Mechanism Of Surface Modification Research Articles

Polyethylene and related hydrocarbon polymers (“plastics”) are not biodegradable

Research on the biodegradation of polyethylene (PE), polystyrene (PS) and related polymers has become popular and the number of publications on this topic is rapidly increasing. However, there is no convincing evidence that the frequently claimed biodegradability of these so-called “plastics” really exists. Rather, a diffuse definition of the term “biodegradability” has led to the publication of reports showing either marginal weight losses of hydrocarbon polymers by the action of isolated bacterial strains or mechanical disintegration and polymer surface modification in case of hydrocarbon polymer-consuming insect larvae. Most of the data can be alternatively explained by the utilization of polymer impurities/additives, by the utilization of low molecular weight oligomers, and/or by physical fragmentation and subsequent loss of small fragments. Evidence for a (partial) biotic and/or abiotic oxidation of the amorphous polymer fraction and of surface-exposed hydrocarbon side chains is not sufficient to claim that PE is biodegradable. To the best of my knowledge, no report has been so far published in which substantial biodegradation and mineralization of PE or related (long chain length) hydrocarbon polymers to carbon dioxide has been convincingly demonstrated by the determination of the fate of carbon atoms in isotope-labeled polymers. It is disappointing that publications with a critical view on biodegradation of hydrocarbon polymers are not cited in most of these reports. The possibility should be considered that the rapidly expanding research field of hydrocarbon polymer biodegradation is chasing rainbows.

Investigation of surface finish and fatigue life of laser Powder Bed fused Ti-6Al-4V

In this fact-pacing world of technological advancement, the rise of additive manufacturing (AM) has found immense applications of metallic alloys such as Ti6Al4V to manufacture key components in automotive, aerospace and healthcare sectors. However, fatigue characteristics of such additively manufactured metal alloys is noticeably weak, and as such requires post-processing. In this study, AM Ti6Al4V manufactured by Laser Powder Bed Fusion (L-PBF) was treated by Hydrodynamic Cavitation Abrasive Finishing (HCAF) and Laser Cavitation Peening (LCP) to observe the improvement in surface roughness as well as fatigue performance. Our investigations revealed a substantial improvement in surface quality post-HCAF processing. Notably, the surface roughness of AM Ti6Al4V specimens showed a significant reduction of about 91.2 %, post surface treatment. However, Laser Cavitation Peening (LCP) treated sample demonstrates a significantly enhanced fatigue strength of 393 ± 22 MPa at 107, which was 1.75 times better than that of as-built one, i.e., 224 ± 16 MPa. This difference can be attributed to the distinct surface modification mechanisms of each technique. LCP, utilizing laser-induced shock waves, likely induces large compressive residual stresses, leading to better fatigue resistance.

Modified Titanium Implants Satisfy the Demands of Diabetic Osseointegration via Sequential Regulation of Macrophages and Mesenchymal Stem Cells.

The application of titanium (Ti) implants for patients with diabetes mellitus (DM) is still facing a significant challenge due to obstacles such as hyperglycemia, reactive oxygen species (ROS), and chronic inflammation, which hinders osseointegration. To address this issue, a Ti implant with dual functions of regulating polarization of macrophages and facilitating osseointergration is developed via hydrothermal reaction and hydrogel coating. The reactive oxygen species (ROS) and glucose (Glu) responsive hydrogel coating can locally deliver adenosine (ADO) in the early stage of implantation. The controlled release of ADO regulated the phenotype of macrophages, restored oxidative balance, and enhanced mitochondrial function during the early stages of implantation. Subsequently, strontium (Sr) ions will be released to promote osteogenic differentiation and proliferation of mesenchymal stem cells (MSCs), as the hydrogel coating degraded. It eventually leads to bone reconstruction during the late stages, aligning with the biological cascade of bone healing. The modified Ti implants showed effective osteogenesis for bone defects in DM patients, shedding light on the design and biological mechanisms of surface modification. This research offers promising potential for improving the treatment of bone-related complications in diabetic patients.

