Ändra sökning
Avgränsa sökresultatet
12 1 - 50 av 63
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1. Allouche, Joachim
    et al.
    Tyrode, Eric
    Laboratorio FIRP, Ingeniería Química, Universidad de Los Andes, Avenida Don Tulio Febres, Mérida .
    Sadtler, Veronique
    Choplin, Lionel
    Salager, Jean-Louis
    Simultaneous Conductivity and Viscosity Measurements as a Technique To Track Emulsion Inversion by the Phase-Inversion-Temperature Method2004Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, nr 6, s. 2134-2140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two kinds of transitions can occur when an emulsified water-oil-ethoxylated nonionic surfactant system is cooled under const. stirring. At a water-oil ratio close to unity, a transitional inversion takes place from a water-in-oil (W/O) to an oil-in-water (O/W) morphol. according to the so-called phase-inversion-temp. method. At a high water content, a multiple W/O/W emulsion changes to a simple O/W emulsion. The continuous monitoring of both the emulsion cond. and viscosity allows the identification of several phenomena that take place during the temp. decrease. In all cases, a viscosity max. is found on each side of the three-phase behavior temp. interval and correlates with the attainment of extremely fine emulsions, where the best compromise between a low-tension and a not-too-unstable emulsion is reached. The studied system contains Polysorbate 85, a light alkane cut oil, and a sodium chloride brine. All transitions are interpreted in the framework of the formulation-compn. bidimensional map.

  • 2. Allouche, Joachim
    et al.
    Tyrode, Eric
    FIRP Laboratory, Universidad de Los Andes, Mérida.
    Sadtler, Veronique
    Choplin, Lionel
    Salager, Jean-Louis
    Single- and Two-Step Emulsification To Prepare a Persistent Multiple Emulsion with a Surfactant-Polymer Mixture2003Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 42, nr 17, s. 3982-3988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The regions corresponding to different emulsion morphol. occurrences have been clearly identified on a bidimensional formulation-compn. map. Multiple emulsions spontaneously form when there is a conflict between the formulation and compn. effects. In such systems the most external emulsion is found to be unstable when the formulation effect is produced by a single surfactant. The use of a proper surfactant-polymer mixt. allows one to strongly inhibit the mass transfer and to considerably lengthen the equilibration between interfaces. As a consequence, the multiple emulsion can be stable enough to be used in encapsulation and controlled-release applications. The area where multiple emulsions occur and their characteristics (cond. and amt. of encapsulated external phase) are reported for a system contg. a sorbitan ester lipophilic surfactant and a diblock poly(ethylene oxide)-poly(propylene oxide) hydrophilic polymer, as a function of the formulation and compn., for a single-step process in which a specific amt. of mech. energy (stirring) is supplied. An increase in the oil viscosity is found to alter the map and to modify the multiple emulsion characteristics. The application of the results to emulsion-making technol. is discussed.

  • 3.
    Bain, Colin D.
    et al.
    Univ Durham, Dept Chem, Durham DH1 3LE, England..
    Churchwell, John H.
    Univ Durham, Dept Chem, Durham DH1 3LE, England..
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE).
    Walker, Robert A.
    Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA..
    TIR Raman spectroscopy of planar supported lipid bilayers2009Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 237Artikel i tidskrift (Övrigt vetenskapligt)
  • 4.
    Bain, Colin D.
    et al.
    Univ Durham, Dept Chem, Durham DH1 3LE, England..
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE).
    Woods, David
    Univ Durham, Dept Chem, Durham DH1 3LE, England..
    Combined Raman and SFG study of the adsorption of cationic surfactants on silica2009Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 237, s. 188-188Artikel i tidskrift (Övrigt vetenskapligt)
  • 5. Björnehohn, E.
    et al.
    Hansen, Martin H.
    Hodgson, Andrew
    Liu, Li-Min
    Limmer, David T.
    Michaelides, Angelos
    Pedevilla, Philipp
    Rossmeisl, Jan
    Shen, Huaze
    Tocci, Gabriele
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Walz, Marie-Madeleine
    Werner, Josephina
    Bluhm, Hendrik
    Water at Interfaces2016Ingår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 116, nr 13, s. 7698-7726Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding.

