Fully aromatic helicenes are fascinating building blocks for the construction of inherently chiral macrocyclic nanocarbons. Such helicene-based non-planar macrocycles interact with each other and underlying substrate and form various 2D crystals. However, the role of their chirality remains unknown. In Atomic Force Microscopy (AFM) the macrocycles show stripes with six-fold symmetry but only faintly visible internal structure that is not sufficient to see individual adsorbed molecules and identify their chirality. Here, AFM data of self-assembled helicene-based 2D molecular crystals are analyzed by a new computational method that combines various information from AFM image and expected molecular shape taken from molecular dynamic simulations. Possible molecule arrangements are thereby computed and four basic structural elements (dimers) with the smallest deviation from AFM topography image are found. Validation procedure using larger AFM image with many 2D crystal domains improves the resolution in AFM data above the expected value for ultrasharp cantilevers and allows reliable and reproducible reconstruction of molecular shape, precise molecules position within the 2D crystal as well their chirality. The presented results and developed mathematical method are generally applicable to study ensembles of molecules with known atom coordinates and to any image with periodic pattern.
{"title":"Racemic Dimers as Models of Chiral Macrocycles Self-Assembled on Pyrolytic Graphite","authors":"E. Ukraintsev, V. Houska, J. Vacek, B. Rezek","doi":"10.2139/ssrn.3935548","DOIUrl":"https://doi.org/10.2139/ssrn.3935548","url":null,"abstract":"Fully aromatic helicenes are fascinating building blocks for the construction of inherently chiral macrocyclic nanocarbons. Such helicene-based non-planar macrocycles interact with each other and underlying substrate and form various 2D crystals. However, the role of their chirality remains unknown. In Atomic Force Microscopy (AFM) the macrocycles show stripes with six-fold symmetry but only faintly visible internal structure that is not sufficient to see individual adsorbed molecules and identify their chirality. Here, AFM data of self-assembled helicene-based 2D molecular crystals are analyzed by a new computational method that combines various information from AFM image and expected molecular shape taken from molecular dynamic simulations. Possible molecule arrangements are thereby computed and four basic structural elements (dimers) with the smallest deviation from AFM topography image are found. Validation procedure using larger AFM image with many 2D crystal domains improves the resolution in AFM data above the expected value for ultrasharp cantilevers and allows reliable and reproducible reconstruction of molecular shape, precise molecules position within the 2D crystal as well their chirality. The presented results and developed mathematical method are generally applicable to study ensembles of molecules with known atom coordinates and to any image with periodic pattern.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72768690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qingchao Cheng, Yanzhuo Lv, Deyu Li, Ning Li, Qiao Ding, Y. Zhao, Qi Zhao
The Sn-Fe alloy coating is a potential choice for decorative coatings and electronic products because of its excellent performance. However, oxidation of the bath is likely to occur in the process of use, which limits the production of electrodeposition of Sn-Fe alloy. Resveratrol has excellent antioxidant capacity and is considered as a non-polluting natural antioxidant. However, the understanding of using of resveratrol as stabilizer for electroplating solution in the field of electrodeposition is limited. In this study, resveratrol, hydroquinone and TBHQ are selected as the stabilizers of the electroplating bath to conduct comparative experiments for measuring the stability effect of resveratrol. The antioxidant capacities of three stabilizers are compared by means of the natural oxidation experiment, H2O2 accelerated oxidation experiment and electrochemical testing. The natural oxidation experiment and H2O2 accelerated oxidation experiment confirm that the antioxidant effect of resveratrol is higher than hydroquinone and TBHQ. To determine the optimal concentration of resveratrol in the electroplating solution, EIS and salt spray test were conducted. These results show that appropriate resveratrol can improve the corrosion resistance of the coating, but excessive resveratrol is detrimental to corrosion resistance. Therefore, the optimal concentration of resveratrol in the electroplating solution is 1.0g/L.
