least 10 days, thus improving the CM coating efficiency. Meanwhile, by taking advantage of the inherent ability of HeLa cell membrane (HM) to interact with specific ligands, HM-camouflaged PMGO showed satisfied adsorption capacity (116.2 mg/g) and selectivity. Finally, three potential active components, byakangelicol, imperatorin, and isoimperatorin, were screened from Angelica dahurica, whose potential antiproliferative activity were further validated by pharmacological studies. These results demonstrated that the purposeful surface engineering is a promising strategy for the design of efficient CM biomimetic nanomaterials, which will promote the development of active components screening in TCM.

The surface properties of nanostructures play a vital role in defining the electrical and optical properties of nanomaterials needed for various applications. In this study, the TiCl4 surface treatment approach was used to enhance the performance of TiO2 nanotubes (T-NTs) based electrochemical sensors. The TiCl4 treated TiO2 nanotubes and pristine TiO2 nanotubes were deposited with a glucose-sensing mediator (Cu2O nanoparticles (NPs)), and a systematic comparison of their performances using cyclic voltammetry (I-V) curves, Nyquist plot, Mott-Schottky plot, chronoamperometry (I-T) curves, and sensitivity curves are presented. The TiCl4 treated sensors demonstrated 2 times higher sensitivity of 0.4 mA mM-1 cm-2 and 2.5 times lower limit of detection of 80 μM, whereas the untreated nanotubes-based sensors had lesser sensitivity of 0.19 mA mM-1 cm-2 and a higher limit of detection of 200 μM. Further, the treated substrates exhibited a higher donor charge density of 8.79 x 1021 cm-3 in comparison to plain T-NTs (6.5 x 1021 cm-3). The enhanced electrocatalytic performance of the surface-treated sensor was due to the formation of an additional TiO2 layer over the surface of nanotubes which reduced the surface defects and introduced Ti3+ ion in the nanotubes. This resulted in improved electronic contacts of T-NTs with the Cu2O NPs, increasing donor charge density, reduced band-gap, and yielded a three-fold enhancement in electrical conductivity, thereby increased the overall electrochemical sensing performance. Thus, the strategy of TiCl4 surface modification on TiO2 nanotube arrays is effective in enhancing the performance of T-NTs based electrochemical sensors.

Aqueous zinc-ion batteries present their unique advantages, such as cost-efficient and non-flammability for large-scale energy storage. However, their widespread application is hindered by the development of cathode materials, sluggish intrinsic ion/electron kinetics, and unsatisfied structural stability. Herein, we report a high-performance NH4V4O10 cathode with oxygen vacancy (denoted as NH4V4O10-x) and reduced graphene oxide (rGO) surface modification. The oxygen vacancies enhance the Zn2+ diffusion ability and stabilize the NH4V4O10 structure. Meanwhile, the density functional theory calculations further confirm the deficiency engineering leads to high electronic conductivity, weak electrostatic interaction, and low Zn2+ diffusion barrier. In addition, the rGO surface modification provides fast electron transfer. The NH4V4O10-x@rGO delivers high capacity (391 mAh g−1 at 1 A g−1), impressive rate ability (211 mAh g−1 at the 15 A g−1), and stable cycle performance with 90.5% capacity retention after 2000 cycles. This work provides a reasonable strategy to design cathode materials with deficiency and surface engineering to improve the electrochemical performance of zinc-ion batteries.

Titanium and its alloys have become the ultimate choice for the next era of orthopedic implants such as Hip stem, acetabular cup, and orthopedic accessories. This critical review presents the challenges in fabrication and solutions (surface engineering) to successfully implement Ti alloys in biomedical industries successfully. A critical review on the application surface modification of Ti-alloy using thermal spray coatings has been reported. Hydroxyapatite (HA) has been used as vital biological coating-materials for load-bearing implant applications, mostly hip implants. Moreover, the research papers also present bibliometric analysis that reveals the researcher's information and their affiliation for significant contribution in the area of Ha-coatings on Ti-alloy using plasma spray techniques.

The production of O2 at TiO2 surface during the photoelectrochemical water splitting is the bottleneck of the reaction process indicating the need for surface engineering of TiO2. Here, 1-D TiO2 was coated with the defect tuned SnO2 nanolayer (via sputtering) for enhanced solar water splitting activity. The sputtering strategy allows oxygen vacancy tuning of SnO2 with complete coverage on TiO2. Importantly, the optimized SnO2/TiO2 system exhibited the record photocurrent of 1.85 mA cm−2 at 1.23 V vs. RHE, incident photon to current efficiency of 95% at 350 nm, and H2 and O2 production with ∼90% of faradaic efficiency. Band structure analysis indicated a decrease in work function along with an upward shift of Fermi level and conduction band at the electrolyte interface after SnO2 coating. The present study demonstrates the utilization of oxygen vacancy in SnO2 for the surface engineered electrodes for facile O2 production during solar water splitting.

