rus
Issue #4/2022
I. A. Filatov, E. A. Davydova, N. N. Shchedrina, A. O. Peltek, V. M. Prokopiev, G. V. Odintsova
Laser Technologies Possibilities for Reducing Biofouling of Metals in the Aquatic Environment
Laser Technologies Possibilities for Reducing Biofouling of Metals in the Aquatic Environment
DOI: 10.22184/1993-7296.FRos.2022.16.4.328.338
The article presents the development of a laser structuring technology of the metals surface for protection against biofouling. This technology involves the processing of the material before placing it in the aquatic environment. Alloys of stainless steel and duralumin were used in the work. The effect of laser structuring on the contact angle and the interaction of laser-structured metal surfaces with microorganisms in water is considered. A positive trend in protection against colonization of microorganisms on the surface of metals after laser treatment was revealed.
The article presents the development of a laser structuring technology of the metals surface for protection against biofouling. This technology involves the processing of the material before placing it in the aquatic environment. Alloys of stainless steel and duralumin were used in the work. The effect of laser structuring on the contact angle and the interaction of laser-structured metal surfaces with microorganisms in water is considered. A positive trend in protection against colonization of microorganisms on the surface of metals after laser treatment was revealed.
Теги: biofouling contact angle laser metal surface microtexturing wetting биообрастание гидрофобность дюралюминий лазер микроструктурирование смачивание сталь
Laser Technologies Possibilities for Reducing Biofouling of Metals in the Aquatic Environment
I. A. Filatov, E. A. Davydova, N. N. Shchedrina,
A. O. Peltek, V. M. Prokopiev, G. V. Odintsova
ITMO University, St. Petersburg, Russia
The article presents the development of a laser structuring technology of the metals surface for protection against biofouling. This technology involves the processing of the material before placing it in the aquatic environment. Alloys of stainless steel and duralumin were used in the work. The effect of laser structuring on the contact angle and the interaction of laser-structured metal surfaces with microorganisms in water is considered. A positive trend in protection against colonization of microorganisms on the surface of metals after laser treatment was revealed.
Keywords: wetting, laser, microtexturing, metal surface, contact angle, biofouling
Received on: 15.04.2022
Accepted on: 04.05.2022
Introduction
Wetting is the physical relationship of any liquid with a solid body represented as the ability to reduce or increase the surface tension of this solid body. Surface tension is a phenomenon when a solid body tends to reduce its excessed surface energy at the interface with the liquid. An increase in the surface tension degree of a solid body causes the liquid to spread, indicating the hydrophilic properties. Reduction in the tension degree, on the contrary, lowers the surface energy and the liquid does not wet the hydrophobic surface.
The metal surface wetting plays an important role in the technological processes [1]. The issue of hydrophobic or hydrophilic coating formation is relevant in many industries and medicine. For example, the hydrophilic surfaces are required to increase the coating adhesion [2], reduce friction [3], and improve the adhesion of biological objects [4–6]. The hydrophobic surfaces are important for development of antibacterial coatings [7], for reducing the surface icing [8], for preventing vessel biofouling [9], as well as metal corrosion [10].
All objects immersed in the sea water and not covered with a protective layer will soon be populated by various microorganisms (algae, bacteria, plankton, crustaceans, mollusks). In nature, this phenomenon is called biofouling, and it has serious consequences for all navy vessels. The microorganisms are settled on the vessel surface and create the raised roughness that leads to the increased fuel consumption of the ship, increased load on the driving units and lowered maneuverability [9, 11]. The friction resistance on some types of marine hulls can be up to 90% of the total value [12]. The greater the vessel resistance, the greater the cost of ship operations, such as increasing the fuel supply, the hull cleaning against microorganisms, etc. According to the analysis, biofouling leads to the increased fuel consumption by 10% compared to the hydraulically smooth condition of the vessel hull [12].
Typically, biofouling of the marine structures is divided into several main stages: primary film formation of the mucous layer of microorganisms (settlement of bacteria, diatoms, blue-green algae, fungi); secondary stage (settlement of macroalgae, shells) and tertiary stage (settlement of mussels, sponges, crustaceans). These are arbitrary sequences that can vary greatly depending on the season and geographic location [13].
The hydrophobic surface development makes it possible to reduce friction resistance and control the biological fouling process [9]. The coatings made of toxic paints, including the resins, heavy metals (lead), arsenic, have an adverse effect on the marine life [11]. Therefore, there is a need to think out new ways for metal processing without any environmental damage.