{"title":"Effect of Resveratrol on Sn-Fe Alloy Electrodeposition","authors":"Qingchao Cheng, Yanzhuo Lv, Deyu Li, Ning Li, Qiao Ding, Y. Zhao, Qi Zhao","doi":"10.2139/ssrn.3946128","DOIUrl":"https://doi.org/10.2139/ssrn.3946128","url":null,"abstract":"The Sn-Fe alloy coating is a potential choice for decorative coatings and electronic products because of its excellent performance. However, oxidation of the bath is likely to occur in the process of use, which limits the production of electrodeposition of Sn-Fe alloy. Resveratrol has excellent antioxidant capacity and is considered as a non-polluting natural antioxidant. However, the understanding of using of resveratrol as stabilizer for electroplating solution in the field of electrodeposition is limited. In this study, resveratrol, hydroquinone and TBHQ are selected as the stabilizers of the electroplating bath to conduct comparative experiments for measuring the stability effect of resveratrol. The antioxidant capacities of three stabilizers are compared by means of the natural oxidation experiment, H2O2 accelerated oxidation experiment and electrochemical testing. The natural oxidation experiment and H2O2 accelerated oxidation experiment confirm that the antioxidant effect of resveratrol is higher than hydroquinone and TBHQ. To determine the optimal concentration of resveratrol in the electroplating solution, EIS and salt spray test were conducted. These results show that appropriate resveratrol can improve the corrosion resistance of the coating, but excessive resveratrol is detrimental to corrosion resistance. Therefore, the optimal concentration of resveratrol in the electroplating solution is 1.0g/L.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76509247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ooraphan Chirayutthanasak, R. Sarochawikasit, A. Wisitsorasak, N. Rujisamphan, T. Frolov, T. Oppelstrup, S. Dangtip, G. Rohrer, S. Ratanaphan
Abstract Describing microstructure evolution in tungsten requires a quantitative description of the anisotropic grain boundary energy. We present a grain boundary energy function for tungsten that specifies the energy of an arbitrary boundary given its five macroscopic crystallographic parameters. A comparison of measured grain boundary areas and the grain boundary energies given by the function at the Σ11, Σ17b, and Σ33a misorientations, which are problematic to determine by measurement or atomistic calculations, reveals inverse correlations that are similar to what have been observed in other metals.
{"title":"Anisotropic Grain Boundary Area and Energy Distributions in Tungsten","authors":"Ooraphan Chirayutthanasak, R. Sarochawikasit, A. Wisitsorasak, N. Rujisamphan, T. Frolov, T. Oppelstrup, S. Dangtip, G. Rohrer, S. Ratanaphan","doi":"10.2139/ssrn.3855728","DOIUrl":"https://doi.org/10.2139/ssrn.3855728","url":null,"abstract":"Abstract Describing microstructure evolution in tungsten requires a quantitative description of the anisotropic grain boundary energy. We present a grain boundary energy function for tungsten that specifies the energy of an arbitrary boundary given its five macroscopic crystallographic parameters. A comparison of measured grain boundary areas and the grain boundary energies given by the function at the Σ11, Σ17b, and Σ33a misorientations, which are problematic to determine by measurement or atomistic calculations, reveals inverse correlations that are similar to what have been observed in other metals.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79847603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chengshang Zhou, F. Lin, Pei Sun, Zoujun Chen, Z. Duan, X. Zhu, Yong Liu, Z. Fang
Full density of sintered Ti alloys is difficult to achieve through conventional pressureless sintering techniques. This paper introduces a novel approach for densifying powder metallurgy Ti alloys through constrained hydrogenation assisted densification (CHAD). This method utilizes hydrogenation-induced volumetric expansion and constrains a sintered Ti body in a rigid mold to achieve densification. The results demonstrate that the residual porosity in powder metallurgy CP-Ti and Ti-6Al-4V alloys can be effectively reduced or removed by CHAD, leading to improved tensile properties. The described method can be used as an efficient and cost-effective technique to make Ti and Ti alloys with high density and improved mechanical properties.
