Read by QxMD icon Read

Langmuir: the ACS Journal of Surfaces and Colloids

Kate Alexandra Bowman, Olav Andreas Aarstad, Bjørn Torger Stokke, Gudmund Skjåk-Bræk, Andrew N Round
Dynamic Single Molecule Force Spectroscopy (SMFS), conducted most commonly using AFM, has become a widespread and valuable tool for understanding the kinetics and thermodynamics of fundamental molecular processes such as ligand-receptor interactions and protein unfolding. Where slowly forming bonds are responsible for the primary characteristics of a material, as is the case in crosslinks in some polymer gels, care must be taken to ensure that a fully equilibrated bond has first formed before its rupture can be interpreted...
November 4, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Michael A Rogers, Alejandro G Marangoni
Changes in solvent chemistry influenced kinetics of both nucleation and crystallization of 12-hydroxyoctadecenoic, as determined using differential scanning calorimetry and applying a modified Avrami model to the calorimetric data. Altering solvent properties influenced solvent-gelator compatibility, which in turn altered the chemical potential of the system at the onset of crystallization, the kinetics of gelation, and the resulting 12HOA crystal fiber length. The chemical potential at the onset of crystallization was linearly correlated to both the hydrogen-bonding Hansen solubility parameter and the solvent-gelator vectorial distance in Hansen space, Rij...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Yingqi Li, Heng-An Wu, Feng-Chao Wang
In this paper, we use a single nanoparticle to achieve active control of the droplet contact line. When the droplet is out of equilibrium, the resulting free-energy excess provides the driving force for the depinning of the contact line and the nanoparticle. There are three ways to increase the energy barriers to be surmounted and to realize the pinning of the contact line, namely, the enhancement of the interactions between the nanoparticle and the substrate, the increase of substrate hydrophilicity, and the reduction of the nanoparticle hydrophilicity...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Andrea Tagliabue, Lorella Izzo, Massimo Mella
Solvent evaporation driven self-assembly of Janus nanoparticles (J-NPs) has been simulated employing lattice-gas models to investigate the possible emergence of new superlattices. Depending on the chemical nature of NP faces (hence solvophilicity and relative interaction strength), zebra-like or check-like patterns, and micellar agglomerates can be obtained. Vesicle-like aggregates can be produced by micelle-based corrals during heterogeneous evaporation. Patterns formed during aggregation appear to be robust against changes in evaporation modality (i...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Hongjie An, Beng Hau Tan, Claus-Dieter Ohl
The widespread application of surface-attached nanobubbles and nanodroplets in biomedical engineering and nanotechnology is limited by numerous experimental challenges, in particular, the possibility of contamination in nucleation experiments. These challenges are complicated by recent reports that it can be difficult to distinguish between nanoscale drops and bubbles. Here we identify clear differences in the mechanical responses of nanobubbles and nanodroplets under various modes of AFM imaging which subject the objects to predominantly vertical or lateral forces...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Ilaria Mannelli, Francesc Sagués, Valerio Pruneri, Ramon Reigada
Active surfaces are presently tailored to cause specific effects on living cells that can be useful in many fields. Their development requires the understanding of the molecular mechanisms of interaction between lipid-enveloped entities and solid surfaces. Here, by means of coarse-grained molecular dynamics simulations, we have analyzed the different interaction modes of coated substrates with lipid vesicles that mimic biological envelopes. For neutral and hydrophobically functionalized substrates, three action modes on contacting vesicles are obtained involving intact, partially broken and completely destroyed vesicles...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Cosimo Buffone, Khellil Sefiane
We report on the formation, evolution and extinction of Standing Waves (SW) detected by Infra-Red (IR) measurements at the upper region of a curved meniscus interface pinned at the mouth of a horizontally positioned capillary pore. The SWs are clear and strong in acetone but absent in ethanol for both tube sizes investigated (1-2 mm diameter). Depending on the tube size and the initial liquid filling ratio, the SWs start sooner for lower filling ratio. The intriguing experimental observation is that the SWs disappear at a specified liquid length between the receding meniscus and the one pinned at the tube mouth, which seems to depend strongly on the tube size and independent of the initial liquid filling ratio...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Kazue Kurihara
This feature article reviews the surface forces measurement as a tool for studying molecular architecture chemistry. The history of the measurement is briefly described in the Introduction. The general overview covers specific features of the surface forces measurement as a tool for studying and using molecular architecture. This measurement is powerful for understanding interaction forces and for characterizing and discovering the phenomena at solid-liquid interfaces and soft complex matter. An apparatus for opaque samples was developed, which can be used to study not only opaque samples in various media but also electrochemical processes under various electrochemical potentials...
