Surface Properties Of Thin Films Research Articles

The new soluble tetra-substituted oxo-titanium phthalocyanines: Synthesis, characterization, spectral and colorimetric pH sensing properties

New imidazole tetrasubstituted oxo-titanium phthalocyanine 1 was synthesized by tetramerization reaction of imidazole substituted phthalonitrile in the presence of titanium(IV) butoxide. N-alkylated imidazole tetrasubstituted oxo-titanium phthalocyanine 2 was prepared by N-alkylation reaction of compound 1 with iodomethane in basic medium. Afterwards, as a result of the quaternization reaction of compound 2, water-soluble oxo-titanium phthalocyanine 3 was prepared. The synthesized compounds were characterized by UV-Vis, FT-IR, 1H-NMR, MALDI-TOF MS and elemental analysis. The spectral properties, surface morphologies in powder form and thin films, colorimetric pH sensing properties and aggregation behaviors of the synthesized compounds were investigated. We also used the UV-Vis spectroscopy technique to experimentally find the optical band gap of compound 1 with the best thin-film surface properties. In this context, transmittance, absorption and band gap energy of compound 1 thin film were investigated.

Influence of Deposition Conditions on Properties of Ta2O5 Films Deposited by Ion Beam Sputtering Coating Technique

Investigation of deposition conditions on structural, optical, and surface properties of Tantalum pentaoxide (Ta2O5) thin films deposited without assisted ion beam (Single Ion Beam Sputtering technique, SIBS) and with assisted ion beam (Dual Ion Beam Sputtering technique, DIBS) is carried out. For both SIBS and DIBS identical coating process conditions are applied for deposition of Ta2O5 films onto highly polished and clean, fused silica substrates. Estimation of deposition rates of Ta2O5 with identical beam energies and coating chamber conditions is done. Benefits of O2 assist beam on the behavior of structural, optical, and surface properties of thin films deposited are studied. The films are characterized with an ellipsometer, optical profilometer, XRD, FE-SEM, and XPS techniques to bring the merits films coated of Ion Beam Sputtering deposition with and without assist Ion Beam. Configuration of ion sources and targets in the coating chamber for DIBS of oxide targets is carried out in the present work are useful for multi-layer coatings for high reflectivity mirrors for electro-optical instruments like ring laser-based rotation sensors.

Effect of Low-Temperature Plasma Treatment and γ Irradiation on the Surface Properties of Thin Films Based on Polylactic Acid

Effect of Low-Temperature Plasma Treatment and γ Irradiation on the Surface Properties of Thin Films Based on Polylactic Acid

Surface properties of thin films of poly(2,3,4,5,6-pentafluorostyrene) and diblock copolymers based on 2,3,4,5,6-pentafluorostyrene and 2-hydroxyethyl methacrylate

Surface properties of thin films of poly(2,3,4,5,6-pentafluorostyrene) and diblock copolymers based on 2,3,4,5,6-pentafluorostyrene and 2-hydroxyethyl methacrylate

Влияние низкотемпературной плазмы и γ-излучения на поверхностные свойства тонких пленок на основе полимолочной кислоты

Effects of the low-temperature plasma exposure, γ-irradiation, and joint g-irradiation and plasma exposure on the structure and surface properties of thin films based on polylactic acid (PLA) have been investigated. Films were obtained by the method a solvent-casting. It has been shown that films based on polylactic acid have topographically different sides: a smoother inner side and embossed outer one. PLA films have properties close to those hydrophobic, with a contact angle in the range of 70°-73° regardless of the surface side and belong to a weakly polar materials. The combined effect of plasma and gamma radiation slightly changes the surface topography. The effect of low-temperature plasma on the surface of the films leads to a decrease in the contact angle by 13°-55° (9-11%) and an increase in surface energy due to the polar component. The results of in vivo experiments on rabbits are presented. Biomicroscopy, optical coherence tomography, morphological and electron microscopic examination of the cornea after implantation of initial and radiation and plasma treated films showed that implantation of the films in the anterior chamber is not accompanied by a pronounced inflammatory reaction and increased intraocular pressure, while maintaining the morphological structure of the cornea almost unchanged.

Combinatorial functionalization with bisurea-peptides and antifouling bisurea additives of a supramolecular elastomeric biomaterial.

