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In this letter, we report hydrogel tip attachment onto tipless silicon cantilevers by ultraviolet curing of hydrogel filled into an elastomeric tip mold, for the first time. By mechanically deforming the tip mold or changing the mold design, attachment of various tip shapes is demonstrated. Hybrid atomic force microscope cantilevers of their tip and beam being hydrogel and silicon are used for imaging various inorganic substrates and HeLa cells. Since the hydrogel tip can be selectively removed by piranha solution, hydrogel tip regeneration is also realized by removing the used hydrogel tip and re-attaching a new tip. [2018-0013]

Wet-etching kinetics of single-layer graphene and multilayer graphene oxide by piranha solution under a mild condition was modeled as a time-reversed crystallization process and was analyzed by Avr...

We report an easy synthesis of uniformly-sized water soluble graphitic-carbon nanoparticles (CNP) from the soot obtained by the incineration of camphor. The soot was characterized by X-ray diffraction (XRD) and Raman spectroscopy which reveal the presence of graphitic domains in the obtained nanoparticles. Scanning electron microscope (SEM) images display uniformly sized CNPs of about ∼50 nm. The camphoric soot was then oxidized with a piranha solution to decorate the CNP surface with a carboxyl group. This presence of carboxyl groups was confirmed by the CO stretching at 1720.17 cm−1 in the Fourier transform-infrared spectroscopy. Following the surface treatment, CNPs were reacted with diisocyanate to form amide linkages, which were exploited in the fabrication of CNP–polyurethane hybrid composite material (CNP–PU). Minuscule incorporation (0.1, 0.5 wt%) of CNP into polyurethanes showed a magnificent improvement in the overall thermo-mechanical properties of the CNP–PU as compared to neat polyurethane films. From the XRD analysis of CNP–PU it is evident that incorporation of CNPs enhances the crystallinity of the resultant composite. Proper dispersion of CNPs into the polyurethane matrix was noticeable in the SEM images of the composite.

A robust method for the synthesis of fluorescent carbon dots (C dots) from camphor, which provides an insight into the mechanism of C dot formation, is reported. Camphor is a biosourced hydrocarbon, which contains an hexagonal ring arranged like an open book. Burning of camphor leads to the formation of soot, which comprises graphitic domains. The soot when treated with piranha solution disintegrates into smaller domains leading to the formation of C dots with a size distribution of ∼1–4 nm. The C dots obtained were carboxyl terminated which was confirmed from the infrared spectroscopic measurements. The D and G bands at ∼1314 cm−1 and ∼1586 cm−1, respectively, found using Raman spectroscopy and the peaks at 25.01° found using X-ray diffraction of C dots confirm the presence of graphitic domains. Photoluminescence studies were carried out which reveal exceptional fluorescence in the as prepared C dots. Interestingly the quantum yield is found to be around 21.16%, which is significantly higher than the values reported in previous papers. The current study deals with the sensing of metal ions. Heavy metal cations such as Cd2+ and Hg2+ were used to check whether they affect the fluorescence properties of C dots. It was found that other metal ions like Cu2+, Fe2+ and Zn2+ also quenched the fluorescence of C dot with a different quenching profile.

To achieve a flexible and transparent conductive film via a simple method, ceria/polypyrrole nanocomposite particles were coated on Piranha-treated polyethylene naphthalate (PEN) film as the flexible substrate. Photo-induced polymerization was carried out by cerium (III) nitrate hexahydrate dissolved in acetonitrile and irradiation by UV wavelengths for 2 h. The effect of Piranha treatment on deposition of the conductive nanocomposite particles was examined. Deposited PEN samples prepared at various conditions were characterized using FESEM, AFM and STM, UV–vis spectroscopy, four-probe conductivity and contact angle measurements. Adhesion quality of the deposited nanoparticles was investigated by Scotch-tape test.

Many applications in nanotechnology require short and unentangled single-walled carbon nanotubes (SWCNT). Liquid-phase oxidative cutting gives nonuniform short tubes and causes significant material loss. Mechanical cutting is good for shortening SWCNT, but it leaves collapsed tube ends and might not be favorable for further manipulation. Solid-state reaction cutting is better for multi-walled carbon nanotubes than for SWCNT. Herein, we present a method combining mechanical and oxidative cutting. The SWCNT sample was first ground with a Wig-L-Bug grinding mill for 30 min, introducing structural defects into the side walls of SWCNT. The treated SWCNT were then soaked in a Piranha solution, in which the oxidants attack the existing side wall defects and give a complete cut. According to statistical analysis from transmission electron microscopy, most of the shortened SWCNT fall in the range of 50–200 nm. The material loss is 12.2 wt%. The functional groups on the tube surface introduced by shortening were removed by refluxing in a soda lime/water suspension. Then, the carbon nanotubes were further annealed by sonicating in ethanol. After annealing, the defect level of shortened carbon nanotubes was reduced significantly, as determined by Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis.

The synthesis of grafted PMMA homopolymer films is reported using a surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization from a RAFT-agent immobilized on a silanized stainless steel surface. Therefore, stainless steel surfaces were hydroxylated with piranha solution followed by silanization with 3-aminopropylsilane (APS). The pendant primary amino groups of the cross-linked polysiloxane layer were reacted with 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid N-hydroxysuccinimide ester to produce a surface with covalently immobilized RAFT agents. PMMA homopolymers of different molecular weights between 13 060 and 45 000 g/mol were then prepared by a surface-initiated RAFT polymerization. Molecular weight (MW) and polydispersity index (PDI) were determined from sacrificial polymerization in solution. The different steps of stainless steel surface modification and the ultrathin films were investigated using atomic force microscopy (AFM), static, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance infrared spectroscopy (ATR-IR), and ellipsometry.

We report a simple approach of tailoring electronic properties of carbon nanotube (CNT) films. The process was carried out in the gas phase using fuming nitric acid vapors, gases generated from piranha solution or ozone in high and low concentration in O2 as reactants. The results showed a significant alteration in terms of electrical resistance, wherein it was changed by –50% up to +1,300% depending on the employed conditions. Furthermore, as a result of chemical functionalization of the CNT backbone, we witnessed changes to the sample morphology both on the micro- and nanoscale, what could be an asset. Most interestingly, fuming HNO3 treatment introduced carboxylic and phenolic groups to the structure and as a result of hydrogen bonding, we observed bundling up of the material. This strategy could be a tool to yield CNT macroassemblies of predetermined electronic and structural properties without the need of problematic multi-step solution processing.