{"title":"A Novel Method for Densification of Titanium Using Hydrogenation-Induced Expansion Under Constrained Conditions","authors":"Chengshang Zhou, F. Lin, Pei Sun, Zoujun Chen, Z. Duan, X. Zhu, Yong Liu, Z. Fang","doi":"10.2139/ssrn.3946393","DOIUrl":"https://doi.org/10.2139/ssrn.3946393","url":null,"abstract":"Full density of sintered Ti alloys is difficult to achieve through conventional pressureless sintering techniques. This paper introduces a novel approach for densifying powder metallurgy Ti alloys through constrained hydrogenation assisted densification (CHAD). This method utilizes hydrogenation-induced volumetric expansion and constrains a sintered Ti body in a rigid mold to achieve densification. The results demonstrate that the residual porosity in powder metallurgy CP-Ti and Ti-6Al-4V alloys can be effectively reduced or removed by CHAD, leading to improved tensile properties. The described method can be used as an efficient and cost-effective technique to make Ti and Ti alloys with high density and improved mechanical properties.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82173278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Ma, Ting-Ting Zhang, Zheng Zhang, Haixia Tong, Xiao-Yi Yi
The diethylphosphonate ligand HL 1 substituted pyridylpyrrole was synthesized by treatment of 2-bromo-6-(1H'-pyrrol-2-yl)pyridine and diethylphosphite in presence of base triethylamine and catalyst Pd(PPh 3 ) 4 under refluxing toluene conditions. The HL 1 ligand was treated with bromotrimethylsilane and followed hydrolysis by methanol to afford diphosphonic acid ligand H 3 L 2 . Treatment of H 3 L 2 with [Ru(NO)Cl 3 ] in presence of triethylamine in refluxing thf was generated diruthenium nitrosyl complex [Ru(L 2 )(NO)(Cl)] 2 ·(Et 3 NH) 2 ([ 1 ]·(Et 3 NH) 2 ), which is water soluble. The ligands and metal complex were fully characterized by NMR, IR, ESI-MS and single crystal X-ray diffraction technology. The solid state structure analysis displays 1 2- is dinuclear species, of which two ruthenium atoms are linked by two PO 3 2- groups. Photorelease of nitric oxide from 1 2- was monitored by UV-Vis spectra and the amount of the NO was determined by Griess reaction and DPPH radical scavenging reaction.
{"title":"Photorelease of Nitric Oxide in Water-Soluble Diruthenium Nitrosyl Complexes with Phosphonate Substituted Pyridylpyrrole","authors":"Fan Ma, Ting-Ting Zhang, Zheng Zhang, Haixia Tong, Xiao-Yi Yi","doi":"10.2139/ssrn.3745220","DOIUrl":"https://doi.org/10.2139/ssrn.3745220","url":null,"abstract":"The diethylphosphonate ligand HL 1 substituted pyridylpyrrole was synthesized by treatment of 2-bromo-6-(1H'-pyrrol-2-yl)pyridine and diethylphosphite in presence of base triethylamine and catalyst Pd(PPh 3 ) 4 under refluxing toluene conditions. The HL 1 ligand was treated with bromotrimethylsilane and followed hydrolysis by methanol to afford diphosphonic acid ligand H 3 L 2 . Treatment of H 3 L 2 with [Ru(NO)Cl 3 ] in presence of triethylamine in refluxing thf was generated diruthenium nitrosyl complex [Ru(L 2 )(NO)(Cl)] 2 ·(Et 3 NH) 2 ([ 1 ]·(Et 3 NH) 2 ), which is water soluble. The ligands and metal complex were fully characterized by NMR, IR, ESI-MS and single crystal X-ray diffraction technology. The solid state structure analysis displays 1 2- is dinuclear species, of which two ruthenium atoms are linked by two PO 3 2- groups. Photorelease of nitric oxide from 1 2- was monitored by UV-Vis spectra and the amount of the NO was determined by Griess reaction and DPPH radical scavenging reaction.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85321297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Acousto-optic (AO) phase matching condition is determined not only by the optical and acoustic waves propagation direction and parameters, but also by the physical characteristics of the AO interaction medium. Wherein, these characteristics, mainly the acoustic wave velocity, are temperature dependent. The change of ultrasound velocity relies on the medium stiffness constants cij variation with temperature. However, even for the most popular AO material – tellurium dioxide, the values of the stiffness constants temperature coefficients, given in various papers, vary significantly. The experimentally observed AO phase matching frequency temperature shift values do not coincide with those evaluated with literature data. In order to eliminate the observed discrepancy between theory and experiment, the AO phase matching frequency temperature dependencies for several AO cells based on TeO2 crystals with cut angles varying from 1.8° to 19° from the [110] axis in the (1‾10) plane were analyzed. The ultrasound velocity variation temperature coefficients were evaluated and the c11-c12 and c44 temperature coefficients that define the slow acoustic mode velocity in the selected plane were determined.