ABSTRACTThe bioactive additive toolbox to functionalize supramolecular elastomeric materials expands rapidly. Here we have set an explorative step toward screening of complex combinatorial functionalization with antifouling and three peptide‐containing additives in a bisurea‐based supramolecular system. Thorough investigation of surface properties of thin films with contact angle measurements, X‐ray photoelectron spectroscopy and atomic force microscopy, was correlated to cell‐adhesion of endothelial and smooth muscle cells to apprehend their respective predictive values for functional biomaterial development. Peptides were presented at the surface alone, and in combinatorial functionalization with the oligo(ethylene glycol)‐based non‐cell adhesive additive. The bisurea‐RGD additive was cell‐adhesive in all conditions, whereas the endothelial cell‐specific bisurea‐REDV showed limited bioactive properties in all chemical nano‐environments. Also, aspecific functionality was observed for a bisurea‐SDF1α peptide. These results emphasize that special care should be taken in changing the chemical nano‐environment with peptide functionalization. © 2019 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1725–1735

Surface and electronic properties of rutile TiO2 thin films coated with PbO2

Binary films of semiconductors have lots of potential applications in material science. Initially, these films were based on In2O3 but, because of its high coast, alternative materials to replace it have been intensely sought after. In this sense, TiO2 and PbO2 are both n-type degenerated semiconductors, which can be good alternatives due to its easy preparation and low cost. Its unique characteristics justify investigating the properties of films composed of both materials. Structural and electronic surface properties of thin films with crystallographic planes (0 0 1), (0 1 0), (1 0 1), and (1 1 0) of TiO2 coated with PbO2 (TiO2/PbO2), both in rutile form, have been investigated in this study. Pure TiO2 and PbO2 bulk and TiO2 thin films have also been studied for comparison purposes. Periodic quantum mechanics DFT calculations have been performed using B3LYP hybrid density functional and taking into account long-range interactions. In both bulks, the energy near the top of the valence band comes mainly from the O 2p orbitals. In the PbO2 the states in the lower energy region of the conducting band are basically composed of Pb 6s and 6p orbitals, while in TiO2 those states come mainly from the Ti 3d orbitals. The relative stability of the TiO2 thin films (surfaces) follows the sequence (1 1 0) > (0 1 0) > (1 0 1) > (0 0 1), but changes substantially in the TiO2/PbO2 binary thin films increasing as (0 1 0) > (1 0 1) > (0 0 1) > (1 1 0). Band gap energies of the four studied pure TiO2 thin films are practically the same as the bulk. However, there is a remarkable decrease in the band gap energies of binary films compared to pure TiO2 films. The decrease in the bottom of the conduction band is due to the contribution of Pb 6s and 6p orbitals at energies below the bottom of the conduction band of the pure TiO2 films.

Influence of physico-mechanical properties of elastomeric material for different cell growth

The tunable mechanical and physical properties of polydimethylsiloxane (PDMS) are commonly utilized for studying cellular dynamics. However, the inherent hydrophobic nature of PDMS limits its application as a cell culture film. Various surface modification techniques render PDMS films hydrophilic, altering their surface chemistry, elasticity, roughness and the cell attachment of anchorage-dependent cell types to the films. The surface properties of thin films lead to the alteration of the biomechano-physical properties of cells, so they can be used as a mechanical signature for the viability testing of different types of cell, such as normal and cancerous ones. In this study, 3T3 fibroblast and HaCaT keratinocyte cells were grown on different pristine and oxidized PDMS compositions by varying their base-to-curing-agent ratios (w/w). The enhanced wettability favors the cell spreading and growth rate of both 3T3 and HaCaT cells, and it varies with the film’s surface chemistry and elasticity. This study focuses on the importance of understanding how various surface modification methods, like oxygen plasma and piranha treatment, can impact cell–cell and cell–substrate interaction for different cell types, thereby assisting in the preparation of various PDMS-based biomedical devices.