To get bioorganic surface with improving biological properties, NiTi shape memory alloy was bonded poly (ethylene glycol) (PEG) by sequentially piranha solution treating, silanizing, and then γ-ray irradiation induced grafting. Piranha solution treating gave hydroxylated surfaces for the benefit of next silanization. The trichlorovinylsilane (TCVS) was performed as a bridge to covalent bond treated NiTi substrates and PEG by γ-irradiation. X-ray photoelectron spectroscopy (XPS) was used to indicate that PEG was bonded on silanized NiTi surface by irradiation. Osteoblast culture of 1 day and methyl-thiazol-tetrazolium (MTT) assay showed that PEG bonded on NiTi surface enhanced cell proliferation and cell amount increased significantly with increasing the concentration of bonded PEG.

Purpose The purpose of this in vitro study was to compare the shear bond strength of an airborne-particle abraded zirconia, an acid-etched zirconia (Piranha solution), an Alloy Primer treated zirconia, and a silaned zirconia to enamel, all bonded with a phosphate-methacrylate resin luting agent. Materials and Methods Seventy extracted intact human molars were collected, cleaned, and mounted in autopolymerizing acrylic resin, with the experimental surface of the teeth exposed. The specimens were randomly divided into seven groups of zirconia specimens (4 mm diameter, 2 mm thick). Group 1: Airborne-particle abrasion; group 2: Airborne-particle abrasion and Z-PRIME Plus; group 3: Airborne-particle abrasion and alloy primer; group 4: Piranha solution 7:1; group 5: Piranha solution 7:1 and Z-PRIME Plus; group 6: Piranha solution 7:1 and Alloy primer; group 7: CoJet and silane. All specimens were luted with a phosphate-methacrylate resin luting agent (Panavia F2.0) and stored in distilled water for 1 day, then thermocycled (5°C and 55°C) for 500 cycles and tested for shear bond strength (SBS), measured in MPa, with a universal testing machine at a 0.55 mm/min crosshead speed. All specimens were inspected under a scanning electron microscope to determine mode of failure. The mean values and standard deviations of all specimens were calculated for each group. A one-way ANOVA was performed, and multiple pairwise comparisons were then completed with post hoc Tukey test (alpha = 0.05). Results The airborne-particle abrasion and Z-PRIME Plus group resulted in a significantly higher SBS than the other groups (21.11 ± 6.32 MPa) (p < 0.001). The CoJet and silane group (15.99 ± 8.92 MPa) and airborne-particle abrasion and alloy primer group (11.07 ± 4.34 MPa) showed high shear bond strength but not statistically significant from the airborne-particle abrasion group (14.23 ± 5.68 MPa). Failure mode was predominately mixed in groups 1, 2, 3, and 7 with islands of retained resin on the zirconia and enamel surfaces; however, groups 4, 5, and 6 showed mostly adhesive failures, which left the zirconia surface free of the adhesive materials. No cohesive failures of the substrates (ceramic, resin, or enamel) were observed. Conclusion Airborne-particle abrasion followed by the application of a zirconia primer produced the highest bond strength to enamel. Therefore, it can be recommended as a promising surface treatment method to achieve a durable bond to densely sintered zirconia ceramics.

This work aims at studying the different chemical bonds formed on hydrogenated nanocrystalline diamond (NCD) films after oxidation. Three different oxidation treatments applied to NCD, namely oxygen plasma, ozone oxidation and piranha solution were investigated using three different analysis techniques namely X-ray photoelectron spectroscopy, UV photoelectron spectroscopy and TOF-secondary ion mass spectrometry. The combination of these techniques allowed us to better discriminate the nature of the carbon oxygen bonds produced by the different oxidation treatments. We demonstrate that the carbon oxygen bonds induced by UV irradiation possess a different nature with respect to those generated by plasma or piranha solution. In particular the prevalent electrostatic nature of the carbon oxygen bonds induced by UV irradiation can explain a negative electron affinity recovery upon NCD annealing, not possible in the case of the other two oxidation processes.

β-Stabilized titanium (Ti) alloys containing non-toxic elements, particularly niobium (Nb), are promising materials for the construction of bone implants. Their biocompatibility can be further increased by oxidation of their surface. Therefore, in this study, the adhesion, growth and viability of human osteoblast-like MG 63 cells in cultures on oxidized surfaces of a β-TiNb alloy were investigated and compared with the cell behavior on thermally oxidized Ti, i.e. a metal commonly used for constructing bone implants. Four experimental groups of samples were prepared: Ti or TiNb samples annealed to 600 °C for 60 min in a stream of dry air, and Ti and TiNb samples treated in Piranha solution prior to annealing. We found that on all TiNb-based samples, the cell population densities on days 1, 3 and 7 after seeding were higher than on the corresponding Ti-based samples. As revealed by XPS and Raman spectroscopy, and also by isoelectric point measurements, these results can be attributed to the presence of T-Nb2O5 oxide phase in the surface of the alloy sample, which decreased its negative zeta (ζ)-potential in comparison with zeta (ζ)-potential of the Ti sample at physiological pH. This effect was tentatively explained by the presence of positively charged defects acting as Lewis sites of the surface Nb2O5 phase. Piranha treatment slightly decreases the biocompatibility of the samples, which for the alloy samples may be explained by a decrease in the number of defective sites with this treatment. Thus, the presence of Nb and thermal oxidation of β-stabilized Ti alloys play a significant role in the increased biocompatibility of TiNb alloys.

A simple two-step process was developed to render steel with lower friction and longer durability. The textured steel substrate was first fabricated by immersed in a piranha solution at room temperature for 10 min. Stearic acid film was then deposited to acquire high hydrophobicity. Scanning electron microscopy and water contact-angle measurements were used to analyze the morphological features and hydrophobicity of prepared samples, respectively. Moreover, the friction-reducing behavior of the organic–inorganic composite film sliding against a steel ball was evaluated in a ball-on-plate configuration. It was found that the stearic acid film on the textured steel led to decreased friction with significantly extended life.

