The development of probes for the efficient detection of volatile organic compounds is crucial for both human health protection and environmental monitoring. In this study, we successfully synthesized a ratiometric fluorescent sensing material [Eu-UiO-67 (1:1)], featuring dual-emission fluorescence peaks via a one-pot method. This material demonstrated exceptional ratiometric fluorescence recognition properties for liquid styrene and isoprene, achieving low limit of detections (LODs) of 6.2 and 20.24 ppb, respectively. Furthermore, we leveraged its outstanding photoluminescence properties to fabricate a Eu-UiO-67 film, which exhibited distinctive fluorescence responses toward gaseous styrene and isoprene. This unique behavior resulted in LODs of 12.42 ppb for gaseous styrene and 15.39 ppb for gaseous isoprene. The investigation into the sensing mechanisms revealed that the fluorescence response for styrene was mediated by an internal filtration effect, which arose from the competitive energy absorption between styrene and the Eu-UiO-67 (1:1) material. In contrast, fluorescence resonance energy transfer occurred between isoprene and the Eu-UiO-67 (1:1) materials. This approach offers a sensitive and reliable method for the detection of liquid/gaseous styrene and isoprene.
{"title":"Ultra-Sensitive Gaseous Styrene and Isoprene Detection with a Ratiometric Fluorescence Probe of Eu(III)-Incorporated UiO-67","authors":"Rui Cao, Xinxin Li, Zhihang He, Hanxiao Tang, Xiao-Ke Zheng, Zhijuan Zhang","doi":"10.1021/acs.langmuir.4c04166","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04166","url":null,"abstract":"The development of probes for the efficient detection of volatile organic compounds is crucial for both human health protection and environmental monitoring. In this study, we successfully synthesized a ratiometric fluorescent sensing material [Eu-UiO-67 (1:1)], featuring dual-emission fluorescence peaks via a one-pot method. This material demonstrated exceptional ratiometric fluorescence recognition properties for liquid styrene and isoprene, achieving low limit of detections (LODs) of 6.2 and 20.24 ppb, respectively. Furthermore, we leveraged its outstanding photoluminescence properties to fabricate a Eu-UiO-67 film, which exhibited distinctive fluorescence responses toward gaseous styrene and isoprene. This unique behavior resulted in LODs of 12.42 ppb for gaseous styrene and 15.39 ppb for gaseous isoprene. The investigation into the sensing mechanisms revealed that the fluorescence response for styrene was mediated by an internal filtration effect, which arose from the competitive energy absorption between styrene and the Eu-UiO-67 (1:1) material. In contrast, fluorescence resonance energy transfer occurred between isoprene and the Eu-UiO-67 (1:1) materials. This approach offers a sensitive and reliable method for the detection of liquid/gaseous styrene and isoprene.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"22 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c04714
Lingling Sun, Yi Zeng, Jitao Li, Haoqi Wang, Qingsong Hua, Shun Lu
Water electrolysis recognizes nickel foam (NF) as an effective current collector due to its excellent conductivity. However, recent studies highlighted NF’s effect on the efficacy of various electrocatalytic reactions, primarily due to the presence of electroactive chemical species at its interface. In contrast, numerous reports suggested that NF has a negligible impact on overall electrocatalytic activity. When evaluated against other current collectors, NF-supported catalysts demonstrate better electrochemical activity, predominantly due to NF’s interfacial design. This study presents an electrochemically relevant NF with a flexible interfacial design, supported by case studies and insights into promising future directions. This Perspective reveals the advantages, challenges, and overall applicability of NF’s interfacial design with the context of electrocatalytic water splitting in mind.