November 3, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Quan-Xing Mao, Shuang E, Jun-Mei Xia, Ru-Sheng Song, Xu-Wei Chen, Yang Shu, Jian-Hua Wang
Tunable fluorescent emission and applications in both in vitro and in vivo imaging of hydrophobic carbon nanodots (CNDs) with rapid penetration capability is reported. The hydrophobic CNDs are prepared via hydrothermal treatment of ionic liquid 1-ethyl-3-methylimidazolium bromide. FT-IR and XPS analysis results indicate that the hydrophobicity originates from alkyl groups on the surface of CNDs. The hydrophobic CNDs show excitation-dependent photoluminescence behavior along with red-shift of their maximum excitation/emission wavelength with the increase of CNDs concentration...
November 2, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Yang Qiu, Le Xin, Fan Jia, Jian Xie, Wenzhen Li
Oxygen reduction reaction (ORR) is the major reaction occurred at the cathodes of fuel cells and metal-air batteries. Development of inexpensive, active and durable heteroatom doped carbon-based ORR catalysts can lead to significant cost reduction of these electrochemical energy devices, which therefore has recently attracted enormous research attention. This work reports a three-dimensional hybrid composite ORR catalyst (P-g-C3N4@NH2-CB) synthesized via a novel self-assembly approach. The NH2-CB was rationally selected as the spacer and self-assembled it with P-doped carbon nitride materials driven by the electrostatic interaction...
November 2, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Udita Uday Ghosh, Monojit Chakraborty, Soham De, Suman Chakraborty, Sunando DasGupta
Exercising control over the evaporation of colloidal suspensions is pivotal to modulate the coating characteristics for specific uses wherein the interactions between the liquid, the particles and the substrate control the process. In the present study, the contact line dynamics of a receding colloidal liquid film comprising of particles of distinctly different sizes (nominal diameters 0.055 μm and 1μm, surface unmodified), during evaporation is analyzed. The role of the liquid polarity is also investigated by replacing the polar (water) liquid with a relatively non-polar liquid (Isopropyl alcohol) in the colloidal suspension...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Sheng-Han Chen, Yung Chang, Kazuhiko Ishihara
To conquer thrombogenic reactions of hydrocarbon-based biomaterials in clinical blood treatment, we introduce a model study of a surface zwitterionization of polypropylene (PP) substrate using a set of well-defined copolymers for controlling the adhesion of blood cells in vitro. Random and block copolymers containing zwitterionic units of 2-methacryloyloxyethyl phosphorylcholine (MPC), [3-(methacryloylamino)propyl] dimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SBAA), or non-ionic units of 2-hydroxyethyl methacrylate (HEMA) with a controlled hydrophobic segment of 70% n-butyl methacrylate (BMA) units in these polymers were synthesized by reversible addition-fragmentation chain transfer polymerization...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Paul R Jones, Ashley R Elliott, Neelesh Ashok Patankar
During pool boiling of water, it is advantageous to keep liquid touching the surface in order to delay the onset of film-wise boiling. This allows water to remain in the nucleate boiling regime, leading to increased heat transfer. In this work, we propose a mechanism to sustain superheated liquid within hydrophilic pores. This mechanism for the design of superwetting hydrophilic surfaces does not rely on the transport of vapor, and offers an additional pathway for wetting via condensation of vapor within surface texture...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Deborah Lee Bitterfield, Anders Utoft, David Needham
When a solute is present in an aqueous droplet, the water activity in the droplet and the rate of droplet dissolution are both decreased (as compared to a pure water droplet). One of the main parameters that controls this effect is the dynamically changing solute concentration, and therefore water activity and chemical potential, at the droplet interface. This work addresses the importance of understanding how water activity changes during solution droplet dissolution. A model for dissolution rate is presented that accounts for the kinetic effects of changing water activity at the droplet interface during the dissolution of an aqueous salt solution microdroplet into a second immiscible liquid phase...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Shih-Ting Lin, Chen-Shin Lin, Ya-Ying Chang, Andrew E Whitten, Anna Sokolova, Chun-Ming Wu, Viktor A Ivanov, Alexei R Khokhlov, Shih-Huang Tung