Elucidating the interaction between different atomic species of the bimetallic nanoparticles under reaction conditions is key to the design of efficient catalysts. Here, we report a laser-assisted strategy towards PtRu alloy, where isolated Pt sites are anchored on the Ru host, and track the variation of the active site under electrocatalytic conditions. Operando X-ray absorption spectroscopy identified the local environment variations around Pt single atoms and revealed the increased PtRu alloying degree during hydrogen evolution reaction (HER). Theoretical simulations confirmed that the increase of alloying extent modulates the d-band center of Ru for enhancing the activity. Surface-restructured PtRu alloy exhibited outstanding HER activity and stability in all pH, achieving an unexpected low overpotential of only 15, 17, and 28 mV at 10 mA cm-2 in 1 M KOH, 1 M PBS, and 0.5 M H2SO4, respectively. This demonstrates the feasibility of surface engineering for designing advanced bimetallic catalysts with atomic-scale platinum decoration.

The use of additively manufactured components specifically utilizing titanium alloys has seen rapid growth particularly in aerospace applications; however, the propensity for retained porosity, high(er) roughness finish, and detrimental tensile surface residual stresses are still a limiting factor curbing its expansion to other sectors such as maritime. The main aim of this investigation is to determine the effect of a duplex treatment, consisting of shot peening (SP) and a coating deposited by physical vapor deposition (PVD), to mitigate these issues and improve the surface characteristics of this material. In this study, the additive manufactured Ti-6Al-4V material was observed to have a tensile and yield strength comparable to its wrought counterpart. It also exhibited good impact performance undergoing mixed mode fracture. It was also observed that the SP and duplex treatments resulted in a 13% and 210% increase in hardness, respectively. Whilst the untreated and SP treated samples exhibited a similar tribocorrosion behavior, the duplex-treated sample exhibited the greatest resistance to corrosion-wear observed by the lack of damage on the surface and the diminished material loss rates. On the other hand, the surface treatments did not improve the corrosion performance of the Ti-6Al-4V substrate., peer-reviewed

A hybrid approach based on laser texturing and surface coating for the combined modification of surface topography and chemistry has been proposed to provide a versatile approach for the development of functional surfaces. The experimental procedure comprised nanosecond pulsed laser texturing of AISI 304 stainless steel substrates followed by the deposition of thin (

The surface characteristics and friction behaviour of titanium Grade 2 with modified nitride (TiN, Ti2N) and boride (TiB) compound layers were investigated. It was shown that during non-contact boriding in oxygen-containing medium of titanium, the diffusion processes take place mainly by the interscale mechanism; however, during nitriding, besides the traditional interscale diffusion mechanism, the grain boundary mechanism of diffusion of nitrogen atoms is also realized. The optimal set of surface roughness parameters (height and step parameters, a combination of kurtosis and asymmetry, and profile reference curve parameters) was obtained after boriding. It was determined that the intensity of the adhesive wear of the tribo-pairs with stainless steel and ultrahigh molecular weight polyethylene under dry sliding conditions was influenced not only by the hardness but also roughness of the modified surface layer. The lowest friction coefficient was fixed for the TiB compound layer in both tribo-pairs.

Alongside the increasing amount of personal healthcare devices being used, also more medical-device related injuries (MDRI’s) are experienced at the interface between the device and the skin. A systems approach showed that the predominant underlying cause of these MDRI's is prolonged skin contact resulting in an unfavourable microclimate, comprising the effects of humidity, temperature and airflow. We hypothesize that these injuries can be prevented through intelligent product design. In general, managing MDRI’s is hard from dermatology and engineering practice: It shows that up till now it is a process of trial-and-error and the focus is on reduction of symptoms, rather than prevention. In the end, the use of these products, as well the treatment of incurred co-morbidities such as pressure ulcers or dermatitis are paired with significant costs. Also, finding an adequate way of treating the symptoms may be a lengthy process. Surface engineering is well known to further modify and possibly enhance the functionality and performance of a product, including the thermo-mechanical interactions taking place at the skin-medical device interface. In order to be able to reduce the trial-and-error time and create personalised solutions for microclimate regulation through surface engineering, steps towards research and design must be taken. Engineers and healthcare professionals report that future work should focus on creating design maps supporting the engineering process in which microclimate regulation mechanisms are designed. This research will address the role of surface engineering in microclimate regulation of personal healthcare devices in prolonged contact with the skin by introducing a design map for the development of interfaces managing both the thermal and moisture component. This will be done with respect to the correlation of texture features, material properties, and product characteristics. The presentation will link knowledge from dermatological, biomechanical and engineering perspectives and current and future microclimate regulation strategies from a systems approach as a first step towards the proposed design map.

