Material Surface Research Articles

Micron silicon-oxide-carbon coated with TiOx(OH)y layer as better performance anode for lithium-ion batteries

Micron-silicon based material is a promising anode material for high performance lithium batteries due to its ultra-high specific capacity. However, the volume expansion exceeds 300 % during charging and discharging, resulting in the collapse of the electrode structure and a rapid decline in electrochemical performance. Coating the surface of silicon-based materials with flexible ionic conductors is an effective method to maintain their high capacity and suppress swelling. Here, to further improve the electrochemical performance of silicon-based materials, we have deposited a titanate-type ionic conductor layer on a micron-sized silicon-carbon oxide (SiOX-C) material to synthesize the SiOX-C@TiOx(OH)y material. The TiOx(OH)y layer not only exhibits the elastic properties of a superpolymer to mitigate swelling strain, but also has a fast capacitance effect to improve its rate performance. In addition, the interfacial charge transport of SiOX-C@TiOx(OH)y is enhanced due to the structural diversity of the TiOx(OH)y layer. For the above mechanisms, the SiOX-C@TiOx(OH)y has a specific capacity of 278.3 mAh g−1 under high current of 3500 mA g−1. Meanwhile, the SiOX-C@TiOx(OH)y with the capacity retention of 67 % is achieved at 2000 mA g−1 after 100 cycles.

Carrier-density-determined Magnetoresistance in Semimetal SrIrO3

Abstract SrIrO3, a Dirac material with a strong spin-orbit coupling (SOC), is a platform for studying topological properties in strongly correlated systems, where its band structure can be modulated by multiple factors, such as crystal symmetry, elements doping, oxygen vacancies, magnetic field, and temperature. Here, we discover that the engineered carrier density plays a critical role on the magnetoelectric transport properties of the topological semimetal SrIrO3. The decrease of carrier density subdues the weak localization (WL) and the associated negative magnetoresistance, while enhancing the SOC-induced weak anti-localization (WAL). Notably, the sample with the lowest carrier density exhibited high-field positive magnetoresistance, suggesting the presence of a Dirac cone. In addition, the anisotropic magnetoresistance (AMR) indicates the anisotropy of the electronic structure near the Fermi level. The engineering of carrier density provides a general strategy to control the Fermi surface and electronic structure in topological materials.

Optimization and characterization of boric acid powder mixed electrical discharge machining of Ti-6Al-4V ELI

The powder mixed electrical discharge machining (PMEDM) process is used for enhancing machining efficiency and improving the surface characteristics of the workpiece compared to normal EDM. The present study evaluates the effect of boric acid powder mixed in deionized water in PMEDM of Ti-6Al-4V ELI (extra low interstitial). The PMEDM process is assessed by evaluating material removal rate (MRR) and surface roughness (SR) at varying powder concentration (PC), current and pulse duration ( Ton). Boric acid PMEDM exhibits advantageous for both MRR and SR, where MRR increases and SR decreases with an increase in PC. To simultaneously achieve higher MRR and lower SR, the grey-fuzzy logic method is employed. Initially, the raw input data is normalized into grey numbers and a single index is obtained through grey relational analysis. Subsequently, triangular membership functions are assigned to the inputs and output. Fuzzy logic rules are then formulated, and grey fuzzy relational grade (GFRG) is calculated for each condition. The optimum condition (GFRG = 0.787) is attained at 15 g/l PC, 9 A current and 106 µs Ton, resulting in a 63% improvement compared to the initial condition. At the optimum condition, MRR increased by 145% and SR decreased by 29% compared to the initial condition. The effect of boric acid in PMEDM can be visualized through the formation of smooth surfaces, exhibiting reduced SR, smaller and shallower craters, and fewer debris and globules. Additionally, the boric acid PMEDM experiments resulted in the formation of a hard TiB phase on Ti-6Al-4V, thus improving its wear resistance.