  • 6.
    Corkery, Robert W.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. The Australian National University, Australia.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    On the colour of wing scales in butterflies: Iridescence and preferred orientation of single gyroid photonic crystals2017Ingår i: Interface Focus, ISSN 2042-8898, E-ISSN 2042-8901, Vol. 7, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lycaenid butterflies from the genera Callophrys, Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue-green-yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 104-105 crystals, for concluding the preferential alignment seen along the k100l at the level of single scales, appears ubiquitous. By contrast, k110l orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the k110l direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the k110l band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures.

  • 7.
    Cyran, Jenee
    et al.
    Max Planck Inst Polymer Res, Dept Mol Spect, Mainz, Germany..
    Donovan, Michael
    Max Planck Inst Polymer Res, Dept Mol Spect, Mainz, Germany..
    Tyrode, Eric
    KTH.
    Bonn, Mischa
    Max Planck Inst Polymer Res, Dept Mol Spect, Mainz, Germany..
    Backus, Ellen
    Max Planck Inst Polymer Res, Dept Mol Spect, Mainz, Germany..
    Hydrophobic water at a hydrophilic interface2017Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Artikel i tidskrift (Övrigt vetenskapligt)
  • 8.
    Dalstein, Laetitia
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Potapova, Elizaveta
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    The elusive silica/water interface: isolated silanols under water as revealed by vibrational sum frequency spectroscopy2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 16, s. 10343-10349Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It has been long recognized that the surface chemistry of silica, and in particular the type and relative amount of surface bound silanol groups, plays a critical role in many of the properties associated with the material, where a typical example is the discrepant adsorption behavior observed depending on the pretreatment history of the surface. However, in spite of its importance, the direct probing of specific surface silanol groups under water has been hampered by instrumental limitations. Here we make use of vibrational sum frequency spectroscopy (VSFS) to first, identify under water the OH stretch of isolated surface silanols, and second, explore its acid/base behavior and dependence on the surface pretreatment method. The properties of other types of silanol groups (i.e. hydrogen bonded/geminal) are also inferred from the data. The ability to directly probe these functional groups under water represents a crucial step to further improving our understanding of this widely used mineral oxide.

  • 9.
    Hedberg, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Baldelli, Steven
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Molecular Structural Information of the Atmospheric Corrosion of Zinc Studied by Vibrational Spectroscopy Techniques I. Experimental Approach2010Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, nr 10, s. C357-C362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As the nature of the interactions taking place on a metal surface during atmospheric corrosion is inherently complex, it imposes demands on the analytical studies that are needed to understand the fundamentals on a molecular level. Corrosion products may spread on the metal surface forming two-and three-dimensional structures. Thus, it is imperative to use different techniques to resolve the different types of growth. In this first part of a series of two papers, a systematic investigation is made to obtain detailed information on the mechanisms of the onset of atmospheric corrosion of zinc exposed to 115 ppb acetic acid in either dry or humidified air. The vibrational spectroscopy techniques used were vibrational sum frequency spectroscopy (VSFS, interface sensitive), infrared reflection absorption spectroscopy (IRAS, near-surface sensitive), and confocal Raman microspectroscopy (CRM, bulk sensitive). The VSFS selectively targeted the two-dimensional structures, IRAS followed the growth of three-dimensional corrosion products, and CRM could provide a laterally resolved chemical map on localized aggregates of zinc hydroxy acetate and ZnO with bulk character. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3479207] All rights reserved.

