Shaofeng Xu, Juhan Lin, Yifan Yu, Hubiao Wang, Junjie Lu
Low flow drag is of great importance to a variety of engineering applications, and an effective way to achieve low drag is to use bioinspired micro-structured surfaces. This work aims to reduce the skin-friction drag in closed channel flow using textured surfaces inspired by leaves of indocalamus and rice. The channel formed by a polydimethylsiloxane chunk and a silicon wafer was fabricated to study drag reduction behavior for water or liquid paraffin oil in laminar flow. Bioinspired textures were processed on silicon wafer surface using deep silicon plasma etching method. We measured the pressure drop of water or paraffin oil passing through textured channels with different velocities. The maximum pressure drop reduction for the paraffin oil flow with low velocity (Re≈1) and for the water flow with high velocity (Re<1000) were about 5.1% and 27.3%, respectively. We also presented the contact angles of bioinspired textured surface, and then proposed mechanisms to explain the drag reduction. The hydrophobicity leading to the changing from the liquid-solid interface to the liquid-air interface is believed to provides the drag reduction for water flow, while the thin oil film formed on the textured surface due to the oleophilicity helps to reduce the oil flow drag.
{"title":"Laminar drag reduction in closed channel using bioinspired textured surfaces","authors":"Shaofeng Xu, Juhan Lin, Yifan Yu, Hubiao Wang, Junjie Lu","doi":"10.1680/jsuin.22.01069","DOIUrl":"https://doi.org/10.1680/jsuin.22.01069","url":null,"abstract":"Low flow drag is of great importance to a variety of engineering applications, and an effective way to achieve low drag is to use bioinspired micro-structured surfaces. This work aims to reduce the skin-friction drag in closed channel flow using textured surfaces inspired by leaves of indocalamus and rice. The channel formed by a polydimethylsiloxane chunk and a silicon wafer was fabricated to study drag reduction behavior for water or liquid paraffin oil in laminar flow. Bioinspired textures were processed on silicon wafer surface using deep silicon plasma etching method. We measured the pressure drop of water or paraffin oil passing through textured channels with different velocities. The maximum pressure drop reduction for the paraffin oil flow with low velocity (Re≈1) and for the water flow with high velocity (Re<1000) were about 5.1% and 27.3%, respectively. We also presented the contact angles of bioinspired textured surface, and then proposed mechanisms to explain the drag reduction. The hydrophobicity leading to the changing from the liquid-solid interface to the liquid-air interface is believed to provides the drag reduction for water flow, while the thin oil film formed on the textured surface due to the oleophilicity helps to reduce the oil flow drag.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44339835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leidenfrost drops have demonstrated promising applications in, for example, drag reduction. However, large Leidenfrost drops may be unstable when their diameters exceed a critical value, leading to less control of such drops in their applications. In this work, through theoretical and experimental investigations, we explore the instability of a Leidenfrost drop in a circular configuration, as well as the suppression of this instability using a small rod. There are four findings. First, the diameter of the largest inscribed cylinder inside a rod-container configuration is the critical dimension to determine Leidenfrost instability. Second, in the cases of water and isopropyl alcohol, the threshold value of this diameter is 8.3λ ± 0.3λ, where λ is the capillary length of a liquid. Third, due to the specific interface profile between the liquid drop and the surrounding vapor layer, the threshold diameter of a circular container for the instability to occur is slightly larger than its counterpart in the corresponding Rayleigh-Taylor instability problem. Fourth and finally, placing a rod inside a circular container reduces the size of the largest inscribed cylinder in the container. If the diameter of this inscribed cylinder is below the threshold value, the instability inside the container is suppressed.