Research on Solid-State Linear Transformer Driver Power Source Driving Atmospheric Pressure Plasma Jet Treatment of Epoxy Resin

The Solid-State Linear Transformer Driver (SSLTD) is a nanosecond pulse power source characterized by its fast rise time and adjustable output waveform. It can generate uniform and stable atmospheric plasma jets, which is suitable for material surface modification. In this study, a 15-stage SSLTD was designed and assembled, which can produce a stable nanosecond pulse voltage up to 15 times the amplitude of the charging voltage at high frequencies, with a rise time of approximately 10 ns. This device can be used to generate stable atmospheric pressure Ar plasma jets with an electron density in the range of 1015~1016 cm−3 and gas temperatures close to room temperature. After the modification treatment by the plasma jets, the content of the C=O groups on the surface of the epoxy resin significantly increased in the wavelength range of 1720~1740 cm−1, and its flashover resistance was noticeably enhanced. The optimal comprehensive modification effect was achieved at a charging voltage of 600 V, pulse width of 50 ns, and pulse frequency in the range of 800~1000 Hz.

A New Process of Chemical Plating Ni-P Electromagnetic Induction Heating Activation on the Surface of Aluminium Alloy Base Material

Nowadays, there are many surface treatment methods for aluminium alloys; the most commonly used of these is the chemical dip galvanizing process, which is complicated due to its use of large quantities of corrosive drugs. In order to simplify the process, this paper proposes a new electromagnetic induction heating activation method instead of the zinc dipping process. The method works as follows: The substrate is first degreased and then activated. The activation process starts by soaking the degreased substrate in an activation solution, taking it out after ten minutes, and placing it into an induction heating unit. The activation solution is sprayed onto the surface of the substrate while heating, using the energy generated by high temperatures to complete the activation reaction. The surface of the activated substrate forms a nanoscale film of nickel, which is finally utilised as a catalytic centre for ENP (an advanced surface treatment process that deposits a very uniform layer). The optimisation of important parameters of the non-destructive activation process was determined using the L9 Taguchi method. The main parameters ranged from 0.15 L/min to 0.25 L/min for spray rate, 200 °C to 400 °C for heat treatment temperature, and 1:4, 1:5, and 1:6 for Ni2+ and H2PO4− ion concentration ratios. The above data were derived from a single variable and were analysed using Minitab 20 software. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy spectrometry (EDS), and ultrasonic experiments were used to characterize and analyse the surface morphology, composition, and bond strength of the coatings. The results show that the nanoscale nickel particles can completely cover the surface of the substrate, forming a layer of nano-film. After activation and ultrasonic cleaning for 30 s at an ultrasonic frequency of 40 KHz and a power of 80 W, the surface nano-film was not destroyed, which proves that it had a high bonding strength. After the application of the plating, the plated surface had a compact microstructure, and the continuity was good. Therefore, compared with the currently commonly used zinc dipping process, this process has the advantages of being a low-cost, simple operation, and non-destructive and environmentally friendly activation process for the substrate.

Optimizing High-Performance Predictive Modeling of the Medium-Speed WEDM Processing of Inconel 718

The purpose of this research was to create a predictive model for a medium-speed wire electrical discharge machine (WEDM) utilizing an artificial neural network (ANN). Medium-speed WEDM experiments were developed based on the I-optimal mixture design for machining, the Inconel 718 superalloy. During the experiment, the input parameters were the spark ontime, spark offtime, wire feed, and current, with the material removal rate (MRR) and surface roughness (Ra) selected as performance indicators. The ANN model was trained on experimental data and built using a feed-forward backpropagation neural network with a (4-8-2) structure and the Bayesian regularization (BR) learning approach. The model correctly predicted the relationship between the medium-speed WEDM’s primary process parameters and machining performance. An integrated ANN model and the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) were used to determine the ideal parameters for the MRR and Ra, resulting in a set of Pareto-optimal solutions. The confirmation experiment revealed that the mean prediction error between the experimental and ideal solutions had a maximum error percentage of 1% for the MRR and 2% for the Ra, which are within acceptable ranges. This showed that the best process–parameter combinations were better for the MRR and Ra.