{"title":"Enhancing Water Electrolysis through Interfacial Design of Nickel Foam","authors":"Lingling Sun, Yi Zeng, Jitao Li, Haoqi Wang, Qingsong Hua, Shun Lu","doi":"10.1021/acs.langmuir.4c04714","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04714","url":null,"abstract":"Water electrolysis recognizes nickel foam (NF) as an effective current collector due to its excellent conductivity. However, recent studies highlighted NF’s effect on the efficacy of various electrocatalytic reactions, primarily due to the presence of electroactive chemical species at its interface. In contrast, numerous reports suggested that NF has a negligible impact on overall electrocatalytic activity. When evaluated against other current collectors, NF-supported catalysts demonstrate better electrochemical activity, predominantly due to NF’s interfacial design. This study presents an electrochemically relevant NF with a flexible interfacial design, supported by case studies and insights into promising future directions. This Perspective reveals the advantages, challenges, and overall applicability of NF’s interfacial design with the context of electrocatalytic water splitting in mind.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"57 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c04777
Ivan U. Vakarelski, Krastanka G. Marinova, Krassimir D. Danov
Spontaneous bubble growths in liquids are usually triggered by rapid changes in pressure or temperature that can lead to liquid gas supersaturation. Here, we report alternative scenarios of the spontaneous growths of bubbles inside a high-saturation-vapor-pressure and high-air-solubility perfluorocarbon liquid (PP1) that were observed under ambient quiescent conditions. First, we investigate spontaneous bubble growth inside the single PP1 phase, which was left to evaporate freely. The bubble growth is explained by the difference in the PP1 vapor pressure inside the bubble and that above the freely evaporating PP1 interface. Next, we study the bubble growth inside the liquid PP1 covered with a layer of a second air-saturated immiscible liquid: low-air-solubility water or higher-air-solubility ethanol. In both cases, the bubble growth rates were accelerated, indicating mass transfer of air from the water or ethanol phases to the PP1 phase. The bubble growth rates significantly increase for bubbles trapped at the PP1–water or PP1–ethanol interfaces due to faster air diffusion through the thin PP1 liquid films separating the bubbles from the upper phases. Finally, we consider the case of bubbles inside millimeter-sized PP1 emulsion droplets in water or ethanol. The bubble growth inside the droplet leads to an increase in the PP1 droplet’s effective buoyancy and to the detachment of the droplets from the substrate. The observed bubble growth rate in the case of emulsion droplets was much faster for PP1 droplets in ethanol than for PP1 droplets in water (minutes vs hours). The underlying physical mechanism of the increase of bubble volumes is the spontaneous mass transfer of both air and PP1 vapor to the bubbles produced by a colloidal diffusion pump effect.
{"title":"Spontaneous Bubble Growth Inside High-Saturation-Vapor-Pressure and High-Air-Solubility Liquids and Emulsion Droplets","authors":"Ivan U. Vakarelski, Krastanka G. Marinova, Krassimir D. Danov","doi":"10.1021/acs.langmuir.4c04777","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04777","url":null,"abstract":"Spontaneous bubble growths in liquids are usually triggered by rapid changes in pressure or temperature that can lead to liquid gas supersaturation. Here, we report alternative scenarios of the spontaneous growths of bubbles inside a high-saturation-vapor-pressure and high-air-solubility perfluorocarbon liquid (PP1) that were observed under ambient quiescent conditions. First, we investigate spontaneous bubble growth inside the single PP1 phase, which was left to evaporate freely. The bubble growth is explained by the difference in the PP1 vapor pressure inside the bubble and that above the freely evaporating PP1 interface. Next, we study the bubble growth inside the liquid PP1 covered with a layer of a second air-saturated immiscible liquid: low-air-solubility water or higher-air-solubility ethanol. In both cases, the bubble growth rates were accelerated, indicating mass transfer of air from the water or ethanol phases to the PP1 phase. The bubble growth rates significantly increase for bubbles trapped at the PP1–water or PP1–ethanol interfaces due to faster air diffusion through the thin PP1 liquid films separating the bubbles from the upper phases. Finally, we consider the case of bubbles inside millimeter-sized PP1 emulsion droplets in water or ethanol. The bubble growth inside the droplet leads to an increase in the PP1 droplet’s effective buoyancy and to the detachment of the droplets from the substrate. The observed bubble growth rate in the case of emulsion droplets was much faster for PP1 droplets in ethanol than for PP1 droplets in water (minutes vs hours). The underlying physical mechanism of the increase of bubble volumes is the spontaneous mass transfer of both air and PP1 vapor to the bubbles produced by a colloidal diffusion pump effect.