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Mixed polymer brushes (MPBs) could be synthesized by surface dilution of homopolymer brushes and subsequent grafting of other type of chains in the formed voids. Nanophase separation and dynamics of surface-grafted chains could be tailored by modification of their molecular architecture. Mixed polyelectrolyte and conjugated chains contribute synergistically to tailor properties of the coating.A new synthetic strategy that allowed spatially controlled grafting of poly(sodium 4-styrenesulfonate) chains (PSSNa) in close neighborhood of poly(3-methylthienyl methacrylate) (PMTM) brushes (precursors of the conjugated chains) using surface-initiated polymerizations was developed. The final mixed conjugated/polyelectrolyte brushes were prepared by template polymerization of pendant thiophene groups in PMTM chains. Surface dynamics and nanophase separation of MPBs were studied by nanoscale resolution IR imaging, SIMS profiling and AFM mapping in selective solvents.Unconjugated MPBs were shown to undergo vertical, and horizontal nanophase separation, while the size and shape of the nanodomains were dependent on molar ratio of the mixed chains and their relative lengths. Generation of the conjugated chains led to diminishing of nanophase separation thanks to stronger mutual interactions of conjugated PMTM and PSSNa (macromolecular mixing). The obtained systems demonstrated tunable interfacial structure and resistance switching phenomenon desired in construction of smart surfaces or memristive devices.

The development of topography plays an important role when low-energy projectiles are used to modify the surface or analyze the properties of various materials. It can be a feature that allows one to create complex structures on the sputtered surface. It can also be a factor that limits depth resolution in ion-based depth profiling methods. In this work, we have studied the evolution of microdendrites on poly(methyl methacrylate) sputtered with a Cs 1 keV ion beam. Detailed analysis of the topography of the sputtered surface shows a sea of pillars with islands of densely packed pillars, which eventually evolve to fully formed dendrites. The development of the dendrites depends on the Cs fluence and temperature. Analysis of the sputtered surface by physicochemical methods shows that the mechanism responsible for the formation of the observed microstructures is reactive ion sputtering. It originates from the chemical reaction between the target material and primary projectile and is combined with mass transport induced by ion sputtering. The importance of chemical reaction for the formation of the described structures is shown directly by comparing the change in the surface morphology under the same dose of a nonreactive 1 keV xenon ion beam.

Here, we report significant activity towards the oxygen evolution reaction (OER) of spherical nickel nanoparticles (NPs) electrodeposited onto free-standing TiO2 nanotubes (TNT) via cyclic voltammetry. It has been shown that simple manipulation of processing parameters, including scan rate and number of cycles, allows for formation of the NPs in various diameters and amounts. The polarization data with respect to transmission electron microscopy (TEM) allowed for determination of the diameter and propagation depth of the Ni NPs leading to the highest activity towards the OER with an overpotential of 540 mV at +10 mA cm−2 and Tafel slope of 52 mV per decade. X-ray photoelectron spectroscopy (XPS) indicates the presence of structure defects within Ni NPs whereas Mott–Schottky analysis provides information on the anodically shifted flat band potential and highly increased donor density. The obtained results along with literature studies allowed a proposal of the origin of the enhancement towards the OER. We believe that combination of transition metal-based NPs and TNT provides valuable insight on efficient and low-cost electrocatalysts.

Domains rich in different blend components phase-separate during deposition, creating a film morphology that determines the performance of active layers in organic electronics. However, morphological control either relies on additional fabrication steps or is limited to a small region where an external interaction is applied. Here, we show that different semiconductor-insulator polymer composites can be rapidly dip-coated with the film structure electrically switched between distinct morphologies during deposition guided by the meniscus formed between the stationary barrier and horizontally drawn solid substrate. Reversible and repeatable changes between the morphologies used in devices, e.g., lateral morphologies and stratified layers of semiconductors and insulators, or between phase-inverted droplet-like structures are manifested only for one polarity of the voltage applied across the meniscus as a rectangular pulse. This phenomenon points to a novel mechanism, related to voltage-induced doping and the doping-dependent solubility of the conjugated polymer, equivalent to an increased semiconductor content that controls the composite morphologies. This is effective only for the positively polarized substrate rather than the barrier, as the former entrains the nearby lower part of the coating solution that forms the final composite film. The mechanism, applied to the pristine semiconductor solution, results in an increased semiconductor deposition and 40-times higher film conductance.

The fibrotic fibroblasts derived from idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP) are surrounded by specific environments, characterized by increased stiffness, aberrant extracellular matrix (ECM) composition, and altered lung architecture. The presented research was aimed at investigating the effect of biological, physical, and topographical modification of the substrate on the properties of IPF- and NSIP-derived fibroblasts, and searching for the parameters enabling their identification. Soft and stiff polydimethylsiloxane (PDMS) was chosen for the basic substrates, the properties of which were subsequently tuned. To obtain the biological modification of the substrates, they were covered with ECM proteins, laminin, fibronectin, and collagen. The substrates that mimicked the 3D structure of the lungs were prepared using two approaches, resulting in porous structures that resemble natural lung architecture and honeycomb patterns, typical of IPF tissue. The growth of cells on soft and stiff PDMS covered with proteins, traced using fluorescence microscopy, confirmed an altered behavior of healthy and IPF- and NSIP-derived fibroblasts in response to the modified substrate properties, enabling their identification. In turn, differences in the mechanical properties of healthy and fibrotic fibroblasts, determined using atomic force microscopy working in force spectroscopy mode, as well as their growth on 3D-patterned substrates were not sufficient to discriminate between cell lines.