Laser Desorption of Explosives from the Surface of Different Real-World Materials Studied Using C2Cl6-Dopant-Assisted Ion Mobility Spectrometry.

A highly efficient and sensitive ion mobility spectrometry (IMS) system with laser desorption sampling was applied for rapid explosive detection using different surface materials. This portable IMS detector, powered by a battery, offers mobility and is suitable for use in the field or combat zones. The laser desorption (LD) sampling of common explosives (Trinitrotoluene-TNT; Dinitrotoluenes-DNTs; Hexogene-RDX; pentaerythritol tetranitrate-PETN; plastic explosives-Compound 4 (C-4) and Semtex) on a wide range of common surface materials, such as metal, ceramic, plastic, glass, drywall, paper, wood, and textiles, was studied. Successful detection was achieved on nearly all surfaces except flammable materials (paper, wood, and textiles). The limit of detection (LOD) was determined for each explosive and specific surface, demonstrating an impressive LOD of 7 ng/mm2 for TNT. RDX, C-4, PETN, and Semtex achieved LOD values of 15 ng/mm2, while DNTs showed an LOD of approximately 50 ng/mm2.

Ni-Doped Pr0.7Ba0.3MnO3-δ Cathodes for Enhancing Electrolysis of CO2 in Solid Oxide Electrolytic Cells.

Solid Oxide Electrolysis Cells (SOECs) can electro-reduce carbon dioxide to carbon monoxide, which not only effectively utilizes greenhouse gases, but also converts excess electrical energy into chemical energy. Perovskite-based oxides with exsolved metal nanoparticles are promising cathode materials for direct electrocatalytic reduction of CO2 through SOECs, and have thus received increasing attention. In this work, we doped Pr0.7Ba0.3MnO3-δ at the B site, and after reduction treatment, metal nanoparticles exsolved and precipitated on the surface of the cathode material, thereby establishing a stable metal-oxide interface structure and significantly improving the electrocatalytic activity of the SOEC cathode materials. Through research, among the Pr0.7Ba0.3Mn1-xNixO3-δ (PBMNx = 0-1) cathode materials, it has been found that the Pr0.7Ba0.3Mn0.9Ni0.1O3-δ (PBMN0.1) electrode material exhibits greater catalytic activity, with a CO yield of 5.36 mL min-1 cm-2 and a Faraday current efficiency of ~99%. After 100 h of long-term testing, the current can still remain stable and there is no significant change in performance. Therefore, the design of this interface has increasing potential for development.

Evaluating the Surface Properties of Prosthodontic Polymer Impression Materials

Surface properties of prosthodontic polymer impression materials, such as hardness, roughness, and accuracy, are crucial for the accurate replication of oral structures in restorative dentistry. To evaluate the surface properties by using different types of polymer impression materials commonly used in dentistry and analyze their surface characteristics. Materials and methods: Forty -five samples of materials were used, including alginate (irreversible hydrocolloid), condensation silicone (putty) and addition silicone (putty), study was conducted at the advanced medical polymer group in the Libyan Polymer Research Center to evaluate the surface properties of prosthodontic polymer impression materials. Three evaluation methods were used: Shore hardness testing, surface roughness testing, and dimensional accuracy measurements. Data analysis included mean, standard deviation, and One-way ANOVA calculations. Alginate has a lower hardness compared to addition silicone (putty) and condensation silicone (putty). The ANOVA test for surface roughness showed no significant differences among the materials, with a p-value of 0.027. For shore hardness, there were no significant differences among the materials, with a p-value of 0.000. The ANOVA test for dimensional accuracy showed no significant differences among the different periods for alginate, condensation silicone (putty) and addition silicone (putty), with p-values of 0.000 respectively. The study concluded that alginate had the lowest hardness and roughness compared to condensation silicone (putty) and addition silicone (putty). There are no significant differences among the material surface properties (Shore hardness and surface roughness) but not in dimensional accuracy among the materials. This information provides valuable insights for dental professionals working with impression material.

