Pub Date : 2025-01-16DOI: 10.1021/acs.langmuir.4c04385
Yundi Lu, Sophia Guzman, Muhammad Rizwan, Kevin R. Hinkle, Zonglin Gu
Porous nanomaterials have shown great promise in many desalination applications. Zeolite nanotubes, featuring abundant but inhomogeneous nanopores on their surface, have been recently synthesized in experiments; however, their capacity for desalination is not yet understood. In this work, we use molecular dynamics simulations to investigate the capability of assembled zeolite nanotube membranes to perform in desalination applications due to their inherent multiscale porous properties. Two different membrane assemblies are examined to determine the effect of membrane orientation on desalination performance. Interestingly, we find that zeolite nanotube membranes present anisotropic desalination behavior, which is directly dependent on the assembled orientation of the zeolite nanotubes. Specifically, directing the transport through the axial channels of the nanotubes results in a water permeability of 59.8 L/cm2/day/MPa and 88% ion rejection. However, when the membrane is rotated 90° and the flow is directed perpendicular to the tube axis, the permeability drops to 22.3 L/cm2/day/MPa, but 100% ion rejection is achieved. This difference is attributed to the multiscale pore dimensions of the zeolite nanotube; that is, they possess large pores (a diameter of 3 nm) along the axial channel direction, but smaller pores (a diameter of 0.25 nm) along the direction perpendicular to the tube axis. The ion rejection capabilities are further verified by quantifying the free energy barriers to transport obtained via umbrella sampling simulations. Therefore, our findings demonstrate the orientation-dependent, anisotropic desalination performance in assembled zeolite nanotube membranes for the first time, which could be useful in designing future advanced desalination membranes.
{"title":"Orientation-Dependent Anisotropic Desalination by Assembled Zeolite Nanotube Membranes","authors":"Yundi Lu, Sophia Guzman, Muhammad Rizwan, Kevin R. Hinkle, Zonglin Gu","doi":"10.1021/acs.langmuir.4c04385","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04385","url":null,"abstract":"Porous nanomaterials have shown great promise in many desalination applications. Zeolite nanotubes, featuring abundant but inhomogeneous nanopores on their surface, have been recently synthesized in experiments; however, their capacity for desalination is not yet understood. In this work, we use molecular dynamics simulations to investigate the capability of assembled zeolite nanotube membranes to perform in desalination applications due to their inherent multiscale porous properties. Two different membrane assemblies are examined to determine the effect of membrane orientation on desalination performance. Interestingly, we find that zeolite nanotube membranes present anisotropic desalination behavior, which is directly dependent on the assembled orientation of the zeolite nanotubes. Specifically, directing the transport through the axial channels of the nanotubes results in a water permeability of 59.8 L/cm<sup>2</sup>/day/MPa and 88% ion rejection. However, when the membrane is rotated 90° and the flow is directed perpendicular to the tube axis, the permeability drops to 22.3 L/cm<sup>2</sup>/day/MPa, but 100% ion rejection is achieved. This difference is attributed to the multiscale pore dimensions of the zeolite nanotube; that is, they possess large pores (a diameter of 3 nm) along the axial channel direction, but smaller pores (a diameter of 0.25 nm) along the direction perpendicular to the tube axis. The ion rejection capabilities are further verified by quantifying the free energy barriers to transport obtained via umbrella sampling simulations. Therefore, our findings demonstrate the orientation-dependent, anisotropic desalination performance in assembled zeolite nanotube membranes for the first time, which could be useful in designing future advanced desalination membranes.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987055","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 : 2025-01-16DOI: 10.1021/acs.langmuir.4c04852
Himani Bisht, Yubin Hong, Suho Park, Yun Hwang, Daewha Hong
In this study, we developed zwitterionic surface coatings of carboxybetaine by mimicking natural melanogenesis. We synthesized an unnatural tyrosine-conjugated carboxybetaine (Tyr-CB) that undergoes melanin-like oxidation upon treatment with tyrosinase under various aqueous conditions. The thickness of the resulting poly(Tyr-CB) film was tuned by adjusting the pH during the coating process. The poly(Tyr-CB)-coated surfaces demonstrated excellent antifouling performance against proteins and cells and imparted (super)hydrophilicity to various substrates. Additionally, post-functionalization with external biotin-PEG-thiol was achieved by targeting the oxidized quinone groups within the poly(Tyr-CB) film network. This enabled biospecific binding to streptavidin, while non-specific interactions were suppressed due to the antifouling background. As our one-step antifouling coating method is simple, involves aqueous conditions, and could be generically used to coat various substrates, it can be a versatile and valuable tool for biosensing, high-throughput screening, and cell-surface engineering.