There are various methods of metal surface treatment to impart hydrophobic or hydrophilic properties due to the amended contact angle. The contact angle can be changed by controlling the chemical composition and surface morphology by the mechanical [14], chemical [14], and thermal [15] methods. Of particular interest is laser processing, due to which it is possible to locally control the contact angle without any consumables. Therefore, it has been decided to explore the capabilities of laser technologies to reduce the metal biofouling in the aquatic environment due to the use of commercially available laser stations.
Methods and materials
The sample structuring was performed under normal conditions in an air atmosphere using a processing unit based on a pulsed ytterbium fiber-optics laser with a power of 50 W and a wavelength of λ = 1.064 μm, generating pulses with a frequency of 50–100 kHz and a duration of 100 ns. AISI 430 (St) stainless steel and AMtsM (Al) duralumin plates were used as the development prototypes. These alloys were selected since they were the most common alloys used for the production of marine hulls and other structural vessel parts. When selecting a laser source, an important factor was that the alloys selected had an absorption peak at the laser source wavelength that makes the sample processing efficient. The surface morphology was studied using a Zeiss Axio Imager A1M optical microscope. The surface morphology and topology were also studied using a Hommel Werke T8000 contact profilometer.
The contact angle was measured using the sessile drop method. The ToupCam digital camera and ToupView software were used for the result processing. Distilled water was used as the test liquid. The drop volume for measurement in the biofouling test was 3 μl. The drop dosing and placement were performed using a Satorius mechanical dispenser with a volume of 0.1–10 µl. After surface placement of the drop, AutoCad software was used to measure the contact angle.
A water specimen was taken from the coastal zone of the Gulf of Finland in Saint-Petersburg as a medium for the samples. This specimen included such microorganisms as cladophora (in Latin: Cladophora), enteromorpha (in Latin: Ulva intestinalis), diatoms (in Latin: Diatomeae), barnacles larvae (in Latin: Cirripedia) [16], Pseudomonas spp., Stenotrophomonas spp, and Rahnella strains [17].
To carry out the experiments to study the contact angle dependence of substrates made of alloys subjected to various laser processing on the time of sample retention in water, we placed the samples in an aquarium with water from the Gulf of Finland. The study kit consisted of unstructured samples and samples obtained immediately after the laser structuring. The experiment concept implied that the surface acquired hydrophobic properties due to the organic compound adsorption from the environment to the oxide surface formed under the laser radiation. In this case, the wetting state changed due to the formation of new functional groups [18]. Therefore, after laser structuring, we decided to hold the samples in air for 3 weeks to deposit organic compounds on their surface. To accelerate the process of transition to the hydrophobic state, the low-temperature annealing in a PM‑10 muffle furnace for 3 hours at a temperature of 100 °C was also used. All samples were placed in an aquarium with water from the Gulf of Finland, the contact angles were measured every week within one month.
To assess the biofouling degree, the biofilm formed on the sample surface was measured using a Leica TCS SP8 confocal microscope. Before this, the samples were formalin-fixed, with the following usage of propidium iodide to stain the nuclei of organisms in water.
Results and discussion
1. Laser Formation of Microstructures on the Metal Surfaces with Various Contact Angles
In our study, we focused on the primary and secondary biofouling stages. Therefore, we studied the behavior of such microorganisms, the size of which varied in the range from 50 microns to 1000 microns, such as cladophora (in Latin: Cladaphora), barnacles (in Latin: Balanus), diatoms (in Latin: Diatomeae), barnacle larvae (in Latin Cirripedia) and other organisms of similar size. We believe that to ensure the least adhesion of these organisms to the surface, the obtained microrelief period should be no more than 100 microns. It is also known that the hydrophobic properties can protect surfaces against biofouling due to the low surface energy at the interface between the solid body and air. It prevents the sticky adhesive of microorganisms from interacting with the material [9]. Fig. 1 shows a schematic representation of metal laser structuring to develop the hydrophobic properties and behavior of a given laser-induced surface in an aqueous environment compared to an untreated one.
When selecting the structuring modes, we took the hydrophobic reliefs of a lotus and a rose as the basis for the resulting geometric structure. They had the so-called columns with dimensions o of 50 μm and 16 μm, respectively, and a height of 10 μm.