The organic residues on titanium(IV) oxide may be a significant factor that decreases the efficiency of dye-sensitized solar cells (DSSC). Here, we suggest the UV-ozone cleaning process to remove impurities from the surface of TiO2 nanoparticles before dye-sensitizing. Data obtained from scanning electron microscopy, Kelvin probe, Fourier-transform infrared spectroscopy, and Raman spectroscopy showed that the amounts of organic contamination were successfully reduced. Additionally, the UV-VIS spectrophotometry, spectrofluorometry, and secondary ion mass spectrometry proved that after ozonization, the dyeing process was relevantly enhanced. Due to the removal of organics, the power conversion efficiency (PCE) of the prepared DSSC devices was boosted from 4.59% to 5.89%, which was mostly caused by the increment of short circuit current (Jsc) and slight improvement of the open circuit voltage (Voc).

The multi-step character of cancer progression makes it difficult to define a unique biomarker of the disease. Interdisciplinary approaches, combining various complimentary techniques, especially those operating at a nanoscale level, potentially accelerate characterization of cancer cells or tissue properties. Here, we study a relation between the surface and biomechanical properties of melanoma cells, measured by mass spectrometry (ToF SIMS) and atomic force microscopy (AFM). In total, seven cell lines have been studied. Six of them were melanoma cells derived from various stages of tumor progression: (1) WM115 cells derived from a 55 year old female skin melanoma at a vertical growth phase (VGP) in the primary melanoma site, (2) WM793 cells established from the vertical growth phase (VGP) of a primary skin melanoma lesion, (3) WM266-4 cells established from a cutaneous skin metastasis detected in the same patient as WM115 cells, (4) WM239 cells derived from a cutaneous skin metastasis, (5) 1205Lu cells originated from a lung metastasis diagnosed in the same patient as WM793 cells, (6) A375P – cells were derived from a solid malignant tumor located in the lung. As a reference cell line, human epidermal melanocytes from adult skin (primary cell line HE-Ma-LP) was used. Cellular deformability reveals low, medium and large deformability of melanoma cells originating from vertical growth phase (VGP), skin and lung metastasis, respectively. These changes were accompanied by distinct outcome from principal component analysis (PCA). In relation to VGP melanoma cells, cells from skin and lung metastasis reveal similar or significantly different surface properties. The largest deformability difference observed for cells from VGP and lung metastasis was accompanied by the largest separation carried out based on unspecific changes in their surface properties. In this way, we show the evidence that biomechanical and surface biochemical properties of cells change in parallel, indicating a potential of being used as nanobiophysical fingerprints of melanoma progression.

Introduction of polar oxygen functional groups into carbon surfaces by plasma treatment results in dramatic changes in their wettability and electronic properties. Herein, we propose the combined theoretical and experimental approach to explore the chemical nature and stability of these functionalities. The DFT calculations were performed to evaluate the value and direction of the formed surface dipoles of Csurf–OH, −CHO, –COOH, =O, Csurf-O-Csurf moieties, whereas the surface-sensitive techniques (XPS, SIMS), allow for their identification. The evolution of functionalization was monitored in time by the means of changes in wettability (water contact angle) and electrodonor properties (work function measured by Kelvin method). The results show that ~6 at.% of surface oxygen (−OH, −CHO, –COOH), led to dramatic changes in work function (increase by 1.15 eV) and water contact angle (decrease by 74°). The evolution of surface functionalization was systematically monitored over the period of 60 days after plasma treatment. Both, electronic properties and wettability tended to recover over time. SIMS depth profiling clearly illustrates the changes in surface composition of the aged graphenic surfaces, which were below the XPS sensitivity. Since plasma treatment is often used as the first step in the surface properties tuning of carbon materials, the practical importance of immediate functionalization after activation is highlighted.

Here, we report significant activity towards the oxygen evolution reaction (OER) of spherical nickel nanoparticles (NPs) electrodeposited onto free-standing TiO

The rapid, only a few minutes long synthesis of FeO, Fe3O4, and Fe2O3 nanoparticles mixture utilizing the pulsed laser ablation using simply pure iron target and water was demonstrated. The size and crystal phase of Fe-based NPs were characterized using DLS and HR-TEM techniques, respectively. The metastable suspension of FeO, Fe3O4, and Fe2O3 nanoparticles was used to the decoration of anodized TiO2 nanotubes (TiO2-NTs) by means of the ultrasonic bath. SEM inspection confirms preservation of the ordered morphology even upon 60 min long exposition to the ultrasounds whereas TOF SIMS indicated penetration of iron species down to the TiO2-NTs base. Finally, the electrochemical investigation of decorated and bare TiO2-NTs has shown a response typical for Fe2+/Fe3+ iron species and the boosted activity towards oxygen evolution reaction in the anodic regime. As of high importance, for the 30 min long ultrasound-assisted modification, the photocurrent was enhanced almost 2.5 times comparing to the pristine material exposed to the solar light, although differences in optical properties were negligible. Taking into account outstanding activity namely response upon irradiation and effectiveness of water splitting, the proposed approach can be regarded as a facile one generating much less waste in comparison to typical wet-chemistry methods.