  • 10.
    Heydari, Golrokh
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Järn, Mikael
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Hydrophobic Surfaces: Topography Effects on Wetting by Supercooled Water and Freezing Delay2013Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, nr 42, s. 21752-21762Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrophobicity, and in particular superhydrophobicity, has been extensively considered to promote ice-phobicity. Dynamic contact angle measurements above 0 degrees C have been widely used to evaluate the water repellency. However, it is the wetting properties of supercooled water at subzero temperatures and the derived work of adhesion that are important for applications dealing with icing. In this work we address this issue by determining the temperature-dependent dynamic contact angle of microliter-sized water droplets on a smooth hydrophobic and a superhydrophobic surface with similar surface chemistry. The data highlight how the work of adhesion of water in the temperature interval from about 25 degrees C to below -10 degrees C is affected by surface topography. A marked decrease in contact angle on the superhydrophobic surface is observed with decreasing temperature, and we attribute this to condensation below the dew point. In contrast, no significant wetting transition is observed on the smooth hydrophobic surface. The freezing temperature and the freezing delay time were determined for water droplets resting on a range of surfaces with similar chemistry but different topography, including smooth and rough surfaces in either the Wenzel or the Cassie-Baxter state as characterized by water contact angle measurements at room temperature. We find that the water freezing delay time is not significantly affected by the surface topography and discuss this finding within the classical theory of heterogeneous nucleation.

  • 11.
    Heydari, Golrokh
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Stenroos, Christian
    Koivuluoto, Heli
    Tuominen, Mikko
    Claesson, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ultralow ice adhesion on hydrophilic and molecularly smooth mica surfacesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Despite much research on designing surfaces for combating icing, no permanent solution has been achievedusing solid materials. Inspired by the slippery surface of ice, attributed to the presence of a quasi-liquid layeracting as a natural lubricant, we hypothesize that flat hydrophilic surfaces with a hydration layer remaining inthe liquid-like state at the solid-ice interface could result in low ice adhesion. Utilizing temperature-controlledice adhesion measurements on the molecularly smooth basal plane of muscovite mica, we observed the lowestreported ice adhesion on solid surfaces down to temperatures of -35 ºC. The ice adhesion is dramatically higheron flat hydrophilic silica surfaces. We discuss these findings in terms of what is known about mica-water andmica-ice interactions.

  • 12.
    Heydari, Golrokh
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Visnevskij, Ceslav
    Makuska, Ricardas
    Claesson, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Temperature-Dependent Deicing Properties of ElectrostaticallyAnchored Branched Brush Layers of Poly(ethylene oxide)2016Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, nr 17, s. 4194-4202Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydration water of hydrophilic polymersfreezes at subzero temperatures. The adsorption of suchpolymers will result in a hydrophilic surface layer that stronglybinds water. Provided this interfacial hydration water remainsliquidlike at subzero temperatures, its presence could possiblyreduce ice adhesion, in particular, if the liquidlike layer isthicker than or comparable to the surface roughness. Toexplore this idea, a diblock copolymer, having one branchedbottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. Theshear ice adhesion strength on such polymer-coated surfaces was investigated down to −25 °C using a homebuilt device. Inaddition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branchedbottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, attemperatures above −15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer.Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of waterinteracting with branched and linear poly(ethylene oxide) (with hydration water melting points of about −18 and −10 °C,respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branchedbottle-brush structured poly(ethylene oxide) at −10 °C, whereas no significant adhesion reduction was obtained with linearpoly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottlebrushstructured poly(ethylene oxide), which, in the bulk, does not freeze until −18 °C.

  • 13.
    Hore, Dennis K.
    et al.
    Univ Victoria, Dept Chem, Victoria, BC V8W 3V6, Canada..
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Probing Charged Aqueous Interfaces Near Critical Angles: Effect of Varying Coherence Length2019Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, nr 27, s. 16911-16920Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Angle-resolved vibrational sum frequency generation experiments have been used to study the silica-water interface as a function of ionic strength. Well below the critical angle, the sum frequency intensity increases up to 10(-4) M NaCl and then drops. However, near the critical angle, a plateau may be observed up to 10(-4) M. We first demonstrate that this is a result of the interaction of a long Debye length at low ionic strength with a long coherence length near the critical angles. In order to account for the behavior at the lowest concentrations where surface potentials are typically large, it is necessary to consider an electrostatic potential that extends into the bulk aqueous phase beyond the Debye-Huckel approximation. Because the extent of second- and third-order contributions to the nonlinear polarization can vary with ionic strength, but not with the angle of incidence, we perform a global fit to the experimental data using our proposed model to extract the relative magnitude of the two susceptibilities. The ionic strength dependence of this ratio points to the critical nature of the silanol deprotonation and the development of surface charge and illustrates how surface water molecules respond. These results highlight the importance of varying the coherence length in order to probe the water structure at charged interfaces.