The aim of this study is practically to establish a chemical strategy for cleaning soiled deposits and encrustations on archaeological glasses. Investigations were performed on a series of Roman glass samples (Fragments and complete objects) coming from different excavations in northern Jordan. The chemical composition of the glass samples was determined by X-ray fluorescence spectrometer (XRF) analysis technique, whereas X-ray powder diffractometer (XRD) and Energy dispersive X-ray (EDX) methods were used to determine the mineralogical and elemental composition of the soiled deposits and encrustations on the glass surfaces. Furthermore, Scanning Electron Microscopy (SEM) examination and optical assessment were performed before and after cleaning glass. The glass samples were subjected to different cleaning protocols such as Calgon (Sodium hexametaphosphate), ethylenediaminetetraacetic acid (EDTA) at different pH values, citric and tartaric acids and piranha solution (a solution of sulphuric acid and hydrogen peroxide). Sepiolite poultices soaked by chemical agents were the most suitable methods used for applying chemical solutions on the glass surface. It can be concluded that EDTA is generally accepted as the most effective chelating agents recommended for cleaning encrustations on durable glass. It was more effective and safe at neutral pH with low concentrations around 5 to 7%. The calcareous crusts can safely be removed by using a piranha solution. Citric and tartaric acids appeared a moderate efficiency on cleaning weathered and stable glass. Calgon has a tendency to damage corroded and iridescent surfaces, and should be avoided when cleaning weathered glass.

In the present work we introduce the formation of highly ordered single-walled TiO2 nanotubes based on anodizing nanoimprinted titanium substrates. In a first step, anodization on nanoimprinted substrates leads to the formation of highly ordered TiO2 nanotubes. These as-formed TiO2 nanotubes have a double-walled nature. After an optimized chemical treatment in piranha solution, the inner wall is removed and an array of single-walled TiO2 nanotubes is obtained that has a high degree of hexagonal ordering. These single walled arrangements show an enhanced photocatalytic activity for H2 evolution in comparison with classic self-ordered TiO2 nanotubes. Keywords: Nanoimprinting, Anodization, Single walled TiO2 nanotube, Photocatalysis

In this study, integrin expression, proliferation, and endothelial differentiation of adipose-derived stem cells (ADSCs) on pristine cobalt chrome (CoCr) surface, microstructured and nanostructured CoCr surfaces (obtained after treatment with piranha solution) were investigated. The results showed that proliferation of ADSCs on the substrates treated with piranha solution is not significantly different from that on the pristine substrates. However, quantitative real-time PCR analysis showed significantly enhanced up-regulation of CD31, vWF and eNOS from gene level by ADSCs on the nanostructured substrates but not on the microstructured substrates. The adsorption of vitronectin from the culture medium on the nanostructured substrates was higher than on the pristine and microstructured substrates. We speculate that this results in increased integrin αvβ3 expression in the ADSCs, which may contribute partially to the enhanced endothelial differentiation of ADSCs on the nanostructured substrates. This study shows that ADSCs can be used to endothelialize stents in vitro and the endothelial differentiation of ADSC is enhanced on the nanostructured surfaces.

Fresh water sponge was used as a silica source for the synthesis of MCM-41 via the hydrothermal process. The silica was extracted from the sponge by washing with nitric acid and piranha solution. Synthesis of MCM-41 was performed at 100 °C for 5 days and the procedure was optimized, with modifications made to the leaching temperature of the silica and the synthesis of mesoporous material, which was characterized by XRD, FT-IR, SEM and adsorption of N2. The optimal result was achieved at a temperature of 135 °C for 3 days, showing ordered mesoporous material with a surface area of 1080 m² g-1.

This study evaluated the effect of surface pretreatments on resin composite bonding to polyetheretherketone (PEEK). Four groups of surface pretreatment (no pretreatment, etched with 98% sulfuric acid, etched with piranha solution and sandblasting with 50 µm alumina) were performed on PEEK. Surface roughness, Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were examined. Shear bond strength (SBS) and interface characteristics were also evaluated after the specimens were bonded with resin materials. Two-way ANOVA analysis revealed significance on two main effects and interactions. Tukey's multiple comparisons test showed that the SBS of resin composite on PEEK were the highest in the group etched with 98% sulfuric acid and bonded with Heliobond(®) (p

Two-dimensional zeolite nanosheets that do not contain any organic structure-directing agents were prepared from a multilamellar MFI (ML-MFI) zeolite. ML-MFI was first exfoliated by melt compounding and then detemplated by treatment with a mixture of H2 SO4 and H2 O2 (piranha solution). The obtained OSDA-free MFI nanosheets disperse well in water and can be used for coating applications. Deposits made on porous polybenzimidazole (PBI) supports by simple filtration of these suspensions exhibit an n-butane/isobutane selectivity of 5.4, with an n-butane permeance of 3.5×10(-7) mol m(-2) s(-1) Pa(-1) (ca. 1000 GPU).

The aim of the study was to develop an immobilized-antigen immunofluorescence glass slide system using fluorescent silica nanoparticles (FSNPs) for the detection of biomarkers to evaluate food functionality. A plain glass slide was first cleaned by treatment with piranha solution, after which C-reactive protein (CRP), a model antigen, was immobilized on the slide via procedures that exploited activation of the slide surface with 3-aminopropyltrimethoxysilane (APTMS) and glutaraldehyde, or 3-mercaptopropyltrimethoxysilane (MPTMS) and N-γ-maleimidobutyryloxysuccinimide ester (GMBS). Streptavidin-modified FSNPs that contained a fluorescent dye, dichlorotris(1,10-phenanthroline)ruthenium(II) hydrate, were conjugated with biotinylated monoclonal anti-rat CRP antibody to produce FSNP–antibody conjugates. The bioconjugate bound more effectively to the surface of slides that had been activated with APTMS before immobilization of the antigen than to those activated with MPTMS–GMBS. Specific binding of the coating antigen and bioconjugate to the slide surface was confirmed by fluorescence and atomic force microscopy. The fluorescence intensity due to formation of a complex between the antigen and bioconjugate increased gradually with increasing bioconjugate concentration up to 0.250 mg/mL.

In this paper, we optimize the AlGaN surface oxidation methods for AlGaN/GaN heterostructure field effect transistor (HFET) biological sensors. Reactive ion etching oxygen plasma, inductively coupled oxygen plasma, and piranha solution are used to oxidize AlGaN surface. After oxidation, X-ray photoelectron spectroscopy and water contact angle measurements are used to check oxidation effectiveness. Labeled streptavidin (SA) molecules are bound to the oxidized surface through linker molecules for comparison of surface modification effectiveness. Schottky diodes are fabricated to investigate the impacts of oxidation processes on electrical properties, such as Schottky barrier heights, sheet carrier concentrations, and interface trap densities. The results show that the inductively coupled plasma oxidation process has a superior behavior compared to the reactive ion etching oxygen plasma and piranha solution oxidation processes. AlGaN/GaN HFET protein sensors fabricated using the inductively coupled plasma oxidation process have exhibited improved sensitivity. An SA solution with the concentration as low as 4.73 pM were successfully detected.