Synthesis, Characterization, and Properties of Poly(aryl)phosphinoboranes Formed via Iron‐Catalyzed Dehydropolymerization

The dehydropolymerization of the primary phosphine–boranes, RPH2•BH3 (1a–f) (R = 3,4‐(OCH2O)C6H3 (a), Ph (b), p‐(CF3O)C6H4 (c), 3,5‐(CF3)2C6H3 (d), 2,4,6‐(CH3)3C6H2 (e), 2,4,6‐tBu3C6H2 (f)) is explored using the precatalyst [CpFe(CO)2OTf] (I) (OTf = OS(O)2CF3), based on the earth abundant element Fe. Formation of polyphosphinoboranes [RPH‐BH2]n (2a–e) is confirmed by multinuclear NMR spectroscopy, but no conversion of 1f to 2f is detected. Analysis by electrospray ionization mass spectrometry confirms the presence of the anticipated polymer repeat units for 2a–e. Gel permeation chromatography (GPC) confirms the polymeric nature of 2a–e and indicates number‐average molecular weights (Mn) of 12 000–209 000 Da and polydispersity indices between 1.14 and 2.17. By contrast, thermal dehydropolymerization of 1a–e in the absence of added precatalyst leads to formation of oligomeric material. Interestingly, polyphosphinoboranes 2c and 2d display GPC behavior typical of polyelectrolytes, with a hydrodynamic radius dependent on concentration. The thermal transition behavior, thermal stability, and surface properties of thin films are also studied.

Inverse Gas Chromatography with Film Cell Unit: An Attractive Alternative Method to Characterize Surface Properties of Thin Films.

Inverse gas chromatography (IGC) is widely used for the characterization of surfaces. The present work describes a novel IGC tool, the recently developed film cell module, which measures monolithic thin solid film surface properties, whereas only samples in powder or fiber state or polymer-coated supports can be studied by classic IGC. The surface energy of four different solid supports was measured using both classic IGC with columns packed with samples in the powder state, and IGC with the new film cell module or the sessile drop technique, using samples in the film state. The total surface energy and its dispersive and specific components were measured for glass, polyethylene, polyamide and polytetrafluoroethylene. Similar results were obtained for the four materials using the three different techniques. The main conclusion is that the new film cell module for IGC is an attractive alternative to the sessile drop technique as it gives very accurate and reproducible results for surface energy components, with significant savings in time and the possible control of sample humidity and temperature. This film cell module for IGC extends the application field of IGC to any thin solid film and can be used to study the effect of any surface treatment on surface energy.

English

SiO2 thin layers in thicknesses (1, 5, 10, 18 nm) on TiO2 thin layer in thickness 79 nm deposited by reactive RF sputtering technique. The deposited films were heat treated at temperatures (200, 400, 500, 600°C). The surface properties of thin films by atomic force microscopy (AFM), surface chemical composition by X-ray photoelectron spectroscopy (XPS) and self-cleaning effect in bi layers, were studied. In addition, enhanced hydrophilicity property in the films under the effect of annealed temperature and persistence without UV light illumination were evaluated.   Key words: Nanolayers, X-ray photoelectron spectroscopy (XPS), hydrophilicity, annealed temperature.

Electro-Optic Modulation Induced Enhancement in Photocatalytic Activity of N-Doped TiO2 Thin Films

In the presence of ultraviolet light, TiO2 photocatalyst finds a lot of applications in degradation of organic and inorganic particles present in environment as well as in water. TiO2 nanoparticles can not be utilized effectively in presence of solar light since solar radiation has very little contribution in UV region. The photoresponse of TiO2 can be shifted to the visible region by nitrogen doping. In the nitrogen-doped TiO2 lattice, the oxygen vacancies are formed below the conduction band in the form of donor energy level. These vacancies increase with increasing nitrogen concentration in TiO2, which results in an increase in the trapping rate. This leads to enhancement of photocatalytic activity of nitrogen-doped TiO2 film. Nitrogen doping results in the creation of defects in nitrogen-doped TiO2, which in other way leads to a modification of the work function of thin films. The observed changes in work function of these films, measured using scanning Kelvin probe microscopy, indicates the shifting of Fermi level with the introduction of defects. The study of work function as well as surface properties of thin films helps in better understanding of the photo activity of nitrogen-doped TiO2 film.

Surface properties of thin films based on the mixtures of chitosan and silk fibroin

Thin films by solvent evaporation from mixture of chitosan and silk fibroin were prepared. The interactions between components in the blend were studied by FTIR spectroscopy. The surface properties of chitosan/silk fibroin blended films were investigated using the technique of Atomic Force Microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films and chitosan/silk fibroin films were made and surface free energy was calculated. The surface of thin films based on the blends of chitosan and silk fibroin was modified by UV-irradiation with the wavelength λ=254nm.It was found that chitosan/silk fibroin blend surface is enriched in high surface energy component i.e. silk fibroin. The contact angle and the surface free energy were altered by UV-irradiation for both chitosan and chitosan/silk fibroin films.The surface roughness of chitosan, silk fibroin and chitosan/silk fibroin blended films was altered by UV-irradiation. UV-irradiation caused the decrease of surface roughness of chitosan films, silk fibroin films and films made of the mixture of chitosan and silk fibroin.

