Pub Date : 2024-05-20DOI: 10.1007/s10971-024-06405-w
N. Haddad, H. Mahdhi, Z. Ben Ayadi
{"title":"Fine-tuning optical bandgap and dielectric properties through fluorine doping in SnO2 nanoparticles","authors":"N. Haddad, H. Mahdhi, Z. Ben Ayadi","doi":"10.1007/s10971-024-06405-w","DOIUrl":"https://doi.org/10.1007/s10971-024-06405-w","url":null,"abstract":"","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141120233","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}
Pub Date : 2024-05-20DOI: 10.1007/s10971-024-06396-8
A. Messaoudi, A. Omri, A. Benali, M. A. Ghebouli, A. Djemli, M. Fatmi, N. Hamdaoui, R. Ajjel, M. Habila, Asma A. Alothman, Saikh Mohammad, B. F. O. Costa, M. F. P. Graca, K. Khirouni
{"title":"Dielectric and structural properties of Co0.6Zn0.4Fe2O4 nanoferrites: sol–gel synthesis","authors":"A. Messaoudi, A. Omri, A. Benali, M. A. Ghebouli, A. Djemli, M. Fatmi, N. Hamdaoui, R. Ajjel, M. Habila, Asma A. Alothman, Saikh Mohammad, B. F. O. Costa, M. F. P. Graca, K. Khirouni","doi":"10.1007/s10971-024-06396-8","DOIUrl":"https://doi.org/10.1007/s10971-024-06396-8","url":null,"abstract":"","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141122345","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}
Pub Date : 2024-05-20DOI: 10.1007/s10971-024-06409-6
B. M. Dayana, J. T. J. Prakash, J. V. Kumar, M. Dhananjaya, Sang Woo Joo, Mir Waqas Alam
{"title":"Solution-gelation synthesis of silver nanoparticles utilizing Justicia tranquebariensis extract for antibacterial, antioxidant, antifungal and anticancer activity","authors":"B. M. Dayana, J. T. J. Prakash, J. V. Kumar, M. Dhananjaya, Sang Woo Joo, Mir Waqas Alam","doi":"10.1007/s10971-024-06409-6","DOIUrl":"https://doi.org/10.1007/s10971-024-06409-6","url":null,"abstract":"","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141121739","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}
Pub Date : 2024-05-18DOI: 10.1007/s10971-024-06411-y
D. Herrera Garcia, M. G. Garnica-Romo, A. Ramos-Corona, F. Cervantes-Alvarez, L. García-González, N. Dasgupta-Schubert, J. J. Alvarado-Gil
One of the most challenging goals in materials science is to shift the absorption band of TiO2 toward the visible region of the electromagnetic spectrum. This is a fundamental strategy to improve its photocatalytic performance. In this paper, we present a simple methodology based on the sol-gel method, which allows the displacement of the band edge of TiO2, accompanied by the appearance of additional absorption bands in the optical spectrum. In our methodology, TiO2 was synthesized and doped with 5% and 10% w/w nickel. The resulting material was dried at 100 °C and subjected to thermal treatment at 500 °C for 1 h each. The obtained material was characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, diffuse reflectance, X-ray diffraction, Raman spectroscopy, and XPS. Our results indicate that Ni doping of TiO2 was successfully carried out, while NiTiO3 appears from the first drying stage at 100 °C and undergoes the transition from the amorphous to the crystalline phase during the sintering process at 500 °C. Furthermore, all the materials studied showed high catalytic activity under UV irradiation. In particular, the nickel-doped thermally treated materials also exhibited good catalytic performance under visible light, even better than the amorphous phases obtained under UV irradiation.