{"title":"Fabrication of Versatile Antifouling Coatings Inspired by Melanogenesis Using a Tyrosine-Conjugated Carboxybetaine Derivative","authors":"Himani Bisht, Yubin Hong, Suho Park, Yun Hwang, Daewha Hong","doi":"10.1021/acs.langmuir.4c04852","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04852","url":null,"abstract":"In this study, we developed zwitterionic surface coatings of carboxybetaine by mimicking natural melanogenesis. We synthesized an unnatural tyrosine-conjugated carboxybetaine (Tyr-CB) that undergoes melanin-like oxidation upon treatment with tyrosinase under various aqueous conditions. The thickness of the resulting poly(Tyr-CB) film was tuned by adjusting the pH during the coating process. The poly(Tyr-CB)-coated surfaces demonstrated excellent antifouling performance against proteins and cells and imparted (super)hydrophilicity to various substrates. Additionally, post-functionalization with external biotin-PEG-thiol was achieved by targeting the oxidized quinone groups within the poly(Tyr-CB) film network. This enabled biospecific binding to streptavidin, while non-specific interactions were suppressed due to the antifouling background. As our one-step antifouling coating method is simple, involves aqueous conditions, and could be generically used to coat various substrates, it can be a versatile and valuable tool for biosensing, high-throughput screening, and cell-surface engineering.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"37 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987056","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}
Molecular aggregation frequently occurs during material synthesis, cellular processes, and drug delivery systems, often resulting in decreased performance and efficiency. One major reason for such aggregation in an aqueous solution is hydrophobicity. While the basic understanding of the aggregation process of hydrophobic molecules from a thermodynamic standpoint is known, the present literature lacks a connection between the aggregation kinetics and the molecular basis of hydrophobicity. This study explores how various fluorescent probes (rhodamine dyes) aggregate in an aqueous solution due to their hydrophobicity. The method employs a combination of modeling and characterization to comprehend the aggregation process by examining the nonbonded intermolecular interactions. The aggregation kinetics was analyzed by measuring the average diffusivity of the molecules using fluorescent correlation spectroscopy and NMR diffusion measurements. Through all-atom molecular dynamics (MD) simulations, it has been observed that the level of hydrophobicity is strongly correlated to the total number of hydrogen bonds between water molecules and dyes. In addition, the aggregation frequency of colliding species, which depends on the concentration, is inversely related to hydrogen bonding and the diffusivity of the molecules. This study of small molecules was applied to predict protein aggregation rates, demonstrating strong alignment with the existing literature. The study has also helped to identify and understand the concentration at which a hydrophobic molecule does not aggregate in an aqueous solution. The method developed here could help investigate the aggregation process and its root causes at the molecular level in aqueous systems to develop strategies to control it.