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"75 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photoelectrochemical sensors have been studied for glucose detection because of their ability to minimize background noise and unwanted reactions. Titanium dioxide (TiO2), a highly efficient material in converting light into electricity, cannot utilize visible light. In this regard, we developed a nonenzymatic glucose sensor by using a simple one-step electrospinning technique to combine cupric oxide with TiO2 to create a heterojunction. The prepared nanofibers exhibit an extremely high aspect ratio and have a dense structure. These characteristics enhance the quantity of electron–hole pairs generated by light and the speed at which electrons are transferred. They also reduce the distance that charges need to travel and offer reactive sites for the catalytic oxidation of glucose. The sensor has a direct and proportional reaction within glucose concentration ranging from 30 μM to 2 mM under sunlight conditions. It achieves a detection limit of 9.9 μM with a signal-to-noise ratio of 3. The sensors also exhibit excellent stability, reproducibility, and selectivity. This study provides insights for development of photoelectrochemical sensors to detect glucose.
{"title":"Photoexcited CuO/TiO2 Heterojunction for Photoelectrochemical Sensors for Nonenzymatic Glucose Detection","authors":"Yuxin Wu, Tongle Gao, Hai-Tao Ren, Mei-Chen Lin, Ting-Ting Li, Ling Liu, Ching-Wen Lou","doi":"10.1021/acs.langmuir.4c05045","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05045","url":null,"abstract":"Photoelectrochemical sensors have been studied for glucose detection because of their ability to minimize background noise and unwanted reactions. Titanium dioxide (TiO<sub>2</sub>), a highly efficient material in converting light into electricity, cannot utilize visible light. In this regard, we developed a nonenzymatic glucose sensor by using a simple one-step electrospinning technique to combine cupric oxide with TiO<sub>2</sub> to create a heterojunction. The prepared nanofibers exhibit an extremely high aspect ratio and have a dense structure. These characteristics enhance the quantity of electron–hole pairs generated by light and the speed at which electrons are transferred. They also reduce the distance that charges need to travel and offer reactive sites for the catalytic oxidation of glucose. The sensor has a direct and proportional reaction within glucose concentration ranging from 30 μM to 2 mM under sunlight conditions. It achieves a detection limit of 9.9 μM with a signal-to-noise ratio of 3. The sensors also exhibit excellent stability, reproducibility, and selectivity. This study provides insights for development of photoelectrochemical sensors to detect glucose.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"36 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
(1) Replacement of Figure 9h,i. After careful review of our published manuscript, we found some errors. In Figure 9, “h” and “i” have not been arranged as per the citations given in the text. Figure 9h,i must be interchanged. In XRD (Figure 9i), inadvertently reused sample data were duplicated with the fresh sample XRD. This occurred due to an error during the figure preparation. (2) Replacement of Figure 10. In Figure 10c, the TC control images at 48 hpf (i) and 96 hpf (s) were accidentally repeated during figure preparation. We sincerely apologize for these errors. These changes do not affect the manuscript content and results. Figure 9. (h) Reusability studies of 20CS-HNT photocatalyst. (i) XRD studies of fresh and used 20CS-HNT photocatalyst against CR degradation. Figure 10. (c) Morphological abnormalities of Zebrafish embryos at different time using standard, CR control, CR final, TC control, and TC final samples. This article has not yet been cited by other publications.