The main efficiency loss is caused by an intensive recombination process at the interface of fluorine-doped tin oxide (FTO) and electrolyte in dye-sensitized solar cells. Electrons from the photoanode can be injected back to the redox electrolyte and, thus, can reduce the short circuit current. To avoid this, the effect of the electron blocking layer (EBL) was studied. An additional thin film of magnetron sputtered TiO2 was deposited directly onto the FTO glass. The obtained EBL was characterized by atomic force microscopy, scanning electron microscopy, optical profilometry, energy dispersive spectroscopy, Raman spectroscopy and UV-VIS-NIR spectrophotometry. The results of the current–voltage characteristics showed that both the short circuit current (Isc) and fill factor (FF) increased. Compared to traditional dye-sensitized solar cell (DSSC) architecture, the power conversion efficiency (η) increased from 4.67% to 6.07% for samples with a 7 7 mm2 active area and from 2.62% to 3.06% for those with an area of 7 80 mm2.

The substantial increase in the efficiency of organic solar cells achieved in recent years would not have been possible without work on the synthesis of new materials and understanding the relationship between the morphology and performance of organic photovoltaic devices. The structure of solvent-cast active layers is a result of phase separation in mixtures of donor and acceptor components. To a large extent, this process depends on the interactions between the components of the mixture. Here, we present a systematic analysis of the morphology of poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl-C71-butyricacid methyl ester (PC70BM) films in terms of the ternary phase diagram. The interaction parameters between PCDTBT and four different solvents, namely chloroform, chlorobenzene, o-dichlorobenzene, and toluene, were estimated based on swelling experiments. Based on these values, ternary phase diagrams of PCDTBT:PC70BM in different solvents were calculated. The morphology of spin-coated films with different blend ratios cast from different solvents is discussed in terms of the obtained phase diagrams.

Cell-substrate interaction is one of the crucial phenomenon that determines cell behavior and fate. Here, we present the results on the effect of physical properties (i.e., hydrophobicity/hydrophilicity and roughness) of polyethylene oxide (PEO) and 1,4-polyisoprene (PI) thin films on adhesion of two melanoma cell lines, originating from primary tumor site from vertical growth phase (VGP WM115 cells) and from its metastasis to skin (WM266-4 cells). Our findings show that cell–substrate interaction is strongly dependent on the stage of melanoma progression. For both studied cell types, the dependence of cellular adhesive properties (quantified from single cell force spectroscopy) on surface free energy, particularly, on its polar component, was observed. Adhesive forces of VGP WM115 cells to thin polymer films (TPF) with various hydrophobicity and roughness are larger as compared to those observed in the case of metastatic WM266-4 cells. The proliferation of the latter cells was higher as for VGP WM115 cells, what agrees with the invasive phenotype of these melanoma cells. In summary, the metastatic WM266-4 cells adapt better to different substrates properties as compared to VGP WM115 ones.

The effect of the presence of titanium dioxide in two new imines, (E,E)-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4-{[(benzo[d][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and (E)-N-[(benzo[d][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol–gel method) exhibited a surface area of 59.5 m2/g according to Brunauer–Emmett–Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett–Joyner–Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m3/g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Colhk). The imine:TiO2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO–LUMO energy levels compared to pure TiO2. This implies that TiO2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO2 surface with SP1 and SP2 were observed. The imine:TiO2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications.

Herein, the heterojunction composed of an inorganic substrate: ordered hydrogenated titania nanotubes (H-TiO2NTs) and a deposited organic film: poly(3,4-ethylenedioxythiophene) (PEDOT) is reported. The conducting polymer is modified with different transition metal haxacyanoferrates (Mehcf), wherein as metal: copper, iron, cobalt and nickel are introduced. The presence of various metal centres provides characteristic redox activity and allows to investigate the impact of the particular Prussian Blue analogues onto the photoactivity of the p-n heterojunction. The formed composites were inspected by means of scanning electron microscopy, spectroscopic techniques, i.e. UV–Vis, Raman and Secondary Ion Mass spectrometry and using electrochemical methods. It is shown that electrochemical and photoelectrochemical performance of the so-fabricated materials is significantly affected by the nature of the redox species introduced into the PEDOT matrix.