Mitigating the deceptive effects of smooth surfaces: subtle surface modifications can eliminate maladaptive drinking attempts by bats

AbstractThe amount of artificial smooth surfaces in the environment increases continuously with urbanization on a global scale. There is growing evidence that smooth surfaces such as windows, solar panels and other objects can serve as sensory traps for many animal species. Artificial smooth surfaces can function as acoustic mirrors, disrupting echolocation of bats and consequently causing maladaptive behaviours such as drinking from and colliding with these surfaces. Therefore, investigating opportunities to mitigate the effects of artificial smooth surfaces is important from a conservation viewpoint. Here, we conducted a field experiment with bats, an ensonification experiment in the laboratory, and a computer simulation, in order to study the effect of mechanical surface modification on the acoustic characteristics of smooth surfaces. In the field experiment, we presented a horizontal smooth plate alone or with strings (diameters between 0.25–2.5 mm) and the behaviour of bats around the plate was video recorded. Bats significantly decreased the frequency of drinking events with increasing diameter of the strings. We also found an indication that a crossed pattern of the strings on the plate may be more effective than a parallel arrangement. The results of the ensonification experiment and the mathematical modelling revealed that a subtle modification of the smooth surfaces with long, linear thin objects can effectively modify the acoustic characteristics of smooth surfaces in general and thereby potentially change the behaviour of bats. Further investigations from sensory, behavioural and ecological viewpoints are proposed to better understand the impact of smooth surfaces on bats and the mitigation solutions that are needed. This research underscores the significance of exploring innovative approaches to minimize the negative impacts of urbanization on wildlife, highlighting the potential of practical interventions to promote coexistence between anthropogenic environments and threatened species.

Differential surface modification mechanism of chalcopyrite and pyrite by Thiobacillus ferrooxidans and its response to bioflotation

Mineral processing encounters the challenge of separating chalcopyrite and pyrite, with the conventional high alkali process characterized by issues such as large dosages of reagents, complex procedures, and environmental pollution. This study addresses this challenge by isolating and enriching Thiobacillus ferrooxidans (T·f) from acidic mine drainage, employing it as a biosurfactant. The modification mechanism of T·f was thoroughly analyzed. Fe dissolution through biological oxidation formed a passivation layer (jarosite [KFe3(SO4)2(OH)6], elemental sulfur (S0), and metal sulfides (Cu/Fe–S) on the surface of minerals. Metal oxides, hydroxides, and sulfates were detected on the surface of two minerals, but the difference was that elemental sulfur (S0) and copper sulfide (Cu-S) were detected on the surface of chalcopyrite. elucidating the fundamental reason for the significant difference in surface hydrophobicity between chalcopyrite and pyrite. T·f has been successfully used as a biosurfactant to achieve copper-sulfur separation.

Laser Shock Peening: Fundamentals and Mechanisms of Metallic Material Wear Resistance Improvement.

With the rapid development of the advanced manufacturing industry, equipment requirements are becoming increasingly stringent. Since metallic materials often present failure problems resulting from wear due to extreme service conditions, researchers have developed various methods to improve their properties. Laser shock peening (LSP) is a highly efficacious mechanical surface modification technique utilized to enhance the microstructure of the near-surface layer of metallic materials, which improves mechanical properties such as wear resistance and solves failure problems. In this work, we summarize the fundamental principles of LSP and laser-induced plasma shock waves, along with the development of this technique. In addition, exemplary cases of LSP treatment used for wear resistance improvement in metallic materials of various nature, including conventional metallic materials, laser additively manufactured parts, and laser cladding coatings, are outlined in detail. We further discuss the mechanism by which the microhardness enhancement, grain refinement, and beneficial residual stress are imparted to metallic materials by using LSP treatment, resulting in a significant improvement in wear resistance. This work serves as an important reference for researchers to further explore the fundamentals and the metallic material wear resistance enhancement mechanism of LSP.