{"title":"Photocatalytic activity under visible light of Ni:TiO2-NiTiO3 synthesized through a modified sol-gel method","authors":"D. Herrera Garcia, M. G. Garnica-Romo, A. Ramos-Corona, F. Cervantes-Alvarez, L. García-González, N. Dasgupta-Schubert, J. J. Alvarado-Gil","doi":"10.1007/s10971-024-06411-y","DOIUrl":"https://doi.org/10.1007/s10971-024-06411-y","url":null,"abstract":"<p>One of the most challenging goals in materials science is to shift the absorption band of TiO<sub>2</sub> toward the visible region of the electromagnetic spectrum. This is a fundamental strategy to improve its photocatalytic performance. In this paper, we present a simple methodology based on the sol-gel method, which allows the displacement of the band edge of TiO<sub>2</sub>, accompanied by the appearance of additional absorption bands in the optical spectrum. In our methodology, TiO<sub>2</sub> was synthesized and doped with 5% and 10% w/w nickel. The resulting material was dried at 100 °C and subjected to thermal treatment at 500 °C for 1 h each. The obtained material was characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, diffuse reflectance, X-ray diffraction, Raman spectroscopy, and XPS. Our results indicate that Ni doping of TiO<sub>2</sub> was successfully carried out, while NiTiO<sub>3</sub> appears from the first drying stage at 100 °C and undergoes the transition from the amorphous to the crystalline phase during the sintering process at 500 °C. Furthermore, all the materials studied showed high catalytic activity under UV irradiation. In particular, the nickel-doped thermally treated materials also exhibited good catalytic performance under visible light, even better than the amorphous phases obtained under UV irradiation.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059114","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}
Pub Date : 2024-05-17DOI: 10.1007/s10971-024-06415-8
Ke Zhang, Pengdang Zhu, Yunsheng Li, Hang Wei, Ruiyu Zhang
Nanogold-modified W18O49 porous polymer spheres were fabricated using a two-step solvothermal method. The material was characterized in various ways by XRD and SEM. The results show that the material is highly crystalline with a porous surface with pore diameters of around 9.0 nm, and that the addition of gold increases the percentage of adsorbed oxygen content from 20.7% to 55.1%. The gas sensitivity test results indicated that the nanogold-modified W18O49 porous polymer spheres achieved a wide detection range of 10–500 ppm acetone, the optimal working temperature was reduced from 280 °C to 220 °C, the sensitivity for 100 ppm acetone was increased by 2.57 times to 66, the response/recovery time was drastically shortened to 5 s/12 s, and the response to acetone was much higher than that of other gases. Excellent selectivity and excellent stability over 35 days were achieved. Gold-modified W18O49 porous polymer spheres have the potential for good acetone gas detection and can potentially be used in high-performance sensors.
{"title":"Highly sensitive acetone gas sensor based on gold nanoparticles modified W18O49 porous polymeric spheres","authors":"Ke Zhang, Pengdang Zhu, Yunsheng Li, Hang Wei, Ruiyu Zhang","doi":"10.1007/s10971-024-06415-8","DOIUrl":"https://doi.org/10.1007/s10971-024-06415-8","url":null,"abstract":"<p>Nanogold-modified W<sub>18</sub>O<sub>49</sub> porous polymer spheres were fabricated using a two-step solvothermal method. The material was characterized in various ways by XRD and SEM. The results show that the material is highly crystalline with a porous surface with pore diameters of around 9.0 nm, and that the addition of gold increases the percentage of adsorbed oxygen content from 20.7% to 55.1%. The gas sensitivity test results indicated that the nanogold-modified W<sub>18</sub>O<sub>49</sub> porous polymer spheres achieved a wide detection range of 10–500 ppm acetone, the optimal working temperature was reduced from 280 °C to 220 °C, the sensitivity for 100 ppm acetone was increased by 2.57 times to 66, the response/recovery time was drastically shortened to 5 s/12 s, and the response to acetone was much higher than that of other gases. Excellent selectivity and excellent stability over 35 days were achieved. Gold-modified W<sub>18</sub>O<sub>49</sub> porous polymer spheres have the potential for good acetone gas detection and can potentially be used in high-performance sensors.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059021","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}
Pub Date : 2024-05-13DOI: 10.1007/s10971-024-06386-w
Wenwen Tan, Yanling Liu, Zao Jiang, Longjun Xu, Qi Feng
In this paper, we employed a hydrothermal method to synthesize different ratios of NH2-MIL-125(Ti) modified manganese dioxide (MnO2@ NH2-MIL-125(Ti)) and explored the effect of pH and mass fraction on the degradation of Rhodamine B. The characterization (XRD, XPS, SEM) of the material proves that MnO2 successfully adheres and grows on the NH2-MIL-125(Ti) frameworks, changing the micromorphology while increasing the yield. In particular, when the NH2-MIL-125(Ti) is introduced at a ratio of 15%, the composite sample reveals optimal degradation performance, with a rate of Rhodamine B degradation as high as 95.8% in 40 min, which is about 1.6 times better than that of pure MnO2. And it can perform superior oxidation performance under acidic conditions. The increased active sites due to the introduction of the framework structure and the higher redox potential under acidic conditions are the main reasons for the improved oxidative properties. In addition, we put forward a mechanism of growth and oxidative degradation for the composite sample for this phenomenon.
