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In this work, nanocomposite polymeric films were fabricated by spin coating technique on the pre-treated glass substrate for sensors application. nanocomposites consist of PEDOT:PSS polymer as a matrix phase and Graphene with different weight percentages (0.5, 1, 1.5, 2) wt% as a dispersion phase. To enhance its surface reactivity, glass substrate were etched chemically using Piranha Solution. FTIR results showed there is no chemical reaction occurred, just only hydrogen bonding arises among components. The mechanism of the proposed model suggested that the interaction achieved by three steps. XRD results showed that, with the Graphene content, the diffraction position shifted upward; from 2θ = 24° to 2θ = 26°, as well as the intensity increased. All crystalline parameters, which either derived from Bragg's Law or from Scherer's equation proved the Graphene dispersion and the increment of the crystallinity. AFM results showed that roughness increased by about 92% through the roughness average (Sa) parameter and by 45% through the density of summits (Sds) parameter. These finding matched with the SEM images, which showed that, the PEDOT:PSS films without Graphene has a comparatively smoother surface than the PEDOT: PSS with Graphene and this confirms that the mechanical strength of the prepared films improved clearly and significantly. UV‐ VIS Spectroscopy results proved that Graphene addition increased the absorbance in UV, VIS, and IR regions, and the absorbance in the UV region is higher than the other two regions, which indicates that the prepared film resists UV- degradation.

Hypothesis: The properties of the oxidized surface for common materials, such as silicon and titanium, are known to be markedly different from the reduced surface. We hypothesize that surface-oxidized aluminum gallium nitride ((oxidized-AlGaN)/GaN) surface charge behavior is different to unoxidized AlGaN (with ultrathin native oxide only), which can be validated via surfactant adsorption. Understanding these differences will explain why (oxidized-AlGaN)/GaN-based sensors are better performing than AlGaN ones, which has been previously demonstrated but not understood. Experiments: The surface of an AlGaN/GaN structure was oxidized with hot piranha solution and oxygen plasma. AFM force measurements and imaging were performed to probe the charge properties of the surface in aqueous solutions of varying pH containing only an acid or base, or with an added ionic surfactant: cationic cetyltrimethylammonium bromide (CTAB) or anionic sodium dodecylsulfate (SDS). Findings: The (oxidized-AlGaN)/GaN surface is positively charged at pH 4 and pH 5.5, although pH 5.5 should be close to the isoelectric point of the surface. The surface is negatively charged at pH 10 and pH 12, and sufficiently charged to attract cooperative adsorption of CTAB aggregates at pH 12. At pH 2, the evidence is inconclusive, but the surface is most likely positively charged. Compared to unoxidized AlGaN, the (oxidized-AlGaN)/GaN surface shows a wider range of surface charge magnitude over pH values between 2 and 12. This suggests that the (oxidized-AlGaN)/GaN surface has a higher surface hydroxyl group density than unoxidized AlGaN, which explains the higher sensitivity for pH sensors based on (oxidized-AlGaN)/GaN structures.

Hydraulic fracturing is the main stimulation technique that enables the economic production of coalbed methane reservoirs. However, massive invasion and retention of coal fines in proppant packs can clog the pore spaces and lead to an impairment of fracture conductivity. In this study, the effects of proppant wettability and size on retention of coal fines in proppant packs during the dewatering stage were investigated, for their optimization to achieve a long-term and effective control of fines retention. First, a series of transport and retention experiments of coal fines were performed on saturated proppant packs with different proppant sizes and wettabilities. Herein, standard quartz sand was used as the proppant carrier, and its surface wettability was modified to either hydrophobicity or stronger hydrophilicity by treatment with fluorocarbon resin and piranha solution, respectively. The experimental results indicated that both the retained amount and the deposition rate coefficient of coal fines decreased with increasing proppant hydrophilicity (or decreasing proppant hydrophobicity) and size. For the proppants treated with piranha solution, almost no coal fines were retained in proppant packs. Second, the forces/torques acting on coal fines in the vicinity of proppants were analyzed to elucidate the underlying mechanisms responsible for the influence of proppant wettability and size on fines retention. The effective filter surface (EFS) parameter was estimated by analyzing forces/torques to evaluate the filtration performance of proppant packs. Theoretical results illustrated that the EFS value decreased with increasing proppant hydrophilicity and size. The EFS value for proppants treated with piranha solution was near zero, which was due to the chemically "unfavorable"retention condition induced by piranha solution treatment. The EFS exhibited a similar tendency to the retention of coal fines observed in experiments, which validated the model. Finally, the recommendations on fines retention control in proppant packs were provided.