The structures with the dimensions of 7 × 7 mm were developed in each sample. The laser beam recording was performed in planes so that the resulting grooves were perpendicular to each other and formed a lattice (Fig. 2). The resulting grooves had a width of 34 µm and a depth of 10–12 µm. Based on the laser beam scanning pitch (M) of 50 µm and 100 µm, the dimensions of the protrusions (columns) were 16 µm and 66 µm, respectively. For each week of contact angle measurements, 5 samples were prepared for one type of treatment and one scanning pitch for individual modes of both metals. Fig. 2 provides photographs of the surface morphology of aluminum and steel obtained using an optical microscope, as well as the profile records of these surfaces.
The contact angles were used to obtain the dependency diagrams of these angles on the sample retention time in water (Fig. 3). On these diagrams, the value given for the first day was the sample contact angle prior to its placement in the aquarium. In some cases, the contact angle was 180 degrees due to the inability to measure the angle, since the drop was not placed on the surface, but remained on the Satorius mechanical dispenser.
During the study of the results obtained for unstructured samples, no explicit dependence is observed. For the specimens which study has begun immediately after the laser structuring process, a slight increase in the angle is observed for all modes after a month in the aquarium.
To obtain the hydrophobic and superhydrophobic structures, we retained our samples after laser structuring in air for 3 weeks to precipitate organics. To speed up this process, other samples after laser structuring were subjected to the low-temperature annealing in a muffle furnace. As a result, we obtained the hydrophobic angles for distilled water prior to the sample placement in the aquarium. The samples exposed to air for 3 weeks after laser structuring demonstrated the higher hydrophobic values for most modes. However, these samples lost their hydrophobicity after exposure to water. We believe that the bond energy of organic compounds with oxides on the metal surface was not high enough, and the organic compounds were washed off with water.
Thus, prior to the sample placement in an aqueous medium for both metals with a scanning pitch of 50 μm (during the treatment for surface hydrophobization), it was possible to obtain hydrophobic angles greater than in the case of processing with a scanning pitch of 100 μm. This was due to the fact that with an increased roughness of the hydrophobic surface within the same material, the hydrophobic properties were also increased, that is, the contact angle was enlarged.
2. Assessment of the Metal Surface Biofouling Degree Before and After Laser Treatment
Fig. 4 shows the results of the biofouling degree for the samples with different treatments. The X-axis indicates the time spent by the samples in water taken from the coastal zone of the Gulf of Finland, and the Y-axis indicates the fluorescent intensity produced by the nuclei of microorganisms. Thus, a qualitative assessment of the fouling degree was based on the fluorescenсу of the nuclei. The results demonstrated the least biofouling in the case of laser structuring and subsequent long-term exposure to air. An analysis of the graphical dependencies led to the conclusion that it was during this treatment (laser structuring and prolonged exposure to air) that the microorganisms did not find these structures convenient for colonization that was related to the superhydrophobic angles.
We link the decrease in the biofouling degree over time during the treatments with the hypothesis that the microorganisms fail to colonize on the surface, since our structures are unfavorable for them both in size and in surface properties preventing their adhesive substance to bind.
Conclusion
Based on the biofouling degree assessment results, it has been concluded that the sample long-term exposure to air after laser structuring is a favorable mode for the metal substrate protection against biofouling, since the biofouling indices have the lowest values. We associate it with the fact that the superhydrophobic angles are obtained for most modes during the laser structuring and air treatment. Thus, in the case of such treatment of both steel and aluminum, imitation of the structure of a lotus and a rose is a possible solution to the problem of protection against biofouling. When comparing the graphical results, we can conclude that a scanning pitch of 50 µm for steel and a scanning pitch of 100 µm for aluminum are optimal for laser structuring and subsequent low-temperature annealing. This conclusion is made based on a comparison of the biofouling degree of unstructured samples and samples obtained immediately after the laser structuring with the samples obtained after laser structuring and low-temperature annealing.
For further study of the results obtained, it is planned to put the system under study in motion during the further experiments so that the samples are not in a stagnant water, as well as to measure the biofouling level by a parametric method, while varying the number of organisms of certain species planted in water.
ABOUT AUTHORS
Filatov Ilya Andreevich, PhD student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-4555-8206
Davydova Evgenia Alexandrovna, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0001-9009-6154
Shchedrina Nadezhda Nikolaevna, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-1517-1043
Oleksii O. Peltek, PhD student, Faculty of Physics, ITMO University, St. Petersburg, Russia
ORCID: 0000-0002-1485-7000
Prokopiev Vladislav Mikhailovich, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-3943-2885
Odintsova Galina Viktorovna, Candidate of Technical Sciences, Senior Researcher, International Scientific Laboratory for Laser Micro- and Nanotechnologies, ITMO University, Department of Nanoelectronics, St. Petersburg, Russia.