Effect of metallic interfacial layers on the properties of diamond-like carbon thin films

Diamond like carbon (DLC) thin films with metallic interfacial layers of aluminum and nickel-chromium (Al and Ni-Cr) were grown using a low cost hybrid technique involving a resistive heating thermal evaporator and radio frequency plasma enhanced chemical vapor deposition techniques. Stress, hardness, elastic modulus, bonding, phase, and electrical conductivity of these films were investigated. Introduction of interfacial Al and Ni-Cr layers in DLC led to drastic improvement of its conductivity along with a significant reduction in residual stress but with some reduction of hardness and the elastic modulus. The structural and surface properties of thin films were studied using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques.

Development of amorphous carbon protective coatings on poly(vinyl)chloride

The great versatility of polymers has promoted their application in a series of ordinary situations. The development of specific devices from polymers, however, requires modifications to fit specific stipulations. In this work the surface properties of thin films grown onto polyvinylchloride (PVC) were investigated. Hydrogenated amorphous carbon films were deposited onto commercial PVC plates from acetylene and argon plasmas excited by radiofrequency (13.56 MHz, 70 W) power. The proportion of acetylene in the gas feed was varied against that of argon, keeping the total pressure constant at 2.5 Pa. Deposition time was 1800 s. Film elemental composition was analyzed by X-ray photoelectron spectroscopy, XPS. Water contact angle measurements were performed using the sessile drop technique. The root mean squared roughness was derived from 50 × 50 µm 2 surface topographic images, acquired by scanning probe microscopy. Nanoindentation and pin-on-disk techniques were employed on the determination of film hardness and sliding wear, respectively. Oxidation resistance was obtained through the etching rate of the samples in oxygen radiofrequency (1.3 Pa, 50 W) plasmas. From XPS analysis it was detected oxygen and nitrogen contamination in all the samples. It was also found that sp 3/sp 2 ratio depends on the proportion of argon in the plasma. At lower argon concentrations, hardness, wear and oxidation resistances were all improved with respect to the uncoated PVC. In such conditions, the surface wettability is low indicating a moderate receptivity to water. This combination of properties, ascribed to a balance between the ion bombardment and deposition processes, is suitable for materials exposed to rigorous weathering conditions.

Surface activity of perfluoropolyalkylether N,N-diphenylamide (PFPEA)

A functional derivative of perfluoropolyalkylether, perfluoropolyalkylether N,N-diphenylamide (PFPEA) was synthesized and characterized by FT-IR, 1H and 19F NMR, and the thermo stability was determined by TG analysis. The surface activity of PFPEA was characterized by the determination of surface tension of organic solvents and the adsorption behavior on the surfaces of solids such as Fe, Al, Cu plates. PFPEA reduced the surface tension of organic solvents greatly such as benzene, toluene, hexane, and cyclohexane. PFPEA was adsorbed on surfaces of solids to form molecular thin films through the end groups. Surface properties of thin films of PFPEA formed by adsorption in organic solutions were characterized using contact angle measurements and X-ray Photoelectron Spectrum (XPS) analysis. The anti-wear performances of adsorbed thin films of PFPEA were determined on a four-ball tribo-tester under the lubrication of liquid lubricants. Films preadsorbed on the substrate surfaces could improve the anti-wear properties of liquid lubricants.