  • 14.
    Jafarzadeh, Shadi
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Technical Research Institute of Sweden, Sweden.
    Sundell, Per-Erik
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Active corrosion protection by conductive composites of polyaniline in a UV-cured polyester acrylate coating2016Ingår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 90, s. 154-162Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polyaniline doped with phosphoric acid (PANI-PA) was synthesized and characterized by impedance and Raman spectroscopy. Exposure to UV-light resulted in a slight decrease in the PANI's electrical conductivity and no significant change in the oxidation state (of an emeraldine salt). Composite coatings containing 0, 1, 3 and 5 wt.% PANI-PA in a UV-curable polyester acrylate (PEA) resin were prepared and applied on polished carbon steel. Closely packed PANI-PA particles of several tens of nanometers were observed inside the composite coating by scanning electron microscopy, and a connected conductive network across the film was detected by Peak Force TUNA atomic force-microscopy. The evolution of open circuit potential and impedance data during long-term exposure to 3 wt.% NaCI electrolyte revealed that the short-term barrier-type corrosion protection provided by the insulating PEA coating can be turned into a long-term and active protection by addition of as little as 1 wt.% PANI-PA to the formulation. Stable ennoblement in the corrosive media was observed for the coatings containing conducting polymer up to 3 wt.%. However, higher content of PANI-PA (5 wt.%) led to poorer protective properties, probably due to the hydrophilicity of PANI-PA facilitating water transport in the coating and the presence of potentially weaker spots in the film. An iron oxide layer was found to fully cover the metal surface beneath the coatings containing PANI-PA after final failure observed by electrochemical testing.

  • 15.
    Johnson, C. Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Study of the adsorption of sodium dodecyl sulfate (SDS) at the air/water interface: targeting the sulfate headgroup using vibrational sum frequency spectroscopy2005Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 7, nr 13, s. 2635-2640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surface sensitive technique vibrational sum frequency spectroscopy (VSFS), has been used to study the adsorption behaviour of SDS to the liquid/vapour interface of aqueous solutions, specifically targeting the sulfate headgroup stretches. In the spectral region extending from 980 to 1850 cm(-1), only the vibrations due to the SO3 group were detectable. The fitted amplitudes for the symmetric SO3 stretch observed at 1070 cm(-1) for the polarization combinations ssp and ppp, were seen to follow the adsorption isotherm calculated from surface tension measurements. The orientation of the sulfate headgroup in the concentration range spanning from 1.0 mM to above the critical micellar concentration ( c. m. c.) was observed to remain constant within experimental error, with the pseudo-C-3 axis close to the surface normal. Furthermore, the effect of increasing amounts of sodium chloride at SDS concentrations above c. m. c. was also studied, showing an increase of approximately 12% in the fitted amplitude for the symmetric SO3 stretch when increasing the ionic strength from 0 to 300 mM NaCl. Interestingly, the orientation of the SDS headgroup was also observed to remain constant within this concentration range and identical to the case without NaCl.

  • 16.
    Johnson, Claes Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Kumpulainen, Atte
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Vibrational Sum Frequency Spectroscopy Study of the Liquid/Vapor Interface of Formic Acid/Water Solutions2009Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 30, s. 13209-13218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The liquid/vapor interface of aqueous formic acid solutions has been studied by vibrational sum frequency spectroscopy (VSFS) in the concentration range extending from water to pure formic acid. Throughout the whole concentration range, the acid molecules at the surface were found to be protonated, and no evidence of the dissociated form was found. A comprehensive picture of the adsorption and structural behavior was obtained by targeting the CH/OH and the C=O stretching regions. The main spectral features were the CH stretch at similar to 2926 cm(-1) and the C=O stretching vibration at similar to 1720 cm(-1), in addition to the OH stretching bands of water. Information regarding the orientation of the interfacial formic acid molecules was also obtained. The tilt angles (theta) of the CH and C=O bonds from the surface normal were determined to be basically concentration independent and attained values in the ranges of 27 degrees < theta(CH) < 43 degrees and 42 degrees < theta(C=O) < 57 degrees. Various models for the surface structure are discussed based on the spectral evolution in the whole concentration range, and a comparison is made to the adsorption behavior of acetic acid from an aqueous solution, which has been previously studied under similar conditions.