ORCID: 0000-0001-9581-4290
CONTRIBUTION OF THE AUTHORS
Filatov I. A. – work planning, organization of the experiment, analysis of the results and preparation of their graphical interpretation; Davydova E. A. – conducting the experiment; Shchedrina N. N. – processing of the results and their interpretation; Peltek A. O. – investigation of the degree of biofouling; Prokopiev V. M. – laser structuring of samples Odintsova G. V. – the concept and design of the work, text editing.
CONFLICT OF INTEREST
The authors declare that they have no conflict of interest and they supplemented the manuscript in part of their work.
I. A. Filatov, E. A. Davydova, N. N. Shchedrina,
A. O. Peltek, V. M. Prokopiev, G. V. Odintsova
ITMO University, St. Petersburg, Russia
The article presents the development of a laser structuring technology of the metals surface for protection against biofouling. This technology involves the processing of the material before placing it in the aquatic environment. Alloys of stainless steel and duralumin were used in the work. The effect of laser structuring on the contact angle and the interaction of laser-structured metal surfaces with microorganisms in water is considered. A positive trend in protection against colonization of microorganisms on the surface of metals after laser treatment was revealed.
Keywords: wetting, laser, microtexturing, metal surface, contact angle, biofouling
Received on: 15.04.2022
Accepted on: 04.05.2022
Introduction
Wetting is the physical relationship of any liquid with a solid body represented as the ability to reduce or increase the surface tension of this solid body. Surface tension is a phenomenon when a solid body tends to reduce its excessed surface energy at the interface with the liquid. An increase in the surface tension degree of a solid body causes the liquid to spread, indicating the hydrophilic properties. Reduction in the tension degree, on the contrary, lowers the surface energy and the liquid does not wet the hydrophobic surface.
The metal surface wetting plays an important role in the technological processes [1]. The issue of hydrophobic or hydrophilic coating formation is relevant in many industries and medicine. For example, the hydrophilic surfaces are required to increase the coating adhesion [2], reduce friction [3], and improve the adhesion of biological objects [4–6]. The hydrophobic surfaces are important for development of antibacterial coatings [7], for reducing the surface icing [8], for preventing vessel biofouling [9], as well as metal corrosion [10].
All objects immersed in the sea water and not covered with a protective layer will soon be populated by various microorganisms (algae, bacteria, plankton, crustaceans, mollusks). In nature, this phenomenon is called biofouling, and it has serious consequences for all navy vessels. The microorganisms are settled on the vessel surface and create the raised roughness that leads to the increased fuel consumption of the ship, increased load on the driving units and lowered maneuverability [9, 11]. The friction resistance on some types of marine hulls can be up to 90% of the total value [12]. The greater the vessel resistance, the greater the cost of ship operations, such as increasing the fuel supply, the hull cleaning against microorganisms, etc. According to the analysis, biofouling leads to the increased fuel consumption by 10% compared to the hydraulically smooth condition of the vessel hull [12].
Typically, biofouling of the marine structures is divided into several main stages: primary film formation of the mucous layer of microorganisms (settlement of bacteria, diatoms, blue-green algae, fungi); secondary stage (settlement of macroalgae, shells) and tertiary stage (settlement of mussels, sponges, crustaceans). These are arbitrary sequences that can vary greatly depending on the season and geographic location [13].
The hydrophobic surface development makes it possible to reduce friction resistance and control the biological fouling process [9]. The coatings made of toxic paints, including the resins, heavy metals (lead), arsenic, have an adverse effect on the marine life [11]. Therefore, there is a need to think out new ways for metal processing without any environmental damage.
There are various methods of metal surface treatment to impart hydrophobic or hydrophilic properties due to the amended contact angle. The contact angle can be changed by controlling the chemical composition and surface morphology by the mechanical [14], chemical [14], and thermal [15] methods. Of particular interest is laser processing, due to which it is possible to locally control the contact angle without any consumables. Therefore, it has been decided to explore the capabilities of laser technologies to reduce the metal biofouling in the aquatic environment due to the use of commercially available laser stations.
