Langmuir最新文献

{"title":"Stability Assessment in Aqueous and Organic Solvents of Metal–Organic Framework PCN 333 Nanoparticles through a Combination of Physicochemical Characterization and Computational Simulations","authors":"Xiaoli Liu, Andres Ortega-Guerrero, Nency P. Domingues, Miriam Jasmin Pougin, Berend Smit, Leticia Hosta-Rigau, Chris Oostenbrink","doi":"10.1021/acs.langmuir.4c01684","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01684","url":null,"abstract":"Mesoporous metal–organic frameworks (MOFs) have been recognized as powerful platforms for drug delivery, especially for biomolecules. Unfortunately, the application of MOFs is restricted due to their relatively poor stability in aqueous media, which is crucial for drug delivery applications. An exception is the porous coordination network (PCN)-series (e.g., PCN-333 and PCN-332), a series of MOFs with outstanding stability in aqueous media at the pH range from 3 to 9. In this study, we fabricate PCN-333 nanoparticles (nPCN) and investigate their stability in different solvents, including water, ethanol, and methanol. Surprisingly, the experimental characterizations in terms of X-ray diffraction, Brunauer–Emmett–Teller (BET), and scanning electron microscopy demonstrated that nPCN is not as stable in water as previously reported. Specifically, the crystalline structure of nPCN lost its typical octahedral shape and even decomposed into an irregular amorphous form when exposed to water for only 2 h, but not when ethanol and methanol were used. Meanwhile, the porosity of nPCN substantially diminished while being exposed to water, as demonstrated by the BET measurement. With the assistance of computational simulations, the mechanism behind the collapse of PCN-333 is illuminated. By molecular dynamics simulation and umbrella sampling, we elucidate that the degradation of PCN-333 occurs by hydrolysis, wherein polar solvent molecules initiate the attack and subsequent breakage of the metal–ligand reversible coordination bonds.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142415482","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}

{"title":"Coalescence and Rebound Dynamics in Two Droplets Train Impacting on a Heterogeneous Wettability Surface","authors":"Tongwei Zhang, Meixuan Li, Fei Dong, Fuxiang Huang, Kaku Chuyo, Jie Wu","doi":"10.1021/acs.langmuir.4c02742","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02742","url":null,"abstract":"Droplets that can be steered and rebound off surfaces are fundamentally interesting and important due to their promising potential in numerous applications, such as anti-icing and -fogging, spray coating, and self-cleaning. Heterogeneous wettability surfaces have been shown to be an effective means of droplet manipulation. This paper combines numerical simulation with theoretical analysis to investigate the dynamics of two droplets training impacting on and bouncing off a heterogeneous surface (superhydrophobic substrate decorated with a hydrophilic strip). First, the time evolutions of the droplet morphology and velocity vectors are examined to explore the particular dynamic behaviors. At different ratios of the impact velocity, three distinct rebound patterns are observed, and a regime diagram is established. After that, the effects of the impact conditions and surface wettability on the rebound performance of the coalesced droplet are studied systematically. Special attention is paid to the variations of the rebound height and the lateral transportation distance with the Weber number of two droplets and the distance between the impacting point and the hydrophilic stripe. Moreover, a theoretical analysis of two droplets’ impact is performed based on the energy conservation. The obtained scaling laws match well with the numerical data in the trend. Our research may strengthen the understanding of the interactions between droplets, which is valuable for the manipulation of multiple droplets in related fields.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142415480","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}

{"title":"PNIPAM Mesoglobules in Dependence on Pressure","authors":"Bart-Jan Niebuur, Vitaliy Pipich, Marie-Sousai Appavou, Dharani Mullapudi, Alec Nieth, Eric Rende, Alfons Schulte, Christine M. Papadakis","doi":"10.1021/acs.langmuir.4c02952","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02952","url":null,"abstract":"Poly(<i>N</i>-isopropylacrylamide) (PNIPAM) in aqueous solution forms mesoglobules above its cloud point temperature <i>T</i>_cp. While these are small and compact at atmospheric pressure, they are large and water-rich at high pressure. To identify the transition between these states, we employed optical microscopy and carried out isothermal pressure scans. Using very small angle neutron scattering, we determined the size and water content of the mesoglobules in pressure scans at different temperatures above <i>T</i>_cp. We observe a distinct transition at pressures of 35–55 MPa with the transition pressure depending on temperature. While the transition is smooth at high temperatures, i.e., far away from the coexistence line, it is abrupt at low temperatures, i.e., close to the coexistence line. Hence, at high temperatures, the swelling of the mesoglobules dominates, whereas at low temperatures, the coalescence of mesoglobules prevails. Subsequently decreasing the pressure results in a gradual deswelling of the mesoglobules at high temperature. In contrast, at low temperatures, small and compact mesoglobules form, but the large aggregates persist. We conclude that, on the time scale of the experiment, the disintegration of the large swollen aggregates into small and compact mesoglobules is only partially possible. Erasing the history by cooling the sample at the maximum pressure into the one-phase state does not result in qualitative changes for the behavior with the only difference that Fewer mesoglobules are formed when the pressure is decreased again. The newly identified transition line separates the low-pressure from the high-pressure regime.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142415481","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}