{"title":"Nonbonded Molecular Interaction Controls Aggregation Kinetics of Hydrophobic Molecules in Water","authors":"Goga Ram, Rajarshi Guha, Surya Parkash, Samanwita Pal, Nirmalya Bachhar","doi":"10.1021/acs.langmuir.4c04317","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04317","url":null,"abstract":"Molecular aggregation frequently occurs during material synthesis, cellular processes, and drug delivery systems, often resulting in decreased performance and efficiency. One major reason for such aggregation in an aqueous solution is hydrophobicity. While the basic understanding of the aggregation process of hydrophobic molecules from a thermodynamic standpoint is known, the present literature lacks a connection between the aggregation kinetics and the molecular basis of hydrophobicity. This study explores how various fluorescent probes (rhodamine dyes) aggregate in an aqueous solution due to their hydrophobicity. The method employs a combination of modeling and characterization to comprehend the aggregation process by examining the nonbonded intermolecular interactions. The aggregation kinetics was analyzed by measuring the average diffusivity of the molecules using fluorescent correlation spectroscopy and NMR diffusion measurements. Through all-atom molecular dynamics (MD) simulations, it has been observed that the level of hydrophobicity is strongly correlated to the total number of hydrogen bonds between water molecules and dyes. In addition, the aggregation frequency of colliding species, which depends on the concentration, is inversely related to hydrogen bonding and the diffusivity of the molecules. This study of small molecules was applied to predict protein aggregation rates, demonstrating strong alignment with the existing literature. The study has also helped to identify and understand the concentration at which a hydrophobic molecule does not aggregate in an aqueous solution. The method developed here could help investigate the aggregation process and its root causes at the molecular level in aqueous systems to develop strategies to control it.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"15 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987347","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 : 2025-01-16DOI: 10.1021/acs.langmuir.4c03842
Kristopher W. Hoyt, Ashleigh C. Block, Jillian Tung, M. Scott Goodman, Igor K. Lednev, Jinseok Heo
Here, we report a simple method to prepare near-IR (NIR) surface-enhanced Raman scattering (SERS) substrates by quickly freezing a citrate-capped Au nanoparticle (AuNP) solution in liquid nitrogen, followed by thawing it at room temperature. This process aggregates AuNPs in a controlled manner by forming ice crystals with smaller grain sizes when compared to a slow freezing process. The resulting smaller AuNP aggregates remain suspended in solution long enough to conduct high-throughput chemical analysis in a microwell plate using the NIR SERS spectroscopy. We named these aggregates quick freezing-induced AuNP aggregates (QFIAAs). The aggregation state of QFIAAs in solution is stable for at least three months when stored at 4 °C. Several QFIAAs were prepared using monodisperse citrate-capped AuNPs of various sizes. QFIAAs prepared from AuNPs with an average diameter of 70 nm (70 nm QFIAAs) showed the best performance, considering both NIR SERS activity and the repeatability of the results. The NIR SERS enhancement factor of the 70 nm QFIAAs measured using 57 nM Rhodamine 6G (R6G) was 5 × 104. The R6G molecules could not displace the citrates present in the hotspots of QFIAAs, indicating that the long-term stability of QFIAAs originates from the tight interparticle binding through the citrates. The limit of detection (LOD) of R6G was 2 × 101 nM using the 70 nm QFIAAs. We anticipate that the QFIAA system can be used not only to screen reporter molecules for the NIR SERS bioimaging but also to detect analytes with background fluorescence that can be suppressed with NIR excitation wavelengths.
{"title":"Quick Freezing-Induced Au Nanoparticle Aggregates (QFIAAs) for Near-IR (NIR) Surface-Enhanced Raman Scattering (SERS) Substrates","authors":"Kristopher W. Hoyt, Ashleigh C. Block, Jillian Tung, M. Scott Goodman, Igor K. Lednev, Jinseok Heo","doi":"10.1021/acs.langmuir.4c03842","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03842","url":null,"abstract":"Here, we report a simple method to prepare near-IR (NIR) surface-enhanced Raman scattering (SERS) substrates by quickly freezing a citrate-capped Au nanoparticle (AuNP) solution in liquid nitrogen, followed by thawing it at room temperature. This process aggregates AuNPs in a controlled manner by forming ice crystals with smaller grain sizes when compared to a slow freezing process. The resulting smaller AuNP aggregates remain suspended in solution long enough to conduct high-throughput chemical analysis in a microwell plate using the NIR SERS spectroscopy. We named these aggregates quick freezing-induced AuNP aggregates (QFIAAs). The aggregation state of QFIAAs