Introduction: Surface engineering of nanocrystals for improving the biopharmaceutical features is a multivariate process involving numerous formulation and process variables, thus making it a complicated process to get the desired biopharmaceutical quality profile. Nano-by-design is hereby proposed as an approach to nanonize an orally active, lipid lowering fenofibrate, to improve feasibility in product development. Methodology: Top-down wet ball milling (media milling) in zirconia planetary chamber was methodically explored for improving the solubility and bioavailability of fenofibrate by formulating a nanosuspension using polyvinyl alcohol as a stabilizer. Several influencing variables were screened using a systematic one-factor-at-a-time approach. DSC, SEM, XRD, and FTIR were utilized for physical characterization of the product during the development stage and study the effect of milling time, milling speed, fenofibrate: stabilizer ratio, premilling time and stabilizer concentration. Potential risk factors affecting critical quality biopharmaceutical attributes of fenofibrate nanocrystals like size, zeta potential, in vitro release, crystallinity and intrinsic solubility were optimized to improve pharmacokinetic performance. Result: Formulated nanosized fenofibrate exhibited a crystalize nature as evident from XRD and DSC, 411 nm size, and a rapid but complete dissolution (~99% in 30 min). This resulted into quick onset of action and improved bioavailability as observed from 51.46% shorter Tmax, 82.63% higher Cmax, and 69.34% higher AUC0–24h, respectively.

The strategy and methodology for selecting of optimal surface treatment for a given tribological application are the main objectives of study. The classification of main methods of coating processes and surface modification is given. The scheme of development of operation technology of surface treatment and coating deposition is proposed. The main initial data: the structure of tribological system (TrS); individual properties of TrS parts; lubricant properties; method of lubrication of TrS parts; properties of sur­rounding environment; external influences on TrS; technological limitations on TrS parts treatment; managerial and economical limitations. The selection of surface technology method is including the next successive steps: the preliminary analysis of TrS part interaction; development of models of friction and wear process of TrS parts; the choice of rational values of parameters of surface layers of TrS parts; the choice of rational composition and structure parameters of surface layers of TrS parts; the choice of rational technological route and methods of surface treatment of TrS parts; the experimental examination of surface strengthened materials and TrS and correction of surface treatment technology

The work presents the results of a study on cavitation erosion (CE) resistance of two NiCrSiB self-fluxing powders deposited by oxy-acetylene powder welding on cast iron substrate grade EN-GJL-200. The mean hardness of deposits A-NiCrSiB, C-NiCrSiB is equal to 908 HV, 399 HV and exceeds those of EN-GJL-200 and X5CrNi18-10 reference specimens 197 HV and 209 HV, respectively. To study CE, the vibratory apparatus has been used and tests were conducted according to the ASTM G32 standard. Cavitation eroded surfaces were examined using a profilometer, optical and scanning electron microscopy. The research indicated that the CE resistance, expressed by the cumulative mass loss decreased in the following order C-NiCrSiB > A-NiCrSiB > X5CrNi18-10 > EN-GJL-200. Therefore, hardfacings were characterised by lower cumulative mass loss, in turn, higher CE resistance than the reference sample and therefore they may be applied as layers to increase resistance to cavitation of cast iron machine components. Results indicate that in the case of multiphase materials, hardness cannot be the main indicator for CE damage prediction while it strongly depends on the initial material microstructure. To qualitatively estimate the cavitation erosion damage (CEd) of NiCrSiB self-fluxing alloys at a specific test time, the following factors should be considered: material microstructure, physical and mechanical properties as well as surface morphology and material loss both estimated at specific exposure time. A general formula for the CEd prediction of NiCrSiB deposits was proposed.