{"title":"Leidenfrost instability in a circular container and its suppression using a rod","authors":"Manjarik Mrinal, Xiang Wang, Z. Han, C. Luo","doi":"10.1680/jsuin.22.01066","DOIUrl":"https://doi.org/10.1680/jsuin.22.01066","url":null,"abstract":"Leidenfrost drops have demonstrated promising applications in, for example, drag reduction. However, large Leidenfrost drops may be unstable when their diameters exceed a critical value, leading to less control of such drops in their applications. In this work, through theoretical and experimental investigations, we explore the instability of a Leidenfrost drop in a circular configuration, as well as the suppression of this instability using a small rod. There are four findings. First, the diameter of the largest inscribed cylinder inside a rod-container configuration is the critical dimension to determine Leidenfrost instability. Second, in the cases of water and isopropyl alcohol, the threshold value of this diameter is 8.3λ ± 0.3λ, where λ is the capillary length of a liquid. Third, due to the specific interface profile between the liquid drop and the surrounding vapor layer, the threshold diameter of a circular container for the instability to occur is slightly larger than its counterpart in the corresponding Rayleigh-Taylor instability problem. Fourth and finally, placing a rod inside a circular container reduces the size of the largest inscribed cylinder in the container. If the diameter of this inscribed cylinder is below the threshold value, the instability inside the container is suppressed.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46953157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antifouling coating faces some critical challenges towards applications, especially poor mechanical properties, complex or expensive fabrications and non-transparency. This work reports a transparent fluorine-free antifouling coating with robust mechanical property. Water, salt solution, alkali and acid solution can slide off the coating surface (water contact angle, CA>105°) and remove dirt. The coating endows remarkable protection of the substrate against exposure to harsh chemical conditions and mechanically robust against extensive abrasion and high hardness (6-9H). The characteristics of this coating is derived from heavily cross-linking branched 3-aminopropyltriethoxysilane with ZrO2 ceramic nanoparticles by a curing agent.
{"title":"A hard durable transparent antifouling coating prepared by crosslinking ZrO2 and branched polysiloxane","authors":"Kaiqiang Zhang, Yong Zhu, Zhang Chen, Zongtao Zhang, Yanfeng Gao","doi":"10.1680/jsuin.22.01049","DOIUrl":"https://doi.org/10.1680/jsuin.22.01049","url":null,"abstract":"Antifouling coating faces some critical challenges towards applications, especially poor mechanical properties, complex or expensive fabrications and non-transparency. This work reports a transparent fluorine-free antifouling coating with robust mechanical property. Water, salt solution, alkali and acid solution can slide off the coating surface (water contact angle, CA>105°) and remove dirt. The coating endows remarkable protection of the substrate against exposure to harsh chemical conditions and mechanically robust against extensive abrasion and high hardness (6-9H). The characteristics of this coating is derived from heavily cross-linking branched 3-aminopropyltriethoxysilane with ZrO2 ceramic nanoparticles by a curing agent.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42461821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiumei Zhu, H. Qi, Jiahao Chen, Jiangbin Su, Zuming He, B. Tang
In the absence of additional oxygen, thin films of tungsten oxide (WO3) were prepared on ITO conductive glass substrates by radio-frequency (RF) magnetron sputtering. The effects of sputtering power, working air pressure, substrate bias voltage and substrate temperature on the surface morphology, microstructure, optical properties and electrochromic (EC) performance of the films were systematically investigated. The research shows that the sputtering power of 80-100 W can ensure a moderate deposition rate of ∼10−2 nm/s and help to obtain nondense films. Similarly, the working air pressure of 1.0 Pa also leads to the deposition of loose films, which benifits for the improving of optical transmittance and EC performance of WO3 thin films. The applied substrate bias has little effect on the optical properties, but it will degrade the coloring and/or bleaching efficiency of WO3 thin films and greatly reduce their optical modulation. When the substrate temperature rises to 600 °C, the film begins to crystallize and exhibits a rods-patterned porous structure, which leads to a small increase in the optical modulation.
