Ion Beam Treatment Research Articles

On the Formation of Nanostructured Carbon Layers on the Surface of Organic Polymers under the Action of a High-Power Ion Beam

The effect of nanosecond high-power ion beam treatment on layers of organic polymers: chlorinated polyvinyl chloride, polyvinyl chloride, polyvinyl chloride + polyvinylidene chloride, vinyproz (vinyl chloride and methyl methacrylate copolymer), polyvinyl acetate, and polyvinylidene fluoride, containing a catalytic additive of inorganic and organic iron compounds, is investigated. The formation of carbon nanofibers with a diameter of 30–150 nm and a length of up to 10 μm on the surface of chlorine-containing polymers and their compositions under exposure to a high-power ion beam is observed. The formation of carbon nanofibers on the surface of other polymers under study after exposure to a high-power ion beam is not observed. A possible mechanism of the effect of the nature of the polymer on the formation of nanostructured carbon on the surfaces of the studied polymers under the action of a high-power ion beam is discussed.

Experimental and theoretical study of electronic structure of disordered MWCNTs

Experimental study of electronic structure of the initial multi-walled carbon nanotubes (MWCNTs) as well as the exposed to annealing and irradiation N-MWCNTs, was carried out by XPS and NEXAFS methods. Based on the obtained photoelectron valence band spectra and C K-edge absorption spectra, a theoretical description of the density of electronic states (DOS) near the Fermi level was proposed to explain the dependence of the DOS and the band gap on temperature, concentration of doping atoms and various atomic configurations formed in a system during synthesis, subsequent ion-beam and heat treatment of MWCNTs.

Adhesion Enhancement of Polymer Surfaces by Ion Beam Treatment: A Critical Review

Polymers are widely used in different types of industries ranging from microelectronics, medical to space applications. However, polymer materials are seldom used in their pristine state and are in need of selective surface treatment to induce a specific response which is a challenging and complex task. Adhesion enhancement of polymers is one of the major requirements that can be achieved with ion beam technology at low cost. Surface enhancement involves keeping the bulk properties of materials unchanged and modifying only the surface properties to achieve optimum results.<br/> In this review, we illustrate the use of ion beam technology to modify the surface properties of polymers for potential biomedical and microelectronics applications. This review focuses on effects on the adhesion characteristics for different polymer materials of various optimizable parameters such as type of ion used, ion energy regime (low to medium to high) and the ion fluence range.

Direct-write crosslinking in vacuum-deposited small-molecule films using focussed ion and electron beams

Recent advances in helium ion microscopy (HIM) have enabled the use of fine-focused He+ beams to image and shape materials at the nanoscale. In addition to traditional ion milling, the beam can also be used to induce reactions, such as cross-linking, in films of organic molecules. Here, we compare the use of focused ion and electron beams to fabricate spatially-defined cross-linked features in nanometre-thick films of tetracene. Ion and electron beam treatments were performed using the focussed energetic beams in a HIM and a scanning electron microscope, respectively. The patterned samples were analysed by optical microscopy, HIM, atomic force microscopy and nanoindentation. For samples fabricated using both energetic beams, the total deposited particle dose could be used to modify the optical properties, thickness and hardness of the dosed regions. X-ray photoelectron spectroscopy revealed that the dosed regions exhibited a higher sp3 content, consistent with crosslinking; rinsing in solvent showed that the patterned regions were insoluble and could be isolated by removing the unmodified film through dissolution. These molecular nanopatterns demonstrate the promise for ultrahigh resolution chemical lithography, and for fabrication of nanocomponents with tailored physical properties.

