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Graphene is an advanced material. We confirmed in our previous paper that graphene is very sensitive to biofilm formation. Therefore, it may be utilized as a sensor for biofilm formation in the future. In this experiment, we used graphite and multi-layer graphene, which we obtained by repeating an exfoliation method. The biofilm formation was evaluated by crystal violet staining, Raman spectroscopy, and chronoamperometry in dilute sulfuric acid. The final technique was an adventurous trial. However, the method provided us with reasonable data, as compared with the results of the other two conventional methods.

A type of polymer brush, made from an ionic liquid, was prepared and used to investigate the behavior and tendency of biofilm formation. The polymer brush specimens were immersed into the wells of microtiter plates filled with culture liquids containing bacteria. Two different combinations of bacteria and liquid cultures were used for this experiment. One was LB liquid medium with E-coli and the other was Heart Infusion liquid medium with S.epidermidis. After the specimens were immersed for a certain amount of time, they were removed from the test wells and evaluated for biofilm formation. The evaluation methods used were Raman Spectroscopy and crystal violet staining. Polymer brush specimens generally showed biofilm formations for specimens tested in both bacterial cases. However, both of these biofilms could be removed, when the specimens were immersed in water for a couple of hours. Probably the use of special polymer brushes will be valuable in the future, for controlling biofilm and related contaminants on a variety of materials and components.

Biofilm formation was carried out using low concentrations of ionic liquid (IL) to investigate the potential control of biofilm formation with IL. A 2000ml reservoir was filled with tap water with/without a low concentration of ionic liquid in aqueous solution. The apparatus (Laboratory Biofilm Reactor: LBR) was a loop type Laboratory Biofilm Reactor (LBR) composed of an acrylic pump and a bottom tank. A pump circulated the water in the loop system of the laboratory biofilm reactor (LBR). The glass specimens were immersed in the LBR with/without a low concentration of ionic liquid in aqueous solution for 2 or 7days. They were observed and evaluated by using Crystal Violet, a 3D optical microscope and a Raman spectrometer to determine their biofilm behavior. The results were discussed from the viewpoint of a cooling pipe system simulation. We found out and confirmed that the formation of biofilm was controlled when a low concentration of aqueous solution of ionic liquids was circulated.

The formation of biofilm on graphene materials was investigated in this study. Two kinds of laboratory biofilm reactors were used to produce biofilms artificially on glass specimens (on the laboratory scale). One of them was a loop-type and the biofilms were measured by Raman spectroscopy. The other one was the static immersion test in a culture containing bacteria. The biofilm formation was evaluated by using crystal violet. We expected that the graphene would have a strong resistance against biofilm formation. However, on the contrary, graphene tended to become more sensitive to biofilm formation when the portion of graphene increased. When we come to think about the future application for graphene, it should not be used for biomaterials, but as sensor for infectious diseases.

A new group of ionic liquids based on tetraethylphosphonium and tetrabutylphosphonium cations together with several carboxylate anions is proposed and presented in this report. In obtained ionic liquids, tetrabutylphosphonium formate and tetrabutyl-phosphonium lactate became room temperature ionic liquids. It was found that the phosphonium ionic liquids showed the typical VTF-type convex curve behaviors. The phosphonium ionic liquids also had a high cathodic stability similar to those of the TFSA- and FSA-anion based phosphonium ionic liquids. On the other hand, relatively low anodic potential window was observed. The thermal stability of the phosphonium ionic liquids showed higher thermal stabilities than those of the corresponding ammonium ionic liquids.

Potential dependence of the friction force between an atomically-flat terrace of Au(100) single crystal and a tip attached to a silicon nitride cantilever of electrochemical atomic force microscope (EC-AFM) have been investigated qualitatively in 0.05 M H2SO4 aqueous solution. It is found that the friction force gains when the potential increases in the potential range between −400 mV and 400 mV vs Hg/Hg2SO4 electrode.

We have tried to develop the following new material processing for the production of value-added materials from by-products such as kish-graphite, Fe & Cu mixed scraps etc. in steelmaking processes : 1) Production of PdCl2 graphite intercalation compound (PdCl2-GIC) in hydrothermal conditions to create nano-particles encapsulated in kish-graphite. 2) Application of “unusual wetting” of liquid Cu on surface-oxidized Fe to produce composite materials between Cu and ceramics.