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted increasing attention as promising energy storage devices in large-scale energy storage systems due to their low cost, high capacity, and inherent safety. However, the poor reversibility of zinc anodes has largely restricted their further development because of the dendrite growth, surface passivation, and hydrogen evolution problems associated with Zn metal anodes during the repeated plating/stripping cycles. Surface engineering with functional protection layer appears to be an effective means to mitigate Zn dendrite issues. We first introduce zinc electrochemistry in mild/neutral environments and elaborate Zn anode degradation mechanism. Then, we give state-of-the-art research progress and provide a specific, comprehensive, and in-depth summary of the mechanisms of different coating materials, and share some examples of advanced characterizations for an in-depth understanding on the working mechanisms of the coating layers. Finally, we propose a design principle for the structural design of an ideal interface layer on the Zn metal and share perspectives. This review would give rise to a broad interest focusing on commercial Zn foils in the community of ZIBs, bring potential ideas and inspiration in surface engineering strategies for the rational design of dendrite-free Zn anodes, and boost the development of advanced aqueous ZIBs with low cost and inherent safety.

Controllable synthesis of large-scale and high-quality graphene film is a basis for development of electronic and spintronic devices. Chemical vapor deposition (CVD) has been considered as a potent...

The surface of lead halide perovskite nanocrystals (PNCs) is unique compared to conventional metal chalcogenide or pnictogenide semiconductor nanoparticles for its ionic character and the dynamic ligand layer, which makes them unstable in stock solutions and hinders the development of surface engineering strategies. This work employs a chelating strategy to form stable coordination on the PNC surface. Through screening a series of heterocyclic aromatic carboxylates, we found the best ligand, picolinate (PIC), with exceptional passivation effect to the surface traps of CsPbBr3 PNCs in the strongly quantum confined regime, resulting in > 0.8 photoluminescence quantum yields. The exciton lifetime in the passivated PNC approaches the radiative decay limit in various solvents. From an NMR titration experiment, the binding affinity of PIC is estimated to be at least 15 to 30 folds stronger than the original ligand from synthesis. The NMR and FTIR spectroscopic data and first-principles calculations elucidate the bidentate nature of the PIC coordination at the surface Pb site and the coadsorption of the ammonium-PIC ion pair. In apolar solvents, such as cyclohexane, the binding of PIC is stoichiometric to the available surface sites, suggesting the structure as a potent candidate for anchoring functional molecular structures to the PNC surface. In polar solvents, the strong affinity of PIC on the PNC surface provides protection for carrying out the precipitation-redissolution purification procedure that removes synthetic residual from the as-synthetic PNC samples. By modifying the purification procedure, we also develop a cation exchange procedure to replace the original oleylammonium cation with desired structures that consist of an ammonium anchoring group. Our results provide a direction for constructing strong interactions to protect the vulnerable surface of PNCs and pave the road for developing surface engineering strategies to functionalize these nanoparticles.

The development of structure/function integrated materials is an important trend in military field. Herein, a hierarchical structure was introduced on carbon fiber surface via the successively grafting of polyacrylic acid (PAA) layer and Fe3O4 nanoparticles. It is found that this hierarchical structure could simultaneously improve the composites interfacial strength (30.5%) and toughness (82.6%), due to the mechanical interlocking by Fe3O4 and polarity matching by PAA layer. Moreover, for fiber's microwave absorption (MA) performance, the introduced magnetic Fe3O4 nanoparticles facilitate the impedance matching and magnetic loss, and large number of dipoles from PAA provide polarization loss for microwave dissipation, and finally lead to enhanced MA properties with strong absorption (−40.6 dB) and a wide effective bandwidth (6.13 GHz). In all, the present study offers a facile strategy for the preparation of structural/microwave-absorbing integrated carbon fiber, and could further provide guidance for other carbon fiber-based multifunctional materials.

Photoelectrochemical (PEC) water splitting is one of promising green method to generated renewable energy such as hydrogen. To realize PEC for hydrogen production, it is indispensable to develop a high-performance photocatalyst. In this study, a facile surface engineering using plasma treatment is developed for TiO2 nanotubes where the surface becomes porous and partially amorphized resulting in the enhanced photocatalytic activity. Moreover, electronic configuration of TiO2 nanotubes were effectively modulated via ion plasma treatment, which improves charge transport and light-absorption in TiO2 nanotubes. Electronic modulations in combination with the intriguing nanoporous structure after ion plasma treatment leads to significantly enhanced photocatalytic activity of TiO2 nanotubes, which can be applied for designing next high-performance photocatalysts.