Significant enhancment of the accuracy of impurity determination in vacuums using classification one-point laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a highly promising technique for the in-situ, real-time diagnosis of impurity deposits on the inner walls of tokamak devices. The deposited impurity on plasma-facing materials (PFCs) pose a significant risk to the steady-state operation of the tokamak. Under vacuum conditions, an accurate quantitative analysis of the thin co-deposition layers is a technical challenge. In this study, 30 co-deposited layer samples of tungsten (10.0–92.3 a.t.%), molybdenum (2.0–77.8 a.t.%), iron (2.9–12.1 a.t.%) and copper (1.2–18.7 a.t.%) were prepared to simulate the co-deposition layers found on PFCs in Experimental Advanced Superconducting Tokamak (EAST). A variation of the CF-LIBS algorithm, the so-called One Point Calibrated LIBS (OPC-LIBS), was employed to analyze these co-deposited layer samples under conditions of 5 × 10−5 mbar. It was found that the matrix matching degree among the measured samples and the selection of standard samples play a decisive role in the quantitative analysis capability of OPC-LIBS. In actual situations, the composition of the co-deposited impurity layers at different locations in the Tokamak will be quite different. We addressed this challenge by developing the Classified OPC-LIBS (COPC-LIBS) model, an enhanced version of OPC-LIBS with pre-classification to offset matrix effects in LIBS analysis. For tungsten in the co-deposition layers, the root mean square (RMSE) calculated by the CF-LIBS method was 14.7, the OPC-LIBS method was 11.5, and the newly invented COPC-LIBS was reduced to only 5.1. The COPC-LIBS method is a highly efficient technique that can precisely measure the distribution of co-deposited layers on the surface of inner wall materials. The diagnostic data obtained from this method will provide valuable insights into the interaction between plasma and wall materials during the operation of fusion devices.

Lithium-rich manganese-based layered oxide cathode materials for lithium-ion batteries modified by MoS2 coatings with two-dimensional graphene-like structures

Lithium-rich manganese-based layered oxide cathode materials (LRMCs) have some unique advantages such as high theoretical capacity (≥ 250 mAh g−1) and high energy density. Therefore, they are deemed as a kind of cathode material for lithium-ion batteries with an excellent prospect of application. However, the redox of oxygen anion is able to generate irreversible lattice oxygen loss, leading to irreversible loss of capacity, bringing about a sharp drop of working voltage, and seriously restricting the commercialization of LRMCs. In this paper, MoS2 coating with two-dimensional graphene-like structure was coated on the surface of LRMCs materials for improving the cycling stability and rate performance. The MoS2 coating can provide a two-dimensional diffusion channel for the migration of lithium-ions, which facilitates the fast release of lithium-ions during cycling process. The results show that the first discharge capacity, initial Coulomb efficiency and rate performance of LRMCs are improved. When the current density is 1 C, the first discharge specific capacity of LRMCs@MoS2 reaches 227.69 mAh g−1, and the capacity retention ratio is 84.98 % after 100 cycles. When the current density is 5 C, it can still provide a discharge specific capacity of 137.87 mAh g−1, demonstrating excellent electrochemical performance. This study comes up a simple and practical idea to realize the modification of cathode materials for high performance lithium-ion batteries.

A Review of the Development of Titanium-Based and Magnesium-Based Metallic Glasses in the Field of Biomedical Materials.

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young's modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young's modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes.