We have investigated the decay of multi-layered islands on Au(100) single crystals and the potential dependence in 0.05 M H2SO4aqueous solution at room temperature by in situ EC-AFM. The initial shape of each layer of the islands is a square or a octagon and it is found that these layers are mainly surrounded by 〈011〉; the step edges with high atomic density. The number of atoms in the first layer decreases linearly with time, suggesting that the detachment of the atoms from the island is a limiting process of the decay. The decay rate of the second or third layer after the complete collapse of the upper layer is almost the same as that of the first layer and it is much faster than that after the complete collapse of the upper layer. This result suggests that the current of atoms from the upper layer to the second or third layer results in the supersaturation of atoms on the terrace near the step edge. When the potential of Au(100) increases in the potential range between 0.15 and 1.2 V, the decay of the island becomes faster. We concluded that an increase of the electrostatic free energy at step edge increases the current of atoms from the island in contact with electrolyte. The decay rate of the holes created by the AFM cantilever is approximately an order of magnitude smaller than that of the first layer of the islands.

The kinetics of thin alloy film formation and growth during Cd electrodeposition on Au(100) and Ag(100) has been studied at room temperature in 50 mM H₂SO₄+1 mM CdSO₄ solution within the Cd underpotential range from -0.3 to -0.45 V. Electrochemical experiments and atomic force microscopy studies have shown that the overall alloying process at the Cd²⁺/Au(100) and Cd²⁺/Ag(100) interfaces consisted of two processes: one very fast, which occurred within a few atomic layers and is characterized by a diffusion coefficient, D≈10^-16 cm² s^-1, and another much slower, which is characterized by D≈10^-19 cm² s^-1, suggesting a solid state diffusion process. Based on a new kinetic approach to the alloying process at the metal/electrolyte interface in the underpotential region, the differences in kinetic parameters are discussed.

A type of polymer brush, made from an ionic liquid, was prepared and used to investigate the behavior and tendency of biofilm formation. The polymer brush specimens were immersed into the wells of microtiter plates filled with culture liquids containing bacteria. Two different combinations of bacteria and liquid cultures were used for this experiment. One was LB liquid medium with E-coli and the other was Heart Infusion liquid medium with S.epidermidis. After the specimens were immersed for a certain amount of time, they were removed from the test wells and evaluated for biofilm formation. The evaluation methods used were Raman Spectroscopy and crystal violet staining. Polymer brush specimens generally showed biofilm formations for specimens tested in both bacterial cases. However, both of these biofilms could be removed, when the specimens were immersed in water for a couple of hours. Probably the use of special polymer brushes will be valuable in the future, for controlling biofilm and related contaminants on a variety of materials and components.

Graphene is an advanced material. We confirmed in our previous paper that graphene is very sensitive to biofilm formation. Therefore, it may be utilized as a sensor for biofilm formation in the future. In this experiment, we used graphite and multi-layer graphene, which we obtained by repeating an exfoliation method. The biofilm formation was evaluated by crystal violet staining, Raman spectroscopy, and chronoamperometry in dilute sulfuric acid. The final technique was an adventurous trial. However, the method provided us with reasonable data, as compared with the results of the other two conventional methods.

The formation of biofilm on graphene materials was investigated in this study. Two kinds of laboratory biofilm reactors were used to produce biofilms artificially on glass specimens (on the laboratory scale). One of them was a loop-type and the biofilms were measured by Raman spectroscopy. The other one was the static immersion test in a culture containing bacteria. The biofilm formation was evaluated by using crystal violet. We expected that the graphene would have a strong resistance against biofilm formation. However, on the contrary, graphene tended to become more sensitive to biofilm formation when the portion of graphene increased. When we come to think about the future application for graphene, it should not be used for biomaterials, but as sensor for infectious diseases.

Biofilm formation was carried out using low concentrations of ionic liquid (IL) to investigate the potential control of biofilm formation with IL. A 2000ml reservoir was filled with tap water with/without a low concentration of ionic liquid in aqueous solution. The apparatus (Laboratory Biofilm Reactor: LBR) was a loop type Laboratory Biofilm Reactor (LBR) composed of an acrylic pump and a bottom tank. A pump circulated the water in the loop system of the laboratory biofilm reactor (LBR). The glass specimens were immersed in the LBR with/without a low concentration of ionic liquid in aqueous solution for 2 or 7days. They were observed and evaluated by using Crystal Violet, a 3D optical microscope and a Raman spectrometer to determine their biofilm behavior. The results were discussed from the viewpoint of a cooling pipe system simulation. We found out and confirmed that the formation of biofilm was controlled when a low concentration of aqueous solution of ionic liquids was circulated.

A new group of ionic liquids based on tetraethylphosphonium and tetrabutylphosphonium cations together with several carboxylate anions is proposed and presented in this report. In obtained ionic liquids, tetrabutylphosphonium formate and tetrabutyl-phosphonium lactate became room temperature ionic liquids. It was found that the phosphonium ionic liquids showed the typical VTF-type convex curve behaviors. The phosphonium ionic liquids also had a high cathodic stability similar to those of the TFSA- and FSA-anion based phosphonium ionic liquids. On the other hand, relatively low anodic potential window was observed. The thermal stability of the phosphonium ionic liquids showed higher thermal stabilities than those of the corresponding ammonium ionic liquids.