Methods and materials
The sample structuring was performed under normal conditions in an air atmosphere using a processing unit based on a pulsed ytterbium fiber-optics laser with a power of 50 W and a wavelength of λ = 1.064 μm, generating pulses with a frequency of 50–100 kHz and a duration of 100 ns. AISI 430 (St) stainless steel and AMtsM (Al) duralumin plates were used as the development prototypes. These alloys were selected since they were the most common alloys used for the production of marine hulls and other structural vessel parts. When selecting a laser source, an important factor was that the alloys selected had an absorption peak at the laser source wavelength that makes the sample processing efficient. The surface morphology was studied using a Zeiss Axio Imager A1M optical microscope. The surface morphology and topology were also studied using a Hommel Werke T8000 contact profilometer.
The contact angle was measured using the sessile drop method. The ToupCam digital camera and ToupView software were used for the result processing. Distilled water was used as the test liquid. The drop volume for measurement in the biofouling test was 3 μl. The drop dosing and placement were performed using a Satorius mechanical dispenser with a volume of 0.1–10 µl. After surface placement of the drop, AutoCad software was used to measure the contact angle.
A water specimen was taken from the coastal zone of the Gulf of Finland in Saint-Petersburg as a medium for the samples. This specimen included such microorganisms as cladophora (in Latin: Cladophora), enteromorpha (in Latin: Ulva intestinalis), diatoms (in Latin: Diatomeae), barnacles larvae (in Latin: Cirripedia) [16], Pseudomonas spp., Stenotrophomonas spp, and Rahnella strains [17].
To carry out the experiments to study the contact angle dependence of substrates made of alloys subjected to various laser processing on the time of sample retention in water, we placed the samples in an aquarium with water from the Gulf of Finland. The study kit consisted of unstructured samples and samples obtained immediately after the laser structuring. The experiment concept implied that the surface acquired hydrophobic properties due to the organic compound adsorption from the environment to the oxide surface formed under the laser radiation. In this case, the wetting state changed due to the formation of new functional groups [18]. Therefore, after laser structuring, we decided to hold the samples in air for 3 weeks to deposit organic compounds on their surface. To accelerate the process of transition to the hydrophobic state, the low-temperature annealing in a PM‑10 muffle furnace for 3 hours at a temperature of 100 °C was also used. All samples were placed in an aquarium with water from the Gulf of Finland, the contact angles were measured every week within one month.
To assess the biofouling degree, the biofilm formed on the sample surface was measured using a Leica TCS SP8 confocal microscope. Before this, the samples were formalin-fixed, with the following usage of propidium iodide to stain the nuclei of organisms in water.
Results and discussion
1. Laser Formation of Microstructures on the Metal Surfaces with Various Contact Angles
In our study, we focused on the primary and secondary biofouling stages. Therefore, we studied the behavior of such microorganisms, the size of which varied in the range from 50 microns to 1000 microns, such as cladophora (in Latin: Cladaphora), barnacles (in Latin: Balanus), diatoms (in Latin: Diatomeae), barnacle larvae (in Latin Cirripedia) and other organisms of similar size. We believe that to ensure the least adhesion of these organisms to the surface, the obtained microrelief period should be no more than 100 microns. It is also known that the hydrophobic properties can protect surfaces against biofouling due to the low surface energy at the interface between the solid body and air. It prevents the sticky adhesive of microorganisms from interacting with the material [9]. Fig. 1 shows a schematic representation of metal laser structuring to develop the hydrophobic properties and behavior of a given laser-induced surface in an aqueous environment compared to an untreated one.
When selecting the structuring modes, we took the hydrophobic reliefs of a lotus and a rose as the basis for the resulting geometric structure. They had the so-called columns with dimensions o of 50 μm and 16 μm, respectively, and a height of 10 μm.
The structures with the dimensions of 7 × 7 mm were developed in each sample. The laser beam recording was performed in planes so that the resulting grooves were perpendicular to each other and formed a lattice (Fig. 2). The resulting grooves had a width of 34 µm and a depth of 10–12 µm. Based on the laser beam scanning pitch (M) of 50 µm and 100 µm, the dimensions of the protrusions (columns) were 16 µm and 66 µm, respectively. For each week of contact angle measurements, 5 samples were prepared for one type of treatment and one scanning pitch for individual modes of both metals. Fig. 2 provides photographs of the surface morphology of aluminum and steel obtained using an optical microscope, as well as the profile records of these surfaces.
The contact angles were used to obtain the dependency diagrams of these angles on the sample retention time in water (Fig. 3). On these diagrams, the value given for the first day was the sample contact angle prior to its placement in the aquarium. In some cases, the contact angle was 180 degrees due to the inability to measure the angle, since the drop was not placed on the surface, but remained on the Satorius mechanical dispenser.