Fenton oxidation modification mechanism of pyrite and its response to Cu-S flotation separation: Experiment, DFT, XPS and ToF-SIMS studies

Surface modification mechanism of pyrite via Fenton reagent and its response to Cu-S flotation separation was examined in a low-alkaline system using micro-flotation experiments, contact angle, UV–vis, SEM, DFT, XPS, and ToF-SIMS analysis. Flotation and contact angle results proved Fenton reagent could effectively separate chalcopyrite from pyrite at pH = 8. The adsorption rate of hydroxyl radical (•OH) on pyrite surface reached 83.28 %. The SEM results show that flocculent hydrophilic substances were produced on the surface of pyrite after oxidation. Further, DFT calculations results on the basis of interaction between •OH and the pyrite (100) surface showed that strong chemical bonds among the O atom of •OH and the Fe and S atoms on the pyrite surface formed. DMOL3 model and XPS analysis confirmed the oxidation products were primarily found in the form of Fe(OH)3, Fe2O3, Fe(OH)2, Fe2(SO4)3, FeOOH and SO42-, which considerably rejected the adsorption of dixanthogen. The peak intensities of FeOH+ and SO4- both increased to 2312 and 2506. The intensity of C2H5+ ion decreased from 4204 to 1009. Thus, the Fenton reagent triggered the formation of multitude hydrophilic species, and offered a simple access to the pyrite depression. This activity provided a viable option for the Cu-S flotation separation.

Cellular experimental study and mechanism of surface modification of 3D printed titanium materials to modulate the sealing and antimicrobial properties of oral implants

Investigating the role of surface-modified 3D printed titanium implants in modulating oral soft tissue closure and antimicrobial properties. Eighteen 6-month-old healthy adult New Zealand White rabbits were selected as experimental animals, the left and right mandibular teeth of each experimental animal were randomly divided into two groups, and the bilateral first premolar teeth were extracted after general anesthesia, and one implant was implanted into each of the magnesium/zinc ionized surface-treated group (experimental group) and the surface-untreated group (control group), with a total of 36 implants, i.e., 18 implants for the experimental group and 18 implants for the control group. Bilateral mandibular samples from both groups were removed after 2 and 4 weeks of implantation to investigate the attachment and spreading of human gingival fibroblasts (HGFs) on the surface of the samples, their proliferative and migratory behaviors as well as the expression levels of related gene proteins (CoL-1 and TGF-β), and HE staining of the soft tissues of the samples and inflammatory cell counts. After 2 and 4 weeks of implantation, the experimental group’s HGFs adhesion and spreading were significantly better than that of the control group, the migration and proliferation of HGFs were significantly greater than that of the control group ( p < .05), and the expression of CoL-1 and TGF-β genes was significantly higher than that of the control group ( p < .05), and the inflammatory cell count was significantly smaller than that of the control group ( p < .05). Surface modification by magnesium and zinc ions enhances the sealing performance and antimicrobial performance of 3D printed titanium implants in oral soft tissues, with significant effects.

The effect of pretreatment and surface modification of porous transport layer (PTL) on the performance of proton exchange membrane water electrolyzer

The surface properties of the anode porous transport layer (PTL) significantly impact the performance of a proton exchange membrane water electrolyzer (PEMWE). The pretreatment (ultrasonic cleaning and acid etching) of a pristine titanium (Ti) felt before it is used as the anode PTL and the surface structural modification of a PTL are two critical methods to improve the performance of an electrolyzer. However, the mechanisms for the pretreatment and surface modification need to be clarified. In this paper, five electrolyzers with five different-fabricated-ways anode PTLs are tested and compared based on I–V curves, EIS curves, and physical characterization techniques. X-ray photoelectron spectroscopy (XPS) results show that the ultrasonic cleaning pretreatment of PTL can improve hydrophilicity by increasing the amount of hydroxyl. In addition, EIS results indicate the significant charge transfer resistance of electrolyzer taking pristine titanium felt as PTL. Adopting the carbon paper as a microporous layer (MPL) or treated titanium felt with acid etching can eliminate or reduce the charge transfer resistance of the electrolyzer. Finally, the mechanism of surface pretreatment and modification of PTL are disclosed to cast light on the improvement of PTLs in further study.