In order to reduce the negative impact of the extra carbon coating on the electrochemical properties of the commonly sandwiched carbon nanotubes@tin dioxide@carbon (CNT@SnO2@C) composites, the external C coating has been designed as a porous carbon in this work. The well-designed porous carbon coating offers an attractive advantage compared to the common carbon coatings, namely, it can not only better mitigate the volumetric variation of SnO2 by means of its spongy structure with better flexibility and rich free space, but also accelerate the lithium-ions diffusion by virtue of its open tunnel-like architecture. For this reason, this composite prepared here shows outstanding electrochemical performance stemming from the cooperative effect of inner CNT supporting and externally porous carbon coating, displaying 819.3 and 576.0 mAh g−1 at 200 and even 1000 mA g−1 after even 500 cycles, respectively. This surface engineering strategy may be valuable for enhancing the cyclical durability of other metal oxides with higher theoretical specific capacities.

Orthopaedic metallic implant design is expected to meet two critical challenges—biocompatibility and mechanical strength. According to a survey conducted in 2017, the global market of implants will grow by ~46% by 2025. Researchers have been trying to alleviate the problems of these implants, namely, biocompatibility, microbial invasion, bio-inertness, corrosion, and wear. Surface modification techniques that operate at low temperature and diffusion-based processes are preferred to circumvent the problems. These methods include thermochemical (carburizing, nitriding, etc.), electrochemical processes (electrochemical deposition, chrome plating, etc.), and ion implantation. This review presents the significance of these methods while meeting various challenges, such as wear, biocompatibility, and corrosion. The implants reviewed are stainless steel, Co-Cr alloys, titanium alloys, and magnesium alloys. Finally, the friction-stir process, another low-temperature process, has been reviewed for Mg and its alloys.

As a type of novel surface engineering technology, the application of cold spraying in the manufacturing and remanufacturing of high-end precision parts is very suitable. However, the disadvantage of low interface bonding strength can easily induce coating peeling at the coating/substrate interface under the effect of applied loads. Therefore, finding a suitable nondestructive testing method is significant to evaluate the cold-sprayed coating peeling process and provide prediction results. To achieve this aim, magnetic Barkhausen noise (MBN) testing was used in this paper because of its high sensitivity to microstructure variation. The Ni-Zn-Al2O3 ferromagnetic coating deposited on the ductile cast iron substrate was prepared by cold spraying. Based on the wavelet coherence analysis, the frequency of MBN signals induced by magnetic domain movement was mainly concentrated in the range of 1–4 kHz. The spectrum power between 1 kHz and 4 kHz was extracted as the characteristic value, and the linear fitting relationship between the characteristic value and applied load was established. When the power reaches the threshold value range of 3.106×10−8–3.557×10−8 W, the probability that the interfacial stress exceeds the coating/substrate bonding strength and that Ni-Zn-Al2O3 coating peeling occurs is 95%. Combined with the microstructure and morphology analysis, the mechanism of cold-sprayed coating peeling was revealed, and the underlying reason for MBN signal variation was explained. This research can accurately evaluate the ferromagnetic cold-sprayed coating peeling process and the interface bonding strength.

Layered O3 type oxides exhibit promising prospects as high-performance cathodes for sodium-ion batteries (SIBs) due to their low cost and high theoretical capacities. Nevertheless, the intrinsic surface composition and bulk structure degradation upon cycling presents a huge obstacle to stable sodium-ion storage/transportation. Besides, the effective surface decoration on layered O3 oxides is still challenging through conventional wet chemical route owing to their extraordinarily high surface sensitivities. Herein, a typical O3 type layered oxide of NaNi0.5Mn0.5O2 (NNMO) was selected and successfully encapsulated by precisely controlled Al2O3 layers via atomic layer deposition (ALD) technology. With the optimally controlled Al2O3 thickness of 3 nm, the surface regulated NNMO delivers a highly reversible capacity of 73.6 mA h g-1, with a significantly improved capacity retention of 68.0% after 300 cycles at 0.5 C, and a superior rate capability of 65.8 mA h g-1 at 10 C. Further air sensitivity tests demonstrate that the protective layer could effectively mitigate the generation of sodium-based impurities on NNMO, and reduce the surface sensitivities. Both chemical and electrochemical aging tests confirm the contribution of Al2O3 coating layer in alleviating ion dissolution as well as stabilizing the structure and morphology of NNMO. Based on regulating the surface of O3 type layered oxides utilizing ALD technique, this work supplies an effective and facile strategy to overcome the challenges from fast structure degradation and electrochemical property decay, which not only highlights the significance and effectiveness of surface engineering in secondary batteries, but also sheds light on accurate interface construction and regulation for active electrode materials, particularly for those sensitive to ambient atmosphere.