in solution is stable for at least three months when stored at 4 °C. Several QFIAAs were prepared using monodisperse citrate-capped AuNPs of various sizes. QFIAAs prepared from AuNPs with an average diameter of 70 nm (70 nm QFIAAs) showed the best performance, considering both NIR SERS activity and the repeatability of the results. The NIR SERS enhancement factor of the 70 nm QFIAAs measured using 57 nM Rhodamine 6G (R6G) was 5 × 10<sup>4</sup>. The R6G molecules could not displace the citrates present in the hotspots of QFIAAs, indicating that the long-term stability of QFIAAs originates from the tight interparticle binding through the citrates. The limit of detection (LOD) of R6G was 2 × 10<sup>1</sup> nM using the 70 nm QFIAAs. We anticipate that the QFIAA system can be used not only to screen reporter molecules for the NIR SERS bioimaging but also to detect analytes with background fluorescence that can be suppressed with NIR excitation wavelengths.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"54 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987052","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 : 2025-01-16DOI: 10.1021/acs.langmuir.4c04368
Carlos Corral-Casas, Carlos Ayestarán Latorre, Chiara Gattinoni, Mark Brewer, Jörn Karl, Daniele Dini, James P. Ewen
Engine deposits can reduce performance and increase emissions, particularly for modern direct-injection fuel delivery systems. Surfactants known as deposit control additives (DCAs) adsorb and self-assemble on the surface of deposit precursors to keep them suspended in the fuel. Here, we show how molecular simulations can be used to virtually screen the ability of surfactants to bind to polyaromatic hydrocarbons, comprising a major class of carbonaceous deposits. We use molecular dynamics with the adaptive biasing force method to generate the potential of mean force as a function of the vertical distance between the surfactants and deposits in gasoline and diesel fuel surrogates. We find that a zwitterionic surfactant outperforms a conventional polyisobutylene succinimide for binding to these aromatic species. The amine groups in the succinimide headgroup only weakly adsorb on the polyaromatic deposit, while additional functional groups in the zwitterionic surfactant, particularly the quarternary ammonium ion, markedly enhance the binding strength. We decompose the adsorption free energies of the surfactants into their entropic and enthalpic components, to find that the latter dominates the attraction from these non-aqueous solvents. The adsorption free energy of both surfactants is slightly weaker from n-hexadecane (diesel) than iso-octane (gasoline), which is due to the larger steric barrier from stronger molecular layering of the former on the deposit. Density functional theory calculations of the adsorption of DCA fragments validate the force field used in the molecular dynamics simulations and provide further insights into the nature of the intermolecular interactions. The approach introduced here shows considerable promise for accelerating the discovery of novel DCAs to facilitate more advanced fuel formulations to reduce emissions.
{"title":"Molecular Insights into the Adsorption of Deposit Control Additives from Hydrocarbon Fuels","authors":"Carlos Corral-Casas, Carlos Ayestarán Latorre, Chiara Gattinoni, Mark Brewer, Jörn Karl, Daniele Dini, James P. Ewen","doi":"10.1021/acs.langmuir.4c04368","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04368","url":null,"abstract":"Engine deposits can reduce performance and increase emissions, particularly for modern direct-injection fuel delivery systems. Surfactants known as deposit control additives (DCAs) adsorb and self-assemble on the surface of deposit precursors to keep them suspended in the fuel. Here, we show how molecular simulations can be used to virtually screen the ability of surfactants to bind to polyaromatic hydrocarbons, comprising a major class of carbonaceous deposits. We use molecular dynamics with the adaptive biasing force method to generate the potential of mean force as a function of the vertical distance between the surfactants and deposits in gasoline and diesel fuel surrogates. We find that a zwitterionic surfactant outperforms a conventional polyisobutylene succinimide for binding to these aromatic species. The amine groups in the succinimide headgroup only weakly adsorb on the polyaromatic deposit, while additional functional groups in the zwitterionic surfactant, particularly the quarternary ammonium ion, markedly enhance the binding strength. We decompose the adsorption free energies of the surfactants into their entropic and enthalpic components, to find that the latter dominates the attraction from these non-aqueous solvents. The adsorption free energy of both surfactants is slightly weaker from <i>n</i>-hexadecane (diesel) than iso-octane (gasoline), which is due to the larger steric barrier from stronger molecular layering of the former on the deposit. Density functional theory calculations of the adsorption of DCA fragments validate the force field used in the molecular dynamics simulations and provide further insights into the nature of the intermolecular interactions. The approach introduced here shows considerable promise for accelerating the discovery of novel DCAs to facilitate more advanced fuel formulations to reduce emissions.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"68 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987054","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 : 2025-01-16DOI: 10.1021/acs.langmuir.4c04305