{"title":"Effects of deposition parameters on RF-sputtered WO3 thin films","authors":"Xiumei Zhu, H. Qi, Jiahao Chen, Jiangbin Su, Zuming He, B. Tang","doi":"10.1680/jsuin.22.01031","DOIUrl":"https://doi.org/10.1680/jsuin.22.01031","url":null,"abstract":"In the absence of additional oxygen, thin films of tungsten oxide (WO3) were prepared on ITO conductive glass substrates by radio-frequency (RF) magnetron sputtering. The effects of sputtering power, working air pressure, substrate bias voltage and substrate temperature on the surface morphology, microstructure, optical properties and electrochromic (EC) performance of the films were systematically investigated. The research shows that the sputtering power of 80-100 W can ensure a moderate deposition rate of ∼10−2 nm/s and help to obtain nondense films. Similarly, the working air pressure of 1.0 Pa also leads to the deposition of loose films, which benifits for the improving of optical transmittance and EC performance of WO3 thin films. The applied substrate bias has little effect on the optical properties, but it will degrade the coloring and/or bleaching efficiency of WO3 thin films and greatly reduce their optical modulation. When the substrate temperature rises to 600 °C, the film begins to crystallize and exhibits a rods-patterned porous structure, which leads to a small increase in the optical modulation.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47196694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
By being exposed to air or moisture or by a chemical reaction, titanium forms an oxide layers on its surface, which is stable and tightly adherent and provides it with protection from the environment, since titanium is a reactive material. Due to their extremely low thickness (∼10 nm), this oxide layer is easy to destroy under corrosion conditions. Through plasma electrolytic oxidation (PEO), titanium and titanium alloys can be equipped with thick and adhesive TiO2 coatings to enhance their surface characteristics. In the PEO process, TiO2 composite coatings can be formed by mixing proper additives with electrolytes, such as powders, particles, sheets, or compounds. The graphene and its family derivatives (i.e., graphene oxide and reduced graphene oxide) are among the most popular additives used in PEO composite coatings due to their high stability in corrosive media. Graphene family nanosheets can accumulate in PEO coatings because of their porous nature, changing the surface characteristics dramatically. The use of graphene family nanosheets in the electrolyte can be useful to reduce coating porosity and improve final corrosion properties by adjusting electrolyte conditions. Therefore, the diffusion pathways for corrosive ions in composite TiO2 coatings become considerably more tortuous than with pure TiO2.
{"title":"Effect of graphene-family incorporation on corrosion performance of PEO coatings formed on titanium alloys: a mini review","authors":"Meysam Pourshadloo, Hesam Asghar Rezaei, Mina Saeidnia, Hossein Alkokab, Masoud Soroush Bathaei","doi":"10.1680/jsuin.22.01043","DOIUrl":"https://doi.org/10.1680/jsuin.22.01043","url":null,"abstract":"By being exposed to air or moisture or by a chemical reaction, titanium forms an oxide layers on its surface, which is stable and tightly adherent and provides it with protection from the environment, since titanium is a reactive material. Due to their extremely low thickness (∼10 nm), this oxide layer is easy to destroy under corrosion conditions. Through plasma electrolytic oxidation (PEO), titanium and titanium alloys can be equipped with thick and adhesive TiO2 coatings to enhance their surface characteristics. In the PEO process, TiO2 composite coatings can be formed by mixing proper additives with electrolytes, such as powders, particles, sheets, or compounds. The graphene and its family derivatives (i.e., graphene oxide and reduced graphene oxide) are among the most popular additives used in PEO composite coatings due to their high stability in corrosive media. Graphene family nanosheets can accumulate in PEO coatings because of their porous nature, changing the surface characteristics dramatically. The use of graphene family nanosheets in the electrolyte can be useful to reduce coating porosity and improve final corrosion properties by adjusting electrolyte conditions. Therefore, the diffusion pathways for corrosive ions in composite TiO2 coatings become considerably more tortuous than with pure TiO2.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48295881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this review we provide a general review of current research themes where complex surface topography plays a role. Recent innovations and research possibilities have opened up using modern micro topography creation techniques. We are considering a large range of themes in limited depth in order to provide an introduction and to illustrate how broad the field is and to those already working in the area to help gain a broad perspective. Due to the breadth of scope this review will not go into much depth into any given area. This review aims to provide a comprehensive understanding and practical guidance on the modern use of micro and nano-topography to control water, adhesion, wettability, control of biological adhesion including implants, cell culture and biofouling and directional fluid transport. The broad range of functionality is highlighted in the many interfacial interactions, however, the manufacturing scale to allow these surfaces to be commonly used is still in development. In order to make it more accessible we have chosen to concentrate on open access articles to cite.