Fibroblast Viability Through Mechanical and Chemical Root Surface Modifications in Periodontal Healing: An In Vitro Comparative Study.

The wound-healing process incorporates a spectrum of periodontal therapeutic interventions that strive to restore the health and function of the periodontium. Fibroblasts play pivotal roles in tissue repair and regeneration. Extensive research has been focused on mechanical and chemical root surface modifications to enhance fibroblast adhesion, which is crucial for successful wound healing. This study aimed to assess the combined efficacy of mechanical and chemical root surface modifications in promoting fibroblast viability to root surfaces affected by periodontitis in comparison to chemical modifications alone. Root samples were collected from healthy individuals and those with advanced periodontitis. The specimens were prepared, and the experimental groups were categorized based on the type of surface modification with mechanical and/or chemical materials, including hyaluronic acid (HA), ethylenediaminetetraacetic acid(EDTA), enamel matrix derivatives (EMD), and EDTA/EMD. Fibroblasts were seeded onto previously treated root samples. Cell adhesion was assessed using a viability assay. Fibroblast viability was significantly higher on root surfaces treated with chemical agents than on those treated with mechanical and chemical modifications. Long-duration EDTA and short-duration EMD treatments were significantly effective in enhancing cell viability. EDTA/EMD surface treatments resulted in significantly higher cell viability in all groups compared to the periodontitis root surfaces. EDTA, EMD, and their combined application can potentially ameliorate periodontitis-induced surface structural impairments. Mechanical surface debridement can significantly affect the effectiveness of EDTA and EMD root conditioning agents.

Mechanism of surface modification on monocrystalline silicon during diamond polishing at nanometric scale

The demand for polished silicon wafers has increased significantly in recent years to cater to the development of the semiconductor industry. For example, polished silicon wafer has direct applications in integrated circuits, radio frequency amplifiers, micro-processors, micro-electromechanical systems, etc. To carry out mechanical polishing, lapping, grinding, or single-point diamond turning of silicon, diamond abrasives were extensively used before the implementation of chemo-mechanical polishing. During the diamond-based polishing, a few problems have already been identified, such as the formation of an amorphous phase, heat-affected zones, low material removal, etc. Some research work has also reported that nano-structured abrasives lead to a thin layer of the amorphous phase and a better material removal rate. In the same direction, a molecular dynamics simulation is carried out in this paper to investigate the mechanism of material removal from monocrystalline silicon during the diamond-abrasive-based polishing process. The present work is mainly focused on the dynamics of material removal phenomena near the abrasive particles at the nanometric scale by considering stress, lattice, cohesive energy, etc. This reveals that a higher value of indentation force results in surface buckling, which creates a zone of both compressive and tensile stresses, which increases the coordination number and forms β-silicon just ahead of the abrasive particle. This mechanism happens by developing a β-silicon phase on the surface with a thickness beyond a certain value of indentation force on the zone of compression. Buckling on this phase happens due to stress localisation in compression, as the flow stress of this phase is less than that of diamond cubic lattices. To avoid the mechanism of surface buckling and process silicon material on the surface, the indentation force needs to be maintained below a critical value. In the present case, it was found that the indentation force of less than or equal to 190 nN for the abrasive size of ϕ8 nm does the material removal by surface processing only without surface buckling. It was also found that surface processing helps to reduce the depth of the amorphous layer significantly without compromising the material removal rate or the generation of a wavy surface. Thus, the present mechanism will help in the polishing of silicon with minimum defects and reduce processing time for the final stage of polishing towards manufacturing ultra-smooth and planer surfaces.