Electrical and optical properties of g-GaN/Al0.5Ga0.5N 2D/3D heterojunction under surface oxidation via first-principles

In this paper, the structural stability, charge transfer, band structure, density of states, absorption coefficient and reflectivity of g-GaN/Al0.5Ga0.5N heterojunction after surface oxidation are investigated. Our results reveal that formation energy of adsorptive oxidation process is negative and the oxidized surface can be formed spontaneously. The substitutional oxidation process is heat-absorbing and structure is unstable, which is not easy to occur. Band structure show that new energy levels are created due to charge transfer between O atom and heterojunction after surface oxidation. The electronic states of O-p orbitals hybridize with those of Ga-s, Ga-p, and Al-p orbitals, while O-s orbitals affect energy levels at low-energy end. Meanwhile, work function of heterojunction increases after oxidation, weakening electron emission properties of material surface. The results of optical properties illustrate that substitutional oxidation is detrimental to light absorption, while adsorption oxidation slightly enhances light absorption, especially when adsorption oxidation occurs in g-GaN layer, which is competitive for improvement of optical properties. This study can be useful for the removal of surface oxides from g-GaN/AlGaN heterojunction.

Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries.

Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g -1, with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.

FEATURES OF WASHING WATER-SOLUBLE PHOSPHORUS-AMMONIUM SALTS OF FIREPROOF WOOD COATING

The article analyzes fire-resistant materials for wooden building structures and establishes the need to develop reliable methods of researching the process of washing out flame retardants from the surface of the building structure, which are necessary for the creation of new types of fire-resistant materials. Therefore, there is a need to determine the conditions for the formation of a barrier for leaching and to establish a mechanism for inhibiting the transfer of moisture to the material. In this regard, a mathematical model of flame retardant leaching has been developed, when a polymer shell made of organic material is used as a coating, which allows evaluating the effectiveness of the polymer shell based on the amount of flame retardant washed out. According to experimental data and theoretical dependences, the dynamics of release of flame retardants from the fire-resistant layer of the coating, which does not exceed 1.0%, is calculated, and accordingly provides fire protection of wood. The results of determining the loss of mass of the sample during exposure to water indicate an ambiguous effect of the nature of the protection on leaching. In particular, this assumes the availability of data sufficient for qualitatively carrying out the process of inhibiting moisture diffusion and identifying, on its basis, the moment in time when the decline in coating efficiency begins. Experimental studies have confirmed that a sample of fire-resistant wood after exposure to water for 30 days withstood the influence of heat flow. In particular, the loss of wood mass after temperature exposure was less than 6%, and the temperature of flue gases did not exceed 185 ºС. Thus, there are reasons to assert the possibility of targeted regulation of wood fire protection processes through the use of polymer coatings capable of forming a protective layer on the surface of the fire retardant material, which inhibits the rate of flame retardant leaching.

Recent Progress in Terrestrial Biota-Derived Anti-Biofilm Agents for Medical Applications

The terrestrial biota is a rich source of biologically active substances whose anti-biofilm potential is not studied enough. The aim of this review is to outline a variety of terrestrial sources of antimicrobial agents with the ability to inhibit different stages of biofilm development, expecting to give some ideas for their utilization in improved anti-biofilm treatments. It provides an update for the last 5 years on anti-biofilm plant products and derivatives, essential oils, antimicrobial peptides, biosurfactants, etc., that are promising candidates for providing novel alternative approaches to combating multidrug-resistant biofilm-associated infections. Based on the reduction in bacterial adhesion to material and cell surfaces, the anti-adhesion strategy appears interesting for the prevention of bacterial attachment in combating a broad range of mono- and multispecies bacterial biofilms. So far, few studies have been carried out in this direction. Anti-biofilm coatings made by or containing biologically active products from terrestrial biota have scarcely been studied although they are of significant interest for a reduction in infections associated with medical devices. Combination therapy with commercial antibiotics and natural products is accepted now as a promising base for future advances in anti-biofilm treatment. In vivo testing and clinical trials are necessary for clinical application.

Silicon Nanowires via Metal-Assisted Chemical Etching for Energy Storage Applications.