Enhanced biocompatibility of titanium implants highly depends on the possibility of achieving high degrees of surface functionalization for a low immune response and/or enhanced mineralization of bioactive minerals, such as hydroxyapatite. In this respect, surface modification with Self Assembled Monolayers (SAMs) has a great potential in delivering artificial surfaces of improved biocompatibility. Herein, the effectiveness of common chemical pre-treatments, i.e. hydrogen peroxide (H(2)O(2)) and Piranha (H(2)SO(4) + H(2)O(2)), in facilitating surface decontamination and hydroxylation of titanium surfaces to promote further surface functionalization by SAMs is investigated. The quality of the octadecyltrichlorosilane (OTS) based SAM appeared to strongly depend upon the surface morphology, the density and nature of surface hydroxyl sites resulting from the oxidative pre-treatments. Contrary to common belief, no further hydroxylation of the titanium substrate was observed after the selected chemical pre-treatments, but the number of hydroxyl groups available on the surface was decreased as a result of the formation of a titanium oxide layer with a gel-type structure. Further examinations by atomic force microscopy, infrared spectroscopy and X-ray photoelectron spectroscopy also revealed that mild oxidizing conditions were sufficient to remove surface contamination without detrimental effects on surface hydroxylation state and surface roughness. Furthermore, the adsorption of the alkylsiloxane molecules forming the SAM film is believed to proceed through hydrolysis at surface acidic hydroxyl groups rather than randomly. This site dependent adsorption process has significant implications for further functionalization of titanium based implants. It also highlights the difficulty of achieving an OTS based SAM at the surface of titanium and question the quality of SAMs reported at titanium surfaces so far.

Successful realization of various BioMEMS devices demands effective surface modification techniques of PDMS elastomer. This paper presents a detailed report on a simple and cost effective approach for surface modification of PDMS films involving wet chemical treatment in two-step processes: primarily involving piranha solution followed by KOH dip to improve hydrophilicity and stability of PDMS surface. Chemical composition of the solution and surface treatment condition have been varied and optimized to significantly increase the surface energy. The effect of surface modification of the elastomer after wet chemical treatment is analyzed using contact angle measurement and FTIR-ATR study. PDMS surface treated in piranha solution with H2O2 and H2SO4 in the ratio of 2:3 followed by a dip in KOH solution for 15 min duration each, demonstrated a maximum reduction of contact angle to ∼27° as compared to untreated sample having a contact angle of ∼110°. The removal of hydrophobic methyl group from elastomer surface and subsequent hydrophilization of surface by wet chemical process was confirmed from FTIR-ATR spectra. This result is also supported by improved adhesion and electrical continuity of deposited aluminum metal film over the modified PDMS surface. Copyright © 2011 John Wiley & Sons, Ltd.

Nanoscale changes to the surface of polymeric materials enables changes in materials' adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is therefore used in applications such as antimicrobial or non-fouling materials, biosensors, and active packaging. The range of available modification and analytical techniques used across laboratories prevents accurate comparison of techniques in terms of their effects on surface chemistry and topography. It was therefore our goal to evaluate the effects of four surface modification techniques (chromic acid, piranha solution, ultraviolet irradiation, and oxygen plasma) on polyethylene films. Changes in surface chemistry and topography were quantified using attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle measurement, and direct measurement of available surface carboxylic acids. Roughness increased in the order: piranha (57.7 nm); oxygen plasma (76.3 nm); UV irradiation (76.4 nm); chromic acid (120 nm). Hydrophobicity decreased in the order: piranha (77.20), chromic acid (73.50), oxygen plasma (61.70), UV irradiation (58.70). Functionalization (by IR absorbance intensity between 1680–1780 cm−1) increased in the order: oxygen plasma (0.06), piranha (0.09), chromic acid (0.34), UV irradiation (0.50). By analyzing these methods using consistent analytical techniques, side-by-side comparisons have been accurately made. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Surface preparation procedures for indium gallium nitride (InGaN) thin films were analyzed for their effectiveness for carbon and oxide removal as well as for the resulting surface roughness. Aqua regia (3:1 mixture of concentrated hydrochloric acid and concentrated nitric acid, AR), hydrofluoric acid (HF), hydrochloric acid (HCl), piranha solution (1:1 mixture of sulfuric acid and 30% H 2 O 2 ) and 1:9 ammonium sulfide:tert-butanol were all used along with high temperature anneals to remove surface contamination. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were utilized to study the extent of surface contamination and surface roughness, respectively. The ammonium sulfide treatment provided the best overall removal of oxygen and carbon. Annealing over 700 °C after a treatment showed an even further improvement in surface contamination removal. The piranha treatment resulted in the lowest residual carbon, while the ammonium sulfide treatment leads to the lowest residual oxygen. AFM data showed that all the treatments decreased the surface roughness (with respect to as-grown specimens) with HCl, HF, (NH 4 ) 2 S and RCA procedures giving the best RMS values (∼0.5–0.8 nm).

We describe the controlled assembly of silane-based copolymers on various interfaces that have surface silanol groups. This assembly occurs as a result of the formation of very robust siloxane bonds (Si-O-Si) due to a condensation reaction between the alkoxysilane groups of the polymers and surface hydroxyl groups of the substrates. Deposition of these copolymers is not self-limiting; therefore, they could not be assembled into discrete monolayers. However, UV-visible data collected as a function of deposition cycle reveals a linear relationship, confirming the deposition of a constant amount of polymer in each deposition cycle. A linear variation of layer thickness with deposition cycles is also observed. The assembled polymer layers are found to be very robust and resistant even when exposed to piranha solution for several hours.