Evaluation Of Silano Adhesive Efficiency in Improvement of Shear Binding Strength of Synthetic Teeth to Thermo-Plastic Denture Material

Background: One of the most serious problems concerning denture performance is the possibility of prosthetic tooth displacement due to increased chewing efficiency. The nature of the mechanical bonding between thermoplastic denture base materials and acrylic teeth has aggravated the problem of tooth debonding. The study aiming to examine the strength of shear bond between prosthetic teeth and thermoplastic base material utilizing silano (silane coupling agent) and mechanical surface modifications (Alumin-ablasting, T. Shape hole) of tooth ridge lap pre and post (100 hrs.) of accelerated ageing conditions. Materials and method: The surface treatments of (120) maxillary central incisors were chosen and grouped into 6 groups of 20 samples each. Each group split into before and after (100hrs.) according to ageing (n=10). Measurement of shear bonding strength applied by a universal testing equipment with 0.5mm/min crosshead speed. Statistical analyses were done using one-way ANOVA test and Tukey’s (HSD) test. Results: Statistics showed high significant variation in average binding force after several surface manipulations in contrast to the control group at (P < 0.000). Regarding surface manipulations, dual treatment of “Alumina-blasting + silano “revealed significant elevation of binding strength in compare to “alumina-blasting” alone (P < 0.001). Similarly, with “T. hole + silano” yielded in greatly increased bonding strength compared to using “T. hole” alone (P < 0.001). a great reduction in bonding strength value was indicated along all treated groups after ageing process (P < 0.000) except the group treated with “T. Hole + silano” show non-significant variations at (p = 0.112). Conclusion: combination treatment (chemo-mechanically) with “T. Hole + silano” improve shear binding strength and not effected with ageing process.

Atmospheric pressure plasma application on the adhesive bonding improvement of CFRP via surface configuration comparison

AbstractCarbon fiber reinforced polymer (CFRP) has a wide range of applications in aerospace, automobile, marine, and other industries, due to its remarkable mechanical properties and lightweight. It can enhance the performance of the structural components and has been presented to be a good alternative over conventional materials. Adhesive bonding has been widely employed, and research studies on the surface modification of CFRP have been conducted to improve the load resistance of adhesive bonding, of which atmospheric pressure (AP) plasma is the most preferred method. However, there is still a lack of study on the effectiveness and strategies of AP plasma surface modification. To gain more insight, possible sources that would have influence on the adhesive bonding were analyzed by preparation of different surface configurations of CFRP. It is confirmed that AP plasma can increase the surface polarity and wettability of the carbon fiber surface. It can contribute to the removal of surface contamination element as well. Although the surface morphology and surface roughness before and after the AP plasma treatment does not show noticeable changes, the single‐lap shear strength of the contaminated samples can be effectively improved. This study validates that AP plasma is effective on surface contamination removal and bonding quality improvement, which provides a potential alternative for the adhesive bonding improvement and surface modification of carbon fiber.Highlights Surface polarity and wettability increase of CFRP by AP plasma. Surface contamination removal and bonding quality improvement by AP plasma. AP plasma provides a potential alternative method for adhesive bonding pre‐treatment. AP plasma surface modification mechanism analysis via surface characterization.

Preparation and performance of surface-modified adsorbent materials from discarded traditional chinese medicine residues

Waste Chinese medicine residue was used as a raw material and pretreated with sodium hydroxide and hydrogen peroxide, followed by chemical modification with a silane to prepare an inexpensive and highly efficient hydrophobic biobased adsorbent material. The adsorbent was characterized with SEM, TGA and FTIR analyses. The adsorption capacities and wettabilities of the Chinese medicine residue were analyzed before and after surface modification to explore the adsorption performance and surface modification mechanism of the material. The results showed that the modified Chinese medicine residue was rough and uniformly modified, with successfully grafted hydrophobic functional groups, and it had added adsorption sites, exhibiting good hydrophobicities and oleophilicities. The contact angles between the modified materials and water reached 127°, and the modified Chinese medicine residue had an adsorption capacity of 51.7 mg g−1 for organic compounds, which was a significant improvement over the original waste Chinese medicine residue. The adsorption kinetics were best described with the pseudosecond-order kinetic model, which exhibited a higher linear correlation and was closer to the measured adsorption equilibrium value based on chemical adsorption. This study demonstrated a novel use of waste Chinese medicine residues for environmental remediation.