{"title":"Correction to “Green Engineered CuO/SnO2/HNT Composites: Illuminating the Photocatalytic Path for Organic Pollutant Remediation and Zebrafish Embryo Toxicity Evaluation”","authors":"Kamalanathan Pouthika, Selvaraj Mohana Roopan, Gunabalan Madhumitha","doi":"10.1021/acs.langmuir.4c05185","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05185","url":null,"abstract":"(1) Replacement of Figure 9h,i. After careful review of our published manuscript, we found some errors. In Figure 9, “h” and “i” have not been arranged as per the citations given in the text. Figure 9h,i must be interchanged. In XRD (Figure 9i), inadvertently reused sample data were duplicated with the fresh sample XRD. This occurred due to an error during the figure preparation. (2) Replacement of Figure 10. In Figure 10c, the TC control images at 48 hpf (i) and 96 hpf (s) were accidentally repeated during figure preparation. We sincerely apologize for these errors. These changes do not affect the manuscript content and results.<named-content content-type=\"anchor\" r type=\"simple\"></named-content><named-content content-type=\"anchor\" r type=\"simple\"></named-content> Figure 9. (h) Reusability studies of 20CS-HNT photocatalyst. (i) XRD studies of fresh and used 20CS-HNT photocatalyst against CR degradation. Figure 10. (c) Morphological abnormalities of Zebrafish embryos at different time using standard, CR control, CR final, TC control, and TC final samples. This article has not yet been cited by other publications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"10 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c03834
He Tao, Ximin Yuan, Debin Shan, Bin Guo, Jie Xu
Flexible electronic patches have been widely studied in various fields. However, they still face serious challenges in cardio-brain signaling monitoring to achieve accurate adhesion and detection with compatibility in mildly humid environments. To tackle these challenges, we engineered a gelatin hydrogel film cross-linked with a biocompatible matrix factor and combined it with a blend of liquid metal and PVP to create the flexible electronic patch. The flexible patch has good biocompatibility and fatigue resistance due to the incorporation of liquid metal and natural gelatin, with the conductivity of liquid metal and minimal toxicity of the gelatin film. It is possible to securely insert it into the body for a duration of 3 weeks while maintaining monitoring functionality and withstanding 10 000 cycles of flexural fatigue. This research provides an innovative approach to the future advancement of flexible electronic patches.
{"title":"Flexible Electronic Patch Utilizing Gelatin Film for Heart and Brain Signal Detection","authors":"He Tao, Ximin Yuan, Debin Shan, Bin Guo, Jie Xu","doi":"10.1021/acs.langmuir.4c03834","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03834","url":null,"abstract":"Flexible electronic patches have been widely studied in various fields. However, they still face serious challenges in cardio-brain signaling monitoring to achieve accurate adhesion and detection with compatibility in mildly humid environments. To tackle these challenges, we engineered a gelatin hydrogel film cross-linked with a biocompatible matrix factor and combined it with a blend of liquid metal and PVP to create the flexible electronic patch. The flexible patch has good biocompatibility and fatigue resistance due to the incorporation of liquid metal and natural gelatin, with the conductivity of liquid metal and minimal toxicity of the gelatin film. It is possible to securely insert it into the body for a duration of 3 weeks while maintaining monitoring functionality and withstanding 10 000 cycles of flexural fatigue. This research provides an innovative approach to the future advancement of flexible electronic patches.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"37 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c03942
Vallil Bavya, Thazhavilai Ponnu Devaraj Rajan, Kattimuttathu Ittara Suresh
Mercury contamination of the environment is extremely hazardous to human health because of its significant toxicity, especially in water. Biomass-derived fluorophores such as carbon dots (CDs) have emerged as eco-friendly and cost-effective alternative sensors that provide comparable efficacy while mitigating the environmental and economic drawbacks of conventional methods. In this work, we report the fabrication of a selective fluorescence-enhancing sensor based on sulfur-doped carbon dots (SCDs) using waste bamboo-derived cellulose and sodium thiosulfate as the soft base dopant, which actively complexes with mercury ions for detection. SCDs with an average size of 4 nm were synthesized hydrothermally, and the sulfur doping was confirmed quantitatively with an atomic percentage of 6.5%. Optical studies reveal an abnormal fluorescence enhancement of SCD in the presence of mercury due to the aggregation of carbon dots via sulfur-containing functional groups. The fabricated sensor exhibits a low detection limit of 5.16 nM, suggesting its application potential as a reliable mercury sensor. Real-time analyses carried out using tap water samples spiked with mercury and industry samples showed high efficiency for Hg(II) detection. The sensing performance was also demonstrated by using SCD-coated filter paper strips.