Purpose: To assess the effect of chemical pre-treatments (piranha, hot acid, and heteropolyacid) on the bond strength (μTBS) to zirconia. Materials and Methods: A total of 8 sintered zirconia blocks were randomly assigned into 4 groups; Group I: Air abrasion, Group II: Air abrasion and etching using piranha solution (3H2SO4: 1H2O2), Group III: Air abrasion and etching using hot acid solution (1HNO3: 1HF), and Group IV: Air abrasion and etching using heteropolyacid solution (2gm/50 mL). Zirconia blocks were bonded to their corresponding pre-constructed composite blocks using adhesive resin cement. For each group, each assembly was sectioned to obtain 20 microbars. All microbars were thermocyled (10,000), then the μTBS test was done with the aid of a Universal Testing machine. To determine the mode of failure, each specimen was examined under stereomicroscope (x40). One-way ANOVA and Post Hoc Tukey tests were used. Results: The piranha pre-treatment displayed the lowest bond strength (16.82 ±5.97 MPa), while heteropolyacid pre-treatment had higher bond strength (26.22 ±4.05 MPa). One-way ANOVA test indicated statistical significant difference between the studied groups (P

The sol-gel process is an innovative advanced method, initially developed to synthesize glass and ceramics at low temperature. Sol-gel process can be used to synthesis materials with a variety of shapes, such as porous membranes, thin fibers, nano-size powders and thin films. In this study, epoxy and methacrylate based silane coupling agents are used together with zirconium oxide to form a hybrid coating system on glass surface. In the experimental study, an organic–inorganic molecular hybrid compound was prepared by sol-gel method. First glasses were cleaned by traditional piranha solution (3:1 H2SO4 : H2O2) to remove contaminants. Silanization was applied to increase the adhesion of hybrid coatings on glass substrates. Glass substrate was coated with this solution by a homemade dip-coater. In this study, (3-Glycidoxypropyltrimethoxysilane, GLYMO and 3-(trimethoxysilyl)propylmethacrylate, TMSPM) were chosen as a silane. Zirconia is inorganic component of hybrid materails. Coated samples were characterized by Fouirer Transform Infrared Spectrophotometer (FTIR), Scanning Electron Microscope with Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Contact Angle Goniometer.

Bacterial adhesion and colonization on stainless steel (SSL) based surgical instruments, hospital equipment, orthopedic implants, water purification and food processing units are a major problem. Imparting rechargeable antibacterial properties to SSL offers the prospect of a reusable and clean surface. In this study, the SSL surface was functionalized with a hydantoin-based antibacterial polymer that prevents bacterial adhesion and colonization. A new hydantoin monomer with three halogen binding sites, (Z)-N-((4-(2,5-dioxoimidazolidin-4-ylidene)methyl)phenyl)methacrylamide (DMPM), was synthesized, characterized and copolymerized with a commercially available 3-(methacryloyloxy)propyltrimethoxysilane monomer to develop the antibacterial polymer. The SSL surface was treated with piranha solution and the copolymer was covalently immobilized on the surface. The modified surface was examined for its antibacterial and anti-biofilm activity. The modified surface exhibited total kill (6 log reduction) of bacteria such as S. aureus and E. coli in 10 and 12 min respectively. The anti-biofilm activity of the modified surface was evaluated using a combination of fluorescence-based metabolic activity and scanning electron microscopy imaging suggested the comprehensive damage of S. aureus and E. coli biofilm architecture.