{"title":"Determination of the Paratellurite Stiffness Constants Temperature Coefficients by the Acousto-Optic Method","authors":"S. Mantsevich, E. Kostyleva","doi":"10.2139/ssrn.3902716","DOIUrl":"https://doi.org/10.2139/ssrn.3902716","url":null,"abstract":"Acousto-optic (AO) phase matching condition is determined not only by the optical and acoustic waves propagation direction and parameters, but also by the physical characteristics of the AO interaction medium. Wherein, these characteristics, mainly the acoustic wave velocity, are temperature dependent. The change of ultrasound velocity relies on the medium stiffness constants cij variation with temperature. However, even for the most popular AO material – tellurium dioxide, the values of the stiffness constants temperature coefficients, given in various papers, vary significantly. The experimentally observed AO phase matching frequency temperature shift values do not coincide with those evaluated with literature data. In order to eliminate the observed discrepancy between theory and experiment, the AO phase matching frequency temperature dependencies for several AO cells based on TeO2 crystals with cut angles varying from 1.8° to 19° from the [110] axis in the (1‾10) plane were analyzed. The ultrasound velocity variation temperature coefficients were evaluated and the c11-c12 and c44 temperature coefficients that define the slow acoustic mode velocity in the selected plane were determined.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73960753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adila Rani, Atul C Khot, Il Gyu Jang, Tae Geun Kim
This paper reports on the synthesis of vacancy-assisted carbon-packed MoSSe (C@MoSSe) nanospheres and their use in memristor and neuromorphic devices. The heterostructure C@MoSSe nanospheres were fabricated using simple hydrothermal and sonication methods to synthesize large-scale, uniform C@MoSSe films on flexible substrates. The carbon skeleton, tightly adhered to the heterostructure MoSSe nanospheres, helped assign low sp 2 characteristics to the vacancies on the defective surface of the MoSSe nanospheres, thereby facilitating the realization of highly stable memristor and neuromorphic performance. In addition, the defects in the crystal lattice of the pure phase of MoSSe increased the band gap (~4.39 eV) to be larger than the bulk and Janus structure of MoSSe (1.2 and 1.9 eV, respectively), resulting in carrier transport owing to trap filling. The C@MoSSe-based memristor successfully mimicked the basic and complex properties of synaptic plasticity, with a critical time window of ~460 μs, lower than that for the human brain. The bipolar memory performance, such as high on/off current ratio, reasonably low operating voltage, and stability, depended on the thickness of the C@MoSSe layers. The findings demonstrate the application potential of C@MoSSe-based memristors and can promote the realization of large-scale neuromorphic circuits.
{"title":"Heterostructure Carbon-Packed Mosse Nanospheres for Flexible Reram and Synapse Devices","authors":"Adila Rani, Atul C Khot, Il Gyu Jang, Tae Geun Kim","doi":"10.2139/ssrn.3935581","DOIUrl":"https://doi.org/10.2139/ssrn.3935581","url":null,"abstract":"This paper reports on the synthesis of vacancy-assisted carbon-packed MoSSe (C@MoSSe) nanospheres and their use in memristor and neuromorphic devices. The heterostructure C@MoSSe nanospheres were fabricated using simple hydrothermal and sonication methods to synthesize large-scale, uniform C@MoSSe films on flexible substrates. The carbon skeleton, tightly adhered to the heterostructure MoSSe nanospheres, helped assign low sp 2 characteristics to the vacancies on the defective surface of the MoSSe nanospheres, thereby facilitating the realization of highly stable memristor and neuromorphic performance. In addition, the defects in the crystal lattice of the pure phase of MoSSe increased the band gap (~4.39 eV) to be larger than the bulk and Janus structure of MoSSe (1.2 and 1.9 eV, respectively), resulting in carrier transport owing to trap filling. The C@MoSSe-based memristor successfully mimicked the basic and complex properties of synaptic plasticity, with a critical time window of ~460 μs, lower than that for the human brain. The bipolar memory performance, such as high on/off current ratio, reasonably low operating voltage, and stability, depended on the thickness of the C@MoSSe layers. The findings demonstrate the application potential of C@MoSSe-based memristors and can promote the realization of large-scale neuromorphic circuits.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82685141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinlong Zhu, Qing Liao, Han Huang, Liyuan Fu, Meihui Liu, Chunling Gu, H. Fu
Modulation of excited-state energy-level structures through controlled molecular-stacking arrangement provides an effective strategy to tuning fluorescence and thermally activated delayed fluorescence (TADF) amplified spontaneous emission (ASE), but remains a critical challenge. Herein, we demonstrated the regulation of fluorescence and TADF ASE in organic crystalline polymorphs by controlling the excited-state dynamics through aggregate effects. Experimental and theoretical studies show that green crystals emit green fluorescence ASE while red crystals emit red TADF ASE, because higher degree of J-aggregation in red crystals significantly results in a substantial decrease of energy gaps between singlet and triplet to 0.24 eV for the realization of reverse intersystem crossing process. Our results suggest that molecular packing presents a powerful approach to tailor the radiative channels and fundamentally important to tuning fluorescence and TADF ASE in pure organic crystals.
