Langmuir最新文献

{"title":"Probing the Influence of Hydrophobicity of Modified Gold Nanoparticles in Modulating the Lipid Surface Behavior Using Vibrational Sum Frequency Generation Spectroscopy","authors":"Preeti Gahtori, Vineet Gunwant, Ravindra Pandey","doi":"10.1021/acs.langmuir.4c02735","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02735","url":null,"abstract":"A deep understanding of how the surface modifications of nanoparticles impact their interactions with cell membranes is vital for advancing safe and effective biomedical applications. Among the pivotal factors governing these interactions, the hydrophobicity of nanoparticles plays a crucial role, predominantly driven by the hydrophobic interactions with the cell membrane. Herein, we study the influence of the hydrophobic alkyl chain length of thiol-capped gold nanoparticles (GNPs) on lipid surfaces with the help of vibrational sum frequency generation spectroscopy. We have utilized the zwitterionic 1,2-dipalmitoyl-<i>sn</i>-glycero-3-phosphocholine (DPPC) lipid monolayer as a representative model of cell membranes on the water surface. Our findings revealed that GNPs capped with the thiol ligand having a shorter alkyl chain such as heptanethiol (HT, C₇) show minimal changes in the C–H stretching vibrations while interacting with the lipid monolayer. These observations could be attributed to the perturbation of the lipid chain due to hydrophobic–hydrophobic interactions between the alkyl chain of thiol-capped GNPs and the hydrophobic group of the lipid membrane or simply by the adsorption of GNPs at the interface without disrupting the monolayer structure. However, with increasing the chain length of thiol-capped GNPs from decanethiol (DDT, C₁₀) to octadecanethiol (ODT, C₁₈), the extent of spectral change in the C–H stretching vibration is increased. The controlled experiment performed with the deuterated lipids conforms that the changes observed in the C–H stretching vibration after adding HT (C₇) GNPs are only because of their presence in the surface without altering the monolayer structure. However, in the case of DT (C₁₀) and DDT (C₁₂) GNPs, the strong hydrophobic interactions between the monolayer and the alkyl chain of the thiol-capped GNPs result in the increased orientational order of the monolayer. Moreover, in the case of ODT (C₁₈) GNPs, the very long alkyl chain induces pronounced perturbations in the monolayer structure with net disordering of the monolayer. These observations are further supported by the spectral changes observed in the O–H vibration of the interfacial water molecules. Our findings reveal the crucial role of the hydrophobic nature of GNPs in influencing the interface. Understanding these effects is crucial for drug delivery applications and improving the stability and effectiveness of lipid-based systems.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321463","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":"Ideal Collision Rate of Symmetric Hexapods in a Simple Shear Flow","authors":"Neeraj Sinai Borker","doi":"10.1021/acs.langmuir.4c01130","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01130","url":null,"abstract":"An ideal collision rate (ICR) is defined as the average rate of contact between two particles that translate and rotate with the imposed fluid flow in the absence of interparticle interactions. ICR in a simple shear flow provides an estimate of the collision rate in a flowing dilute particle suspension, and its value is known only for traditional convex shapes such as spheres and cylinders. In this work, we compute the ICR for a family of <i>symmetric hexapods</i> (shown in Figure 1) that are particles composed of three orthogonal cylinders with coinciding centers (forming six arms) with at least two cylinders having the same length. We employed the finite-element method to obtain the rotational dynamics of hexapods and Monte Carlo simulations to calculate their ICR. Our results indicate that the ICR for hexapods is not directly proportional to the volume of the particle, in contrast to what is observed for convex shapes such as spheres and cylinders. For hexapods of the same size, the ICR could be similar for particles with order-of-magnitude differences in their volumes and it could also vary by an order of magnitude for particles with similar volumes. Specifically for hexapods termed branched fibers, which have one longer cylinder, the ICR changes by an order of magnitude even when the shorter cylinders are significantly smaller than the longer cylinder. This change is attributed to the increase in the tumbling frequency of the particle due to hydrodynamic forces acting on the shorter arms, in addition to the increased probability of collision afforded by them. Using asymptotic theory for high-aspect ratio cylinders, we showed that the tumbling period of hexapods was proportional to an algebraic power of the ratio of its arm lengths and has a weaker logarithm relationship with the aspect ratio of its arms. The