  • 17.
    Johnson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Baldelli, Steve
    Rutland, Mark
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    A vibrational sum frequency spectroscopy study of the liquid-gas interface of acetic acid-water mixtures: 1: surface speciation2005Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, nr 1, s. 321-328Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aqueous acetic acid solutions have been studied by vibrational sum frequency spectroscopy (VSFS) in order to acquire molecular information about the liquid-gas interface. The concentration range 0-100% acetic acid has been studied in the CH/OH and the C-O/C=O regions, and in order to clarify peak assignments, experiments with deuterated acetic acid and water have also been performed. Throughout the whole concentration range, the acetic acid is proven to be protonated. It is explicitly shown that the structure of a water surface becomes disrupted even at small additions of acetic acid. Furthermore, the spectral evolution upon increasing the concentration of acetic acid is explained in terms of the different complexes of acetic acid molecules, such as the hydrated monomer, linear dimer, and cyclic dimer. In the C=O region, the hydrated monomer is concluded to give rise to the sum frequency (SF) signal, and in the CH region, the cyclic dimer contributes to the signal as well. The combination of results from the CH/OH and the C-O/C=O regions allows a thorough characterization of the behavior of the acetic acid molecules at the interface to be obtained.

  • 18.
    Johnson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    A vibrational sum frequency spectroscopy study of the liquid/vapor interface of formic acid/water solutionsManuskript (preprint) (Övrigt vetenskapligt)
  • 19.
    Johnson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Atmospheric corrosion of zinc by organic constituents I. The role of the zinc/water and water/air interfaces studied by infrared reflection/absorption spectroscopy and vibrational sum frequency spectroscopy2006Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 153, nr 3, s. B113-B120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The zinc oxide/water and water/air interfaces have been investigated in order to elucidate the role of these two interfaces in an atmospheric corrosion process. Vibrational sum frequency spectroscopy (VSFS) has been used to study the water/air interface of aqueous acetic acid and acetaldehyde solutions. The VSFS studies revealed that the interfacial region of the acetic acid solutions is dominated by various species formed by hydrogen bonding, whereas acetaldehyde underwent a hydration process to form a gem-diol. In both cases, even small additions resulted in a breakdown of the surface structure found in pure water. Infrared reflection/absorption spectroscopy (IRAS) has been utilized to examine the zinc oxide/ water interface upon exposure of gaseous acetic acid and acetaldehyde at various relative humidities. The in situ IRAS investigations indicated a formation of zinc acetate both when the zinc oxide surface was exposed to acetic acid and acetaldehyde. Thus, despite being different in nature, these compounds resulted in the same end product in the corrosion process studied.

  • 20.
    Kumpulainen, Atte J
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Eriksson, Jan Christer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Soluble monolayers of sugar-based surfactants at the air-solution interface2009Ingår i: Sugar-Based Surfactants / [ed] Cristobal Carnero Ruiz, CRC Press, 2009, Vol. 143, nr Sugar-Based Surfactants, s. 153-206Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    A review. Surface activity, thermodn. relations for sol. monolayers, surface tension isotherms, adsorption, VSFS spectroscopy, Henry range, micelle formation, mixed solns., surface entropy, and some types of surfactants are discussed. [on SciFinder(R)]