Two bent-shaped imines (9E)-N-(3-((E)-(4-hexadecylphenylimino)methyl)benzylidene)-4-hexadecylbenzenamine (SL1) and (10E)-N-(3-((E)-(4-(perfluorooctyl)phenylimino)methyl)benzylidene)-4-(perfluorooctyl)benzenamine (SL2) were prepared by condensation reaction in N,N-dimethylacetamide to study their thermal, structural and electrochemical properties, as well as their mixtures with titanium dioxide. Chemical structure, temperature and TiO2 influences on the phase transition temperatures, enthalpy, texture and molecular dynamics of both imines were investigated by differential scanning calorimetry, polarising optical microscopy and Fourier transform middle-infrared absorption spectroscopy during heating and cooling. Changes in the surface morphology of the imines and their mixtures with TiO2 were registered by atomic force microscopy. X-ray study showed the tendency to form lamellas in the case of SL2 as an effect of the presence of two terminal perfluorinated alkyl chains connected to a polar mobile aromatic core, which resulted in microsegregation. Additionally, TiO2 influences the energy gap and HOMO–LUMO levels of imines as was detected by cyclic voltammetry. Finally, devices with two types of architectures, such as ITO/TiO2/SL1(or P3HT)/Au and ITO/TiO2/SL1:P3HT/Au were constructed and investigated under irradiation intensity of 97.7 mW/cm2.

The stability of chemical bonds at the molecule–metal interface is of fundamental importance for a majority of applications based on organic materials. It remains, however, extremely difficult to determine this stability using experimental and theoretical methods. A detailed analysis of the static SIMS (S-SIMS) data obtained for the homologous series of thiolate- and selenolate-based self-assembled monolayers (SAMs) on the Ag(111) substrate reveals positional oscillations in the stability of consecutive chemical bonds in the vicinity of the molecule–metal interface. The observed oscillations are much more pronounced compared to recently reported analogous data for the Au(111) substrate, which confirms the universal nature of this phenomenon and its strong dependence on the type of molecule binding atom (S or Se) and the substrate (Ag or Au). Importantly, such an analysis has not been conducted to date using any other technique, and this study not only reveals the universal mechanisms of molecule–metal interface stability but also presents S-SIMS as a unique tool for such an analysis.

Various techniques have been already reported to differentiate between normal (non-malignant) and cancerous cells based on their physico-chemical properties. This is relatively simple when studied cancerous cells originate from distant stages of cancer progression. Here, studies on chemical properties of two closely related human melanoma cell lines are presented: WM115 melanoma cells were taken from the vertical growth phase while WM266-4 from the skin metastatic site of the same patient. Their chemical properties were studied by two techniques, namely time-of-flight secondary ion mass spectra (ToF SIMS) and photothermal microspectroscopy (PTMS), used to record mass and photothermal spectra of cells, respectively. In our approach, independently of the spectra type, its full range, i.e. masses and wavenumbers within the range 0–500 kDa and 500–4000 cm^{−1}, underwent a similar methodology for principal component analysis (PCA). PCA outcome shows results groupped depending on the sample type (either WM115 or WM266-4 cells). The results are independent of the method applied to study chemical properties of melanoma cells, indicating that cancer-related changes are large enough to be identified with these techniques and to differentiate between cells originating from vertical growth phase and skin metastatis.

The simple junction between the organic semiconductor and insulator possesses fascinating properties. The increase of the conductivity of conjugated material is one of the effects that is well documented in the literature. However, to-this-day there is no consistent explanation for this phenomenon. Herein, a lamellar system based on the regioregular poly(3-hexylthiophene) (R-P3HT), and the recently developed poly(4-vinylpyridine) (P4VP) cross-linked with d-block metal complexes is studied. Bilayer samples, mimicking organic Field Effect Transistors, are fabricated in a three-step procedure: (i) R-P3HT thin film casting, (ii) subsequent P4VP film casting on top of the R-P3HT, and (iii) cross-linking of the P4VP surface. The Cobalt and Zinc complexes exist only on the surface of the bilayer and do not penetrate the semiconductor. The conductivity of the system increases with each preparation step, to reach a value four orders higher as compared to the as-cast R-P3HT. Additional experiments show that the described effect is a consequence of the contact of R-P3HT and P4VP. Observed increase in the system's conductivity is attributed to the electric field induced in the semiconductor area by the pyridine dipole moments directed by surface-oriented metal complex. These findings open up new possibilities in tuning the performance of organic electronic devices.

We report on the application of l,d-poly(lactic acid) (l,d-PLA) with dispersed Single-Walled Carbon Nanotubes (SWCN) as a flexible translucent electrode for organic devices. We used commercially available nanotubes in various weight ratios from 0 to 8% dispersed in chloroform polymeric solution by ultrasonication and were drop cast. The created hybrid materials were investigated by differential scanning calorimetry to determine the influence of SWCN content on the thermal behavior, while polarizing optical microscope was used to find the effect of mechanical deformations on the textures. Drop-cast films were studied by optical transmittance, conductivity, dielectric properties and by thermal imaging under applied potential. Thermal imaging provided evidence of visible voltage-activated conduction. Simple mechanical deformation such as bending with stretching at edge to ca. 90 and elongation test were performed. Moreover, interactions between l,d-poly(lactic acid) and SWCN were investigated by FT-IR and NMR spectroscopy. Finally, we can conclude that the thermographic examination of created films permits fast, simple and inexpensive localization of defects on the surface of l,d-PLA:SWCN film, together with the electrical properties of the films.