{"title":"Design of Fluorescence Enhancing Sensor for Mercury Detection via Bamboo Cellulose-Derived Carbon Dots","authors":"Vallil Bavya, Thazhavilai Ponnu Devaraj Rajan, Kattimuttathu Ittara Suresh","doi":"10.1021/acs.langmuir.4c03942","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03942","url":null,"abstract":"Mercury contamination of the environment is extremely hazardous to human health because of its significant toxicity, especially in water. Biomass-derived fluorophores such as carbon dots (CDs) have emerged as eco-friendly and cost-effective alternative sensors that provide comparable efficacy while mitigating the environmental and economic drawbacks of conventional methods. In this work, we report the fabrication of a selective fluorescence-enhancing sensor based on sulfur-doped carbon dots (SCDs) using waste bamboo-derived cellulose and sodium thiosulfate as the soft base dopant, which actively complexes with mercury ions for detection. SCDs with an average size of 4 nm were synthesized hydrothermally, and the sulfur doping was confirmed quantitatively with an atomic percentage of 6.5%. Optical studies reveal an abnormal fluorescence enhancement of SCD in the presence of mercury due to the aggregation of carbon dots via sulfur-containing functional groups. The fabricated sensor exhibits a low detection limit of 5.16 nM, suggesting its application potential as a reliable mercury sensor. Real-time analyses carried out using tap water samples spiked with mercury and industry samples showed high efficiency for Hg(II) detection. The sensing performance was also demonstrated by using SCD-coated filter paper strips.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"6 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The adsorption behavior of an anionic surfactant, hydroxy alkane sulfonate with an alkyl chain length of 18 (C18HAS), from its hard water solution onto a mica surface and resulting lubrication properties were investigated. Because of the double chain-like chemical structure and aggregation behavior, C18HAS formed vesicles in hard water, which adsorbed onto a negatively charged mica surface via cation (Ca2+) bridging and then transformed into a bilayer film. The number of bilayers formed on the surface was evaluated by force curve measurements using an atomic force microscope (AFM), and the results showed a time-dependent increase of the number of adsorbed bilayers. Friction and lubrication properties were evaluated for the confined film of the C18HAS hard water solution between mica surfaces using the surface forces apparatus (SFA). When the two surfaces were brought into contact under load and sheared against each other, the lubricating film consisted of two adsorbed C18HAS bilayers whose friction coefficient μ was of the order of 10–3 or below. The detailed analysis of the friction features revealed that the slipping in the boundary film does not occur at the interface between the opposed headgroup region of the two adsorbed bilayers, which is the typical mechanism for the low friction of adsorbed phospholipid bilayers extensively studied in the literature. Instead, slipping occurs at the interface between opposed liquid-like alkyl chain tails within the adsorbed bilayers; the low friction coefficient comes from the existence of two slip planes in the boundary film.