{"title":"Composite NH2-MIL-125(Ti) to modulate the microstructure of MnO2 and improve oxidation properties","authors":"Wenwen Tan, Yanling Liu, Zao Jiang, Longjun Xu, Qi Feng","doi":"10.1007/s10971-024-06386-w","DOIUrl":"https://doi.org/10.1007/s10971-024-06386-w","url":null,"abstract":"<p>In this paper, we employed a hydrothermal method to synthesize different ratios of NH<sub>2</sub>-MIL-125(Ti) modified manganese dioxide (MnO<sub>2</sub>@ NH<sub>2</sub>-MIL-125(Ti)) and explored the effect of pH and mass fraction on the degradation of Rhodamine B. The characterization (XRD, XPS, SEM) of the material proves that MnO<sub>2</sub> successfully adheres and grows on the NH<sub>2</sub>-MIL-125(Ti) frameworks, changing the micromorphology while increasing the yield. In particular, when the NH<sub>2</sub>-MIL-125(Ti) is introduced at a ratio of 15%, the composite sample reveals optimal degradation performance, with a rate of Rhodamine B degradation as high as 95.8% in 40 min, which is about 1.6 times better than that of pure MnO<sub>2</sub>. And it can perform superior oxidation performance under acidic conditions. The increased active sites due to the introduction of the framework structure and the higher redox potential under acidic conditions are the main reasons for the improved oxidative properties. In addition, we put forward a mechanism of growth and oxidative degradation for the composite sample for this phenomenon.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940107","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}
Pub Date : 2024-05-10DOI: 10.1007/s10971-024-06387-9
Naara Felipe da Fonsêca, José de Oliveira Alves-Júnior, Genil Dantas de Oliveira, Kammila Martins Nicolau Costa, Demis Ferreira de Melo, Pedro José Rolim Neto, Meiry Gláucia Freire Rodrigues, João Augusto Oshiro-Junior
The aim of this study was to demonstrate the influence of laponite smectite clay on the structural properties and release profile of the ureasil-polyether organic-inorganic hybrid nanocomposite. The sol–gel process was used to synthesize the systems combined with the nano-clay, and three concentrations of D-glucose (3, 5, and 10 wt.%) were analyzed for incorporation. The nanocomposite with the most stable D-glucose concentration was used for the release test. The characterization of the laponite colloidal solution was carried out using different viscosity analyses which showed that the 1.5% proportion was the most suitable for formulation due to the formation of a stable gel. The hybrid membrane characterization techniques using infrared spectroscopy and differential thermal analysis show that the formulation components have no chemical or physical incompatibility with D-glucose; the XRD diffractograms confirm that the crystalline domains of D-glucose are suppressed when incorporated into the amorphous Ureasil-polyether material, indicating complete solubilization in the matrix. Finally, the release results show that 20% of the D-glucose was released in 700 min, with a Korsmeyer-Peppas-type kinetic model. Thus, we can conclude that the nanocomposite developed here showed homogeneity and integrity, with satisfactory and adjustable properties such as its mechanical characteristics and the amount of active release, paving the way for its use in various therapies such as bone regeneration.