{"title":"Recent innovations in surface topography","authors":"Lily Chambers, P. Roach, N. Shirtcliffe","doi":"10.1680/jsuin.22.01041","DOIUrl":"https://doi.org/10.1680/jsuin.22.01041","url":null,"abstract":"In this review we provide a general review of current research themes where complex surface topography plays a role. Recent innovations and research possibilities have opened up using modern micro topography creation techniques. We are considering a large range of themes in limited depth in order to provide an introduction and to illustrate how broad the field is and to those already working in the area to help gain a broad perspective. Due to the breadth of scope this review will not go into much depth into any given area. This review aims to provide a comprehensive understanding and practical guidance on the modern use of micro and nano-topography to control water, adhesion, wettability, control of biological adhesion including implants, cell culture and biofouling and directional fluid transport. The broad range of functionality is highlighted in the many interfacial interactions, however, the manufacturing scale to allow these surfaces to be commonly used is still in development. In order to make it more accessible we have chosen to concentrate on open access articles to cite.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48226881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sezin Eren Demirbüken, Bengu Aktas, M. Ö. Ö. Öncel, Deniz Hür, L. Uzun, B. Garipcan
Protein adsorption has a crucial effect on biocompatibility during the interaction of biomaterial surfaces and the biological environment. It is significant to understand and control the interactions among biomaterials and proteins for several biomedical applications. Surface engineering plays a significant role to determine biocompatibility via tuning the effects directly on proteins. In this study, amino acid (histidine and leucine) conjugated self-assembled molecules (SAMs) were synthesized and used to modify silicon dioxide (SiO2) surfaces to investigate protein adsorption behavior. SiO2 surfaces were modified with (3-aminopropyl) triethoxysilane (APTES) conjugated histidine and leucine amino acids. Modified SiO2 surfaces were characterized by water contact angle measurements (WCA) and X-Ray Photoelectron Spectroscopy (XPS) analysis. Protein adsorption [Human Serum Albumin (HSA), fibrinogen, and Immunoglobulin G (IgG)] on SiO2 coated crystals was investigated in situ by using Quartz Crystal Microbalance (QCM) biosensor. According to the results, model proteins have shown different selectivity to the amino acid conjugated SiO2 coated crystals depending on the type of the amino acids and concentration. Consequently, this controlled chemistry on the surface of biomaterials has a great potential to manipulate protein adsorption and enhance the biocompatibility of biomaterials for various biomedical applications.
{"title":"Characterization of protein adsorption of amino acid conjugated self-assembled molecules modified SiO2 surfaces by QCM","authors":"Sezin Eren Demirbüken, Bengu Aktas, M. Ö. Ö. Öncel, Deniz Hür, L. Uzun, B. Garipcan","doi":"10.1680/jsuin.22.01017","DOIUrl":"https://doi.org/10.1680/jsuin.22.01017","url":null,"abstract":"Protein adsorption has a crucial effect on biocompatibility during the interaction of biomaterial surfaces and the biological environment. It is significant to understand and control the interactions among biomaterials and proteins for several biomedical applications. Surface engineering plays a significant role to determine biocompatibility via tuning the effects directly on proteins. In this study, amino acid (histidine and leucine) conjugated self-assembled molecules (SAMs) were synthesized and used to modify silicon dioxide (SiO2) surfaces to investigate protein adsorption behavior. SiO2 surfaces were modified with (3-aminopropyl) triethoxysilane (APTES) conjugated histidine and leucine amino acids. Modified SiO2 surfaces were characterized by water contact angle measurements (WCA) and X-Ray Photoelectron Spectroscopy (XPS) analysis. Protein adsorption [Human Serum Albumin (HSA), fibrinogen, and Immunoglobulin G (IgG)] on SiO2 coated crystals was investigated in situ by using Quartz Crystal Microbalance (QCM) biosensor. According to the results, model proteins have shown different selectivity to the amino acid conjugated SiO2 coated crystals depending on the type of the amino acids and concentration. Consequently, this controlled chemistry on the surface of biomaterials has a great potential to manipulate protein adsorption and enhance the biocompatibility of biomaterials for various biomedical applications.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42239126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Toumi, B. Tiss, N. Bouguila, D. Cristea, C. Croitoru, I. Ghiuta, A. Marin, Ioana-Laura Velicu, V. Tiron, V. Craciun, M. Kraini, S. Alaya, C. Moura, Luis Cuhna