{"title":"Evaporation-Induced Switching from Flocculated to Dispersed TiO2 Nanoparticles in Binary Solvents","authors":"Ryushi Fukuhara, Akio Nasu, Susumu Inasawa","doi":"10.1021/acs.langmuir.4c03285","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03285","url":null,"abstract":"Evaporation in mixed solutions containing both volatile and involatile solvents changes the properties of the binary solvent. We found that evaporating one solvent drastically increased the affinity of the mixed solvent to dispersant molecules and induced a switch from flocculated to dispersed TiO₂ nanoparticles (TiO₂NPs). We prepared dispersions of TiO₂NPs with mixtures of volatile cyclosiloxane (D<i>x</i>), involatile polar oil, and a dispersant, namely polyhydroxystearic acid (PHSA). D<i>x</i> is a nonsolvent but the polar oil is a good solvent for PHSA. The dispersions were applied on a quartz substrate, and D<i>x</i> was evaporated. The original applied films were turbid, in which flocculated TiO₂NPs formed network structures. However, as the evaporation of D<i>x</i> progressed, the drying films became transparent and the network structures of TiO₂NPs loosened and disappeared. After the evaporation of D<i>x</i>, the applied films were transparent to visible light but blocked the transmission of UV light. The flow characteristics of the dispersions also changed. The original dispersions showed shear-thinning but became more Newtonian-like as the fraction of D<i>x</i> decreased. Generally, particles are concentrated in drying dispersions and become packed or flocculated as evaporation progresses. Our findings show that initially flocculated nanoparticles can be redispersed after evaporating a specific solvent. The effects of different D<i>x</i>s and compositions on the switch from flocculated to dispersed TiO₂NPs and their applicability as sunscreens are discussed.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405509","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}

{"title":"Impact of the Hydrophobic Phase on the Interfacial Dilational Rheology of Alkoxy Carboxylate/Cetyltrimethyl Ammonium Chloride Mixtures","authors":"Xiujuan He, Zhiqing Su, Wei Liu, Jun Jin, Jun Qiu, Leyu Cui, Yingcheng Li","doi":"10.1021/acs.langmuir.4c02458","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02458","url":null,"abstract":"Despite extensive investigations on the interfacial activities of mixed anionic and cationic surfactants (S_a/c), the influence of the hydrophobic phase on their interfacial assembly and dilational rheology remains unaddressed. In this study, the interfacial dilational rheology of alkoxy carboxylate (anionic)/cetyltrimethylammonium chloride (cationic) surfactant mixtures was studied at various interfaces. The dilational modulus of S_a/c increases linearly with interfacial pressure at the interfaces of air, <i>n</i>-hexane/<i>n</i>-octane/<i>n</i>-hexadecane, and toluene. The limit elasticity (ε₀) is similar at air and alkane interfaces but significantly decreases at the toluene interface. To explain these phenomena, all-atom molecular simulation was carried out to investigate the microscopic features of surfactants at the interface. The findings emphasize the crucial role of anionic/cationic surfactant bound pairs in regulating interfacial rheology. S_a/c tend to form large aggregates at the air/water surface. When mixed with alkanes like octane, most S_a/c remain as ion pairs. However, when toluene is employed, the coordination number between anionic and cationic surfactants sharply decreases due to π–π interactions between the toluene molecules and the phenyl groups in the anionic surfactant. This leads to a much lower interfacial modulus because interactions between oil molecules and surfactants cannot compensate for weakened interactions among anionic/cationic surfactants. These results suggest that S_a/c in this study tolerate alkanes but are not resistant to aromatics, which helps explain why S_a/c demonstrate excellent performance for the chemical enhanced oil recovery of a high-wax reservoir and further provides fundamental knowledge of their potential applications, such as gas well deliquification using foamers in the presence of condensate oil, textiles, etc.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405497","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}