{"title":"Modified release of D-glucose incorporated into laponite/ureasil–poly(ethylene oxide) hybrid nanocomposite","authors":"Naara Felipe da Fonsêca, José de Oliveira Alves-Júnior, Genil Dantas de Oliveira, Kammila Martins Nicolau Costa, Demis Ferreira de Melo, Pedro José Rolim Neto, Meiry Gláucia Freire Rodrigues, João Augusto Oshiro-Junior","doi":"10.1007/s10971-024-06387-9","DOIUrl":"https://doi.org/10.1007/s10971-024-06387-9","url":null,"abstract":"<p>The aim of this study was to demonstrate the influence of laponite smectite clay on the structural properties and release profile of the ureasil-polyether organic-inorganic hybrid nanocomposite. The sol–gel process was used to synthesize the systems combined with the nano-clay, and three concentrations of D-glucose (3, 5, and 10 wt.%) were analyzed for incorporation. The nanocomposite with the most stable D-glucose concentration was used for the release test. The characterization of the laponite colloidal solution was carried out using different viscosity analyses which showed that the 1.5% proportion was the most suitable for formulation due to the formation of a stable gel. The hybrid membrane characterization techniques using infrared spectroscopy and differential thermal analysis show that the formulation components have no chemical or physical incompatibility with D-glucose; the XRD diffractograms confirm that the crystalline domains of D-glucose are suppressed when incorporated into the amorphous Ureasil-polyether material, indicating complete solubilization in the matrix. Finally, the release results show that 20% of the D-glucose was released in 700 min, with a Korsmeyer-Peppas-type kinetic model. Thus, we can conclude that the nanocomposite developed here showed homogeneity and integrity, with satisfactory and adjustable properties such as its mechanical characteristics and the amount of active release, paving the way for its use in various therapies such as bone regeneration.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940048","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}
Pub Date : 2024-05-10DOI: 10.1007/s10971-024-06401-0
Tamoor Ahmad, Albandari W. Alrowaily, B. M. Alotaibi, Haifa A. Alyousef, A. Dahshan, A. M. A. Henaish
Growing populations and development led to a higher utilization of fossil fuels and more CO2 emissions; which prompted researchers to look for pollution-free energy sources and improved energy-storage technologies. Supercapacitors (SCs) are thought to be the most advanced available energy-storage technology and are improving day by day via modifying the electrode composition. In this work, we described the hydrothermal production of SrCeO3/RGO nanocomposite as an effective and high-performance electrode material for SCs. Different approaches were adopted to look at the structural features along with the electrochemical behaviors of the prepared nanocomposite. X-ray structural analysis data and surface analysis showed that the nanocomposite had a pure crystalline phase and enhanced surface area. SrCeO3/RGO nanocomposite possessed a specific capacitance of 1359.9 F/g at 1 A/g, while it was 653.1 F/g for pure SrCeO3 electrode. The nanocomposite showed a small decrease in its polarization curve area following the 6000th cycle of the stability test. Additionally, SrCeO3 and SrCeO3/RGO nanocomposite exhibited specific energy of 28.7 and 63.5 Wh/kg at 1 A/g value with specific power of 281.5 and 290.1 W/kg, respectively. Numerous findings demonstrated that the enhanced ion/electron mobility and electric conductivity of nanocomposite lead to a rapid charge-storing approach and significantly boost electrochemical performance. The exceptional functionality of the SrCeO3/RGO nanocomposite demonstrated its favorable potential for the future generation of energy storage by reducing reliance on materials with a spinel-like structure.