In this work, synergistic effects derived from surface engineering and dielectric property tuning were exploited to enhance the output performance of a triboelectric nanogenerator (TENG) based on an inorganic/porous PDMS composite in a contact-separation mode. BaTiO3 (BT)/porous PDMS films with different BT weight ratios were fabricated and evaluated for triboelectric nanogenerator (TENG) application. Maximum output signals of ca. 2500 V, 150 μA, and a power density of 1.2 W m-2 are achieved from the TENG containing 7 wt % BT, which is the best compromise in terms of surface roughness, dielectric constant, and surface contact area as evidenced by SEM and AFM studies. These electrical signals are 2 times higher than those observed for the TENG without BT. The 7BT/porous PDMS-based TENG also shows high stability without a significant loss of output voltage for at least 24 000 cycles. With this optimized TENG, more than 350 LEDs are lit up and a wireless transmitter is operated within 9 s. This work not only shows the promoting effects from porous surfaces and an optimized dielectric constant but also offers a rapid and template/waste-free fabrication process for porous PDMS composite films toward large-scale production.

While perfluorinated polymers such as polytetrafluoroethylene (PTFE) is considered to be resistant to natural weathering, it can still be degraded over time, during which it may release harmful short-chain polyfluorinated alkyl substances (PFASs). Additional concern regarding PTFE particles is their role as vectors for toxic trace organic compounds, particularly towards co-existing fluorinated compounds. Our research focuses on examining PTFE potential to act as source and sink of PFAS, including further implications on human health. Based on previous degradation protocols developed by our group (Sarkar et al., ES&T, 2020), [N1] we degrade raw PTFE particles in a set of accelerated weathering laboratory conditions. In this procedure, pristine PTFE particles are exposed to various oxidation, mechanical and repeated thermal treatments. Then, we evaluate the leaching of short-chained PFASs, sorption potential towards co-existing PFASs, and the corresponding desorption potential in realistic post scenarios of transport from environmental media to biological media following ingestion by living forms. Lastly, the potential toxic effects of PTFE particles, PFAS, and PTFE-sorbed-PFAS are investigated using a single-cell model of Caco2 (human colon epithelial cell line). Our results showed that when pristine PTFE particles suspensions were probe sonicated (i.e., mechanically treated[N2] ), the number of particles was doubled. The ATR-equipped Fourier transform infrared spectrometry (FT-IR) spectra of ozone treated raw PTFE particles ( 17,008 mg/L) showed new peaks at approximately 1100, 1700 and 2900 cm−1, which were not observed in the raw PTFE spectra. These new peaks are respectively associated with C-O stretching, carboxyl groups, and O-H stretching. Therefore, we conclude that PTFE does degrade in extreme condition and may result in PFAS release. Currently, the project is being conducted in parallel at the technical university of Munich (sorption studies) and at Tel Aviv University (toxicity studies) to shed light on the relationships between these two emerging fluorinated contaminants. Also see: https://micro2022.sciencesconf.org/427158/document, In MICRO 2022, Online Atlas Edition: Plastic Pollution from MACRO to nano

This paper reports the optimization of a two-step atmospheric pressure plasma process to modify the surface properties of a polyurethane (PU) foam and, specifically, to prepare a superhydrophobic/superoleophilic absorbent for the removal of oils and nonpolar organic solvents from water. In particular, in the first step, an oxygen-containing dielectric barrier discharge (DBD) is used to induce the etching/nanotexturing of the foam surfaces; in the second step, an ethylene-containing DBD enables uniform overcoating with a low-surface-energy hydrocarbon polymer film. The combination of surface nanostructuring and low surface energy ultimately leads to simultaneous superhydrophobic and superoleophilic wetting properties. X-ray photoelectron spectroscopy, scanning electron microscopy and water contact angle measurements are used for the characterization of the samples. The plasma-treated PU foam selectively absorbs various kinds of hydrocarbon-based liquids (i.e., hydrocarbon solvents, mineral oils, motor oil, diesel and gasoline) up to 23 times its own weight, while it completely repels water. These absorption performances are maintained even after 50 absorption/desorption cycles and after immersion in hot water as well as acidic, basic and salt aqueous solutions. The plasma-treated foam can remove mineral oil while floating on the surface of mineral oil/water mixtures with a separation efficiency greater than 99%, which remains unaltered after 20 separation cycles.