Enhanced nanofiltration performance of graphene-based membranes on wrinkled polymer supports

In this study, nanofiltration performance of an ultrathin graphene oxide (GO) membrane was significantly improved by optimizing surface morphology of polycarbonate (PC) support via ion beam treatment. Ion beam can precisely control the dimensions of the wrinkled structure by adjusting exposure time. The wrinkle formation can be attributed to increased degree of polymer cross-linking and heat generation by penetrating Ar+ ions that result in a stiff skin layer. Upon filtration testing, water flux of the GO membrane with 20 nm thickness was enhanced by 6.4 times with wrinkled PC support. The root mean square (RMS) of the height was 0.83 nm for flat PC and 11.5 nm for wrinkled PC. A high rejection rate (greater than 90%) was also observed with dye molecules of sub-nanometer size. The influence of support morphology on the water flux was found to be especially significant when the thickness of the GO membrane was below 10 nm, which enhances the water flux from 4.21 L m−2 h−1 bar−1 at an RMS of 0.827 nm–26.9 L m−2 h−1 bar−1 at an RMS of 11.5 nm. These results indicate that the support morphology is a critical parameter that determines the performance of ultrathin graphene-based membranes.

Titanium Alloy Surface Complex Modification

Results are provided for a study of the effect of mechanical and ion-beam treatment on titanium alloys surface relief parameters. The possibility is demonstrated of changing component surface roughness over a wide range after comprehensive surface treatment including successive mechanical treatment and irradiation with powerful ion beams in order to improve adhesion properties that expands the range for application of titanium alloys, in particular in medicine. Surface modification and its treatment is a problem for titanium alloys since in view of physical properties titanium alloys exhibit very poor tribological properties and low adhesive strength.

Anchoring strength of indium tin oxide electrode used as liquid crystal alignment layer

To reduce the manufacturing cost of liquid crystal (LC) panels, we examine the potential of an ion-beam-treated indium tin oxide (ITO) film as an LC alignment layer as well as a transparent electrode. In this study, thus, an ITO film in an LC panel is developed to serve as an LC alignment layer as well as an electrode. To determine if they can be utilized for liquid crystal display (LCD) applications, we investigate the anchoring strength of ITO alignment layers according to ion beam conditions through the roll pattern in electroconvection of LCs. In the optimized ion beam condition of our experiment, the azimuthal surface anchoring strength of the ITO alignment layer is approximately 3.1 × 10−6 N/m, which corresponds to that of polyvinyl alcohol (PVA) and is ten times higher than that of rubbed ITO alignment layers. To further enhance the anchoring strength of the ITO film by the synergistic effect of alignment methods (rubbing + ion beam treatment), we perform ion beam treatment after rubbing on the ITO film, after which the azimuthal surface anchoring strength of the ITO alignment layer is approximately 1.7 × 10−5 N/m, which is four times higher than that of rubbed PVA, thus achieving an appropriate value for LCD applications. As a result of the electro-optical characteristics of twisted nematic LC cells with rubbed and ion-beam-treated ITO alignment layers, we obtained good dark and bright states as verified by the voltage vs. transmittance curves.

The effect of low-energy Ar+ irradiation on the surface of monocrystalline α-Al2O3 (0001)

Single crystals α-Al2O3 (0001) were exposed to the energetic Ar+-ions for two periods of 4 min with kinetic energy of 2 keV and 4 min of 5 keV at an incident angle of 45°. The samples were studied by X-ray photoemission spectroscopy (XPS) before and after Ar+-ion beam exposure. The average values of the bandgap energy before and after Ar+-ion beam treatment were measured to be (7.8 ± 0.2) eV and (6.3 ± 0.2) eV, respectively. The dynamic change in the XPS spectra of the valence band (VB) region before and after Ar+-ion beam treatment were explained using the theoretical calculation of the density of state (DOS) and the molecular orbital (MO) theory. This change is attributed to the transformation of α-phase to γ-Al2O3 phase at the surface. The surface morphology of the samples before and after Ar+-ion bombardment was also examined using scanning electron microscopy (SEM). Creation of circular well-shaped nanoholes with diameters in the range of (20–550) nm was observed at the surface after exposure to 2 keV Ar+-ions. Whereas, a series of irregular nanovoids were observed on the surface of the sample which was exposed to 5 keV Ar+-ions.