  • 21.
    Liljeblad, Jonathan F. D.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Bulone, Vincent
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Johnson, Magnus C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Molecular Structure and Stability of Phospholipid Monolayers Probed by Vibrational Sum Frequency Spectroscopy (VSFS)2012Ingår i: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 102, nr 3, s. 591A-591AArtikel i tidskrift (Övrigt vetenskapligt)
  • 22.
    Liljeblad, Jonathan F. D.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Furo, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    The premolten layer of ice next to a hydrophilic solid surface: correlating adhesion with molecular properties2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 1, s. 305-317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to establish the potential correlation between the macroscopic ice adhesion and the molecular properties of the premolten layer (PML), the adhesion strength between ice and hydrophilic silica has been measured as a function of temperature. In addition, temperature-dependent molecular properties have been determined using techniques that are sensitive to different aspects of the PML, specifically total internal reflection (TIR) Raman, vibrational sum frequency (VSFS) and NMR spectroscopies. The ice shear adhesion strength was observed to increase linearly with decreasing temperature until -25 degrees C, where a plateau marked the adhesive strength having reached the cohesive strength of ice. Interestingly, at temperatures higher than -20 degrees C the ice samples slid on smooth (R-a < 0.4 nm) silica surfaces. This sliding behavior was not observed on rougher silica surfaces (R-a similar to 6 nm). By varying the penetration depth of the evanescent field, TIR Raman was used to establish an upper limit to the thickness of the PML in contact with silica (<3 nm even at -0.3 K below the bulk melting temperature). Additional quantitative determination of the temperature-dependent thickness of the PML was obtained from H-2 NMR measurements in mesoporous silica particles. Finally, the inherently surface specific technique, VSFS, which probed changes in the hydrogen bond environment, indicated at approximately -25 degrees C the onset of PML, followed by a marked structural change occurring just a fraction of a degree below the melting temperature. Jointly, the experimental approaches link, strongly and consistently, ice adhesion to the PML properties. Specifically, it is inferred that the premolten layer facilitates sliding and contributes to the observed friction behavior, provided its thickness is comparable to the surface roughness of the underlying silica substrate.

  • 23.
    Liljeblad, Jonathan F. D.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Vibrational sum frequency spectroscopy studies at solid/liquid interfaces: Influence of the experimental geometry in the spectral shape and enhancement2012Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, nr 43, s. 22893-22903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of the experimental geometry, specifically the angles of incidence (AOI) of the exciting beams, on the enhancement of the vibrational sum frequency spectroscopy (VSFS) spectra has been systematically investigated, particularly when approaching total internal reflection (TIR) conditions. Theoretical simulations of the spectral intensity as a function of the AOI and infrared wavelength at three different polarization combinations were critically compared to experimental data obtained from a hydrophobized silica/water interface. The spectra were recorded using a newly established femtosecond VSFS spectrometer designed to allow rapid and accurate changes of the angles of incidence. At the most favorable AOI, when the IR, visible, and/or emitted sum frequency beams were close to TIR conditions, the spectral enhancement could be up to several orders of magnitude. The effect from the IR beam was however less pronounced due to absorption from the aqueous phase. Furthermore, the relative enhancement of the spectral features across the CH and OH stretching regions varied significantly depending on the angles of incidence chosen. The uneven enhancement is a consequence of the large dispersion in the IR refractive index of water. Although the theoretical simulations qualitatively predict this trend, the quantitative agreement with the experimental data is poor. The simulations underestimate the amplification in the free OH range by 2−4 times as the IRbeam approaches TIR, and overestimates it as the visible beam approaches the critical angle. These observations may suggest a need to review the fundamental equations describing the angular dependence of the SF intensity. The practical advantages of selecting specific angles of incidence, as well as the expected variations for two other frequently encountered solid/liquid interfaces (CaF2/water and sapphire/water), are also discussed.