11th International Conference on Through-life Engineering Services - TESConf2022 8-9 November 2022, Cranfield UK Surface engineering is a vital aspect of manufacturing industries owing to its benefits both in surface protection and aesthetics. It has been extensively used in various industries to guard against corrosion which is a naturally occurring and highly undesirable phenomenon. Present research has endeavored to analyze protection of ASTM A516 (Grade 70) from corrosion through surface engineering. Different methods of surface treatment and conversion coating were carried out to efficiently enhance corrosive protection. Comparative analysis of various samples was conducted to analyze their ability to resist corrosion. Samples with surface treatment followed by conversion coating were found to be effective even against 0.7% aqueous sulfuric acid with no significant cracks in the coating layer. On the other hand, conversion coated only samples showed protection against 0.35% acid. The coating of conversion coated only samples was found to have gaps/ cracks as indicated by 3% Cupric Sulfate whereas no such gaps were found in surface treated samples. Optical microscopy identified a more uniform coating thickness for surface treated samples in comparison with conversion coated only samples. In depth morphology analysis using SEM highlighted that surface treated samples had low porosity preventing the corrosion elements to reach the substrate thereby implementing higher corrosion potential. DMG Mori

The synthesis and study of the tripeptide Arg-Gly-Asp (RGD), the binding site of different extracellular matrix proteins, e.g., fibronectin and vitronectin, has allowed the production of a wide range of cell adhesive surfaces. Although the surface density and spacing of the RGD peptide at the nanoscale have already shown a significant influence on cell adhesion, the impact of its hierarchical nanostructure is still rather unexplored. Accordingly, a versatile colloidal system named quatsomes, based on fluid nanovesicles formed by the self-assembling of cholesterol and surfactant molecules, has been devised as a novel template to achieve hierarchical nanostructures of the RGD peptide. To this end, RGD was anchored on the vesicle's fluid membrane of quatsomes, and the RGD-functionalized nanovesicles were covalently anchored to planar gold surfaces, forming a state of quasi-suspension, through a long poly(ethylene glycol) (PEG) chain with a thiol termination. An underlying self-assembled monolayer (SAM) of a shorter PEG was introduced for vesicle stabilization and to avoid unspecific cell adhesion. In comparison with substrates featuring a homogeneous distribution of RGD peptides, the resulting hierarchical nanoarchitectonic dramatically enhanced cell adhesion, despite lower overall RGD molecules on the surface. The new versatile platform was thoroughly characterized using a multitechnique approach, proving its enhanced performance. These findings open new methods for the hierarchical immobilization of biomolecules on surfaces using quatsomes as a robust and novel tissue engineering strategy., This work was supported by MICINN (PID2019-105622RBI00, MAT2016-80826-R, PID2019-111682RB-I00, PID2020-115296RA-I00, CTQ2015-66194-R; SAF2014-60138-R, RTI2018-093831-B-I00, and PDC2021-121481-I00); Instituto de Salud Carlos III (ISCIII) through the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBER-BBN (FlexQS-skin, FlexCAB, BBN18PI01, BBN20PIV02, and CB/06/0074); Generalitat de Catalunya (grants 2017-SGR-918, 2017-SGR-229, 2017-SGR-1442, 2017-SGR-1439); the Fundació Marató de TV3 (Nr. 201812); the COST Action CA15126 Between Atom and Cell, and “ERDF A way of making Europe”. J.G. acknowledges financial support from the Ramón y Cajal Program (RYC-2017-22614) from MICINN and the Max Planck Society through the Max Planck Partner Group “Dynamic Biomimetics for Cancer Immunotherapy” in collaboration with the Max Planck Institute for Medical Research (Heidelberg, Germany). This work has received funding from the European Union’s Horizon 2020 research and innovation program through grant agreements 953110 (PHOENIX), 720942 (Smart4Fabry), 101007804 (MICRO4NANO), and 801342 (granted to the Agency for Business Competitiveness ACCIÓ through a Tecniospring Industry fellowship (TECSPR19-1-0065)). ICMAB acknowledges support from MICINN through the “‘Severo Ochoa”’ Programme for Centres of Excellence in R&D (CEX2019-000917-S). J.M. acknowledges a “Juan de la Cierva” fellowship from MICINN. J.T-M. acknowledges an FI-AGAUR grant (2020FI_B2 00137) from Generalitat de Catalunya and the European Social Fund. We also acknowledge the ICTS “NANBIOSIS for the support of the Synthesis of Peptides Unit (U3) at IQAC–CSIC (https://www.nanbiosis.es/portfolio/u3-synthesis-of-peptides-unit/) and the Biomaterial Processing and Nanostructuring Unit (U6) at ICMAB-CSIC (https://www.nanbiosis.es/portfolio/u6-biomaterial-processing-and-nanostructuring-unit/). We are grateful to the SMP unit of the Scientific and Technological Centers of University of Barcelona (CCiTUB). This work has been developed under the “Biochemistry, Molecular Biology and Biomedicine” and “Materials Science” Ph.D. programs of Universitat Autònoma de Barcelona (UAB)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