The surface properties of poly(3,4-ethylenedioxythiophene):(polystyrene sulfonate) (PEDOT:PSS) affect the performance of many organic electronic devices. The work function determines the efficiency of the charge carrier transfer between PEDOT:PSS electrodes and the active layer of the device. The surface free energy affects phase separation in multicomponent blends that are typically used to fabricate active layers of organic light-emitting diodes and photovoltaic devices. Here, we present a method to prepare PEDOT:PSS films with a gradient work function and surface free energy. This modification was achieved by evaporation of trimethoxy(3,3,3-trifluoropropyl)silane in such a way that the degree of surface coverage of the molecules varied in the selected direction. Gradient films were used as electrodes to fabricate two-terminal PEDOT:PSS/poly(3-hexyl thiophene)/Au devices to rapidly screen for the influence of the modification on the performance of the prepared polymer diodes. Gradual changes in the morphology of the solution-cast model poly(3-butyl thiophene)/poly-bromostyrene films followed changes in the surface energy of the substrate.

A new piperazine imine, (7E)-N-((4-((E)-(4-hexadecylphenylimino)methyl)piperazin-1-yl)methylene)-4-dodecylbenzenamine, has been synthesized by the condensation of 1,4-piperazinedicarboxaldehyde wit...

Photovoltaic performance of hybrid devices consisting of zinc sulphide (ZnS) one-dimensional (1D) nanowires and P3HT polymer was studied. As we previously reported, hybrid solar cell architecture based on ZnS, where open circuit voltage reaches high value, deserves special attention. In this work, compared to our previous research, zero-dimensional (0D) ZnS nanoparticles were replaced by one-dimensional (1D) ZnS nanowires synthesized simply with a hot injection method. In order to improve the charge transport in hybrid solar cells, additionally, the initial ligand of octadecylamine (ODA) was partially replaced by the o-phenylenediamine. The as-synthesized products were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, photoluminescence (PL) spectroscopy, energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The performance of the devices significantly depended on the concentration of one-dimensional ZnS nanowires incorporated in the active layer (optimal 10 wt.%) and their morphology. In the presented work, we showed that devices based on 1D ZnS nanowires were distinguished by the high value of Voc parameter (with the maximum achieved value of 0.634 V). Also we investigated the spatial layout of nanocrystals in the device, depending on its post treatment, using atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and ultraviolet photoelectron spectroscopy (UPS). Our study showed spatial segregation of nanocrystals to both interfaces with electrodes, and also we showed significant changes (0.71 eV at the top) in the PEDOT:PSS work function after mixing with ZnS nanocrystals, which resulted in an increase in the difference in contact potential at respective electrodes, which explained the high value of Voc. In comparison to our previous study, by replacing an active layer of the 0D ZnS nanocrystals with 1D ZnS nanowires, nearly a triple increase of the overall efficiency (maximum of % η of 0.568) of the device was observed.

The creation of functional magnetic materials for application in high-density memory storage or in the new field of molecular spintronics is a matter of widespread interest among the material research community. Herein, we describe a new approach that combines the qualities of single ion magnets, displaying slow magnetic relaxations, and the merits of polymers, being easy to process and widely used to produce thin films. Basing the idea on cobalt(II) ions and pyridine-based single ion magnets, a new macromolecular magnetic material was obtained – a polymeric matrix of poly(4-vinylpyridine) (P4VP) cross-linked by a cobalt(II) salt bound within it, effectively forming a network of single ion magnets, with field-induced magnetic relaxations preserved in both bulk and thin film forms. The binding of cobalt is confirmed by a series of methods, like secondary ion mass spectroscopy or high-resolution X-ray photoelectron spectroscopy. The magnetic relaxation times, up to 5 $\times$ 10−6 s, are controllable simply by dilution, making this new material a semi-solid solution. By this approach, a new path is formed to connect molecular magnetism and polymer science, showing that the easy polymer processing can be used in forming self-organizing functional magnetic thin films.

In this work we show that performing a numerical correction for beam attenuation and indirect excitation allows one to fully restore element sensitivity in the three-dimensional reconstruction of the atomic structure. This is exemplified by a comparison of atomic images reconstructed from holograms measured for ordered and disordered phases of a Cu3Au crystal that clearly show sensitivity to changes in occupancy of the atomic sites. Moreover, the numerical correction, which is based on quantitative methods of X-ray fluorescence spectroscopy, was extended to take into account the influence of a disturbed overlayer in the sample.