In this study, the surface chemistry and morphology, the photocatalytic and antibacterial potential of pure and chlorine doped indium sulfide thin films, produced by spray pyrolysis, were analyzed. The RMS roughness seems not to be significantly affected by the chlorine concentration in three of the doped films (around 12 nm). The roughness seems not to affect the characteristics of the films analyzed in this study. The samples presented a photocatalytic efficiency higher than 80%, but no correlation with the amount of Cl concentration was found. The antibacterial potential of the films was assessed against the multidrug-resistant bacteria Pseudomonas aeruginosa, responsible by serious infections, which are extremely difficult to treat in hospitals. The obtained results evidence an increase of antibacterial activity with the increase of Cl concentration. These results encourage further studies to support the potential of this material to be used in biomedical applications.
{"title":"Chlorine doping impact on the photocatalytic and antibacterial activity of sprayed In2S3 films","authors":"M. Toumi, B. Tiss, N. Bouguila, D. Cristea, C. Croitoru, I. Ghiuta, A. Marin, Ioana-Laura Velicu, V. Tiron, V. Craciun, M. Kraini, S. Alaya, C. Moura, Luis Cuhna","doi":"10.1680/jsuin.22.01040","DOIUrl":"https://doi.org/10.1680/jsuin.22.01040","url":null,"abstract":"In this study, the surface chemistry and morphology, the photocatalytic and antibacterial potential of pure and chlorine doped indium sulfide thin films, produced by spray pyrolysis, were analyzed. The RMS roughness seems not to be significantly affected by the chlorine concentration in three of the doped films (around 12 nm). The roughness seems not to affect the characteristics of the films analyzed in this study. The samples presented a photocatalytic efficiency higher than 80%, but no correlation with the amount of Cl concentration was found. The antibacterial potential of the films was assessed against the multidrug-resistant bacteria Pseudomonas aeruginosa, responsible by serious infections, which are extremely difficult to treat in hospitals. The obtained results evidence an increase of antibacterial activity with the increase of Cl concentration. These results encourage further studies to support the potential of this material to be used in biomedical applications.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49523879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unique properties of magnetite (Fe3O4) nanoparticles (MNPs) have promoted wide applications in various fields, but specifying and defining preparation conditions of MNPs are still challenges for the desired monodispersed size. We discussed systematically the influence of synthesis conditions on the structure and size of MNPs in co-precipitation method without stabilizer in one system. NH4OH/Fe3+ ratio, Fe3+/Fe2+ ratio, initial concentration of HCl, total concentration of iron ions, reaction temperature, aging time and washing times were investigated. The surface of magnetite crystal was easily oxidized at high NH4OH/Fe3+ ratio, and the high pH value of the reaction system can induce the large crystalline size. The hydrodynamic diameter of MNPs was efficiently controlled by the equilibrium of DLVO forces and non-DLVO forces. An appropriate initial concentration of HCl and higher reaction temperature can reduce the crystalline size due to the decelerated nucleation rate. The aging time and the total concentration of iron affected the crystalline size positively. Noticeably, pH value of MNPs dispersion in distilled water would remarkably reduce after each washing by centrifugation due to surface absorption of hydroxy group. This research provided the fundamental support for the reproducible preparation of MNPs in co-precipitation method.