Effect of proton and ion beam treatment on cyclic olefin copolymer parts prepared via injection molding

The aim of this study is to analyze the effect of proton and ion beam treatment on injection molded plastic parts. We employed cyclic olefin copolymers (COCs) as a resin for the manufacturing. A light guide panel was designed and fabricated via injection molding. The size and fluence of ions were changed for the analysis. The physical and chemical properties of the samples irradiated with proton and nitrogen ion beams were investigated through UV–Vis spectroscopy, FT-IR, differential scanning calorimetry (DSC), nanoindentation, residual stress, and electrical analyses. The penetration behavior of ion beams was modeled numerically, and the injection molding process was simulated. The finding showed that the irradiation of proton and nitrogen ion beams led to a change in the chemical structure and energy level of the samples. We anticipate that this study could provide a meaningful strategic way to engineer a polymeric part for broader applications using proton and ion beams.

Влияние ионно-лучевой обработки в процессе ВЧ магнетронного распыления на свойства плeнок ZnO

The effect of ion-beam treatment, alternating with the magnetron sputtering process, on the properties zinc oxide of thin films is considered. Ion-beam treatment causes a decrease in the growth rate, the size of the coherent scattering regions and resistivity. The stoichiometric index, the band gap and the refractive index increase. The transparency of the films in the area of weak absorption does not change.

A study of structural and spectral properties of ion-beam modified polyethylene terephthalate membrane

In this study, we investigated a modification of the structure of polyethylene terephthalate (PET) membrane exposed to 100 keV N5+ ions with fluences varying from 1014 to 1016 ions/cm2. The changes in the properties of the ion-beam modified samples of PET membrane were analyzed by Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–Vis) and dielectric spectroscopies. FTIR spectra showed a change in the intensity of the typical bands after the irradiation of the polymers. The results of the optical measurements showed that the increase in the ion irradiation fluence induced a decrease in the transmittance of the PET membrane. The estimated value of the energy band gap decreased with the increase of the fluence. A significant decrease of the energy band gap was observed for the ion beam fluence of 1016 ions/cm2. The dielectric measurements performed in a wide frequency band in the range from 20 Hz to 10 MHz and temperature range from 120 K to 400 K revealed that ion beam treatment with a fluence of 1016 ions/cm2 changed the characteristic temperature dependence of the dielectric loss tanδ (T).

Aluminum Ion Beam Treatment of Zirconium Ceramics

The paper presents the radiation and thermal treatment of zirconium ceramics with high-energy Al ion beams generated at an accelerating voltage of 1.5 kV, which modifies the structure and electrophysical properties of zirconium ceramics. Compact powder and ceramic samples are used for the radiation and thermal treatment performed at 1123–1173 K. The surface treatment of compact powders leads to the increase in the grain size, whereas the surface of ceramic samples turns black and electrically conductive in depth. This is because the change in the oxygen stoichiometry of zirconium ceramics. Air annealing of treated ceramics returns the sample to the initial state. The phase composition, microhardness and density of ceramic samples display no changes after the radiation and thermal treatment. Under the experimental conditions, the diffusion of aluminum ions in the surface layer is not observed. It is found that the ion beam treatment leads to the decrease in aluminum-containing impurity in the surface layers of zirconium ceramics.

Ion-beam chemical-thermal treatment of aluminum

The paper reports on a study of A7 aluminum alloy exposed to thermochemical treatment with a nitrogen ion beam produced in a source based on a non-self-sustained hollow-cathode glow discharge. The material was placed in a plasma generated by a source with a thermionic and hollow cathodes and simultaneously treated by accelerated ions and neutrals of the working gas. No negative bias was used, allowing dielectric surface treatment with no cathode spots. The ion charge at the treated surface was compensated by electrons from the plasma. The specimen temperature was maintained independent of the ion beam energy and current using an active screen whose temperature was controlled by applying a negative bias. The method provides the formation of a nitride film on the Al surface.