{"title":"J-Aggregation Enhanced Thermally Activated Delayed Fluorescence for Amplified Spontaneous Emission","authors":"Jinlong Zhu, Qing Liao, Han Huang, Liyuan Fu, Meihui Liu, Chunling Gu, H. Fu","doi":"10.2139/ssrn.3919971","DOIUrl":"https://doi.org/10.2139/ssrn.3919971","url":null,"abstract":"Modulation of excited-state energy-level structures through controlled molecular-stacking arrangement provides an effective strategy to tuning fluorescence and thermally activated delayed fluorescence (TADF) amplified spontaneous emission (ASE), but remains a critical challenge. Herein, we demonstrated the regulation of fluorescence and TADF ASE in organic crystalline polymorphs by controlling the excited-state dynamics through aggregate effects. Experimental and theoretical studies show that green crystals emit green fluorescence ASE while red crystals emit red TADF ASE, because higher degree of J-aggregation in red crystals significantly results in a substantial decrease of energy gaps between singlet and triplet to 0.24 eV for the realization of reverse intersystem crossing process. Our results suggest that molecular packing presents a powerful approach to tailor the radiative channels and fundamentally important to tuning fluorescence and TADF ASE in pure organic crystals.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72577222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eun-Hyuk Lee, Jinsoo Ahn, Y. Lim, H. Kwon, Myung-Joo Kim
This study investigated the effect of post-curing time on the color stability and related properties, such as degree of conversion (DC), surface roughness, water contact angle, water sorption (Wsp), and water solubility (Wsl) of 3D-printed resin for dental restorations. The 3D-printed specimens were divided into four groups according to the post-curing time (0, 5, 10, and 20 min). Color changes (ΔE00) of the specimens immersed in aging media were measured using a spectrophotometer at different aging times. The DC of the resin was measured using a FTIR. The surface roughness (Ra) of the resin immersed in coffee was measured at different aging times. Water contact angle was evaluated using the sessile drop method, and Wsp and Wsl were tested according to the ISO 4049:2019. The ΔE00 values of the specimens immersed in coffee and red wine decreased with increasing post-curing time. As the post-curing time increased up to 10 min, the DC increased and water contact angle decreased. The Ra value of the group without post-curing (0 min) increased gradually for 30 days, except between 7 and 15 days. However, when the post-curing time increased to greater than 10 min, no apparent change in Ra value was detected. The Wsp and Wsl of the group without post-curing were significantly lower and larger than that of the other groups, respectively. The longer the post-curing time of the tooth-colored 3D-printed resin, the better the color stability. The post-curing time of the 3D-printed resin affected the DC, surface roughness after aging in the staining media, water contact angle, water sorption, and water solubility.