{"title":"Effect of DMSO Addition on the Hexagonal Phase of the System Triton X/Water.","authors":"Leila T Thieghi, Sarah I P M N Alves","doi":"10.1021/acs.langmuir.4c01937","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01937","url":null,"abstract":"<p><p>This research studied the role of DMSO in a binary system of Triton X and water in the hexagonal mesophase. One effect of DMSO addition, determined using polarized optical microscopy and small-angle X-ray scattering measurements, is to promote a decrease in the hexagonal to isotropic phase transition temperature, <i>T</i>_H-ISO, decreasing the range of temperatures of the hexagonal phase until the hexagonal phase completely disappears when DMSO is added up to 5.0 mol %. The periodicity and the lattice parameter of the hexagonal arrangement, calculated as a function of DMSO concentration, slight increased due to the insertion of DMSO molecules in the water region, causing a greater distance between the cylindrical micelles, while the radius of the apolar domains kept constant at 22 (1) Å.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142398637","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}

{"title":"Nanoscale Topography Dictates Residue Hydropathy in Proteins.","authors":"Jingjing Ji, Advait D Shukla, Ratnakshi Mandal, Wafiq Ibsan Khondkar, Catilin R Mehl, Arindam Chakraborty, Shikha Nangia","doi":"10.1021/acs.langmuir.4c02142","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02142","url":null,"abstract":"<p><p>Proteins exhibit diverse structures, including pockets, cavities, channels, and bumps, which are crucial in determining their functions. This diversity in topography also introduces significant chemical heterogeneity, with polar and charged domains often juxtaposed with nonpolar domains in proximity. Consequently, accurately assessing the hydropathy of amino acid residues within the intricate nanoscale topology of proteins is essential. This study presents quantitative hydropathy data for 277,877 amino acid residues, computed using the Protocol for Assigning a Residue's Character on a Hydropathy (PARCH) scale. Leveraging this data set comprising 1000 structurally diverse proteins sourced from the Protein Data Bank, we examined residues situated in various nanoscale environments and analyzed hydropathy in relation to protein topography. Our findings indicate that the hydropathy of a residue is intricately linked to both its individual characteristics and the geometric features of its neighboring residues in response to water. Changes in the number and chemical identity of the neighbors, as well as the nanoscale topography surrounding a residue, are mirrored in its hydropathy profile. Our calculations reveal the intricate interplay of hydrophilic, hydroneutral, and hydrophobic residues distributed across the surface and core of proteins. Notably, we observe that protein surfaces can be ten times more hydrophilic than their cores.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142398641","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}

{"title":"Effect of the Dispersion Medium on NMR Relaxation Properties of Superparamagnetic Iron Oxide Nanoparticles between 0.24 mT and 14.1 T.","authors":"Lyns Verel Che Dji, Roua Kaddah, Thomas Girardet, Solenne Fleutot, Sabine Bouguet-Bonnet","doi":"10.1021/acs.langmuir.4c02448","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02448","url":null,"abstract":"<p><p>Due to weak exchange interactions, magnetite particles at a critical diameter of about 20 nm are considered monodomain. At this size, they exhibit a phenomenological magnetic property called superparamagnetism, making them useful as magnetic resonance imaging contrast agents, or MRI CAs. However, questions persist regarding the impact of using different physiological solvents and varying the environment in which these particles are dispersed on their performance, determined by their relaxivity. A colloidal suspension of superparamagnetic iron oxide nanoparticles (SPIONs) electrostatically stabilized by citrate ligand was synthesized using a fast, reliable, and reproducible developed microwave approach, ensuring high stability over time at pH 7. We studied the effects of three physiological media on these MRI CAs. Ultrapure water was used for the synthesis, while phosphate-buffered saline and physiological liquid were used to disperse the nanoparticles, as these media contain essential electrolytes for the functioning of the human body. The SPIONs underwent systematic characterizations to determine their physicochemical and magnetic properties. This study reports the longitudinal relaxivities of SPIONs at medically relevant magnetic field strengths. Field dependence of their relaxivity (efficacy) was evaluated using a nuclear magnetic resonance dispersion (NMRD) profile measured over a wide range of proton resonance frequencies between 5 kHz and 600 MHz. The Roch et al. model (Roch, A.; et al. <i>J. Chem. Phys.</i>, <b>1999,</b> <i>110,</i> 5403-5411) was used to analyze the NMRD profile and evaluate the impact of SPIONs on water proton relaxation in the different redispersion media. It was observed in this study that the dynamics of water protons are not influenced by the redispersion media of these citrate-coated SPIONs. However, the presence of salt ions notably reduces their relaxivities by lowering the saturation magnetization of SPIONs.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142398638","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}