Analysis of in-mold coating process and ion beam irradiation

We explored in-mold coating process that can conduct injection molding and coating in the cavity. First, rubber particles were embedded into polymethylmethacrylate (PMMA), and injection molding was carried out. After then, coating was performed on the surface of the injection molded part, and nitrogen ion beam was implanted. The in-mold coating process was also simulated numerically. Effect of the ion beam treatment was analyzed, and rheological and morphological characteristics of the samples were investigated. Distribution of the residual stress in the sample was measured and computed numerically. It revealed that both the coating process and the ion beam irradiation significantly enhanced the surface properties of the injection molded parts, such as surface hardness and scratch resistance.

Flexible W-doped In2O3 films grown on ion beam treated polyethylene terephthalate substrate using roll to roll sputtering

We investigated the effect of Ar ion beam treatment on a polyethylene terephthalate (PET) substrate to grow high-quality flexible W-doped In2O3 (IWO) films using a lab-scale roll-to-roll (RTR) sputtering system at room temperature. The electrical, optical, morphological, and mechanical properties of the flexible IWO films sputtered on the ion beam-treated PET and untreated PET substrates were comprehensively compared. In particular, the mechanical flexibility of the RTR sputtered IWO films was investigated in detail using custom-made bending, rolling, and twisting testers. Based on water contact angle and X-ray photoelectron spectroscopy (XPS) measurements, we found that the surface energy change and decreased C-O and C˭O groups on the PET substrate led to flexible IWO films with improved adhesion and better mechanical properties. In addition, we compared repeating cooling and heating cyclic stability of the flexible thin film heaters with RTR sputtered IWO films before and after ion beam treatment to show feasibility of ion beam treating process during RTR sputtering.

Dual-Layer Coated Drug-Eluting Stents with Improved Degradation Morphology and Controlled Drug Release

Drug-eluting stents (DESs) are used to treat cardiovascular diseases such as atherosclerosis. The anti-proliferative drug released from the DES suppress the proliferation of smooth muscle cells and reduced in-stent restenosis. However, a burst release of the drug in the early stages and degradation morphology of the polymer coating represent major disadvantages, which might increase the incidence of in-stent restenosis and/or thrombosis under in vivo clinical studies. To solve these problems, in this study, a double-layer coating system composed of poly(lactide) (PLLA) bottom layer and poly(lactide-co-glycolide) (PLGA) top layer are used for the fabrication of DES. PLLA bottom layer was firstly coated on the metal surface followed by oxygen ion beam treatment. It was found that increasing the ion beam exposure time, increased the roughness of PLLA surface with a nanoscale pocket (or hole)-like structure. The top layer coating represented a mixture of PLGA and paclitaxel (PTX) with 5, 10, and 20% PTX contents. The coating was performed through ultrasonic spray technique, and the morphology showed not only a smooth and uniform surface but also no irregularities were observed at zero day. The drug release and degradation morphology for single-layer (PLGA/PTX) and double-layer (PLLA/PLGA/PTX) coatings were compared. The drug release from the double-layer stainless steel (SS) group showed a slower and controlled drug release for all PTX content samples as compared to single-layer SS group. Moreover, the degradation morphology of double-layer SS group presented a smoother and uniform surface after 12 weeks of degradation under physiological conditions. Therefore, an oxygen ion beam technique with double-layer coating system could effectively control the drug release, i.e., prevent initial burst drug release, and improve the degradation morphology of biodegradable polymer-based DESs.