In the present work we report for the first time the carbonization of biomass waste, such as stale bread and spent coffee, in piranha solution (H2SO4-H2O2) at ambient conditions. Carbonization is fast and exothermic, resulting in the formation of carbon nanosheets at decent yields of 25–35%, depending on the starting material. The structure and morphology of the nanosheets were verified by X-ray diffraction, Raman, X-ray photoelectron and microscopy techniques. Interestingly, the obtained carbon spontaneously ignites upon contact with fuming nitric acid HNO3 at ambient conditions, thus offering a rare example of hypergolicity involving carbon as the solid fuel (i.e., hypergolic carbon). Based on the relatively large interlayer spacing of the as-produced carbons, a simple structural model is proposed for the observed hypergolicity, wherein HNO3 molecules fit in the gallery space of carbon, thus exposing its basal plane and defect sites to a spontaneous reaction with the strong oxidizing agent. This finding may pave the way towards new type hypergolic propellants based on carbon, the latter exclusively obtained by the carbonization of biomass waste in piranha solution.

This work aimed to prepare a composite with a polyamide (PA) matrix and surface-modified ZrO2 or Al2O3 to be used as ceramic fillers (CFs). Those composites contained 30 wt.% ceramic powder to 70 wt.% polymer. Possible applications for this type of composite include bioengineering applications especially in the fields of dental prosthetics and orthopaedics. The ceramic fillers were subjected to chemical surface modification with Piranha Solution and suspension in 10 M sodium hydroxide and Si3N4 to achieve the highest possible surface development and to introduce additional functional groups. This was to improve the bonding between the CFs and the polymer matrix. Both CFs were examined for particle size distribution (PSD), functional groups (FTIR), chemical composition (XPS), phase composition (XRD), and morphology and chemical composition (SEM/EDS). Filaments were created from the powders prepared in this way and were then used for 3D FDM printing. Samples were subjected to mechanical tests (tensility, hardness) and soaking tests in a high-pressure autoclave in artificial saliva for 14, 21, and 29 days.

Nickel foam (NF) can be directly utilized as an electrochemical electrode because of its conductive, rigid and porous structure. Herein, a novel robust binder-free Fe–Ni hydroxide-loaded NF electrode is prepared by simple corrosion of NF in a home-made piranha solution with an Fe3+ precursor. The roughened NF surface observed after the sample treatment indicates the formation of active species associated with amorphous Fe-hydroxide and/or FeNi-hydroxide particles. The piranha solution-corroded NF electrode generates more hydroxide groups compared to the water-corroded NF electrode, and exhibits remarkable electrochemical oxygen evolution reaction activity in alkaline medium with a low overpotential of 245 mV at 10 mA cm−2. It also maintains low working potential below 267 mV at 10 mA cm−2 over 500 h operation without any sign of degradation, indicating excellent long-term stability, which can be attributed to the robust binder-free electrode and the cooperative synergistic interaction between Fe-hydroxides and Ni-hydroxides in the FeNi hybrid composite of individually incompetent OER components, generated over the NF. The role of Fe doped in Ni(OH)2 is theoretically studied by DFT calculations, and it is found that the adsorption free energies of OH* and OOH* are significantly reduced by the addition of Fe into Ni(OH)2, accelerating the OER compared to bare Ni(OH)2. Furthermore, when the active electrode is equipped with a solar cell, a high current density of 23–24 mA cm−2 is observed for 10 h under AM 1.5G 1 sun irradiation, suggesting high possibility for the production of green hydrogen from renewable solar energy.