The possibility of using an aqueous non-toxic electrolyte of ammonium nitrate and glycerin for the cathodic plasma electrolytic nitrocarburizing of low-carbon steel is considered in this paper. Surface morphology and roughness, element and phase compositions, and microhardness of the modified layer were investigated. Kinetic calculations of the processes of nitrogen and carbon diffusion into the steel surface are proposed, taking into account their mutual influence. Wear resistance was studied under dry friction conditions with tool alloy steel as a counter-body. Corrosion studies are performed using potentiodynamic polarization curves in 3.5% sodium chloride solution. The plasma electrolytic nitrocarburizing in an aqueous electrolyte with ammonium nitrate and glycerin is established to increase surface hardness up to 980 HV due to the formation of a nitrocarburized layer with 1.35 ± 0.12% carbon and 0.32 ± 0.08% nitrogen concentration. The influence of erosion in electrolyte plasma and high-temperature oxidation on the morphology and surface roughness is shown. The presence of a dense oxide layer, low surface roughness, and high hardness of the diffusion layer favor a decrease in the friction coefficient by 1.3 times, weight wear by 1.8 times and corrosion current density by 1.4 times.

The surface feature of solid electrolytes fundamentally governs their own physical properties and significantly affects the interaction with the electrode materials. The evaluation of interfacial contact between the electrolyte and the metallic anode is largely relied on the macroscopic contact angle measurement, which is influenced by the intrinsic wettability and the microstructure of the electrolyte. In this work, the surface chemistry of the solid electrolyte is first regulated via facile thermal treatments. Then, scanning probe microscopy (SPM)-based techniques are comprehensively adopted to study the interaction between the electrolyte and metallic anode at the nanoscale. By manipulating the overpotential applied on the SPM tip, the mobile sodium ions at the subsurface of the solid electrolyte can be extracted toward the surface, and the eventual topography of the products is deliberately correlated with the sodium wettability. In this context, the impact of surface treatment on the sodium wettability of the surface layer is systematically evaluated based on the topographic evolution at the nanoscale. Furthermore, the local electrochemical reaction dynamics is revealed by correlating the surface ionic activity and current-voltage (I-V) curves. This work presents a new methodology to effectively evaluate the sodium wettability of the solid electrolyte, and these findings can provide meaningful implications to the surface engineering of ceramic electrolytes for high-performance solid-state batteries.

Triboelectric nanogenerator (TENG) is the new technique that can convert low-frequency mechanical energy into effective electricity. As an energy collector, the pursuit of high output characteristics is understandable. Although high charge density has been achieved by working in high vacuum or charge pumping techniques, it remains challenging to obtain the high output performance directly in the atmosphere. Herein, surface-engineering of the triboelectric layer for enhancing output performance has been reviewed carefully. By constructing surface morphology or developing surface modification, high performance of TENGs is finally presented in the review.

A surface engineering approach is exploited to enhance the performance of H2 sensors consisting of a single-wall carbon nanotube film/graphene 3D electrode decorated with catalytic Pt nanoparticles using atomic layer deposition (Pt-NPs/SWCNTs/Gr). Specifically, C-band ultraviolet (UVC) radiation has been applied on the Pt-NPs/SWCNTs/Gr sensors for up to 20 minutes to activate the carbon surface and enhanced H2 sensitivity and response speed have been obtained. Remarkably, at the optimal UVC irradiation of 10 minutes (intensity of 4.6 mW/cm2), the H2 gas response was enhanced by up to 4.3 fold, together with an enhanced response speed by 3.6 times as compared to that of the as-made Pt-NPs/SWCNTs/Gr sensors before the UVC irradiation. Specifically, a high H2 response up to 32% has been achieved at 10% H2 concentration. This enhancement can be attributed to desorption of residual molecules adsorbed on the SWCNTs and graphene surfaces during the sensor fabrication using UVC irradiation. This result illustrates the importance of the carbon surface activation in development of high-performance H2 sensors using carbon nanostructures. The obtained high performance in the Pt-NPs/SWCNTs/Gr sensors can be attributed to the large sensing surface area of SWCNT films with carbon surface activated using UVC treatment, the catalytic benefit of the conformally coated Pt-NPs, and high mobility signal transport through graphene. In addition, this result demonstrates that the UVC irradiation can provide an effective, non-destructive, and facile method to activate the carbon surface on sensors composed of carbon nanostructures.