During the study of the results obtained for unstructured samples, no explicit dependence is observed. For the specimens which study has begun immediately after the laser structuring process, a slight increase in the angle is observed for all modes after a month in the aquarium.
To obtain the hydrophobic and superhydrophobic structures, we retained our samples after laser structuring in air for 3 weeks to precipitate organics. To speed up this process, other samples after laser structuring were subjected to the low-temperature annealing in a muffle furnace. As a result, we obtained the hydrophobic angles for distilled water prior to the sample placement in the aquarium. The samples exposed to air for 3 weeks after laser structuring demonstrated the higher hydrophobic values for most modes. However, these samples lost their hydrophobicity after exposure to water. We believe that the bond energy of organic compounds with oxides on the metal surface was not high enough, and the organic compounds were washed off with water.
Thus, prior to the sample placement in an aqueous medium for both metals with a scanning pitch of 50 μm (during the treatment for surface hydrophobization), it was possible to obtain hydrophobic angles greater than in the case of processing with a scanning pitch of 100 μm. This was due to the fact that with an increased roughness of the hydrophobic surface within the same material, the hydrophobic properties were also increased, that is, the contact angle was enlarged.
2. Assessment of the Metal Surface Biofouling Degree Before and After Laser Treatment
Fig. 4 shows the results of the biofouling degree for the samples with different treatments. The X-axis indicates the time spent by the samples in water taken from the coastal zone of the Gulf of Finland, and the Y-axis indicates the fluorescent intensity produced by the nuclei of microorganisms. Thus, a qualitative assessment of the fouling degree was based on the fluorescenсу of the nuclei. The results demonstrated the least biofouling in the case of laser structuring and subsequent long-term exposure to air. An analysis of the graphical dependencies led to the conclusion that it was during this treatment (laser structuring and prolonged exposure to air) that the microorganisms did not find these structures convenient for colonization that was related to the superhydrophobic angles.
We link the decrease in the biofouling degree over time during the treatments with the hypothesis that the microorganisms fail to colonize on the surface, since our structures are unfavorable for them both in size and in surface properties preventing their adhesive substance to bind.
Conclusion
Based on the biofouling degree assessment results, it has been concluded that the sample long-term exposure to air after laser structuring is a favorable mode for the metal substrate protection against biofouling, since the biofouling indices have the lowest values. We associate it with the fact that the superhydrophobic angles are obtained for most modes during the laser structuring and air treatment. Thus, in the case of such treatment of both steel and aluminum, imitation of the structure of a lotus and a rose is a possible solution to the problem of protection against biofouling. When comparing the graphical results, we can conclude that a scanning pitch of 50 µm for steel and a scanning pitch of 100 µm for aluminum are optimal for laser structuring and subsequent low-temperature annealing. This conclusion is made based on a comparison of the biofouling degree of unstructured samples and samples obtained immediately after the laser structuring with the samples obtained after laser structuring and low-temperature annealing.
For further study of the results obtained, it is planned to put the system under study in motion during the further experiments so that the samples are not in a stagnant water, as well as to measure the biofouling level by a parametric method, while varying the number of organisms of certain species planted in water.
ABOUT AUTHORS
Filatov Ilya Andreevich, PhD student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-4555-8206
Davydova Evgenia Alexandrovna, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0001-9009-6154
Shchedrina Nadezhda Nikolaevna, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-1517-1043
Oleksii O. Peltek, PhD student, Faculty of Physics, ITMO University, St. Petersburg, Russia
ORCID: 0000-0002-1485-7000
Prokopiev Vladislav Mikhailovich, student, Faculty of Nanoelectronics, ITMO University, St. Petersburg, Russia.
ORCID: 0000-0002-3943-2885
Odintsova Galina Viktorovna, Candidate of Technical Sciences, Senior Researcher, International Scientific Laboratory for Laser Micro- and Nanotechnologies, ITMO University, Department of Nanoelectronics, St. Petersburg, Russia.
ORCID: 0000-0001-9581-4290
CONTRIBUTION OF THE AUTHORS
Filatov I. A. – work planning, organization of the experiment, analysis of the results and preparation of their graphical interpretation; Davydova E. A. – conducting the experiment; Shchedrina N. N. – processing of the results and their interpretation; Peltek A. O. – investigation of the degree of biofouling; Prokopiev V. M. – laser structuring of samples Odintsova G. V. – the concept and design of the work, text editing.
CONFLICT OF INTEREST
The authors declare that they have no conflict of interest and they supplemented the manuscript in part of their work.
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