In the present work we introduce a simple approach to produce porous PtPdAg alloy nanoparticles on TiO2 nanotubes by a simple combined sputtering-dewetting-dealloying process. In a first step, three individual metals (Pt, Pd and Ag) were sequentially sputter-deposited on spaced TiO2 nanotubes, followed by a thermal dewetting treatment in Ar to convert these metal layers into ternary PtPdAg alloyed particles. Dealloying was carried out by a selective chemical dissolution of Ag in piranha solution that finally generated porous alloyed nanoparticles located on the TiO2 nanotube walls. The porous PtPdAg-decorated TiO2 nanotubes show enhanced photocatalytic H2 generation in comparison with porous Pt (67% increase) or any monometallic decoration (>120% increase). The photocatalytic enhancement is not only due to the increased number of active sites (larger surface area) of the porous particles but also due to the synergistic effects of the different alloying elements.

The nanostructured titanium (Ti) obtained by the equal-channel angular pressing (ECAP) has shown great promise as a biomedical implant material over the past few decades. The present work aims to investigate the effect of topographical changes caused by ECAP and piranha treatment (Tr) on the surface performance and biological properties of Ti for bone tissue engineering applications. The effects of dual treatments, i.e., ECAP and Tr, on Ti were systematically investigated by multiple characterization techniques, surface wettability, apatite-forming ability, cellular behavior, and antibacterial studies. We demonstrate that both ECAP and ECApTr samples possess desirable mechanical and physical properties and are biocompatible to cultured human fetal osteoblast (hFOB) cells. The potential of adhesion and proliferation of hFOB cells on ECAP and ECApTr samples was found to be superior to that of control unprocessed sample (annealed). Ti samples prepared by both methods showed excellent antimicrobial properties against clinical strains of the most common pathogenic bacteria causing orthopedic implant infections, Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). This study supports the established claim about mechanical properties improvement by ultrafine refinement and further enhances the antibacterial properties when chemically etched with a piranha solution.

The usability of nanomaterials in various research endeavour has been on the front. burner in the past few decades. This is due to its high aspect ratio and steep electrical, molecular defined structure, mechanical and physical properties. This present study reports the synthesis of carbon nanomaterials (CNM) from Eucalyptus globulus leaves. Fresh green leaves of Eucalyptus globulus were collected and dried under the sun. The dried brown leaves were later incinerated completely under atmospheric oxygen. Obtained ashes were treated with acid piranha solution in other to modify the peripheral of the ashes with carboxyl groups (CNM-COOH). Scanning electron microscopy image divulges the presence of carbon nanorods in the ash. CNM-COOH materials in percentages were then incorporated within the polyurethane polymer matrix of which Castor seed oil (Ricinus communis) and trimethylopropane (TMP) provided the hydroxyl base for urethanation. Infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis was used to confirm material modification. Synthesized urethane composites of CNM-COOH material shows improved thermal, mechanical, hydrophobicity and anticorrosion properties when compared with that of pristine polyurethane (PU).

We report controllable adjustment of the flow dynamics of polystyrene films supported by oxide-covered silicon by using a combination of ultraviolet ozone (UVO) treatment of the polymer and variable treatments of the substrate that adjust the contents of Si–OH and Si–H groups on the surface. The latter were achieved by submerging the substrates in a piranha solution and then in deionized water (leading to enrichment of Si–OH) or an aqueous hydrogen fluoride solution (leading to enrichment of Si–H) or both (leading to intermediate surface chemistry). X-ray photoelectron spectroscopic chemical analyses showed that the UVO treatment produced oxygenated functional groups in the polymer. Alongside, effective viscosity (ηeff) of the films became enhanced. However, the degree of enhancement increases (decreases) with the content of Si–OH (Si–H) groups on the substrate surface, ascribable to the resulting increases in the attractive interactions between the UVO-induced oxygenated groups in the polymer and Si–OH o...

To date, significant progress has been achieved in the development of biomedical superelastic Ti-based alloys with high mechanical properties. In view of the high probability of implant-associated infection, an urgent task is to impart bactericidal properties to the material. Herein, advanced superelastic Ti-18Zr-15Nb alloys were surface-etched in a piranha solution, and then Ag nanoparticles were deposited on their surface using a polyol process. This led to the formation of a porous surface layer with a thickness of approximately 100 nm and pore size of less than 20 nm, filled with metallic Ag nanoparticles with an average size of 14 nm. The surface-modified samples showed superior antibacterial activity against E.coli cells. The enhanced bactericidal efficiency is explained by the combination of a higher rate of Ag+ ions release and direct contact of E.coli cells with Ag nanoparticles.