1 - Article; Bioactive polymers bearing sulfonate (styrene sodium sulfonate, NaSS) and carboxylate (methylacrylic acid, MA) groups were grafted onto Ti6Al4V alloy surfaces by a two-step procedure. The Ti alloy surfaces were first chemically oxidized in a piranha solution and then directly subjected to radical polymerization at 70 degrees C in the absence of oxygen. The grafted surfaces were characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and the toluidine blue colorimetric method. Toluidine blue results showed 1-5 mu g cm(-2) of polymer was grafted onto the oxidized Ti surfaces. Grafting resulted in a decrease in the XPS Ti and 0 signals from the underlying Ti substrate and a corresponding increase in the XPS C and S signals from the polymer layer. The ToF-SIMS intensities of the S(-) and SO(-) ions correlated linearly with the XPS atomic percent S concentrations and the ToF-SIMS intensity of the TiO(3)H(2)(-) ion correlated linearly with the XPS atomic per cent Ti concentration. Thus, the ToF-SIMS S(-) SO(-) and TiO(3)H(2)(-) intensities can be used to quantify the composition and amount of grafted polymer. ToF-SIMS also detected ions that were more characteristic of the polymer molecular structure (C(6)H(4)SO(3)(-) and C(8)H(7)SO(3)(-) from NaSS, C(4)H(5)O(2)(-) from MA), but the intensity of these peaks depended on the polymer thickness and composition. An in vitro cell culture test was carried out with human osteoblast-like cells to assess the influence of the grafted polymers on cell response. Cell adhesion after 30 min of incubation showed significant differences between the grafted and ungrafted surfaces. The NaSS grafted surfaces showed the highest degree of cell adhesion while the MA-NaSS grafted surfaces showed the lowest degree of cell adhesion. After 4 weeks in vivo in rabbit femoral bones, bone was observed to be in direct contact with all implants. The percentage of mineralized tissue around the implants was similar for NaSS grafted and non-grafted implants (59% and 57%). The MA-NaSS grafted implant exhibited a lower amount of mineralized tissue (47%).

Chemical modifications on the surface of optical fibers have played an important role in the immobilization of biological recognition molecules. In this article, the specific goal was to characterize the covalent bond on the surface of optical fiber by scanning electron microscopy and energy dispersive X-ray spectrometry (EDS) and chemical analysis after silanization. Optical fibers pretreated with hydrofluoric acid and piranha solution were silanized in the 3-aminopropyltriethoxysilane solution, then microscopic components of silanized optical fibers were determined to validate the silanization. Results showed that carbon atom was measured with EDS, and the ratio of silicon and oxygen atom was 1:3.6 on its surface by calculation. Fluorescence experiments on the short silanized optical fiber segments indicated that the intensity of fluorescence was relatively weak and reached equilibrium after 3 h. Both methods, EDS and fluorescence test, were effective to characterize the covalent bond of different silanes and biological recognition molecules on the optical fibers for biosensor applications. Copyright © 2009 John Wiley & Sons, Ltd.

This paper describes a new fabrication technique for RF MEMS switches where the coplanar waveguide (CPW) is fabricated in a basin. A planar profile and good coverage at the edges in a basin is achieved by spinning and baking the sacrificial positive photoresist (PPR) in multiple steps to fill the basin. The basin structure allows an increase in the length of the membrane resulting in lower pull-in voltage and better isolation. The PPR is removed using Piranha solution (H2SO4:H2O2::3:1). Structures with the gap of about 2.5 µm and the thickness of the gold membrane varying from 1µm to 2.5 µm have been successfully realized.

We have studied the properties of photoresist (resist) as a sacrificial material for fabricating suspended metal bridges and developed a process to release RF MEMS switches by dissolving thermal cross-linked extra hard photoresist. At the edges of the patterned photoresist, the contact angle with the substrate can be tuned using hard-baking parameters. From the experiment we have found that the resist angle reduces both with baking temperature and time. The baking temperature has a stronger effect on resist slope than the baking time has. It is also observed that at a certain baking temperature, and after a certain time, the resist angle does not reduce further. The RF MEMS switch with photoresist as the sacrificial layer can be released by plasma ashing to strip the initial resist skin, followed by dissolution of the bulk resist in Microposit 1165 solution with heating. The heating of the Microposit 1165 solution accelerates and improves the dissolving process. The Piranha solution is also very effective in dissolving hard resist for releasing RF MEMS switches.

X-ray photoelectron spectroscopy (XPS) has been used to evaluate the reactivity of different chemical cleaning procedures on the surface of archaeological glasses. Investigations were performed on a series of Roman glass samples coming from Sicilian excavations. The ancient freshly fractured glass samples were subjected to different cleaning protocols such as piranha solution (solution of sulphuric acid and hydrogen peroxide) and EDTA/ammonia and citric acid/ammonia solutions at different pH values. The atomic concentrations of alkaline and alkaline-earth ions, measured using XPS spectra acquired at the surface of all the samples, revealed that, in acid solution, the reactivities of the EDTA and citric acid solutions were higher than that of the piranha solution. Moreover, in alkaline conditions, the reactivities of the chelating agent/ammonia solutions seem to be very high and effective in taking out alkaline and alkaline-earth ions and in destroying the external glassy structure with the formation of a silica gel thin film.

A dramatic, ∼20-fold, reduction in the contact resistance of the bottom-contact poly(3,3‴-didodecylquaterthiophene) (PQT-12) thin-film transistors was achieved through a simple treatment of gold (Au) source and drain electrodes. The Au electrode treatment involved simply immersing the Au electrodes into Piranha solution prior to the deposition of the organic semiconductor. This treatment led to significant improvement of device performance. Channel length scaling analysis indicates that the contact resistance is reduced by about one order of magnitude, resulting in enhancement of estimated field-effect mobility by about a factor of five. Transport characteristic analysis suggests that the improved efficiency of charge carrier injection is probably due to increased dopant density of PQT-12 at the electrode/PQT-12 interface.

We study the plasma activation systematically in an attempt to simplify and optimize the formation of hydrophilic silicon (Si) surface critical for self-assembly of nanostructures that typically uses piranha solution, a high molarity cocktail of sulfuric acid and hydrogen peroxide at elevated temperatures. In the proposed safer and simpler approach, O2 plasma is used under optimized process conditions in a capacitively coupled parallel-plate chamber to induce strong hydrophilic behavior on silicon surfaces associated with the formation of suboxide groups. Surface activation is validated and studied via contact angle measurements as well as XPS spectra and consequently optimized using a novel atomic force spectroscopy approach, which can streamline characterization. It is found that plasma power around 100 W and exposure duration of ∼65 s are the most effective parameters to enhance surface activation for the reactive ion etcher system used. Other optimum plasma process conditions for pressure and flow-rate are also reported along with temporal development of activation, which peaks within 1 h and wears off in 24 h scale in air. The applicability of the plasma approach to nanoassembly process was demonstrated using simple drop coating and spinning of polystyrene (d500 nm, 2.5-4.5% w/v) and inkjet printing on polydimethylsiloxane.