{"title":"Hydrothermal formation of novel SrCeO3/RGO nanocomposite as supercapacitor electrode material","authors":"Tamoor Ahmad, Albandari W. Alrowaily, B. M. Alotaibi, Haifa A. Alyousef, A. Dahshan, A. M. A. Henaish","doi":"10.1007/s10971-024-06401-0","DOIUrl":"https://doi.org/10.1007/s10971-024-06401-0","url":null,"abstract":"<p>Growing populations and development led to a higher utilization of fossil fuels and more CO<sub>2</sub> emissions; which prompted researchers to look for pollution-free energy sources and improved energy-storage technologies. Supercapacitors (SC<sub>s</sub>) are thought to be the most advanced available energy-storage technology and are improving day by day via modifying the electrode composition. In this work, we described the hydrothermal production of SrCeO<sub>3</sub>/RGO nanocomposite as an effective and high-performance electrode material for SC<sub>s</sub>. Different approaches were adopted to look at the structural features along with the electrochemical behaviors of the prepared nanocomposite. X-ray structural analysis data and surface analysis showed that the nanocomposite had a pure crystalline phase and enhanced surface area. SrCeO<sub>3</sub>/RGO nanocomposite possessed a specific capacitance of 1359.9 F/g at 1 A/g, while it was 653.1 F/g for pure SrCeO<sub>3</sub> electrode. The nanocomposite showed a small decrease in its polarization curve area following the 6000th cycle of the stability test. Additionally, SrCeO<sub>3</sub> and SrCeO<sub>3</sub>/RGO nanocomposite exhibited specific energy of 28.7 and 63.5 Wh/kg at 1 A/g value with specific power of 281.5 and 290.1 W/kg, respectively. Numerous findings demonstrated that the enhanced ion/electron mobility and electric conductivity of nanocomposite lead to a rapid charge-storing approach and significantly boost electrochemical performance. The exceptional functionality of the SrCeO<sub>3</sub>/RGO nanocomposite demonstrated its favorable potential for the future generation of energy storage by reducing reliance on materials with a spinel-like structure.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940050","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}
Pub Date : 2024-05-10DOI: 10.1007/s10971-024-06390-0
Ekaterina Filimonova, Thomas Bergmann, Shanyu Zhao, Valery A. Dyatlov, Wim J. Malfait, Tingting Wu
Polyimide aerogels display excellent mechanical strength, high thermal stability, low thermal conductivity, and outstanding dielectric properties. Typically, the synthesis of polyimide aerogels involves the polycondensation of dianhydride and diamine into poly(amic acid) (PAA) oligomers, which are then cross-linked and chemically imidized into polyimide. The stoichiometry of dianhydride and diamine determines the number of repeat units and length of the PAA oligomers, which in turn determines the cross-linking density. Despite the critical role of polymer concentration and number of repeating units in determining the microstructure and properties of polyimide aerogels, few detailed studies exist on these two parameters. Here, we synthesized and characterized 16 polyimide aerogel formulations from the common monomers biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA), with different repeat units (n = 5, 15, 30, 45) and total polymer concentrations (4, 7, 10, 13 wt%). An increased polymer concentration accelerated gelation and enhanced the mechanical performance of aerogels, but surprisingly, it also led to higher volumetric shrinkage during aging, solvent exchange, and supercritical drying (SCD). Specific surface areas (SSAs) reached a maximum at intermediate polymer concentrations. A shorter oligomer chain length, i.e., a higher cross-linking density, led to moderately higher SSAs (between 320 and 400 m2/g) and reduced shrinkage, resulting in lower densities for a given polymer concentration. The density dependence of the thermal conductivity exhibits a pronounced U-shaped curve with a minimum in thermal conductivity of 21–23 mW/(m·K) between 0.080 and 0.120 g/cm3, with somewhat lower values for more highly cross-linked aerogels. This systematic study of polyimide aerogels forms the basis for designing polyimide aerogels with tailored properties for targeted applications.