Shuai Ning, Bin Pei, Jialei Li, Ruizeng Liu, Dianwen Liu
The sulfidization-xanthate flotation process has been used commercially with some success in recovering azurite, but it remains unsatisfactory in terms of the environmental impact and flotation index. To remediate these deficiencies, this study evaluated the flotation performance of sodium trithiocarbonate (Na2CS3) as a green sulfidizing agent for azurite. Flotation test results demonstrated that Na2CS3 has the same efficacy as sodium sulfide but markedly superior activation performance. At one-fifth the dose, the maximum flotation recovery for Na2CS3 is about 20 percentage points higher than that observed for sodium sulfide. Contact angle measurements and field emission scanning electron microscopy analysis revealed that Na2CS3 modifies the pristine azurite surface by forming a relatively uniform sulfur-rich layer composed of nanoparticles, which in turn increases the collector efficacy and thus improves flotation recovery. The results of X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry further suggest that this sulfur-rich hydrophobic layer could be cuprous trithiocarbonate. The reduction of Cu(II) in the azurite lattice is considered a key step in forming the sulfur-rich layer, and the resultant Cu(I) interacts with Na2CS3 through the latter’s carbon–sulfur bonds. The results of this study will facilitate the development of better technologies to process copper oxide ores.
{"title":"Sodium Trithiocarbonate as a Promising Sulfidizing Agent for Efficient and Green Recovery of Azurite: Flotation Properties and Interaction Mechanism","authors":"Shuai Ning, Bin Pei, Jialei Li, Ruizeng Liu, Dianwen Liu","doi":"10.1021/acs.langmuir.4c04305","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04305","url":null,"abstract":"The sulfidization-xanthate flotation process has been used commercially with some success in recovering azurite, but it remains unsatisfactory in terms of the environmental impact and flotation index. To remediate these deficiencies, this study evaluated the flotation performance of sodium trithiocarbonate (Na<sub>2</sub>CS<sub>3</sub>) as a green sulfidizing agent for azurite. Flotation test results demonstrated that Na<sub>2</sub>CS<sub>3</sub> has the same efficacy as sodium sulfide but markedly superior activation performance. At one-fifth the dose, the maximum flotation recovery for Na<sub>2</sub>CS<sub>3</sub> is about 20 percentage points higher than that observed for sodium sulfide. Contact angle measurements and field emission scanning electron microscopy analysis revealed that Na<sub>2</sub>CS<sub>3</sub> modifies the pristine azurite surface by forming a relatively uniform sulfur-rich layer composed of nanoparticles, which in turn increases the collector efficacy and thus improves flotation recovery. The results of X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry further suggest that this sulfur-rich hydrophobic layer could be cuprous trithiocarbonate. The reduction of Cu(II) in the azurite lattice is considered a key step in forming the sulfur-rich layer, and the resultant Cu(I) interacts with Na<sub>2</sub>CS<sub>3</sub> through the latter’s carbon–sulfur bonds. The results of this study will facilitate the development of better technologies to process copper oxide ores.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987346","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}
Durable and fluorine-free superhydrophobic films were fabricated by a simple two-step process involving the pretreatment of glass substrates with an epoxysilane, which acted as an adhesive. The next step involved the aerosol-assisted chemical vapor deposition of a simple mixture of polydimethylsiloxane (PDMS) and SiO2 nanoparticles (NPs). Various parameters were studied, such as deposition time as well as PDMS and SiO2 loadings. The optimum film generated was with a 1:1 loading of PDMS and SiO2, deposited at 360 °C for 40 min. The resultant film demonstrated excellent water repellency with a water contact angle of 165 ± 3° and a sliding angle of 2°. The epoxysilane underlayer provided the adhesion between the film and substrate. The films maintained superhydrophobicity and durability after being exposed to solvents such as diethyl ether, toluene, and ethanol for up to 5 h, 400 tape peel cycles, UV exposure, and heat exposure at 400 °C. The robustness results indicated enhanced durability relative to the superhydrophobic film without the epoxysilane underlayer.