© 2015 Elsevier B.V. Abstract Coupling surface plasmon resonance (SPR) to optical fiber (FO) technology has brought tremendous advancements in the field by offering attractive advantages over the traditional prism-based SPR platforms, such as simplicity, cost-effectiveness and miniaturization. However, the performance of the existing FO-SPR sensors widely depends on the adhesion of the gold (Au) layer to the FO silica core, thereby often representing a major limiting factor in achieving the properties of the benchmark SPR systems. In this paper, we used (3-marcaptopropyl)trimethoxysilane (MPTMS) as an adhesion promoter for developing robust Au surfaces on the three-dimensional (3D) FO-SPR sensing probe. Carefully prepared FO substrates were first silanized using a wet chemistry approach, with MPTMS concentrations ranging from 2.5 to 24 mM, and subsequently exposed to a drying treatment at room temperature (RT) or at 100 C, before coating them with a ∼50 nm Au plasmonic film. Differently prepared silanized FOs were next used for evaluating their sensitivities, by performing refractive index (RI) measurements in sucrose dilutions. Advanced statistical analysis of the obtained data indicated that using 8 mM MPTMS solution coupled with a RT post-drying treatment is an efficient way of producing FOs with dramatically improved Au adhesion properties. The role of the MPTMS underlayer was further investigated by exposing the reference and silanized FOs to stress conditions, such as strong mechanical (adhesion tape tests), chemical (piranha solution treatments) and thermal variations. Although additional studies using scanning electron microscopy (SEM) revealed changes in the Au film morphology after these endurance tests, the silanized FOs exhibited an enhanced robustness while retaining the overall sensor's capabilities. In contrast, the reference FOs consistently failed the mechanical and chemical tests, while only resisting under thermal variations. Moreover, the improved resistance of the silanized FO-SPR probes allowed them to be reused up to three times with no significant loss in the sensor performance, while implementing bioassays based on two types of bioreceptors (a DNA aptamer against thrombin protein and a polyclonal antibody against human immunoglobulin E - hIgE). All these results might represent a step forward in the fabrication of more robust and reusable FO-SPR biosensors, featuring great potential for developing highly-sensitive biochemical assays. publisher: Elsevier articletitle: Improved surface plasmon resonance biosensing using silanized optical fibers journaltitle: Sensors and Actuators B: Chemical articlelink: http://dx.doi.org/10.1016/j.snb.2015.04.069 content_type: article copyright: Copyright © 2015 Elsevier B.V. All rights reserved. ispartof: Sensors and Actuators B, Chemical vol:216 pages:518-526 status: published

The silicon surface of commercial atomic force microscopy (AFM) probes loses its hydrophilicity by adsorption of airborne and package-released hydrophobic organic contaminants. Cleaning of the probes by acid piranha solution or discharge plasma removes the contaminants and renders very hydrophilic probe surfaces. Time-of-flight secondary-ion mass spectroscopy and X-ray photoelectron spectroscopy investigations showed that the native silicon oxide films on the AFM probe surfaces are completely covered by organic contaminants for the as-received AFM probes, while the cleaning methods effectively remove much of the hydrocarbons and silicon oils to reveal the underlying oxidized silicon of the probes. Cleaning procedures drastically affect the results of adhesive force measurements in water and air. Thus, cleaning of silicon surfaces of the AFM probe and sample cancelled the adhesive force in deionized water. The significant adhesive force values observed before cleaning can be attributed to formation of a bridge of hydrophobic material at the AFM tip-sample contact in water. On the other hand, cleaning of the AFM tip and sample surfaces results in a significant increase of the adhesive force in air. The presence of water soluble contaminants at the tip-sample contact lowers the capillary pressure in the water bridge formed by capillary condensation at the AFM tip-sample contact, and this consequently lowers the adhesive force.

This work reports the supercapacitive properties of composite films of multiwalled carbon nanotubes (MWNT) and ruthenium oxide (RuO 2 ). Transmission and scanning electron microscopy, cyclic voltammetry, and electrochemical studies revealed that the nanoporous three-dimensional arrangement of RuO 2 -coated MWNT in these films facilitated the improvement of electron and ion transfer relative to MWNT films. The capacitance was measured for films of different RuO 2 loading, revealing specific capacitances per mass as high as 628 F g −1 . The energy storage density of the electrode has increased about three times as compared to MWNT treated with piranha solution.

The surface of AISI 316 grade stainless steel (SS) was modified with a layer of poly(ethylene glycol) (PEG) (molecular weight 5000) with the aim of preventing protein adsorption and bacterial adhesion. Model SS substrates were first modified to introduce a very high density of reactive amine groups by the adsorption of branched poly(ethylenimine) (PEI) from water. Methoxy-terminated aldehyde-poly(ethylene glycol) (M-PEG-CHO) was then grafted onto the PEI layers using reductive amination at the lower critical solution temperature (LCST) of the PEG in order to optimize the graft density of the linear PEG chains. The chemical composition and uniformity of the surfaces were determined using X-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectrometry (ToF-SSIMS) in the imaging mode. The effects of PEI concentration and different substrate pre-cleaning methods on the structure and stability of the final PEG layer was examined. Piranha solution proved to be the most effective method for removing adventitious hydrocarbon contamination, compared to cleaning with ultrasonication in organic solvents, and was the SS substrate that produced the most stable and thickest PEI layer. The surface density of PEI was shown to increase with increasing PEI concentration (up to 30 mg/ml), as determined from XPS measurements, and subsequently produced the PEG layer with the highest density of attached chains. In model experiments using β-lactoglobulin no protein adsorption was detected on the optimized PEG surface as determined by XPS and ToF-SSIMS analysis. However, neither the adhesion of a Gram-negative (Pseudomonas sp.) nor a Gram-positive (Listeria monocytogenes) bacterium was affected by the coating as equal numbers adhered to all surfaces tested. Our results show that preventing protein adsorption is not a prerequisite stopping bacterial adhesion, and that other mechanisms most likely play a role.