{"title":"Magnetoelectric Tuning of 2D Ferromagnetism in 1T-CrTe₂ through In₂Se₃ Substrate.","authors":"Lijing Luo, Qilong Sun, Meng Guo, Cui Jin, Ying Dai","doi":"10.1021/acs.langmuir.4c02588","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02588","url":null,"abstract":"<p><p>Electric field control of two-dimensional (2D) materials with optimized magnetic properties is not only of scientific interest but also of technological importance in terms of the functionality of various nanoscale devices. Here, we report the multiferroic control of the 2D ferromagnetism in 1T-CrTe₂ monolayer through a ferroelectric In₂Se₃ sublayer. Our results reveal the effect of polarization switching on the electronic structures and magnetic properties of 1T-CrTe₂/In₂Se₃ heterostructures, enabling effective manipulation of their magnetic anisotropy energy (MAE) and magnetization orientation. Additionally, we also demonstrate the strong dependence of their MAE and switching effect on the external strain and surface hydrogenation. Notably, polarization switching exhibits a reversal modification in the hydrogenated multiferroic structures. These tunable behaviors are primarily attributed to the alteration of p-orbitals near the Fermi level of the interfacial Te atoms due to magnetoelectric coupling. Our findings suggest the potential of 1T-CrTe₂/In₂Se₃ heterojunctions for the practical application of 2D multiferroic spintronic devices.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142398640","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}

{"title":"Unlocking the Electrocatalytic Behavior of Cu₂MnS₂ Nanoflake-Anchored rGO for the Oxygen Evolution Reaction in an Alkaline Medium.","authors":"Harshini Sharan, Jayachandran Madhavan, Ganeshbabu Mariappan, Ramakrishnan Kalai Selvan, Alagiri Mani","doi":"10.1021/acs.langmuir.4c02824","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02824","url":null,"abstract":"<p><p>A catalyst of the oxygen evolution reaction (OER) that is viable, affordable, and active for effective water-splitting applications is critical. A variety of electrocatalysts have been discovered to replace noble metal-based catalysts. Of these, transition metal-based sulfides are essential for incorporating carbonaceous materials to improve electrical conductivity, resulting in better electrocatalytic performance. Our study illustrates the synthesis of Cu₂MnS₂ (CMS) nanoflakes and their different rGO composites (10 to 40 wt %) via a hydrothermal technique for an effective water oxidation reaction. The X-ray diffraction pattern reveals that the prepared Cu₂MnS₂ nanoflakes exhibit a cubic crystal structure. The high-resolution scanning electron microscopy and the high resolution transmission electron microscopy images corroborate the formation of the nanoflake-like morphology of Cu₂MnS₂ with the strong interaction of rGO. The selected area electron diffraction analysis pattern reveals a polycrystalline nature. The Fourier transform infrared spectrum shows the existence of a metal sulfur vibrational band at 590 cm^-1, and Raman analysis infers the presence of rGO. The X-ray photoelectron spectroscopy spectra reveal the oxidation states of the elements present in the samples. Using Brunauer-Emmett-Teller analysis, the surface area of CMS-20 is found to be 117.04 m²/g. The measured OER overpotentials using linear sweep volammetry and the values are 380, 370, 340, 376, and 400 mV at 10 mA/cm² for CMS, CMS-10, CMS-20, CMS-30, and CMS-40, respectively, and the corresponding Tafel slope values are 179, 158, 149, 206, and 240 mV/decade, respectively. The electrochemical active surface area is estimated using cyclic voltammetry for all of the catalysts, where CMS-20 showed a larger surface area. Also, the same catalyst exhibits good stability for ∼24 h at a constant potential, which is confirmed via chronoamperometry. Thus, combining transition metal-based sulfides with carbonaceous materials indicates improved catalytic behavior for the preparation of high-performance OER electrocatalysts. Overall, the prepared CMS-20 performed as an efficient OER electrocatalyst and can be utilized for practical applications in energy conversion.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142405718","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}