{"title":"Boundary Lubrication with Adsorbed Anionic Surfactant Bilayers in Hard Water","authors":"Aya Toyoda, Hikaru Kimura, Tadashi Sugahara, Atsushi Miyazaki, Takaya Sakai, Shinji Yamada","doi":"10.1021/acs.langmuir.4c04155","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04155","url":null,"abstract":"The adsorption behavior of an anionic surfactant, hydroxy alkane sulfonate with an alkyl chain length of 18 (C18HAS), from its hard water solution onto a mica surface and resulting lubrication properties were investigated. Because of the double chain-like chemical structure and aggregation behavior, C18HAS formed vesicles in hard water, which adsorbed onto a negatively charged mica surface via cation (Ca<sup>2+</sup>) bridging and then transformed into a bilayer film. The number of bilayers formed on the surface was evaluated by force curve measurements using an atomic force microscope (AFM), and the results showed a time-dependent increase of the number of adsorbed bilayers. Friction and lubrication properties were evaluated for the confined film of the C18HAS hard water solution between mica surfaces using the surface forces apparatus (SFA). When the two surfaces were brought into contact under load and sheared against each other, the lubricating film consisted of two adsorbed C18HAS bilayers whose friction coefficient μ was of the order of 10<sup>–3</sup> or below. The detailed analysis of the friction features revealed that the slipping in the boundary film does not occur at the interface between the opposed headgroup region of the two adsorbed bilayers, which is the typical mechanism for the low friction of adsorbed phospholipid bilayers extensively studied in the literature. Instead, slipping occurs at the interface between opposed <i>liquid-like</i> alkyl chain tails within the adsorbed bilayers; the low friction coefficient comes from the existence of two slip planes in the boundary film.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"25 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c04515
Chao Li, Dongdong Gao, Liang Zhang, Jianan Li, Fenming Zhang, Han Xiao, Gang Cheng
Antifouling zwitterionic materials have extensive applications in the biomedical field. This study designed and successfully synthesized a novel poly(carboxybetaine) diacrylate (PCBDA) via cationic ring-opening polymerization of 2-methyl-2-oxazine, chain modification by the Michael reaction, and chain end transformation to acrylate. The cross-linker was obtained with a tunable molecular weight. Through photopolymerization, poly(carboxybetaine) (PCB) hydrogels with varying solid contents were obtained, and the effects of the solid content on the hydration properties, mechanical properties, and microstructure of the PCB hydrogels were investigated. Furthermore, the non-fouling properties of the PCB hydrogels were compared to those of commercial polyethylene glycol (PEG) hydrogels. Protein adsorption on PCB hydrogels was reduced by more than 60% compared to low-fouling PEG hydrogels. PCB hydrogels exhibit antibacterial adhesion properties similar to those of PEG hydrogels. In cell adhesion experiments, no cell adhesion was observed on the PCB hydrogels, indicating their superior anti-cell adhesion function. This advancement offers a more promising alternative to polyethylene glycol diacrylate (PEGDA) cross-linkers in the design of hydrogels.
{"title":"Antifouling Hydrogel Based on Zwitterionic Poly(carboxybetaine diacrylate) Cross-Linkers","authors":"Chao Li, Dongdong Gao, Liang Zhang, Jianan Li, Fenming Zhang, Han Xiao, Gang Cheng","doi":"10.1021/acs.langmuir.4c04515","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04515","url":null,"abstract":"Antifouling zwitterionic materials have extensive applications in the biomedical field. This study designed and successfully synthesized a novel poly(carboxybetaine) diacrylate (PCBDA) via cationic ring-opening polymerization of 2-methyl-2-oxazine, chain modification by the Michael reaction, and chain end transformation to acrylate. The cross-linker was obtained with a tunable molecular weight. Through photopolymerization, poly(carboxybetaine) (PCB) hydrogels with varying solid contents were obtained, and the effects of the solid content on the hydration properties, mechanical properties, and microstructure of the PCB hydrogels were investigated. Furthermore, the non-fouling properties of the PCB hydrogels were compared to those of commercial polyethylene glycol (PEG) hydrogels. Protein adsorption on PCB hydrogels was reduced by more than 60% compared to low-fouling PEG hydrogels. PCB hydrogels exhibit antibacterial adhesion properties similar to those of PEG hydrogels. In cell adhesion experiments, no cell adhesion was observed on the PCB hydrogels, indicating their superior anti-cell adhesion function. This advancement offers a more promising alternative to polyethylene glycol diacrylate (PEGDA) cross-linkers in the design of hydrogels.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"3 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-10DOI: 10.1021/acs.langmuir.4c02919