  • 24.
    Liljeblad, Jonathan F. D.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby, Denmark.
    Dublanchet, Ann-Claude
    L’Oréal Research and Innovation, Aulnay-sous-Bois, France.
    Luengo, Gustavo
    L’Oréal Research and Innovation, Aulnay-sous-Bois, France.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Self-assembly of long chain fatty acids: effect of a methyl branch2014Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 33, s. 17869-17882Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The morphology and molecular conformation of Langmuir Blodgett deposited and floating monolayers of a selection of straight chain (eicosanoic acid, EA), iso (19-methyl eicosanoic acid, 19-MEA), and anteiso (18-methyl eicosanoic acid, 18-MEA) fatty acids have been investigated by Vibrational Sum Frequency Spectroscopy (VSFS), AFM imaging, and the Langmuir trough. While the straight chain fatty acid forms smooth, featureless monolayers, all the branched chain fatty acids display 10-50 nm sized domains (larger for 19-MEA than the 18-MEA) with a homogeneous size distribution. A model is suggested to explain the domain formation and size in terms of the branched fatty acid packing properties and the formation of hemispherical caps at the liquid air interface. No difference between the chiral (S) form and the racemic mixture of the 18-MEA is observed with any of the utilized techniques. The aliphatic chains of the straight chain fatty acids appear to be oriented perpendicular to the sample surface, based on an orientational analysis of VSFS data and the odd/even effect. In addition, the selection of the subphase (neat water or CdCl2 containing water buffered to pH 6.0) used for the LB-deposition has a profound influence on the monolayer morphology, packing density, compressibility, and conformational order. Finally, the orientation of the 19-MEA dimethyl moiety is estimated, and a strategy for performing an orientational analysis to determine the complete molecular orientation of the aliphatic chains of 19-MEA and 18-MEA is outlined and discussed.

  • 25.
    Liljeblad, Jonathan F.D.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Bulone, Vincent
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. Institute for Surface Chemistry, Stockholm, Sweden.
    Johnson, Magnus C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Phospholipid Monolayers Probed by Vibrational Sum Frequency Spectroscopy: Instability of Unsaturated Phospholipids2010Ingår i: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 98, s. L50-L52Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The surface specific technique vibrational sum frequency spectroscopy has been applied to in situ studies of the degradation of Langmuir monolayers of 1,2-diacyl-phosphocholines with various degrees of unsaturation in the aliphatic chains. To monitor the degradation of the phospholipids, the time-dependent change of the monolayer area at constant surface pressure and the sum frequency intensity of the vinyl CH stretch at the carbon-carbon double bonds were measured. The data show a rapid degradation of monolayers of phospholipids carrying unsaturated aliphatic chains compared to the stable lipids carrying fully saturated chains when exposed to the ambient laboratory air. In addition, the degradation of the phospholipids can be inhibited by purging the ambient air with nitrogen. This instability may be attributed to spontaneous degradation by oxidation mediated by various reactive species in the air. To further elucidate the process of lipid oxidation in biological membranes artificial Langmuir monolayers probed by a surface specific spectroscopic technique as in this study can serve as a model system for studying the degradation/oxidation of cell membrane constituents.

  • 26.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface Forces and Friction between Silica and a Cross-Linked Nanohydrogel Layer of ChitosanManuskript (preprint) (Övrigt vetenskapligt)
  • 27.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Tech Res Inst Sweden.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface Grafted Chitosan Gels: Part I. Molecular Insight into the Formation of Chitosan and Poly(acrylic acid) Multi layers2014Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, nr 29, s. 8866-8877Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Si lane chemistry was used to graft the first chitosan layer to prevent film detachment and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAP.. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra, provided information regarding composition, including water content, and ionization state of weak acidic and basic groups present in the thin composite film. Low molecular weight PAA, mainly in its protonated form, diffuses into and out of the composite film during adsorption and rinsing steps. The higher molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAP.. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using atomic force microscopy operating in PeakForce tapping mode. The multilayer consists of islands that grow in lateral dimension and height during the build-up process, leading to close to exponentially increasing roughness with deposition number. Both diffusion in and out of at least one of the two components (PAA) and the island-like morphology contribute to the nonlinear growth of chitosan/PAA multilayers.

  • 28.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Tech Res Inst Sweden, Sweden.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface Grafted Chitosan Gels: Part II. Gel Formation and Characterization2014Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, nr 29, s. 8878-8888Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels with respect to pH changes was probed by quartz crystal microbalance with dissipation (QCM-D) and TIRR. Highly cross-linked gels show a small and fully reversible behavior when the solution pH is switched between pH 2.7 and 5.7. In contrast, low cross-linked gels are more responsive to pH changes, but the response is fully reversible only after the first exposure to the acidic solution, once an internal restructuring of the gel has taken place. Two distinct plc's for both chitosan and poly(acrylic acid), were determined for the cross-linked structure using TIRR. They are associated with populations of chargeable groups displaying either a bulk like dissociation behavior or forming ionic complexes inside the hydrogel film.