{"title":"Robust, Fluorine-Free Superhydrophobic Films on Glass via Epoxysilane Pretreatment","authors":"Fang Chen, Julie Jalila Kalmoni, Shuhui Li, Claire J Carmalt","doi":"10.1021/acs.langmuir.4c02630","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02630","url":null,"abstract":"Durable and fluorine-free superhydrophobic films were fabricated by a simple two-step process involving the pretreatment of glass substrates with an epoxysilane, which acted as an adhesive. The next step involved the aerosol-assisted chemical vapor deposition of a simple mixture of polydimethylsiloxane (PDMS) and SiO<sub>2</sub> nanoparticles (NPs). Various parameters were studied, such as deposition time as well as PDMS and SiO<sub>2</sub> loadings. The optimum film generated was with a 1:1 loading of PDMS and SiO<sub>2</sub>, deposited at 360 °C for 40 min. The resultant film demonstrated excellent water repellency with a water contact angle of 165 ± 3° and a sliding angle of 2°. The epoxysilane underlayer provided the adhesion between the film and substrate. The films maintained superhydrophobicity and durability after being exposed to solvents such as diethyl ether, toluene, and ethanol for up to 5 h, 400 tape peel cycles, UV exposure, and heat exposure at 400 °C. The robustness results indicated enhanced durability relative to the superhydrophobic film without the epoxysilane underlayer.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"8 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987051","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}
Designing efficient drug delivery systems for optimum therapeutic outcomes and minimum adverse effects remains a pivotal focus in pharmaceutical research. Understanding the nature of interactions between drugs and drug carriers and the drug-release mechanism are the key aspects for the development of effective delivery systems. This work presents a detailed investigation into the intricate interactions between niosomes and the drug Phenosafranin (PSF), and the subsequent release induced by a variety of cyclodextrins (CDs) employing a multifaceted approach. Ensemble average spectroscopic and single molecular level investigations based on fluorescence correlation spectroscopy (FCS), are employed to explore the binding interactions of PSF with the niosome membrane. Subsequently, the release of the drug was studied by disrupting the niosome structure using various CDs, and their efficacy was accessed through steady-state and time-resolved photophysical responses. FCS experiments provided precise insights into the binding and drug release process at the single-molecule level through the variation in translational and diffusion characteristics of the drug. Additionally, isothermal titration calorimetric (ITC) investigations further revealed the thermodynamics governing the CD-niosome host:guest interactions and the varying potential of different CDs in disrupting the niosome to release the drug which were further validated by electron microscopy and confocal fluorescence microscopy analyses. A broader analysis of niosomes prepared with various nonionic surfactants highlighted the influence of cavitand size and structure on the interaction with different niosome constituents. This comprehensive analysis sheds light on the complex interplay of these components and their interactions, providing insights into drug delivery systems and their potential therapeutic applications.