Tailoring Surface Properties of ArF Resists with Functionally Graded Materials (FGM)

Our recent research effort has been focused on new top coating-free 193nm immersion resists with regard to leaching of the resist components and lithographic performance. We have examined methacrylate-based resins that control the surface properties of ArF resists thin films by surface segregation behavior. For a better understanding of the surface properties of thin films, we have prepared the six resins (Resin 1-6) that have three types fluorine containing monomers, a new monomer (Monomer A), Monomer B and Monomer C, respectively. We blended the base polymer (Resin 0) with Resin (1-6), respectively. We evaluated contact angles, surface properties and lithographic performances of the polymer blend resists. The static and receding contact angles of the resist that contains Resin (1-6) are greater than that of the base polymer (Resin 0) resist. The chemical composition of the surface of blend polymers was investigated with x-ray photoelectron spectroscopy (XPS) and TOF-SIMS with gradient shaving preparations. It is confirmed that there is significant segregation of the fluorine containing resins to the surface of the blend films. We analyzed Quantitative Structure-Property Relationships (QSPR) between the surface properties and the chemical composition of the surface of polymer blend resists. The addition of 10 wt% of the polymer (Resin 1-6) to the base polymer (Resin 0) did not influence the lithographic performance. Consequently, the surface properties of resist thin films can be tailored by the appropriate choice of fluorine containing polymer blends.

Characteristics of Thin Film of Nano-Hybrid Synthesized from Acrylic Resin and Colloidal Silca-Silane Sol

Organic-inorganic hybrid blends were prepared in variation with the ratio of sol solution to urethaneacrylic resin. Such sol solutions were synthesized from colloidal silica (CS)/ methyltrimethoxysilane(MTMS)/vinyltrimethoxysilane(VTMS) by sol-gel reaction through two step reactions. Thin films of organic-inorganic hybrid blends were prepared using spin coater on the glass and aluminum sheets. In order to understand surface properties of thin films, contact angle and roughness were measured. Surface contact angle and roughness of thin films increased as the amount of sol solution increased. Thermal dissociation temperature of thin films was observed using TGA. Thin films were stable until 270 oC. Thermal dissociation temperature of thin films improved with increasing sol solution. In order to observe insulation property of thin films, electrical resistance measurements were performed. Surface and volume resistance of thin films increased as the amount of sol solution increased.

Polymer thin film photodegradation and photochemical crosslinking: FT-IR imaging, evanescent waveguide spectroscopy, and QCM investigations

Photodegradation and photocrosslinking of benzophenone blended polystyrene (PS) thin films were investigated primarily using Fourier transform infrared (FT-IR) imaging, evanescent waveguide spectroscopy (WS), and quartz crystal microbalance (QCM) methods. The main objective is to observe the changes (spectral and chemical) indicative of these competitive processes in an ultrathin polymer film. This also serves as a model study in the application of combined spectroscopic, optical, and acoustic methods towards understanding crosslinking and degradation phenomena within the same time frame of observation. To induce photocrosslinking, 1,12-dodecanediylbis(oxy-4,1-phenylene)] [bis[phenylmethanone] (2BP12), a small molecule with two benzophenone groups, was blended with PS in solution, spincast onto glass and silicon substrates, and irradiated with ultraviolet light. Photodegradation and benzophenone-mediated crosslinking were observed both directly via functional group spectroscopies and indirectly via their effects on thin film surface properties and morphologies. Atomic force microscopy (AFM) and QCM were used to elucidate local morphology change and mass-uptake kinetics in the presence of O 2 in air, respectively. All results correlated well with the two photoprocesses occurring simultaneously and competitively on these films with the refractive index, thickness, and mass change differing with the presence of 2BP12. Crosslinking was observed to cause an increase in thickness while photodegradation gave a decrease. Both processes resulted in an increase in the refractive index and mass. While various methods have separately identified these observations, this is the first instance that the in situ chemical, optical, and structural dimensionality of the photodegradation and photocrosslinking phenomena in a thin polymer film is correlated within the same time frame of observation.

Correlation between the Susceptibility to Breakdown and Surface Properties of Thin Films on Titanium Alloys in Physiological Fluids

AbstractCorrelation between the susceptibility to breakdown and surface properties of thin films on implant titanium alloys Ti-5Al-4V and Ti-6Al-4Fe in Ringer 1 and Ringer 2 solutions of different pH values (6.98, 4.35, 2.5) which simulate the conditions that can appear at the longterm (13,000 hours) contact between implant and tissues were studied in this paper. The passive films are very stable up to +1.8 V; Ti-6Al-4Fe alloy presents pitting attack at a pitting initiation potential of +3.5 V in Ringer 1 solution and at +3.9 V in Ringer 2 solution. The pitting protection potential is about +1.75 V in both solutions; this is a very noble potential. Impedance spectra were modeled with one time constant equivalent electrical circuit, typically for a compact oxide film, for all materials, in all tested solutions. The fitting parameters indicate a long-term stability.