Structure Design, Surface Modification, and Application of CNT Microwave‐Absorbing Composites

AbstractElectromagnetic (EM) contamination has now become a non‐negligible problem. To solve the EM contamination problem, it is imperative to develop high‐efficiency absorption materials with thin thickness, light weight, strong absorption properties, and broad absorption bands. Carbon nanotubes (CNTs) have a special helical structure and chirality, which will lead to special EM effects and therefore can absorb EM microwaves through magnetic polarization attenuation such as hysteresis loss, domain wall resonance, and aftereffect loss. Moreover, they have the characteristics of light weight, good compatibility, wide absorption frequency band, and high electrical loss angle tangent. In this paper, the different structures of CNT microwave‐absorbing composites are reviewed and the effects of the composite structures on the microwave‐absorbing properties are systematically discussed. The methods and mechanisms of surface modification of CNT absorber composites and the effects of modification on the absorber properties are summarized in detail. The progress of two specific CNT microwave‐absorbing composites, namely flexible and high‐temperature microwave‐absorbing composites, is briefly described. The shortcomings and challenges in the application of CNT microwave‐absorbing composites are described and future research directions for CNT microwave‐absorbing composites are explored.

Synthesis, microstructure, and electrophysical properties of surface-modified polyantimonic acid nanoparticles

This work has considered the modern ideas on the mechanism of surface modification for used nanodispersed inorganic modifiers with an acidic surface, which significantly affect the hydrate and transport properties of polymeric proton-conducting electrolytes. Authors have proposed an alternative approach consisting of the synthesis of new composite nanoscale systems characterized by high ionic conductivity and developed a method for obtaining composite materials with "core-shell" structure based on an inorganic proton conductor (polyantimonic acid) modified with silicon oxide. The surface morphology of the synthesized nanoparticles has been studied by transmission electron microscopy, and their sizes have been determined. The data on frequency dependence of the electrical impedance are presented and the behavior of the active and reactive components of the impedance and conductivity in the frequency range from 100 Hz to 1 MHz has been analyzed. An equivalent electrical circuit simulating the impedance dispersion for obtained composites with "core-shell" structure based on PAA and SiO2 has been proposed.

Evaluation of the effect of mechanical alteration of enamel surface on shear bond strength of self-adhering composites utilizing different adhesive modalities

Abstract Background: Self-adhering flowable composite (SAC), which has currently been launched, is said to be postoperatively responsive and less technique-reactive than previous materials. Clinical demands for bonding to undamaged, modified, or prepared enamel surfaces—which may attach differently with adhesive resins—often accompany restorative demands. Very little information was available for SAC. Aim: This study was carried out to determine the impact of mechanical enamel surface modification on shear strength properties in various bonding procedures. Materials and Methods: The three groups of prepared enamel surfaces (group A, n = 60), unprepared enamel surfaces (group B, n = 60), and prepared enamel surfaces plus etch-and-rinse (group C, n = 20), which served as the control group, were randomly assigned to the 140 constructed samples. Subgroups A1, B1 (nanohybrid composite + self-etch), A2, B2 (self-adhering composite), and A3, B3 (self-adhering composite + self-etch) were created from groups A and B, respectively (n = 40). Composite resin cylinders with the unique bonding protocols of each group were created using Teflon ring molds. Testing for shear bond strength was done, and information was examined. Results: The control group C was found to have the highest mean shear bond strength (29.77 MPa), whereas subgroup B2 had the lowest mean shear bond strength (8.4 MPa). For all adhesive techniques, shear bond strength values for prepared enamel surfaces were considerably greater than those for unprepared enamel surfaces (P < 0.01). The following were the mean shear bond strength values: C > A1 > A3 > A2 > B1 > B3 > B2. Conclusions: Shear bond tensile properties on prepared enamel surfaces were higher than those of unprepared enamel surfaces. Higher shear bond strength values of the self-adhering composite in prepared and unprepared enamel surfaces were produced by using a self-etch agent first.