Macroporous glass membranes were prepared from glass fiber filters via chemical crosslinking and modification, and used for the membrane affinity chromatography of fibronectin from human blood plasma. The filters were first treated with a piranha solution (a concentrated solution of H 2 SO 4 +H 2 O 2 in water), and then crosslinked with bifunctional organosilanes and modified to introduce amino or aniline moieties. Ligand immobilizations via diazotization and glutaraldehyde pathways were carried out and compared. Characterization of the membranes was performed using bovine serum albumin and trypsin as test ligands. By using a cartridge containing gelatin immobilized affinity membranes followed by another cartridge containing heparin immobilized membranes, fibronectin from human blood plasma could be separated.

Electrochemical methods, including cyclic voltammetry and scanning electrochemical microscopy, as well as surface techniques, including conductive atomic force microscopy (AFM) and X-ray photoelectron spectroscopy, were utilized to evaluate and characterize the extent of an oxide layer on platinum silicide (PtSi) surfaces that were pretreated by a variety of approaches; piranha solution (1:4 H2O2+H2SO4), hydrofluoric acid (HF), chemical reduction in NaBH4 and after mechanically polishing the surface. Electrochemical methods showed that in the presence of an oxide layer, the rate of electron transfer depended upon the charge of the redox couple: the more negative the charge, the slower is the rate of electron transfer. Additionally, the current levels observed in the presence of an extensive oxide layer were considerably lower than those observed after the oxide layer was removed either with HF acid or by mechanically polishing. Surface analysis and depth profiles obtained using Auger electron spectroscopy demonstrated that PtSi surfaces pretreated with piranha contained the largest amounts of surface oxides. AFM topographic scans along with localized surface conductivity showed that in the presence of this oxide layer, electron transfer occurred at nanoscale domains located between the PtSi grains with the rest of the surface, which most likely contains an oxide layer, being non-conductive. The surface oxide layer was used to attach the electrogenerated chemiluminescent (ECL) label, Ru(bpy)32+ covalently, either directly or via single-stranded DNA. Emission during oxidation in the presence of the co-reactant tri-n-propylamine was observed, illustrating the possible use of PtSi as a platform for ECL-based bioassays.

Film stability and dewetting is important to control for applications in coatings such as photoresists, paints, adhesives, lubricants, and biomaterials. We demonstrate the use of 2D combinatorial libraries to investigate thin film dewetting. Substrate libraries with gradients in contact angle ðuÞ were prepared by immersing Si ‐ H passivated Si in a Piranha solution (H2SO4/H2O2/H2O) at a controlled rate. Libraries of thin films of polystyrene on gradient etched silicon substrates containing orthogonal continuous variation of thickness were screened for dewetting behavior using automated optical microscopy. After comparing the high-throughput screening method to conventional studies of thickness effect on dewetting, a detailed morphological phase-map of the effects of contact angle on dewetting of polystyrene film was generated. Dewetting trends were visibly apparent. The number of polygons of dewetted polymer is sensitive to surface hydrophilicity as characterized by contact angle studies. q 2002 Elsevier Science Ltd. All rights reserved.

We report etching-free and iodine-free transfer of highly aligned array of armchair-edge graphene nanoribbons (ACGNRs) and their field-effect transistor (FET) characteristics. They were prepared by on-surface polymerization on Au(788) templates. The ACGNRs were mechanically delaminated and transferred onto insulating substrates with the aid of a nano-porous support layer composed of hydrogen silsesquioxane (HSQ). The key process in the mechanical delamination is the intercalation of octanethiol self-assembled monolayers (SAMs), which penetrate the HSQ layer and intercalate between the ACGNRs and Au(788). After the transfer, the octanethiol SAMs were removed with Piranha solution, enabling the reuse of the Au single crystals. The FETs fabricated with the transferred ACGNR array showed ambipolar behavior when the channel length was as long as 60 nm. Quasi-one-dimensional conductivity was observed, which implies a good alignment of GNRs after the transfer. In contrast, short-channel ACGNR FETs (channel length ∼20 nm) suffer from a geometry-dependent short-channel effect. This effect is more severe in the FETs with ACGNRs parallel to the channel, which is an ideal geometry, than in ones perpendicular to the channel. Since the ID-VD curve is well fitted by the power-law model, the short-channel effect likely stems from the space-charge limited current effect, while the wide charge-transfer region in the GNR channel can be another possible cause for the short-channel effect. These results provide us with important insights into the designing short-channel GNR-FETs with improved performance.

WOS: 000350247900008, PubMed ID: 25079110, Sarcosine was recently identified as a differential metabolite that is present in urine in elevated concentration as prostate cancer develops metastases. The aim of this study is to prepare reflectometric interference spectroscopy (RIfS) nanosensors for the detection of sarcosine. Sarcosine imprinted nanoparticles were prepared by two phase miniemulsion polymerization and characterized with transmission electron microscopy, dynamic light scattering, and atomic force microscopy measurements. The glass substrates (10 x 10 mm(2)) were treated with Piranha solution and incubated in polyethyleneimine solution. The sarcosine imprinted nanoparticles were attached to glass substrates by spin coating of nanoparticle solution. The recognition properties of the nanosensors were evaluated by reflectometric interferometric spectroscopy. To show selectivity of sarcosine imprinted RIfS nanosensor, real-time l-alanine detection was also performed. Sarcosine detection studies were performed from aqueous solution and urine sample. A good linearity was revealed with a correlation coefficient of 0.9622 and a detection limit of 45 nM, Anadolu University, Commission of Scientific Research Projects [1110F158], This work has been supported by Anadolu University, Commission of Scientific Research Projects (Project No: 1110F158).

Statement of problem Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses (FDPs). However, information about the fracture load of veneered PEEK FDPs is still scarce. Purpose The purpose of this in vitro study was to investigate the influence of different PEEK surface pretreatments and adhesive systems on the fracture load of 2 differently veneered FDPs. Material and methods Four hundred eighty anatomically shaped 3-unit PEEK frameworks were milled, airborne-particle abraded with 50 μm alumina powder, and divided into 4 groups according to the following surface pretreatment (n=120): plasma treatment, etching with either sulfuric acid or piranha solution, and no further treatment. All groups were then allocated to 4 conditioning groups: visio.link, Ambarino P60, Signum PEEK Bond, or no conditioning. They were veneered with Signum Composite (n=15) or Signum Ceramis (n=15). Upon completion, the FDPs were thermally aged, and fracture loads and failure types were determined. Statistical analysis was performed with 3/2/1-way ANOVA with the post hoc Tukey HSD test (α=.05). Results The highest fracture loads were achieved without treatment in combination with visio.link (737 ±138 N). The lowest values were obtained after piranha acid etching and conditioning with visio.link (277 ±71 N); both groups were veneered with Signum Composite. The results, however, indicated no clear influence of either pretreatment or conditioning. With few exceptions, FDPs veneered with Signum Composite showed higher fracture load values compared to Signum Ceramis. After thermocycling, all FDPs showed cracks in the veneering composite resin material in the pontic region, regardless of the PEEK pretreatment or the adhesive system used. After loading, no fractures of the PEEK frameworks were evident in any FDPs, but chipping of the veneering material was observed. Conclusions With respect to the fracture types after thermocycling, pretreatment, conditioning, or veneering resin cement did not affect the fracture results.