Structural properties and stability of the self-assembled monolayers (SAMs) of two prototypical azobenzene-based alkanethiols (C6H5–N═N–C6H4–(CH2)n–SH) on Au(111) and Ag(111) substrates were studied in detail using a combination of complementary experimental techniques. The azobenzene moiety in these films was linked to the thiol headgroup via short aliphatic spacers of variable length, i.e., (CH2)3 or (CH2)4, corresponding to a different parity of n. For both Au(111) and Ag(111) substrates, a pronounced dependence of the packing density and molecular inclination on the parity of n was observed, with a higher packing density (by ∼14%) and smaller inclination (by ∼17°) of the azobenzene moieties for n = odd as compared to n = even on Au(111) and reversed, but somewhat reduced, behavior on Ag(111). This dependence was related to the well-known odd–even effects in molecular assembly on noble metal substrates, reported previously for a variety of oligophenyl-substituted alkanethiolate SAMs and observed now fo...

The effect of the presence of titanium dioxide in two new imines, (E,E)-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4-{[(benzo[d][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and (E)-N-[(benzo[d][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol–gel method) exhibited a surface area of 59.5 m2/g according to Brunauer–Emmett–Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett–Joyner–Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m3/g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Colhk). The imine:TiO2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO–LUMO energy levels compared to pure TiO2. This implies that TiO2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO2 surface with SP1 and SP2 were observed. The imine:TiO2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications.

Tuning the transition between stable hydrophilicity and high etching-rate and simultaneous hydrophilization of polymethylmethacrylate (PMMA) films was achieved in an open-air environment simply by adjusting the O2 content in He gas injection through the showerhead-type electrode of a novel atmospheric pressure dielectric barrier discharge source. A comparative study was performed for He and He-O2 plasma treatment of PMMA. Electrical and optical measurements indicated severe alteration of plasma characteristics when O2 is added in gas feed. The enhancement of oxygen emission band intensities indicates an enhanced concentration of atomic oxygen, resulting in very high PMMA etching rates of ∼320 nm/min, ∼four times higher compared to pure He. In contrast, the He plasma showed higher nitrogen emission band intensities, translated into a higher nitrogen content on the PMMA surface according to x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. This enhanced nitrogen content du...

In this work we present the outstanding energy storage of prepared inorganic-organic heterojunction where hydrogenated ordered titania nanotubes (H-TiO 2 NT) were modified by the hybrid made of poly(3,4-ethylenedioxythiophene) (pEDOT) and iron hexacyanoferrate centres (Fehcf, Prussian Blue). The material TiO 2 NT/pEDOT:Fechf was obtained electrochemically by means of: anodization, hydrogenation and finally, electropolymerization of EDOT in the presence of Fe(CN) 6 3 −/4 − ions. Inorganic-organic hybrids were characterized using Raman spectroscopy and secondary ion mass spectrometry (SIMS). The morphology of obtained materials was inspected using scanning electron microscopy (SEM). Electrodes were tested using cyclic voltammetry and galvanostatic charge/discharge cycles in an aqueous electrolyte. The characterization of capacitance was studied by means of multiple (up to 10,000) charge/discharge cycles with the current density of 0.45 mA cm − 2 . Electrode materials consisting of H-TiO 2 , pEDOT and Prussian Blue exhibited the highest capacitance of 26 mF cm − 2 even after 10,000 cycles. Thus, the capacitance of TiO 2 NT/pEDOT:Fehcf was c.a. 15 and 8 times higher than the capacitance registered for pure and hydrogenated TiO 2 , respectively.

The arrangement, composition and orientation of immunoreagents employed in an indirect immunoassay for determination of mycotoxin OchraToxin A (OTA) are specified for Si3N4 substrate, aiming to imitate biosensor transducers made of the same material. Si3N4 surfaces are examined after modification with (3-aminopropyl)triethoxysilane, spotting with OTA-ovalbumin conjugate (probe), blocking with bovine serum albumin, reaction with a mouse monoclonal antibody against OTA and, finally, reaction with a goat anti-mouse secondary antibody. Atomic force micrographs, their autocorrelation and height histogram parameters, show the stepwise development of a multi-component monolayer covered by groups of secondary antibody molecules. Time-Of-Flight Secondary Ion Mass Spectrometry reveals the composition of probe and blocking protein, as well as their partial desorption during the primary immunoreaction. Ellipsometry provides surface amount of all proteins, increasing step-by-step from 0.7 to 6.9mg/m2. In addition, ellipsometry combined with TOF-SIMS reveals the mass loadings of different molecules in the intermediate and the final overlayer. Based on this, some orientations of the immobilized molecules are proposed and a molar ratio of ∼2.5 for secondary to primary antibody is calculated. The orientations of the primary and secondary antibody are further clarified by Principal Component Analysis of TOF-SIMS data, through which a side-on and a head-on orientation is deduced for the primary and the secondary antibody, respectively. These findings demonstrate how the combination of multiple surface analysis techniques can provide insight on the arrangement, composition and orientation of biomolecules in the course of multi-step procedures employed in biosensors.