collision cross-section provided the relative cross-streamline particle separations for the most likely binary collisions in the suspensions, and its value was sensitive to the arm lengths, as well. The collision rate of hexapods also could not be estimated within an order of magnitude from existing geometric models, such as the ICR of a circumscribing convex shape, ICR for one of the individual cylinders of the hexapod, or using the particle volume times the shear rate. Our work indicates that collision rate for non-convex particles in shear flows critically depends on the shape of the particle due to nontrivial changes in the particle’s orientational dynamics, and the ICR calculation serves as a more reliable method for estimating their true collision rates in the suspension.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317501","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":"Attapulgite-Reinforced Cellulose Hydrogels with High Conductivity and Antifreezing Property for Flexible Sensors","authors":"Hu Liu, Xiong-Fei Zhang, Mengjie Li, Jianfeng Yao","doi":"10.1021/acs.langmuir.4c02244","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02244","url":null,"abstract":"Ionic conductive cellulose hydrogels are some of the most promising candidates for flexible sensors. However, it is difficult to simultaneously prepare cellulose hydrogels with high mechanical strength, good ionic conductivity, and antifreeze performance. In this work, a natural clay (attapulgite)-reinforced cellulose hydrogel was fabricated. Through a one-pot method, cellulose and attapulgite were dispersed in a concentrated ZnCl₂ solution. The obtained hydrogel exhibited a dual network of hydrogen bonds and Zn²⁺-induced ionic interactions. Attapulgite serves as an inorganic filler that can regulate the hydrogen-bonding density among cellulose molecules and provides abundant channels for fast ion transport. By optimizing the attapulgite loading, a mechanically strong (compressive strength up to 1.10 MPa), tough (fracture energy up to 0.36 MJ m^–3), highly ionic conductive (4.15 S m^–1), and freezing-tolerant hydrogel was prepared. These hydrogels can be used for sensitive and stable human motion sensing, demonstrating their great potential for healthcare applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317502","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":"Dual Anticorrosive and Self-healing Coating Based on Multiresponsive Polyaniline Porous Microspheres","authors":"Qingqing Zhang, Kaiyun Wu, Ren Liu, Jing Luo","doi":"10.1021/acs.langmuir.4c01703","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01703","url":null,"abstract":"In this work, a smart self-healing coating with long-term anticorrosion ability was developed based on multiresponsive polyaniline (PANI) porous microspheres. The polyaniline porous microspheres loaded with corrosion inhibitor (benzotriazole, BTA) was prepared by the emulsion template method and photopolymerization. The BTA loaded in the polyaniline microspheres acted as a corrosion inhibitor, while the polyaniline in the shell performed the multiple functions of corrosion inhibition, pH-responsive and photoresponsive release, and photothermal conversion. Owing to the inherent corrosion-inhibiting nature of BTA and PANI, the BTA-loaded polyaniline microsphere could endow coating with dual anticorrosive properties. The coating with polyaniline microspheres did not show any corrosion product after 700 h of salt spray testing, while obvious pitting corrosion could be observed for the blank coating after 100 h of the salt spray test. Thanks to the photothermal properties of PANI, the composite coating exhibited self-healing behavior under NIR light irradiation. The coating with 10 wt % polyaniline microspheres could achieve rapid closure and recover its barrier properties within 5 s of NIR irradiation. And the release of BTA could form a passivation film on scratches to further repair coating defects. The on-command responsive release, high healing efficiency, and excellent anticorrosion properties of this dual self-healing anticorrosion coating provide perspectives on extending the service life of metals.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321462","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":"Constructing of Core–Satellite Structure Bimetallic MOFs for Synergistic Enhanced Adsorption–Photocatalytic Degradation","authors":"Yaxin Zheng, Fei Sun, Pengjin Zeng, Yi Su, Guojin Liu","doi":"10.1021/acs.langmuir.4c02230","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02230","url":null,"abstract":"Various industries generate a large amount of wastewater, which contains soluble organic compounds that can seriously jeopardize the environment and human health. Therefore, new photocatalytic materials with the function of efficiently degrading pollutants have become a research hotspot. In this research, bimetallic metal–organic frameworks (MOFs) with a core–satellite structure were prepared through a simple