Compared with polymer microfluidic devices, glass microfluidic devices have advantages for diverse lab-on-a-chip applications due to their rigidity, optical transparency, thermal stability, and chemical/biological inertness. However, the bonding process to construct glass microfluidic devices usually involves treatment(s) like high temperature over 400 °C, oxygen plasma or piranha solution. Such processes require special skill, apparatus or harsh chemicals, and destroy molecules or cells in microchannels. Here, we present a simple method for glass-glass bonding to easily form microchannels. This method consists of two steps: placing water droplets on a glass substrate cleaned by neutral detergent, followed by fixing a cover glass plate on the glass substrate by binding clips for a few hours at room temperature. Surface analyses showed that the glass surface cleaned by neutral detergent had a higher ratio of SiOH over SiO than glass surfaces prepared by other cleaning steps. Thus, the suggested method could achieve stronger glass-glass bonding via dehydration condensation due to the higher density of SiOH. The pressure endurance reached over 600 kPa within 6 h of bonding, which is sufficient for practical microfluidic applications. Moreover, by exploiting the reversibility of this bonding method, cell recoveries after cultivating cells in a microchannel were demonstrated. This new bonding method can significantly improve both the productivity and the usability of glass microfluidic devices and extend the possibility of glass microfluidic applications in future.

An integrated approach combining severe plastic deformation (SPD), chemical etching (CE), and atomic layer deposition (ALD) was used to produce titanium implants with enhanced osseointegration. The relationship between morphology, topography, surface composition, and bioactivity of ultra-fine-grained (UFG) titanium modified by CE and ALD was studied in detail. The topography and morphology have been studied by means of atomic force microscopy, scanning electron microscopy, and the spectral ellipsometry. The composition and structure have been determined by X-ray fluorescence analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. The wettability of the surfaces was examined by the contact angle measurement. The bioactivity and biocompatibility of the samples were studied in vitro and in vivo. CE of UFG titanium in basic (NH4OH/H2O2) or acidic (H2SO4/H2O2) piranha solution significantly enhances the surface roughness and leads to microstructures, nanostructures, and hierarchical micro-/nanostruc...

Implant-associated infections are the major concern for failure of arthroplasty operations. The functionalisation of implant surface can provide solutions to the problem by either inhibiting the adherence of the bacteria or introducing a contact-killing mechanism. This work is focused on Ti6Al7Nb biomedical alloy modification involving chemical and plasma surface activation, followed by the deposition of chitosan layers enhanced with metal nanoparticles. A benign method using chitosan as an efficient reducing and stabilizing agent was applied to produce Au and Ag nanoparticles in situ with the size of ca. 20 nm and 5 nm, respectively. Piranha solution and O2/NH3/Ar plasma were used as a surface activation method, while Au and Ag NPs provide antimicrobial properties, as a viable alternative to the antibiotic-based approach. The surface topography on submicrometre scale of deposited layers was evaluated. Chitosan and chitosan–Ag NPs composite layers showed excellent hydrophilicity, characterised by wetting angles below 13°. Modified alloy showed minimal toxicity towards MG-63 cell line in vitro, acceptable corrosion resistance and release of titanium, aluminium as well as niobium ions from the resulting modified alloys. The chitosan layers were proven to uphold satisfactory Au (over 2.8 mg/dm3) and Ag (over 5.1 mg/dm3) ion dosages up to 96h.

This paper describes the effect of calcination temperature on the phase composition, chemical composition, and morphology of ZrO2 and Al2O3 powders modified with 3-aminopropyltriethoxysilane (APTES). Both ceramic powders were modified by etching in piranha solution, neutralization in ammonia water, reaction with APTES, ultrasonication, and finally calcination at 250, 350, or 450 °C. The obtained modified powders were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, particle size distribution (PSD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), and thermogravimetric analysis (TGA).