{"title":"Effect of polymer concentration and cross-linking density on the microstructure and properties of polyimide aerogels","authors":"Ekaterina Filimonova, Thomas Bergmann, Shanyu Zhao, Valery A. Dyatlov, Wim J. Malfait, Tingting Wu","doi":"10.1007/s10971-024-06390-0","DOIUrl":"https://doi.org/10.1007/s10971-024-06390-0","url":null,"abstract":"<p>Polyimide aerogels display excellent mechanical strength, high thermal stability, low thermal conductivity, and outstanding dielectric properties. Typically, the synthesis of polyimide aerogels involves the polycondensation of dianhydride and diamine into poly(amic acid) (PAA) oligomers, which are then cross-linked and chemically imidized into polyimide. The stoichiometry of dianhydride and diamine determines the number of repeat units and length of the PAA oligomers, which in turn determines the cross-linking density. Despite the critical role of polymer concentration and number of repeating units in determining the microstructure and properties of polyimide aerogels, few detailed studies exist on these two parameters. Here, we synthesized and characterized 16 polyimide aerogel formulations from the common monomers biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA), with different repeat units (<i>n</i> = 5, 15, 30, 45) and total polymer concentrations (4, 7, 10, 13 wt%). An increased polymer concentration accelerated gelation and enhanced the mechanical performance of aerogels, but surprisingly, it also led to higher volumetric shrinkage during aging, solvent exchange, and supercritical drying (SCD). Specific surface areas (SSAs) reached a maximum at intermediate polymer concentrations. A shorter oligomer chain length, i.e., a higher cross-linking density, led to moderately higher SSAs (between 320 and 400 m<sup>2</sup>/g) and reduced shrinkage, resulting in lower densities for a given polymer concentration. The density dependence of the thermal conductivity exhibits a pronounced <i>U</i>-shaped curve with a minimum in thermal conductivity of 21–23 mW/(m·K) between 0.080 and 0.120 g/cm<sup>3</sup>, with somewhat lower values for more highly cross-linked aerogels. This systematic study of polyimide aerogels forms the basis for designing polyimide aerogels with tailored properties for targeted applications.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940349","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}
Pub Date : 2024-05-10DOI: 10.1007/s10971-024-06391-z
R. S. Diab, L. M. S. El-Deen, M. Moustafa, A. A. EL-Hamalawy, A. S. Abouhaswa
In the present investigation, the sol–gel auto-combustion process was used to synthesize spinel ferrite nanoparticles Cu1−xCoxEu0.025Fe1.975O4 with x = 0.0, 0.25, 0.5, 0.75, and 1. Through the use of various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersion X-ray analysis (EDX), Fourier transform Infrared analysis (FTIR), and magnetic measurements, the as-prepared ferrite nanoparticles have been examined and characterized. The X-ray diffraction (XRD) spectra confirmed the presence of a tetragonal spinel structure in the sample (x = 0), and the structure transformed into a cubic spinel with a space group of Fd3m as the Co content was increased. The lattice parameter changed from tetragonal phase with a = 5.820 Å and c = 8.710 Å for x = 0.00 to cubic phase with a = 8.372 Å for x = 1.00. The crystal size increases from 23.45 nm for x = 0.00 to 25.03 for x = 1.00 with increase in the amount of Co2+ content. The cation distribution for Cu1−xCoxEu0.025Fe1.975O4 spinel ferrites has been estimated. Scanning electron microphotographs (SEM) of the prepared spinel ferrite samples demonstrated well-defined crystalline nanoparticles. The existence of every major element (Co, Cu, Fe, Eu, and O) and no discernible impurities in the samples is confirmed by the EDX analysis. FTIR spectra of Cu1−xCoxEu0.025Fe1.975O4 committed the formation of the spinel nanoferrites and confirmed the solid-state reaction completion. The values of saturation magnetization (Ms), coercivity (Hc), remnant magnetization (Mr), magnetic moment (μB), squareness ratio (Mr/Ms) and anisotropy constant (K) have been estimated from the magnetic measurements. The (Ms) values increase from 22.561 emu/g for x = 0.00 to 68.794 emu/g for x = 1.00 while the (Hc) values decrease from 1898Oe for x = 0.00–1023 Oe for x = 1.00 with increasing the Co2+ content. The minor Eu+3 doped Cu1−xCoxEu0.025Fe1.975O4 nanoferrites’s switching field distribution (SFD) evaluations were calculated by considering the first derivative of the demagnetization data.