one-pot method in the presence of a polyvinylpyrrolidone structure-directing agent and crystal size. Also, the synergy of the adsorption–catalytic properties of the core–satellite structure bimetallic MOFs was achieved via the interaction of aluminum and iron groups. Meanwhile, the type I heterojunction structure based on MIL-53(Al@Fe)–OH realized the effective separation of the photogenerated carriers. Under the synergistic adsorption–catalytic degradation, the degradation efficiency of methylene blue (MB) was nearly 100% after adsorption (of 2 h) and photocatalysis (of 2 h), and the removal rate of MB still reached 90.43% after five cycles. This study provides a new strategy for the construction of bimetallic MOF structures for efficient adsorption-catalyzed degradation of environmental pollutants.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317098","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":"Engineered Amine-Functionalized Metal–Organic Framework to Fabricate a Composite for Next-Generation Asymmetric Supercapacitors with Ultrahigh Performance: Modulating the Energy Storage Barrier","authors":"Shabnam Khan, Aadil Rashid Lone, Mohammad Yasir Khan, Sabiar Rahaman, Kavita Pandey, Aasif Helal, Farasha Sama, M. Shahid","doi":"10.1021/acs.langmuir.4c02522","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02522","url":null,"abstract":"The present work summarizes the fabrication of an amine-functionalized cadmium-based metal–organic framework (MOF), {[Cd(AT)(BP)]·4DMF}_<i>n</i> or <b>Cd_AT-BP</b>, by adopting a simple solvothermal approach using 2-aminoterephthalic acid (AT) as the main linker, while 4,4′-bipyridyl (BP) as an auxiliary linker. The structure of <b>Cd_AT-BP</b> was validated by the single-crystal X-ray diffraction technique that revealed the formation of an overall three-dimensional network with BP acting as a bridge between the 2D sheets of the MOF. The robust framework of <b>Cd_AT-BP</b> decorated with a free amine functional group was utilized for energy storage application. The electrochemical measurements of <b>Cd_AT-BP</b> revealed a maximum areal capacitance of 9.8 mF/cm² at a scan rate of 5 mV/s. Further, to enhance the practical utility of <b>Cd_AT-BP</b> in energy storage devices, two composites of <b>Cd_AT-BP</b> with reduced graphene oxide (rGO) and multiwalled carbon nanotubes (CNTs), viz., <b>Cd_AT-BP/rGO</b> and <b>Cd_AT-BP/CNT</b>, were prepared by adopting a facile ultrasonication approach. The synthesized <b>Cd_AT-BP/rGO</b> and <b>Cd_AT-BP/CNT</b> composites displayed an impressive areal capacitance of 117 and 37 mF/cm² (58.5 and 17.5 F/g) at a scan rate of 5 mV/s, respectively, and a capacitance retention of up to 118 and 100% after 5000 cycles at a constant current density of 5 mA/cm². The highest energy density of about 4.23 mW h/cm² (2.12 W h/kg) at a current density of 1 mA/cm² was shown by <b>Cd_AT-BP/rGO</b> among all the three materials attributable to the layered structure of rGO, providing a larger surface area accessible for ion adsorption. Enticed by the remarkable outcomes exhibited by <b>Cd_AT-BP/rGO</b>, we fabricated a two-electrode asymmetric supercapacitor (ASC) device. The developed ASC device revealed energy and power densities of 26.7 mW h/cm² (13.4 W h/kg) and 3760 mW/cm² (1880 W/kg), respectively, with a galvanostatic charge–discharge stability of up to 10,000 cycles. The findings identify <b>Cd_AT-BP/rGO</b> as a potential contender for future-generation supercapacitors.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317505","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":"Photoinduced Charge Transfer Empowers Ta4C3 and Nb4C3 MXenes with High SERS Performance","authors":"Leilei Lan, Ziheng Ni, Caiye Zhao, Juan Gao, Xiao Tang, Zhongwei Qu, Lingcheng Zheng, Xingce Fan, Teng Qiu","doi":"10.1021/acs.langmuir.4c02165","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02165","url":null,"abstract":"This study introduces two-dimensional (2D) Ta₄C₃ and Nb₄C₃ MXenes as outstanding materials for surface-enhanced Raman scattering (SERS) sensing, marking a significant departure from traditional noble-metal substrates. These MXenes exhibit exceptional SERS capabilities, achieving enhancement factors around 10⁵ and detection limits as low as 10^–7 M for various analytes, including environmental pollutants and drugs. The core of their SERS functionality is attributed to the robust interfacial photoinduced charge-transfer interactions between the MXenes and the adsorbed molecules. This deep insight not only advances our understanding of MXene materials in SERS applications but also opens new avenues for developing highly sensitive and selective SERS sensors. The potential of Ta₄C₃ and Nb₄C₃ MXenes to revolutionize SERS technology underscores their importance in environmental monitoring, food safety, and beyond.