Jing Hu, Svetoslav E. Anachkov, Teanoosh Moaddel, Joseph O. Carnali
Mixtures of multiple surfactants that have superior performance to the individual components are highly sought-after commercially. Mixtures with a reduced Krafft point (TK) are particularly useful as they enable applications at lower temperatures. Such an example is the soap maker’s eutectic: the mixture of sodium laurate (NaL) and sodium oleate (NaOl). A true eutectic implies that the two surfactants do not mix in the solid state but mix readily in the micellar solution above TK, leading to a sharp TK depression at a specific composition. However, the NaL/NaOl mixture shows a broad TK depression of >15 °C at a NaOl weight fraction (wO) of about 0.5. Our tie-line analysis shows that pure NaL and NaOl do not coexist in the solid phase on either side of the TK minimum. X-ray analysis of the isolated solids with varying wO reveals that a unique intermediate compound (I.C.) forms in the solid state with a NaL-to-NaOl mole ratio of about 4/3. Below the TK minimum, NaL and the I.C. coexist in the solids for wO < 0.5, whereas the I.C. and NaOl coexist in the solids for wO > 0.5. Each pair of solids exhibits eutectic or monotectic solubility behavior, and the congruent I.C. melting point is so close to that of the eutectic point(s) that a broad TK minimum ensues. Thermal analysis and modeling via the freezing-point depression approach support the above interpretation. The fact that surfactants with other headgroups but the same blend of chain lengths do not exhibit similar depressed TK is a topic for further study.
{"title":"Reexamining the Enhanced Solubility of Sodium Laurate/Sodium Oleate Eutectic Mixtures","authors":"Jing Hu, Svetoslav E. Anachkov, Teanoosh Moaddel, Joseph O. Carnali","doi":"10.1021/acs.langmuir.4c02919","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02919","url":null,"abstract":"Mixtures of multiple surfactants that have superior performance to the individual components are highly sought-after commercially. Mixtures with a reduced Krafft point (<i>T</i><sub>K</sub>) are particularly useful as they enable applications at lower temperatures. Such an example is the soap maker’s eutectic: the mixture of sodium laurate (NaL) and sodium oleate (NaOl). A true eutectic implies that the two surfactants do not mix in the solid state but mix readily in the micellar solution above <i>T</i><sub>K</sub>, leading to a sharp <i>T</i><sub>K</sub> depression at a specific composition. However, the NaL/NaOl mixture shows a broad <i>T</i><sub>K</sub> depression of >15 °C at a NaOl weight fraction (<i>w</i><sub>O</sub>) of about 0.5. Our tie-line analysis shows that pure NaL and NaOl do not coexist in the solid phase on either side of the <i>T</i><sub>K</sub> minimum. X-ray analysis of the isolated solids with varying <i>w</i><sub>O</sub> reveals that a unique intermediate compound (I.C.) forms in the solid state with a NaL-to-NaOl mole ratio of about 4/3. Below the <i>T</i><sub>K</sub> minimum, NaL and the I.C. coexist in the solids for <i>w</i><sub>O</sub> < 0.5, whereas the I.C. and NaOl coexist in the solids for <i>w</i><sub>O</sub> > 0.5. Each pair of solids exhibits eutectic or monotectic solubility behavior, and the congruent I.C. melting point is so close to that of the eutectic point(s) that a broad <i>T</i><sub>K</sub> minimum ensues. Thermal analysis and modeling via the freezing-point depression approach support the above interpretation. The fact that surfactants with other headgroups but the same blend of chain lengths do not exhibit similar depressed <i>T</i><sub>K</sub> is a topic for further study.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"14 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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