Fabrication of Hydrophobic Surface by Controlling Micro/Nano Structures Using Ion Beam Method

The fabrication of a controlled surface is of great interest because it can be applied to various engineering facilities due to the various properties of the surface, such as self-cleaning, anti-bio-fouling, anti-icing, anti-corrosion, and anti-sticking. Controlled surfaces with micro/nano structures were fabricated using an ion beam focused onto a polypropylene (PP) surface with a fluoridation process. We developed a facile method of fabricating hydrophobic surfaces through ion beam treatment with argon and oxygen ions. The fabrication of low surface energy materials can replace the current expensive and complex manufacturing process. The contact angles (CAs) of the sample surface were 106° and 108° degrees using argon and oxygen ions, respectively. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy were used to determine the chemical composition of the surface. The morphology change of the surfaces was observed by scanning electron microscopy (SEM). The change of the surface morphology using the ion beam was shown to be very effective and provide enhanced optical properties. It is therefore expected that the prepared surface with wear and corrosion resistance might have a considerable potential in large scale industrial applications.

IP-Dip photoresist surfaces for photonic applications prepared by laser lithography and studied by AFM

To summarize, this paper explores new application of laser lithography based on direct laser writing and focused ion beam technique, to pattern optically smooth surface of IP-Dip polymer for photonic devices and on-chip photonic applications. The surface image in nanometer scale was obtained by atomic force microscope. The surface analysis was made in XEI commercial software by use of areal roughness parameter Sq. We have found that with this technique we can obtain much better results than the Raileigh criterion for smoothness. Finally, we found optimal process parameters of laser lithography for optically smooth surfaces and demonstrated the effect of ion beam treatment on surface quality.

Plasma Ion Implantation of Silk Biomaterials Enabling Direct Covalent Immobilization of Bioactive Agents for Enhanced Cellular Responses.

Silk fibroin isolated from Bombyx mori cocoons is a promising material for a range of biomedical applications, but it has no inherent cell-interactive domains, necessitating functionalization with bioactive molecules. Here we demonstrate significantly enhanced cell interactions with silk fibroin biomaterials in the absence of biofunctionalization following surface modification using plasma immersion ion implantation (PIII). Further, PIII treated silk fibroin biomaterials supported direct covalent immobilization of proteins on the material surface in the absence of chemical cross-linkers. Surface analysis after nitrogen plasma and PIII treatment at 20 kV revealed that the silk macromolecules are significantly fragmented, and at the higher fluences of implanted ions, surface carbonization was observed to depths corresponding to that of the ion penetration. Consistent with the activity of radicals created in the treated surface layer, oxidation was observed on contact with atmospheric oxygen and the PIII treated surfaces were capable of direct covalent immobilization of bioactive macromolecules. Changes in thickness, amide and nitrile groups, refractive index, and extinction coefficient in the wavelength range 400-1000 nm as a function of ion fluence are presented. Reactions responsible for the restructuring of the silk surface under ion beam treatment that facilitate covalent binding of proteins and a significant improvement in cell interactions on the modified surface are proposed.

Changes in the Elastic-Stress State and Phase Composition of TiAlN Coatings under Thermal Cycling

By means of XRD structural analysis and transmission electron microscopy, changes in the microstructure of TiAlN coatings deposited via magnetron sputtering after thermal cycling procedures (140 cycles) have been investigated. The thermal cycling procedure consisted in heating to 900°C and further cooling to room temperature. The sputtered target represented a 60 Ti–40 Al (at %) alloy. The coatings were deposited either onto a quenched austenitic steel substrate or onto the same substrate after preliminary Ti ion beam treatment. It is established that a layer of Ti and Al oxides with microcrystalline structure is formed on the coating surface in the course of thermal cycling. Compressive macrostresses under the oxide layer in the TiAlN coating decrease, whereas the heterogeneity of the Al distribution in the Ti1–хAl х N phase exhibits an increase. The preliminary Ti ion beam treatment of the substrate leads to an improvement of the coating thermal stability, to a decrease in the oxide layer thickness for the same number of thermal cycles, and to a wider Al concentration range in the Ti1–хAl х N phase of the surface coating layers.