{"title":"Influence of synthesis conditions on the structure and size of magnetite nanoparticles in co-precipitation method without stabilizer in one system","authors":"Maoxue Xia, Yu Liu, N. Huang, Hongyu Zhu, J. Hao","doi":"10.1680/jsuin.22.01044","DOIUrl":"https://doi.org/10.1680/jsuin.22.01044","url":null,"abstract":"Unique properties of magnetite (Fe3O4) nanoparticles (MNPs) have promoted wide applications in various fields, but specifying and defining preparation conditions of MNPs are still challenges for the desired monodispersed size. We discussed systematically the influence of synthesis conditions on the structure and size of MNPs in co-precipitation method without stabilizer in one system. NH4OH/Fe3+ ratio, Fe3+/Fe2+ ratio, initial concentration of HCl, total concentration of iron ions, reaction temperature, aging time and washing times were investigated. The surface of magnetite crystal was easily oxidized at high NH4OH/Fe3+ ratio, and the high pH value of the reaction system can induce the large crystalline size. The hydrodynamic diameter of MNPs was efficiently controlled by the equilibrium of DLVO forces and non-DLVO forces. An appropriate initial concentration of HCl and higher reaction temperature can reduce the crystalline size due to the decelerated nucleation rate. The aging time and the total concentration of iron affected the crystalline size positively. Noticeably, pH value of MNPs dispersion in distilled water would remarkably reduce after each washing by centrifugation due to surface absorption of hydroxy group. This research provided the fundamental support for the reproducible preparation of MNPs in co-precipitation method.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47454465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atomic force microscopy force-volume technique was used to investigate the surface properties of two hydrogels during their enzymatic degradation. Agarose gels with concentrations of 0.5%, 1.0%, and 1.5% w/v were selected for the degradation study to show that the mechanical effects of degradation could be measured in a spatially resolved way on hydrogel surface. Agarase enzyme was used to degrade the agarose gels. The agarose gels were found to be heterogeneous with multiple stiffness domains that were degraded with different erosion rates. It was inferred that agarose gels contained both tightly and loosely packed regions. The loosely packed regions degraded first, followed by the regions that were packed more tightly. Second hydrogel containing hyaluronic acid and gelatin with 5% w/v hyaluronic acid and 5% w/v gelatin cross-linked in equal amounts were also studied. These hybrid gels were degraded either by using hyaluronidase or collagenase type IV. With hyaluronidase, gelatin was left on the surface as a homogenous layer. With collagenase, cross-linked hyaluronic acid remained on the surface. Post-degradation the hyaluronic acid rich surface had a stiffness of ∼20 kPa, while the gelatin rich surface stiffness was only ∼15 kPa.
{"title":"Spatially resolved mapping of hydrogel stiffness during enzymatic degradation","authors":"Nathan Strong, A. Pungor, V. Hlady","doi":"10.1680/jsuin.22.01029","DOIUrl":"https://doi.org/10.1680/jsuin.22.01029","url":null,"abstract":"Atomic force microscopy force-volume technique was used to investigate the surface properties of two hydrogels during their enzymatic degradation. Agarose gels with concentrations of 0.5%, 1.0%, and 1.5% w/v were selected for the degradation study to show that the mechanical effects of degradation could be measured in a spatially resolved way on hydrogel surface. Agarase enzyme was used to degrade the agarose gels. The agarose gels were found to be heterogeneous with multiple stiffness domains that were degraded with different erosion rates. It was inferred that agarose gels contained both tightly and loosely packed regions. The loosely packed regions degraded first, followed by the regions that were packed more tightly. Second hydrogel containing hyaluronic acid and gelatin with 5% w/v hyaluronic acid and 5% w/v gelatin cross-linked in equal amounts were also studied. These hybrid gels were degraded either by using hyaluronidase or collagenase type IV. With hyaluronidase, gelatin was left on the surface as a homogenous layer. With collagenase, cross-linked hyaluronic acid remained on the surface. Post-degradation the hyaluronic acid rich surface had a stiffness of ∼20 kPa, while the gelatin rich surface stiffness was only ∼15 kPa.","PeriodicalId":22032,"journal":{"name":"Surface Innovations","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2022-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43463978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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