Irrigation water is a primary source of fresh produce contamination by bacteria during the preharvest, particularly in hydroponic systems where the control of pests and pathogens is a major challenge. In this work, we demonstrate the development of a Listeria biosensor using platinum interdigitated microelectrodes (Pt-IME). The sensor is incorporated into a particle/sediment trap for the real-time analysis of irrigation water in a hydroponic lettuce system. We demonstrate the application of this system using a smartphone-based potentiostat for rapid on-site analysis of water quality. A detailed characterization of the electrochemical behavior was conducted in the presence/absence of DNA and Listeria spp., which was followed by calibration in various solutions with and without flow. In flow conditions (100 mL samples), the aptasensor had a sensitivity of 3.37 &plusmn, 0.21 k log-CFU&minus, 1 mL, and the LOD was 48 &plusmn, 12 CFU mL&minus, 1 with a linear range of 102 to 104 CFU mL&minus, 1. In stagnant solution with no flow, the aptasensor performance was significantly improved in buffer, vegetable broth, and hydroponic media. Sensor hysteresis ranged from 2 to 16% after rinsing in a strong basic solution (direct reuse) and was insignificant after removing the aptamer via washing in Piranha solution (reuse after adsorption with fresh aptamer). This is the first demonstration of an aptasensor used to monitor microbial water quality for hydroponic lettuce in real time using a smartphone-based acquisition system for volumes that conform with the regulatory standards. The aptasensor demonstrated a recovery of 90% and may be reused a limited number of times with minor washing steps.

The mechanically mixed aluminum and cubic boron nitride (cBN) powder are important raw materials for preparing super-hard metal cutting tools. So aluminum shell-coated cBN may have significant economic potential. A Brownian motion based electrostatic self-assembly route in liquid salt of high temperature was developed using silica nanolayer bridge joint for the aluminum coating of cBN microparticles. In this approach, piranha solution method was first used to activate the surface of cBN cores, the silica nanolayer via sol-gel method served as the substrate for an outer aluminum coating of cBN cores. Coating of aluminum on cBN cores was accomplished by a self-assembly process from a liquid state solution of molten salt and aluminum powders. To distinguish small amounts of non-reacted aluminum powders which acted as aluminum source with the core - shell structure product, bromoform (CHBr3) was used to separate both of them due to the density differences. Samples were characterized by SEM, XRD, EDX and DSC. The contribution of our work lies in the creation of a novel strategy to fabricate a light metal element coating on the inert material particles in view of the versatility of sol-gel process and the controllability of the molten salt process.

Organic dye detection requires high sensitivity, low-cost equipment, simplified procedures, and real-time capabilities; thus, electrochemical methods are gradually emerging in this field instead of chromatography. However, much attention has been paid to toxic and complex metal or noble-metal hybrid materials for constructing electrochemical sensors, which is extremely limiting for practical applications. In this study, a metal-free electrocatalyst, MWNTs with carboxylic groups (MWNTs–COOH), was prepared through surface oxidation in a piranha solution and a simple hydrothermal treatment. The obtained MWNTs–COOH possessed superior hydrophilicity, increased conductivity and substantial active carbon or carboxylic group sites, as determined by characterization using Raman spectroscopy, contact angle measurements, electrochemical surface area analysis, and X-ray photoelectron spectroscopy. The above advantages enabled MWNTs–COOH to exhibit excellent electrochemical activities, with a satisfactory utilization for determining trace Rhodamine B (RhB), showing a lower calculated detection limitation of 2.66 nM and a wider linear range from 0.05 to 850 μM with outstanding specificity and reproducibility. Furthermore, it was found that the carboxyl group on the MWNTs would probably have triggered the electron redistribution and exposed more adjacent active carbon sites, which facilitate the electrocatalytic function to CN on the RhB directly.