Objectives: Purpose of this in vitro study was to evaluate the effect of surface modifications on the tensile bond strength between zirconia ceramic and resin. Methods: Zirconia ceramic surfaces were treated with 150-mm abrasive alumina particles, 150-mm abrasive zirconia particles, argon-ion bombardment, gas plasma, and piranha solution (H2SO4:H2O2 = 3:1). In addition, slip casting surfaces were examined. Untreated surfaces were used as the control group. Tensile bond strengths (TBS) were measured after water storage for 3 days or 150 days with additional 37,500 thermal cycling for artificial aging. Statistical analyses were performed with 1-way and 3-way ANOVA, followed by comparison of means with the Tukey HSD test. Results: After storage in distilled water for three days at 37 °C, the highest mean tensile bond strengths (TBS) were observed for zirconia ceramic surfaces abraded with 150-mm abrasive alumina particles (TBSAAP = 37.3 MPa, TBSCAAP = 40.4 MPa), and 150-mm abrasive zirconia particles (TBSAZP = 34.8 MPa, TBSCAZP = 35.8 MPa). Also a high TBS was observed for specimens treated with argon-ion bombardment (TBSBAI = 37.8 MPa). After 150 days of storage, specimens abraded with 150-mm abrasive alumina particles and 150-mm abrasive zirconia particles revealed high TBS (TBSAAP = 37.6 MPa, TBSCAAP = 33.0 MPa, TBSAZP = 22.1 MPa and TBSCAZP = 22.8 MPa). A high TBS was observed also for specimens prepared with slip casting (TBSSC = 30.0 MPa). A decrease of TBS was observed for control specimens (TBSUNT = 12.5 MPa, TBSCUNT = 9.0 MPa), specimens treated with argon-ion bombardment (TBSBAI = 10.3 MPa) and gas plasma (TBSGP = 11.0 MPa). A decrease of TBS was observed also for specimens treated with piranha solution (TBSPS = 3.9 MPa, TBSCPS = 4.1 MPa). A significant difference in TBS after three days storage was observed for specimens treated with different methods (p < 0.001). Thermal cycling significantly reduced TBS for all groups (p < 0.001) excluding groups: AAP(p > 0.05), CAAP(p > 0.05) and SC(p > 0.05). However, the failure patterns of debonded specimens prepared with 150-mm abrasive zirconia particles were 96.7% cohesive. Conclusion: Treatment of zirconia ceramic surfaces with abrasive zirconia particles is a promising method to increase the tensile bond strength without significant damage of the ceramic surface itself. An alternative promising method is slip casting.

We have found in the SR-HXPS measurement of Piranha-treated Au(111)/mica that the gold surface underwent sulfur modification during this treatment, which was believed to have only removed impurities from the gold surface. We also successfully developed a practical Pd material, SAPd, whose Pd was immobilized on sulfur-modified Au. With the lowest Pd-releasing levels and high recyclability, this is one of the best Pd materials thus far developed. Because it leaches extremely low levels of Pd into reaction mixtures, removal of the residual Pd is unnecessary using SAPd, even in syntheses involving pharmaceutical ingredients.

It has been found that a common shipping and packaging material for commercial AFM cantilever tips, poly(dimethylsiloxane) (PDMS), causes a thin layer of silicone oil contamination on AFM cantilever tips. Due to the similarity of elemental compositions between silicone oils and AFM cantilevers (both contain silicon and oxygen), it is difficult to detect such contaminants with the widely used surface characterization technique, X-ray photoelectron spectroscopy (XPS), since XPS provides mainly elemental and short-range chemical information. However, by using static time-of-flight secondary-ion mass spectrometry (TOF-SIMS), a technique that is extremely surface-sensitive, silicone oils on AFM cantilevers can easily be identified by their molecular fragments. A simple dip cleaning procedure using a mixture of concentrated sulfuric acid and hydrogen peroxide (piranha solution) was found to be an easy and effective way to remove organic contamination, including silicone oils, from AFM cantilever tips. It has al...

An improved process for the preparation of sulfur-modified gold-supported palladium material [SAPd, second generation] is presented. The developed preparation method is safer and generates less heat (aqueous Na2S2O8 and H2SO4) for sulfur fixation on a gold surface, and it is superior to the previous method of preparing SAPd (first generation), which requires the use of the more heat-generating and dangerous piranha solution (concentrated H2SO4 and 35% H2O2) in the sulfur fixation step. This safer and improved preparation method is particularly important for the mass production of SAPd (second generation) for which the catalytic activity was examined in ligand-free Buchwald–Hartwig cross-coupling reactions. The catalytic activities were the same between the first and second generation SAPds in aromatic aminations, but the lower palladium leaching properties and safer preparative method of second generation SAPd are a significant improvement over the first generation SAPd.

In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions) and the etching time on the morphology and surface relief of ultrafine grained (UFG) and coarse grained (CG) titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF) and X-ray Photoelectron Spectroscopy (XPS). Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed.

In this work, various methods to enable tailoring of polydimethylsiloxane film surfaces are implemented and compared to determine their influence on surface energy and roughness. Films were prepared containing various levels of hydrophilic silica filler. Ultraviolet-ozone, and Piranha solution treatments were also implemented and characterised. Lastly, the combination of both silica filler and treatments were utilised and characterised to understand interactive effects. Influence of filler loading, and surface treatment on roughness, and surface energy of films was determined. Regardless of surface treatment, addition of silica significantly influences total surface energy. Addition of silica influenced total surface energy of the films by itself, and in combination with the Piranha and UV-ozone treatments. The lowest surface energy was that of the control Polydimethylsiloxane film 21.5 N/m. The overall highest surface energy achieved was that of the 10% filled 30-minute Piranha solution treated sample, having a surface energy of 44.1 N/m.