We report on the systematic exploration of electronic and structural changes of Nb-doped rutile TiO2(110) single crystal surfaces due to the thermoreduction under ultra-high vacuum conditions (without sputtering), with comparison to undoped TiO2(110) crystals. It has been found that the surface of the doped sample undergoes a previously unknown transition during reduction above 850 °C, as provided by LEED, STM and LC-AFM. This transition involves a change from heterogeneous conductivity (due to the presence of conducting filaments) to homogeneous conductivity, connected with a new (4 × 2) reconstruction of rows parallel to the [001] direction. DFT calculations suggest substitution of Ti by Nb atoms in the first atomic layer. Due to the strong reducing conditions during annealing, oxygen is released from the crystal and Nb diffuses from the subsurface into the bulk, agglomerating however on the surface, as shown by SIMS depth profiling. We present that 0.5% Nb doping significantly influences the reduction process and in turn the structural properties of the surface by supporting the evolution of the new reconstruction. It is shown that the thermal treatment of TiO2:Nb under low oxygen partial pressure gives an opportunity to tune the electrical conductivity and work function of the surface.

Mass fabrication of integrated biosensors on silicon chips is facilitated by contact pin-printing, applied for biofunctionalization of individual Si 3 N 4 -based transducers at wafer-scale. To optimize the biofunctionalization for immunochemical (competitive) detection of fungicide thiabendazole (TBZ), Si 3 N 4 surfaces are modified with (3-aminopropyl)triethoxysilane and examined after: immobilization of BSA-TBZ conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin (BSA), and immunoreaction with a mouse monoclonal antibody against TBZ. Nanostructure, surface density, probe composition and coverage uniformity of protein layers are evaluated with Atomic Force Microscopy, Spectroscopic Ellipsometry, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy. Contact pin-printing of overlapping probe spots is compared with hand spotted areas. Contact pin-printing resulted in two-fold increase of immobilized probe surface density as compared to hand spotting. Regarding BSA-TBZ immobilization, an incomplete monolayer develops into a bilayer as the concentration of BSA-TBZ molecules in the printing solution increases from 25 to 100 μg/mL. Upon blocking, however, a complete protein monolayer is formed for all the BSA-TBZ concentrations used. Free surface sites are filled with BSA for low surface coverage with BSA-TBZ, whereas loosely bound BSA-TBZ molecules are removed from the BSA-TBZ bilayer. As a consequence immunoreaction efficiency increases with the printing probe concentration.

The thermal stability of self-assembled monolayers (SAMs) is of fundamental importance for the majority of their applications. It strongly depends on the type of chemical group used for bonding the molecules forming the SAMs to the selected substrate. Here, we compare the impact of using S and Se bonding groups on the thermal stability of aromatic model SAMs based on naphthalene, containing a polar substituent, and formed on a Au(111) substrate. Using a combination of secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS) while heating the samples, we show that the thermal stability of S-bonded SAMs is higher although the bonding between Se and the Au substrate is stronger. This seeming contradiction is found to result from a higher stability of the S–C compared to the Se–C bond. The latter forms the weakest link in the SAMs with Se anchor and, thus, controls its thermal stability. These conclusions are supported by state-of-the art dispersion-corrected density functional theory (DFT) calculations. Notably, full qualitative agreement between the experiments and simulations is obtained only when including Au adatoms in the setup of the unit cells, as these reinforce the bonding between the docking groups and the metal surface. This is an indication for the occurrence of such surface reconstructions also for SAMs consisting of comparably large aromatic molecules.

Ein generelles Konzept der Chemie besagt, dass die Starkung einer chemischen Bindung eine Schwachung der unmittelbar benachbarten Bindungen bewirkt. Bis heute ist es jedoch unklar, ob und wie sich dieser Effekt uber diese Bindungen hinaus auf das Molekulruckgrat auswirkt. Durch die Anbindung von Molekulen an Oberflachen in Form selbstorganisierter Monoschichten kann die Starke der primaren Bindung selektiv verandert werden. Wir berichten hier zum ersten Mal, dass bei der Sekundarionen-Massenspektrometrie adsorbierter Molekule eine positionsabhangige Oszillation der Stabilitat konsekutiver Bindungen beobachtet werden kann, deren Amplitude sich mit zunehmendem Molekul-Metall-Grenzflachen-Abstand vermindert. Zur Erklarung wurden molekulardynamische Simulationen und DFT-Rechnungen durchgefuhrt. Unsere Berechnungen zeigen, dass der beobachtete Oszillationseffekt der chemischen Bindungsstarke genereller Natur ist und einen Bruch der Translationssymmetrie in langkettigen Molekulen bewirkt.