A Dual-Antioxidative Coating on Transmucosal Component of Implant to Repair Connective Tissue Barrier for Treatment of Peri-Implantitis.

Since the microgap between implant and surrounding connective tissue creates the pass for pathogen invasion, sustained pathological stimuli can accelerate macrophage-mediated inflammation, therefore affecting peri-implant tissue regeneration and aggravate peri-implantitis. As the transmucosal component of implant, the abutment therefore needs to be biofunctionalized to repair the gingival barrier. Here, a mussel-bioinspired implant abutment coating containing tannic acid (TA), cerium and minocycline (TA-Ce-Mino) is reported. TA provides pyrogallol and catechol groups to promote cell adherence. Besides, Ce3+ /Ce4+ conversion exhibits enzyme-mimetic activity to remove reactive oxygen species while generating O2 , therefore promoting anti-inflammatory M2 macrophage polarization to help create a regenerative environment. Minocycline isinvolved on the TA surface to create local drug storage for responsiveantibiosis. Moreover, the underlying therapeutic mechanism is revealed whereby the coating exhibits exogenous antioxidation from the inherent properties of Ce and TA and endogenous antioxidation through mitochondrial homeostasis maintenance and antioxidases promotion. In addition, it stimulates integrin to activate PI3K/Akt and RhoA/ROCK pathways to enhance VEGF-mediated angiogenesis and tissue regeneration. Combining the antibiosis and multidimensional orchestration, TA-Ce-Mino repairs soft tissue barriers and effector cell differentiation, thereby isolating the immune microenvironment from pathogen invasion. Consequently, this study provides critical insight into the design and biological mechanism of abutment surface modification to prevent peri-implantitis.

Study on the Photosensitivity of a Composite Based on Lead Selenide and Selenite

This paper discusses the technology of formation of photoresistive structures based on a composite of lead selenide and lead selenite. The structures are formed by the oxidation of n-PbSe polycrystalline films. Film The surface modification mechanism of n-PbSe films in the oxidation process is analyzed by a Zeiss Merlin scanning electron microscope (SEM). The new results of the authors on the oxidation mechanism of n-PbSe, together with their earlier publications, are summarized and their consistency with each other is examined. A theoretical model (hypothesis) of the potential profile of a photosensitive heterojunction is proposed, in which each crystal of the n-PbSe film during oxidation in an atmosphere of dry air forms a continuous shell on the p-PbSeO3 surface. The hypothesis on the structural model of the photosensitive heterojunction proposed by other authors, which is based on the oxidation mechanism proposed by us, is practically confirmed in this study.

Surface modification of polymers by ion irradiation: Reactivity principle and application

Modifying polymers through ion irradiation is an advantageous method for controlling polymer with desirable properties. The surface modification mechanism and application of polymers by ion irradiation are under exploration. This review systematically analyzes the recent progress on the surface modification of common polymers by ion irradiation. The fundamentals of irradiation principle and chemical interaction, the irradiation effect of microstructure, macroproperties, and related characterization methods are introduced for the innovated applications. The effect of ion beam conditions (heavy or light ions, high or low energy/fluences) on different polymers is systematically analyzed for the different irradiation effect to achieve surface modification, in which the coupling mechanism between nuclear and electronic stopping power is provided. To meet the requirement of various application, the relationship between micro representation and macro performance is thoroughly discussed and established combined with the concerns regarding ion irradiation induced regulation mechanism. For the practical/potential application prospects, the frontier research on membrane separation, electrical, and biomedical applications are discussed. This review offers valuable insights into the modified microstructures versus the necessary surface properties of polymer by ion irradiation.