We fabricated the first solid, mechanically robust inverse opal photonic crystals that diffract in the deep ultraviolet (UV) spectral region. These photonic crystals are fabricated by self-assembling

In this article, we used modified woven carbon fiber mat (wCF-COOH), as one of the contact-electrification Triboelectric Nanogenerator (TENG) friction layer to generate high open circuit voltage (Voc) and short circuit current (Isc). We designed the contact-separation mode TENG which is functional using spring structure. The oxidation of wCF into wCF-COOH by Piranha solution followed by coupling of aniline through electrostatic interactions and in-situ oxidative polymerization to get woven carbon fiber-polyaniline emeraldine salt (wCF.PANI.ES) composite is a novel approach. The wCF-PANI.ES composite displays the surface resistivity of 0.324 Ω m and serves as a friction layer to generate charges by harvesting energy through vertical contact-separation mode TENG against PVDF membrane. The dynamic interactions of novel wCF-PANI.ES and PVDF membrane produced high Voc of 95 V, and Isc of 180 μA, respectively. In particular, wCF-PANI.ES-TENG has shown an enhancement of 498% of Voc with respect to wCF-COOH-TENG due to availability of PANI layer. In addition, it was observed that the proposed wCF-PANI.ES-TENG has shown the output power of 12.4 mW at 5 Hz, and the rectified current upto 180 μA. The novel wCF-PANI.ES is the potential candidate for fulfilling the need of optimized energy harvesting device as an alternate material option for contact-separation mode TENGs.

Failures of biomedical implants due to implant-related infections and implant loosening remains a major concern in orthopaedic fixations. The current work aims to address the issues by examining the effect of dual interaction i.e surface modification and surface coatings on orthopaedic implant materials, i.e. commercially pure titanium (cpTi). The cpTi surface was initially modified with piranha solution (H 2 SO 4 + H 2 O 2 ) to create an antibacterial surface. Further, the biological properties similar to bone tissue were improved by electrospun coating on the piranha treated substrate with poly(e-caprolactone)(PCL)/hydroxyapatite (HA) composite nanofibers. The PCL/HA composite nanofibers have been characterized using SEM, XRD, EDS contact angle measurements, and FTIR spectroscopy. The coating adhesion of PCL/HA on cpTi was evaluated by cross-cut tape test (ASTM D3359-09). The newly fabricated substrates showed favourable properties and higher wettability. The antibacterial tests on piranha treated nanostructured substrates also confirmed a substantial reduction in bacterial growth over large areas. Cellular interactive responses such as adhesive and proliferation of osteosarcoma MG-63 cell lines has also demonstrated that presence of PCL/HA electrospun coating on the modified surface have improved the biological properties. The currently developed piranha treated and PCL/HA nanocomposite coated cpTi substrates seems to be a promising method to obtain both antibacterial and bioactive titanium surfaces.

Cell adhesion is essential for a cell to maintain its functions, and biomaterials acting as the extracellular matrix (ECM) play a vital role. However, conventional methods for evaluating the functions of biomaterials become insufficient and sometimes incorrect when we give a deeper insight into single-cell research. In this work, we reported a novel methodology for the measurement of cell-matrix adhesion at single-cell resolution that could precisely evaluate the functions of biomaterials for adherent cell culture. A microfludic device, a live single-cell extractor (LSCE), was used for cell extraction. We applied this method to evaluate various modified biomaterials. The results indicated that poly(l-polylysine) (PLL)-coated glass and fibronection (FN)-coated glass slides showed the best biocompatibility for adherent cell culture following by the (3-aminopropyl)triethoxysilane (APTES)-coated glass, while piranha solution treated glass slide and octadecyltrichlorosilane (OTS)-coated glass showed weak biocompatibilities. Furthermore, APTES, PLL, and FN modifications enhanced the cell heterogeneity, while the OTS modification weakened the cell heterogeneity compare to the initial piranha solution treated glass. The method not only clarified the cell-matrix adhesion strength at single-cell resolution but also revealed the influences of biomaterials on cell-matrix adhesion and heterogeneity of cell-matrix adhesion for adherent cell culture. It might be a general strategy for precise evaluation of biomaterials.