Graphical Abstract
本研究采用溶胶-凝胶自动燃烧工艺合成了尖晶石铁氧体纳米粒子 Cu1-xCoxEu0.025Fe1.975O4，x = 0.0、0.25、0.5、0.75 和 1。通过使用 X 射线衍射 (XRD)、扫描电子显微镜 (SEM)、能量色散 X 射线分析 (EDX)、傅立叶变换红外分析 (FTIR) 和磁性测量等多种技术，对制备的铁氧体纳米粒子进行了检测和表征。X 射线衍射（XRD）光谱证实了样品中存在四方尖晶石结构（x = 0），随着钴含量的增加，该结构转变为空间群为 Fd3m 的立方尖晶石结构。晶格参数从 x = 0.00 时 a = 5.820 Å 和 c = 8.710 Å 的四方相转变为 x = 1.00 时 a = 8.372 Å 的立方相。随着 Co2+ 含量的增加，晶体尺寸从 x = 0.00 时的 23.45 nm 增大到 x = 1.00 时的 25.03 nm。对 Cu1-xCoxEu0.025Fe1.975O4 尖晶石铁氧体的阳离子分布进行了估算。制备的尖晶石铁氧体样品的扫描电子显微照片（SEM）显示出清晰的结晶纳米颗粒。电离辐射 X 分析证实了样品中存在各种主要元素（Co、Cu、Fe、Eu 和 O），且无明显杂质。Cu1-xCoxEu0.025Fe1.975O4 的傅立叶变换红外光谱证实了尖晶石纳米铁氧体的形成，并确认了固态反应的完成。磁性测量结果估算出了饱和磁化（Ms）、矫顽力（Hc）、剩磁（Mr）、磁矩（μB）、方差比（Mr/Ms）和各向异性常数（K）的值。随着 Co2+ 含量的增加，（Ms）值从 x = 0.00 时的 22.561 emu/g 增加到 x = 1.00 时的 68.794 emu/g，而（Hc）值则从 x = 0.00 时的 1898 Oe 下降到 x = 1.00 时的 1023 Oe。通过考虑退磁数据的一阶导数，计算了次要 Eu+3 掺杂 Cu1-xCoxEu0.025Fe1.975O4 纳米铁氧体的开关场分布（SFD）评估。
{"title":"Eu3+ ions doped Cu1−xCoxEu0.025Fe1.975O4 spinel ferrite nanocrystals: insights on structural, cation distribution, magnetic properties, and switching field distribution","authors":"R. S. Diab, L. M. S. El-Deen, M. Moustafa, A. A. EL-Hamalawy, A. S. Abouhaswa","doi":"10.1007/s10971-024-06391-z","DOIUrl":"https://doi.org/10.1007/s10971-024-06391-z","url":null,"abstract":"<p>In the present investigation, the sol–gel auto-combustion process was used to synthesize spinel ferrite nanoparticles Cu<sub>1−x</sub>Co<sub>x</sub>Eu<sub>0.025</sub>Fe<sub>1.975</sub>O<sub>4</sub> with <i>x</i> = 0.0, 0.25, 0.5, 0.75, and 1. Through the use of various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersion X-ray analysis (EDX), Fourier transform Infrared analysis (FTIR), and magnetic measurements, the as-prepared ferrite nanoparticles have been examined and characterized. The X-ray diffraction (XRD) spectra confirmed the presence of a tetragonal spinel structure in the sample (<i>x</i> = 0), and the structure transformed into a cubic spinel with a space group of Fd3m as the Co content was increased. The lattice parameter changed from tetragonal phase with a = 5.820 Å and c = 8.710 Å for <i>x</i> = 0.00 to cubic phase with <i>a</i> = 8.372 Å for <i>x</i> = 1.00. The crystal size increases from 23.45 nm for <i>x</i> = 0.00 to 25.03 for <i>x</i> = 1.00 with increase in the amount of Co<sup>2+</sup> content. The cation distribution for Cu<sub>1−<i>x</i></sub>Co<sub><i>x</i></sub>Eu<sub>0.025</sub>Fe<sub>1.975</sub>O<sub>4</sub> spinel ferrites has been estimated. Scanning electron microphotographs (SEM) of the prepared spinel ferrite samples demonstrated well-defined crystalline nanoparticles. The existence of every major element (Co, Cu, Fe, Eu, and O) and no discernible impurities in the samples is confirmed by the EDX analysis. FTIR spectra of Cu<sub>1−<i>x</i></sub>Co<sub><i>x</i></sub>Eu<sub>0.025</sub>Fe<sub>1.975</sub>O<sub>4</sub> committed the formation of the spinel nanoferrites and confirmed the solid-state reaction completion. The values of saturation magnetization (<i>M</i><sub>s</sub>), coercivity (<i>H</i><sub>c</sub>), remnant magnetization (<i>M</i><sub>r</sub>), magnetic moment (<i>μ</i><sub>B</sub>), squareness ratio (<i>M</i><sub>r</sub>/<i>M</i><sub>s</sub>) and anisotropy constant (<i>K</i>) have been estimated from the magnetic measurements. The (<i>M</i><sub>s</sub>) values increase from 22.561 emu/g for <i>x</i> = 0.00 to 68.794 emu/g for <i>x</i> = 1.00 while the (<i>H</i><sub>c</sub>) values decrease from 1898Oe for <i>x</i> = 0.00–1023 Oe for <i>x</i> = 1.00 with increasing the Co<sup>2+</sup> content. The minor Eu<sup>+3</sup> doped Cu<sub>1−<i>x</i></sub>Co<sub><i>x</i></sub>Eu<sub>0.025</sub>Fe<sub>1.975</sub>O<sub>4</sub> nanoferrites’s switching field distribution (SFD) evaluations were calculated by considering the first derivative of the demagnetization data.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140940046","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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