{"title":"Cyclodextrin Derivatives as Modulators for Enhanced Drug Delivery from Niosome Membrane: A Fluorescence Correlation Spectroscopy and Isothermal Titration Calorimetry Approach","authors":"Saurabh Rai, Madhumita Mukherjee, Bijan Kumar Paul, Saptarshi Mukherjee","doi":"10.1021/acs.langmuir.4c03400","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03400","url":null,"abstract":"Designing efficient drug delivery systems for optimum therapeutic outcomes and minimum adverse effects remains a pivotal focus in pharmaceutical research. Understanding the nature of interactions between drugs and drug carriers and the drug-release mechanism are the key aspects for the development of effective delivery systems. This work presents a detailed investigation into the intricate interactions between niosomes and the drug Phenosafranin (PSF), and the subsequent release induced by a variety of cyclodextrins (CDs) employing a multifaceted approach. Ensemble average spectroscopic and single molecular level investigations based on fluorescence correlation spectroscopy (FCS), are employed to explore the binding interactions of PSF with the niosome membrane. Subsequently, the release of the drug was studied by disrupting the niosome structure using various CDs, and their efficacy was accessed through steady-state and time-resolved photophysical responses. FCS experiments provided precise insights into the binding and drug release process at the single-molecule level through the variation in translational and diffusion characteristics of the drug. Additionally, isothermal titration calorimetric (ITC) investigations further revealed the thermodynamics governing the CD-niosome host:guest interactions and the varying potential of different CDs in disrupting the niosome to release the drug which were further validated by electron microscopy and confocal fluorescence microscopy analyses. A broader analysis of niosomes prepared with various nonionic surfactants highlighted the influence of cavitand size and structure on the interaction with different niosome constituents. This comprehensive analysis sheds light on the complex interplay of these components and their interactions, providing insights into drug delivery systems and their potential therapeutic applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"205 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142987345","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 : 2025-01-15DOI: 10.1021/acs.langmuir.4c04687
Bangbang Nie, Yihong Zhu, Zongxu Luo, Jingjiang Qiu, Mingfu Zhu, Ming Zhai, Guobi Chai, Xiangming Li, Jinyou Shao, Ronghan Wei
The rapid development of wearable technology, flexible electronics, and human–machine interaction has brought about revolutionary changes to the fields of motion analysis and physiological monitoring. Sensors for detecting human motion and physiological signals have become a hot topic of current research. Inspired by the muscle fiber structure, this paper proposed a highly stable strain sensor that was composed of stretchable Spandex fibers (SPF), multiwalled carbon nanotubes (MWCNTs), and silicone rubber (Ecoflex). This sensor adopted an immersion coating process in which MWCNTs were conformally deposited on SPF, and Ecoflex was filled into the fiber interstices, completing the encapsulation and filling of the SPF to construct a stable three-dimensional conductive network. Thanks to the filling of Ecoflex, contact between conductive fibers during the stretching process was avoided, resulting in a significant change in the resistance. The sensitivity of the sensor reached 54.84, which is 10 times higher than before the Ecoflex filling with a stretchable strain range of up to 70%. The encapsulation of Ecoflex also prevented the detachment of MWCNTs on the fibers during stretching, improving the mechanical stability. The sensor can be easily attached to the surface of human skin to rapidly monitor various human motion signals. Furthermore, the sensor was related to the manipulator through wireless Bluetooth to realize the intelligent control of the manipulator. This work not only provided a more precise data monitoring method for medical and motion analysis fields but also offered an innovative solution for manipulator control.
{"title":"Muscle Fiber-Inspired High-Performance Strain Sensors for Motion Recognition and Control","authors":"Bangbang Nie, Yihong Zhu, Zongxu Luo, Jingjiang Qiu, Mingfu Zhu, Ming Zhai, Guobi Chai, Xiangming Li, Jinyou Shao, Ronghan Wei","doi":"10.1021/acs.langmuir.4c04687","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04687","url":null,"abstract":"The rapid development of wearable technology, flexible electronics, and human–machine interaction has brought about revolutionary changes to the fields of motion analysis and physiological monitoring. Sensors for detecting human motion and physiological signals have become a hot topic of current research. Inspired by the muscle fiber structure, this paper proposed a highly stable strain sensor that was composed of stretchable Spandex fibers (SPF), multiwalled carbon nanotubes (MWCNTs), and silicone rubber (Ecoflex). This sensor adopted an immersion coating process in which MWCNTs were conformally deposited on SPF, and Ecoflex was filled into the fiber interstices, completing the encapsulation and filling