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317097","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":"Forced Wetting of Shear-Thinning Fluids in Confined Capillaries","authors":"Xiong Wang, Zhenyue Yuan, Feipeng Chen, Xiaoxue Yao, Fanfei Yu, Steven Wang","doi":"10.1021/acs.langmuir.4c02728","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02728","url":null,"abstract":"Dynamic wetting in confined spaces is pivotal for the functional efficiency of biological organisms and offers significant potential for optimizing microdevices. The fluids encountered in such scenarios often exhibit shear-thinning behavior, which gives rise to complex interfacial phenomena. Here, we present an intriguing wetting phenomenon for shear-thinning fluids in confined capillary spaces. The employed shear-thinning fluids, carboxymethyl cellulose aqueous solutions with mass fractions of 0.5, 1.0, and 1.5 wt %, exhibit an intermediate state between ideal viscoelastic liquids, viscoelastic solids, and gel-like properties. We elucidate the geometric effect on its capillary wetting behavior, demonstrating that distortion of the moving contact line alters flow dynamics near the front corner, modifying the viscous resistance. This intricate interplay between the modified viscous resistance and the driving force results in a novel dynamic equilibrium distinct from that in Newtonian fluids. We further reveal that the viscous resistance in confined capillaries is controlled by both the morphology of the moving contact line and the shear-thinning exponent, particularly within the range of 0.7 to 1. This novel mechanism provides a pathway for manipulating the wetting dynamics of complex fluids in confined spaces.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317099","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":"Entrapment of Amphipathic Drugs in Core–Shell Polymeric Nanoparticles under Batch Conditions─The Role of Control and Solubility Parameters","authors":"Łukasz Lamch, Rafał Szukiewicz","doi":"10.1021/acs.langmuir.4c02721","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02721","url":null,"abstract":"The amphipathic bioactive compounds curcumin, resveratrol, and mitomycin C, which have similar solubility parameter component distributions, have been studied for encapsulation under batch conditions into core–shell nanocarriers composed of external hydrophobically functionalized polyelectrolytes and an inner matrix of polyesters or polyester blends: poly(<span>l</span>-lactide), poly(lactide-<i>co</i>-glycolide), and/or poly(ethylene succinate). Our contribution comprises determining the influence of process parameters on the properties and quality of the final products, namely core–shell nanoparticles loaded with appropriate drugs, according to process analysis technologymanagement. The crucial roles of the organic phase dosing rates and process temperatures were carefully investigated. Moreover, a technically feasible method of removing organic solvents from aqueous dispersions─stripping with inert gas─was employed and evaluated via FT-IR studies. The experiments were supported by the calculation and analysis of solubility parameters (δ) and dispersion (δ_d), polar (δ_p), and hydrogen bond (δ_h) components utilizing HSPiP software. The payload locus and sample morphology were studied via atomic force microscopy and X-ray photoelectron spectroscopy analyses with Ar⁺ sputtering. It was demonstrated that dosing rates of organic phases not exceeding ca. 0.5 mL/min per 1 L of aqueous dispersion of hydrophobically functionalized polyelectrolytes made it possible to obtain core–shell nanoparticles of ca. 100–150 nm with a very narrow polydispersity (PdI &lt; 0.2). The locus of amphipathic payloads in nanocarriers, mostly within the core polymeric structure, was in good agreement with the results of solubility parameter component studies: water-insoluble polyesters with both polar and nonpolar interactions between chains serve as good host materials for amphipathic drugs.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313531","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":"Regulating Monodispersity by Controlling Droplet Spacing.","authors":"Dheeraj Sapkota, Laura L A Adams","doi":"10.1021/acs.langmuir.4c02058","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02058","url":null,"abstract":"<p><p>We report a new method for regulating monodispersity in the generation of single emulsions. The spacing between two consecutive emulsions during their generation is used to identify monodisperse and polydisperse regimes, with monodispersity having a size dispersion of <9% as an upper limit. A theoretical fit to our data is also presented. Moreover, a phase diagram of drop diameter as a function of inner and outer fluid flow rates indicates optimal flow parameters for the production of monodisperse drops. Our findings emphasize the robustness of using droplet spacing as a controlled parameter in regulating monodispersity, despite geometric differences in microfluidic devices.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142306604","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}