Protein interactions with surfaces of promising conducting polymers are critical for development of bioapplications. Surfaces of spin-cast and postbaked poly(3-alkylthiophenes), regiorandom P3BT, and regioregular RP3HT are examined prior to and after adsorption of model protein, bovine serum albumin, with time-of-flight secondary ion mass spectrometry, atomic force microscopy, and X-ray photoelectron spectroscopy. The multivariate method of principal component analysis applied to ToF-SIMS data maximizes information on subtle differences in surface chemistry: PCA reveals alkyl side chains and conjugated backbones, exposed for RP3HT and P3BT, respectively. Phase imaging AFM shows semicrystalline microstructure of RP3HT and amorphous morphology of P3BT films. A cellular-like pattern of proteins adsorbed on RP3HT develops with coverage to more uniform overlayer, observed always on P3BT. The amount of adsorbed protein, determined by XPS as a function of BSA concentration (up to 10 mg/mL), is $\sim$ 21% lower for RP3HT than P3BT (up to 1.1 mg/m$^{2}$). Although PCA differentiates protein from polythiophene, relative protein surface composition evaluated from ToF-SIMS saturates rather than increases with amount of adsorbed BSA from XPS. This reflects ToF-SIMS sensitivity to outermost layer of proteins, enabling multivariate analysis of protein conformation or orientation. PCA distinguishes between amino acids characteristic for external regions of BSA adsorbed to P3BT and RP3HT. These amino acids are identified for P3BT and RP3HT as hydrophilic and hydrophobic, respectively, by relative hydrophobicity of amino acid side chains. Alternative identification with BSA domains fails, pointing to substrate-induced changes in conformation and degree of denaturation rather than orientation of adsorbed protein.

In the present study, a one dimensional polymeric photonic crystal is designed, fabricated and evaluated as a humidity sensor. The polymeric photonic crystal is consisted of a multilayer stack of sequential hydrophobic and hydrophilic layers applied using conventional photolithographic steps: spin-coating and DUV exposure. During exposure in a humidity environment, the hydrophilic layers of the sensor swell, hence growing its optical path and giving a red-shift of the reflectance peak and consequently a different color of the device. The spectroscopic humidity sensor does not require external power since its sensing ability is based on the reflectance peak shift of the photonic crystal in the visible spectrum (color change of the sensor). The design, fabrication, evaluation and characterization of the device and its evaluation as humidity sensor is presented.

To immobilize effectively oligonucleotide probes on SiO 2 modified with (3-aminopropyl)triethoxysilane, four procedures based on streptavidin–biotin system are compared with Atomic Force Microscopy, Angle-Resolved X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. The first approach involves: adsorption of biotinylated Bovine Serum Albumin, blocking free surface sites with BSA, binding of streptavidin and biotinylated oligonucleotide (b-oligo). Final steps are exchanged in the second procedure with immobilization of preformed streptavidin–b-oligo conjugate. The third approach consists of streptavidin adsorption, blocking with BSA and b-oligo binding. Finally, streptavidin–b-oligo conjugate is immobilized directly within the fourth method. Surface coverage with biomolecules, determined from ARXPS, accords with average AFM height, and is anti-correlated with the intensity of Si+ ions. Higher biomolecular coverage was achieved during the last steps of the first (2.45(±0.38) mg/m 2 ) and second (1.31(±0.22) mg/m 2 ) approach, as compared to lower surface density resulting from the third (0.58(±0.20) mg/m 2 ) and fourth (0.41(±0.11) mg/m 2 ) method. Phosphorus atomic concentration indicates effectiveness of oligonucleotide immobilization. Secondary ions intensities, characteristic for oligonucleotides, streptavidin, BSA, and proteins, allow additional insight into overlayer composition. These measurements verify the ARXPS results and show the superiority of the first two immobilization approaches in terms of streptavidin and oligonucleotide density achieved onto the surface.

Organic&ndash, inorganic hybrids based on liquid crystalline symmetrical imine (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine (AZJ1) with two aliphatic chains and TiO2 nanomaterials were obtained and investigated taking into account thr crystallographic form of titanium dioxide i.e. anatase versus rutile. The type of TiO2 influences the mesomorphic properties of imine AZJ1, as observed by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques. Fourier-Transform Infrared Spectroscopy (FT-IR) was used to investigate the interactions of oxygen vacancies located on the TiO2 surface with the studied AZJ1 imine together with studying the influence of temperature. Both imine:TiO2 anatase versus rutile hybrids possessed the highest occupied molecular orbital (HOMO) levels of about &minus, 5.39 eV (AZJ1:anatase) and &minus, 5.33 eV (AZJ1:rutile) and the lowest unoccupied molecular orbital (LUMO) levels of about &minus, 2.24 eV. The presence of TiO2 in each hybrid did not strongly affect the redox properties of imine AZJ1. Organic devices with the configuration of ITO/TiO2/AZJ1 (or AZJ1:TiO2 anatase versus rutile)/Au were fabricated and investigated in the presence and absence of visible light irradiation with a light intensity of 93 mW/cm2. Finally, to analyze defects in the constructed organic devices we used thermal imaging and atomic force microscopy (AFM). The addition of TiO2 in both crystallographic forms has a positive influence on layer-forming properties that manifests itself as a very homogenous heat distribution for the whole sample.

Buried interfaces between a polystyrene (PS) or polar poly(methyl methacrylate) (PMMA) thin film and the gold surface patterned with CH_{3}- and COOH-terminated alkanethiols self-assembled monolayers (SAM) were examined via Kelvin probe force microscopy. Chemical composition of the interface was probed by secondary ion mass spectrometry. The contact potential difference maps measured on the PS and the PMMA films show inverted contrast. This observation is discussed in terms of reorientations of the COOH-SAM net dipole moments induced by interactions with PMMA.