of the SPF to construct a stable three-dimensional conductive network. Thanks to the filling of Ecoflex, contact between conductive fibers during the stretching process was avoided, resulting in a significant change in the resistance. The sensitivity of the sensor reached 54.84, which is 10 times higher than before the Ecoflex filling with a stretchable strain range of up to 70%. The encapsulation of Ecoflex also prevented the detachment of MWCNTs on the fibers during stretching, improving the mechanical stability. The sensor can be easily attached to the surface of human skin to rapidly monitor various human motion signals. Furthermore, the sensor was related to the manipulator through wireless Bluetooth to realize the intelligent control of the manipulator. This work not only provided a more precise data monitoring method for medical and motion analysis fields but also offered an innovative solution for manipulator control.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"47 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142981743","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 : 2025-01-15DOI: 10.1021/acs.langmuir.4c04566
Fernando Gomez, Samuel F Roter, Daniel Rossi, Guangyao Wu, Maryam Safaripour, Dean Webster, Zhan Chen
Poly(dimethylsiloxane) (PDMS) materials have been widely researched and applied as fouling-release coatings. Incorporation of silicone oils into PDMS has been shown to improve the antifouling properties of PDMS materials. In this research, we applied sum frequency generation (SFG) vibrational spectroscopy to study PDMS materials incorporated with various silicone oils containing phenyl groups in air, water, and protein solutions. It was found that the surface structures of various silicone oils varied, which results in different surface structures of PDMS with different oils incorporated. Such different PDMS surfaces interact with water molecules differently, leading to different surface hydrations. A model protein, fibrinogen, was used to study molecular interactions between oil-incorporated PDMS and biological molecules, testing the antifouling and fouling-release performance of different PDMS materials. It was found that fibrinogen has different adsorption behaviors on different PDMS surfaces, while adsorbed fibrinogen adopts bent structures. This study demonstrated that SFG can be used to deduce molecular information on silicone oil, PDMS, water, and fibrinogen on surfaces/at interfaces in situ in real-time. The different silicone oils incorporated into PDMS changed the PDMS surfaces, leading to varied interactions with water and biological media, influencing the antifouling and fouling-release activities. In most cases, the presence of silicone oils could enhance the surface hydration. However, the presence of phenyl groups could reduce the level of surface hydration. Nevertheless, our studies demonstrated that incorporation of silicone oils into PDMS led to better antifouling or fouling-release properties.
{"title":"Molecular Structures of Surfaces and Interfaces of Poly(dimethylsiloxane) Incorporated with Silicone Oils Containing Phenyl Functionality","authors":"Fernando Gomez, Samuel F Roter, Daniel Rossi, Guangyao Wu, Maryam Safaripour, Dean Webster, Zhan Chen","doi":"10.1021/acs.langmuir.4c04566","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04566","url":null,"abstract":"Poly(dimethylsiloxane) (PDMS) materials have been widely researched and applied as fouling-release coatings. Incorporation of silicone oils into PDMS has been shown to improve the antifouling properties of PDMS materials. In this research, we applied sum frequency generation (SFG) vibrational spectroscopy to study PDMS materials incorporated with various silicone oils containing phenyl groups in air, water, and protein solutions. It was found that the surface structures of various silicone oils varied, which results in different surface structures of PDMS with different oils incorporated. Such different PDMS surfaces interact with water molecules differently, leading to different surface hydrations. A model protein, fibrinogen, was used to study molecular interactions between oil-incorporated PDMS and biological molecules, testing the antifouling and fouling-release performance of different PDMS materials. It was found that fibrinogen has different adsorption behaviors on different PDMS surfaces, while adsorbed fibrinogen adopts bent structures. This study demonstrated that SFG can be used to deduce molecular information on silicone oil, PDMS, water, and fibrinogen on surfaces/at interfaces in situ in real-time. The different silicone oils incorporated into PDMS changed the PDMS surfaces, leading to varied interactions with water and biological media, influencing the antifouling and fouling-release activities. In most cases, the presence of silicone oils could enhance the surface hydration. However, the presence of phenyl groups could reduce the level of surface hydration. Nevertheless, our studies demonstrated that incorporation of silicone oils into PDMS led to better antifouling or fouling-release properties.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"94 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986941","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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