Silicon nanowires (SiNWs) have demonstrated great potential for energy storage due to their exceptional electrical conductivity, large surface area, and wide compositional range. Metal-assisted chemical etching (MACE) is a widely used top-down technique for fabricating silicon micro/nanostructures. SiNWs fabricated by MACE exhibit significant surface areas and diverse surface chemistry. Since the material composition and surface chemistry have a significant impact on the electrochemical energy storage performance, integrating SiNWs with diverse materials like porous carbon, metal oxides/sulfides, and polymers, can establish composites with excellent properties. Hence, it is imperative to meticulously fabricate SiNW-based materials with customizable morphologies and enhanced electrochemical energy-storage performance. This review provides an in-depth study of recent advancements in SiNW-based materials with enhanced performance for energy storage systems, such as supercapacitors (SCs) and lithium-ion batteries (LIBs). It includes a concise overview of the history, MACE synthesis, and characteristics of SiNWs. Further, it also explores the key elements that influence the MACE process of SiNWs and delves into structural engineering. Additionally, we introduce recent advances in SiNW-based materials for the design of high-performance energy-storage devices, namely SCs and LIBs. Finally, we present the crucial future prospects of SiNW-based materials for energy-storage applications.

Improvement of High Temperature Wear Resistance of Laser-Cladding High-Entropy Alloy Coatings: A Review

As a novel type of metal material emerging in recent years, high-entropy alloy boasts properties such as a simplified microstructure, high strength, high hardness and wear resistance. High-entropy alloys can use laser cladding to produce coatings that exhibit excellent metallurgical bonding with the substrate, thereby significantly improvement of the wear resistance of the material surface. In this paper, the research progress on improving the high-temperature wear resistance of high entropy alloy coatings (LC-HEACs) was mainly analyzed based on the effect of some added alloying elements and the presence of hard ceramic phases. Building on this foundation, the study primarily examines the impact of adding elements such as aluminum, titanium, copper, silicon, and molybdenum, along with hard ceramic particles like TiC, WC, and NbC, on the phase structure of coatings, high-temperature mechanisms, and the synergistic interactions between these elements. Additionally, it explores the potential of promising lubricating particles and introduces an innovative, highly efficient additive manufacturing technology known as extreme high-speed laser metal deposition (EHLMD). Finally, this paper summarizes the main difficulties involved in increasing the high-temperature wear resistance of LC-HEACs and some problems worthy of attention in the future development.

Liquid Metal Oxide-Assisted Integration of High-k Dielectrics and Metal Contacts for Two-Dimensional Electronics.

Two-dimensional van der Waals semiconductors are promising for future nanoelectronics. However, integrating high-k gate dielectrics for device applications is challenging as the inert van der Waals material surfaces hinder uniform dielectric growth. Here, we report a liquid metal oxide-assisted approach to integrate ultrathin, high-k HfO2 dielectric on 2D semiconductors with atomically smooth interfaces. Using this approach, we fabricated 2D WS2 top-gated transistors with subthreshold swings down to 74.5 mV/dec, gate leakage current density below 10-6 A/cm2, and negligible hysteresis. We further demonstrate a one-step van der Waals integration of contacts and dielectrics on graphene. This can offer a scalable approach toward integrating entire prefabricated device stack arrays with 2D materials. Our work provides a scalable solution to address the crucial dielectric engineering challenge for 2D semiconductor-based electronics.

Microbiological indicators of the biofilms microparticles of quartz sand and polypropylene after short-term exposure in soil

The purpose of this study was to investigate dynamics of biofilm biomass on microparticles of natural material quartz sand and the artificial material polypropylene (plastisphere) as well as change in biofilm-forming microorganisms’ number under a short-term in situ field study. In this study microparticles of polypropylene and quartz sand ranging in size from 3 to 5 mm were used. The total microbial count and the number of sulfate-reducing bacteria in the biofilm (by traditional culture-based microbiological methods) and the biofilm biomass (by the method with the crystal violet) were investigated. According to the determined microbiological indicators, over time (90 days) on the polypropylene it was observed decreasing of both the number of studied groups of microorganisms and the formation of a microbial biofilm, compared to the quartz sand. Determination of microbiological indicators of the materials surface allows understanding the aspects of their preservation/removal from the environment and requires additional research.