Membrane separations enable biogas upgrading, but their energy efficiency must still be improved for industrial upscaling. Nevertheless, UV treatment affects the permeation properties of the polyamide functional layer of reverse osmosis (RO) and nanofiltration thin film composite (TFC) membranes. In this work, after membrane activation via Piranha solution, cysteamine grafting and UV irradiation, we determined the gas permeability of dry and swelled samples. The samples exhibited higher permeability to gases (CO2, CH4 and N2) than pristine membranes, reaching a 100% increase in RO membranes grafted with cysteamine after UV activation. Permeability increased more than twofold compared to TFC RO membranes activated by diode discharge plasma, as recently reported. Separation favored smaller gas molecules, and the increase in permeability resulting from all modifications did not adversely affect selectivity. CO2/CH4 selectivity remained almost constant over the range of trans-membrane pressure difference to 400 kPa. The grafting with cysteamine to the activated functional layer at the RO membrane positively affected permeability despite the detrimental effect of activation with a Piranha solution. The same activation or cysteamine grafting method at the nanofiltration membrane led only to a very short operation time, although the pristine nanofiltration membrane was stable. The pristine nanofiltration membrane were less permeable to all gasses than all RO membranes. Mixed gas separation of model binary biogas mixtures enhanced CH4 and CO2 permeability only in membranes activated with UV radiation. Decrease of mixed gas selectivity with the growing feed pressure showed that the gas mixture is more effectively separated at lower trans-membrane pressures. Therefore, our model for describing gas mixture separations in cylindrical permeation cells can be utilized to better evaluate the mass transfer coefficient and assess the strength of the coupling effect.

COF (covalent organic framework)-based composite membranes offer the opportunity for breakthroughs in separation performance through endowing COFs with easy film-forming properties. However, tough challenges of poor filler dispersity, limited functionality and interfacial compatibility severely restrict the development of COF-based composite membranes. Therefore, the careful design of physical and chemical structures for COFs is urgently needed. Here, a geometry transformation strategy, i.e. converting FCTF-1 (fluorinated covalent triazine frameworks) from 2D nanosheets to 0D quantum dots (QDs), is implemented to overcome some of the challenges. The greatly decreased filler size increases the solvent dispersibility and processability of FCTF-1 quantum dots (QD-FCTF-1), giving rise to thorough mixing between the polymer matrix and quantum dot filler. Apart from the changes in physical characteristics of filler, the geometry transformation using piranha solution introduces chemical functionality at the quantum dot edges, further strengthens the interfacial compatibility through the hydrogen bond interactions between polar hydroxy and amidine groups of QD-FCTF-1 and nitrile groups of PIM-1 (polymer of intrinsic microporosity). Moreover, these edge polar groups intensify favorable gas sorption due to their high affinity to CO2 molecules and thus significantly improve membrane gas pair selectivity. This work broadens the scope of framework-based materials and offers a new avenue for molecular separation.

Two alumina samples, a high surface powder γ-alumina and a sintered α-alumina have been studied as substrates for apatite growth. In the first case, the initial stage was the calcium adsorption in an alkaline solution, followed by phosphate uptake. On the other hand, the α-alumina was firstly subjected to an acid piranha treatment at 80 °C for four hours, before alternate immersions on calcium and phosphate solutions. Next, the alumina samples were immersed repeatedly in a glycine buffer, pH 10.2, and then in tris buffer solutions, pH 7.4 at 32 °C. The resultant solids were studied by means of XRD, TEM or SEM. Calcium phosphate growth was observed in both cases. An almost uniform and continuous layer was formed on the sintered α-alumina. The results suggest that pretreatment with piranha solution seems to be a fast and efficient alternative to bioactivate the α-alumina surface.