{"title":"Effect of Post-Curing Time on the Color Stability and Related Properties of a Tooth-Colored 3D-Printed Resin Material","authors":"Eun-Hyuk Lee, Jinsoo Ahn, Y. Lim, H. Kwon, Myung-Joo Kim","doi":"10.2139/ssrn.3944573","DOIUrl":"https://doi.org/10.2139/ssrn.3944573","url":null,"abstract":"This study investigated the effect of post-curing time on the color stability and related properties, such as degree of conversion (DC), surface roughness, water contact angle, water sorption (Wsp), and water solubility (Wsl) of 3D-printed resin for dental restorations. The 3D-printed specimens were divided into four groups according to the post-curing time (0, 5, 10, and 20 min). Color changes (ΔE00) of the specimens immersed in aging media were measured using a spectrophotometer at different aging times. The DC of the resin was measured using a FTIR. The surface roughness (Ra) of the resin immersed in coffee was measured at different aging times. Water contact angle was evaluated using the sessile drop method, and Wsp and Wsl were tested according to the ISO 4049:2019. The ΔE00 values of the specimens immersed in coffee and red wine decreased with increasing post-curing time. As the post-curing time increased up to 10 min, the DC increased and water contact angle decreased. The Ra value of the group without post-curing (0 min) increased gradually for 30 days, except between 7 and 15 days. However, when the post-curing time increased to greater than 10 min, no apparent change in Ra value was detected. The Wsp and Wsl of the group without post-curing were significantly lower and larger than that of the other groups, respectively. The longer the post-curing time of the tooth-colored 3D-printed resin, the better the color stability. The post-curing time of the 3D-printed resin affected the DC, surface roughness after aging in the staining media, water contact angle, water sorption, and water solubility.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75037643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Lepró, C. Aracne-Ruddle, D. Malone, Haley Hamza, E. Schaible, S. Buchsbaum, Alicia Calonico-Soto, J. Bigelow, E. Meshot, S. Baxamusa, M. Stadermann
Carbon nanotubes (CNTs) possess exceptional mechanical properties, surpassing stiffness and strength metrics of common materials such as steel alloys by 100× at the nanoscale. However, when myriads of individual CNTs are bundled together into macroscopic ensembles like fibers or sheets, the result is a 100-fold drop in strength compared to its individual components. Here we present a general strategy aimed to close this gap in property scaling. By using vapor-phase polymerization of a cross-linkable polymer, we reinforced the weak interlinkages among individual CNTs within both yarns and sheets to promote a better transference of mechanical load across the structure. After the treatment, dry-spun, low-density 2.3 μm thin yarns increased their elastic moduli by at least 300%, and free-standing CNT sheets exhibited a 10× boost. In-situ synchrotron small-angle X-ray scattering revealed that polymer-reinforced yarns undergo limited CNT bundle rearrangement when subjected to tensile loads compared to pristine yarns. This evidence supports the hypothesis that the polymer hinders CNTs slippage, the root cause of the poor scaling of mechanical properties in these materials. While we demonstrated this reinforcement method for CNT structures, it is not specific to CNTs and could be used to reinforce a wide variety of hierarchical nanostructured ensembles.
{"title":"Liquid-Free Covalent Reinforcement of Carbon Nanotube Dry-Spun Yarns and Free-Standing Sheets","authors":"X. Lepró, C. Aracne-Ruddle, D. Malone, Haley Hamza, E. Schaible, S. Buchsbaum, Alicia Calonico-Soto, J. Bigelow, E. Meshot, S. Baxamusa, M. Stadermann","doi":"10.2139/ssrn.3937822","DOIUrl":"https://doi.org/10.2139/ssrn.3937822","url":null,"abstract":"Carbon nanotubes (CNTs) possess exceptional mechanical properties, surpassing stiffness and strength metrics of common materials such as steel alloys by 100× at the nanoscale. However, when myriads of individual CNTs are bundled together into macroscopic ensembles like fibers or sheets, the result is a 100-fold drop in strength compared to its individual components. Here we present a general strategy aimed to close this gap in property scaling. By using vapor-phase polymerization of a cross-linkable polymer, we reinforced the weak interlinkages among individual CNTs within both yarns and sheets to promote a better transference of mechanical load across the structure. After the treatment, dry-spun, low-density 2.3 μm thin yarns increased their elastic moduli by at least 300%, and free-standing CNT sheets exhibited a 10× boost. In-situ synchrotron small-angle X-ray scattering revealed that polymer-reinforced yarns undergo limited CNT bundle rearrangement when subjected to tensile loads compared to pristine yarns. This evidence supports the hypothesis that the polymer hinders CNTs slippage, the root cause of the poor scaling of mechanical properties in these materials. While we demonstrated this reinforcement method for CNT structures, it is not specific to CNTs and could be used to reinforce a wide variety of hierarchical nanostructured ensembles.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88516015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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