The interactions between ions and phospholipids are closely associated with the structures and functions of cell membrane. Instead of conventional aqueous systems, we systematically investigated the effects of inorganic ions on the self-assembly of lecithin, a zwitterionic phosphatidylcholine, in cyclohexane. Previous studies have shown that addition of inorganic salts with specific divalent and trivalent cations can transform lecithin organosols into organogels. In this study, we focused on the effect of monovalent alkali halides...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Monika Gosecka, Stanislaw Slomkowski, Teresa Basinska, Mohamed Mehdi Chehimi
Stable three-dimensional colloidal crystals were fabricated in aqueous suspension of Tris buffer at pH>8. The basic building blocks of the crystals were the submicron-sized polystyrene-polyglycidol core-shell particles (Dn(SEM) = 270 ± 18 nm) with covalently bound 3,4-dihydroxyphenylalanine (L-DOPA). Growth of the crystals was triggered by thermodynamically favorable arrangement of particles leading to their close packing, and by the formation of covalent cross-links between the individual particles. In alkaline conditions, molecules of L-DOPA are oxidized which allows their participation in cross-linking, necessary for the stabilization of the formed colloidal crystals...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Juan Feng, Lihua Zeng, Kunyu Chen, Haobin Fang, Jianyong Zhang, Zhenguo Chi, Cheng-Yong Su
Supramolecular gels with hierarchical order and complexity have been assembled. The gels contain well-defined Ag4L2 luminescent supramolecular cages as cores, which are crosslinked via Ag-P coordination bonding. The resulting gels are highly luminescent and exhibit rich stimuli-responsive behaviors toward mechanical and chemical (nitroexplosive and anions) stimuli. The gels could be transformed to highly luminescent crystal materials upon addition of halogen anions, in which only trace of lumiphor is accommodated in a host crystal matrix...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Guihua Li, Yitong Wang, Ling Wang, Aixin Song, Jingcheng Hao
The gelation behavior of mixtures of sodium deoxycholate (NaDC) and glutathione (GSH) in water is investigated. The system exhibits a structural transition of self-assembled hydrogels from nanofibers to nanohelix structures, and then to helical ribbons with increasing GSH concentration. Super-long helical nanofibers with left- and right-handed orientations are produced by tuning the concentration of GSH at a fixed concentration of NaDC. Random coil and β-sheet structures are significant for the formation of the helical structures, and are indicated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectra...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Xueyi Chang, Zhukang Du, Feiyan Hu, Zhiyu Cheng, Biye Ren, Shiyu Fu, Zhen Tong
In this work, we present a novel redox-responsive ferrocene-functionalized hydrophobically modified ethoxylated urethane (Fc-HEUR) model polymer. The effects of redox-induced hydrophobicity change of ferrocenyl hydrophobes on the self-assembly and rheological properties of Fc-HEUR in aqueous solution were investigated. In view of the redox-induced change in the hydrophilic-lipophilic balance of polymer, the Fc-HEUR polymer in aqueous solution can reversibly self-assemble into spherical micelles and larger micellar aggregates of different nanoscales, and also disassemble by redox reactions immediately...
November 1, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Weijin Guo, Jonas Hansson, Wouter van der Wijngaart
Capillary flow is a dominating liquid transport phenomenon on the micro- and nanoscale. As described at the beginning of the 20th century, the flow rate during imbibition of a horizontal capillary tube follows the Washburn equation, i.e. decreases over time and depends on the viscosity of the sample. This poses a problem for capillary driven systems that rely on a predictable flow rate and where the liquid viscosity is not precisely known. Here we introduce and successfully experimentally verify the first compact capillary pump design with a flow rate constant in time and independent of the liquid viscosity that can operate over an extended period of time...
October 31, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"