  • 29.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface grafted chitosan nanogels: Part I: Multilayer build-upManuskript (preprint) (Övrigt vetenskapligt)
  • 30.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Surface grafted chitosan nanogels: Part II: Gel formation and characterizationManuskript (preprint) (Övrigt vetenskapligt)
  • 31.
    Liu, Chao
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Charge regulation and energy dissipation while compressing and sliding a cross-linked chitosan hydrogel layer2015Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 443, s. 162-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Interactions between a silica surface and a surface coated with a grafted cross-united hydrogel made from chitosan/PAA multilayers are investigated, utilizing colloidal probe atomic force microscopy. Attractive double-layer forces are found to dominate the long-range interaction over a broad range of pH and ionic strength conditions. The deduced potential at the hydrogel/aqueous interface is found to be very low. This situation is maintained in the whole pH-range investigated, even though the degree of protonation of chitosan changes significantly. This demonstrates that pH-variations change the concentration of counterions within the hydrogel to keep the interior close to uncharged, which is similar to what has been observed for polyelectrolyte brushes. Changes in pH and ionic strength affect the adhesion force and the friction force between the silica surface and the hydrogel layer, but not the friction coefficient. This suggests that the main energy dissipation mechanism arises from processes occurring within the hydrogel layer, rather than at the silica/hydrogel interface, and we suggest that it is related to stretching of polymer chains between the cross-linking points. We also find that an increased cross-linking density, from 40% to 100%, in the hydrogel reduces the friction coefficient. (C) 2014 Elsevier Inc. All rights reserved.

  • 32. Mille, C.
    et al.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Corkery, Robert W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi (stängd 20110630).
    3-D chiral photonic crystals replicated from butterfly wing scales2011Ingår i: Materials Research Society Symposium Proceedings: Volume 1389, 2011, s. 7-12Konferensbidrag (Refereegranskat)
    Abstract [en]

    Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized using the butterfly Callophrys rubi as a template. The replicas are synthesized with a high degree of fidelity, which is confirmed by the spectral and morphological characterization. Further, the material is shown to be optically active.

  • 33. Mille, Christian
    et al.
    Tyrode, Eric C.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Corkery, Robert W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    3D titania photonic crystals replicated from gyroid structures in butterfly wing scales: approaching full band gaps at visible wavelengths2013Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, nr 9, s. 3109-3117Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    3D titania photonic crystals are replicated from single gyroid structures found in the butterfly Callophrys rubi. Photonic crystals were characterised using SEM imaging, X-ray and Raman scattering and reflection spectroscopy. The overall symmetry and topology of the original single gyroid structures is replicated with high fidelity. Titania replicas display photonic responses that are thermal history dependent. Replicas treated at 700 degrees C, show up to 96% reflectivity at similar to 505 nm, while at lower and higher treatment temperatures the photonic response was not as pronounced. Simulated band structures fitted to the observed spectral reflectivity data constrain the solid volume fractions and dielectric constants of the replicas. The titania photonic crystals were also found to be optically active, with both left- and right-handed single gyroids contributing to the chiral response. The 3D titania photonic crystals replicated here have nearly complete overlapping of partial band gaps, strongly suggesting that materials with full photonic band gaps are experimentally within reach using the general replication approach reported here.

  • 34. Mille, Christian
    et al.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Corkery, Robert W.
    Inorganic chiral 3-D photonic crystals with bicontinuous gyroid structure replicated from butterfly wing scales2011Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, nr 35, s. 9873-9875Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized. The butterfly Callophrys rubi was used as a biotemplate. This material represents a significant addition to the small family of synthetic bicontinuous photonic crystals.

  • 35.
    Niga, Petru
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Rutland, Mark W.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    The Influence of Unsaturation on the Surface Structure of Fatty Acids Monolayers Studied by Vibrational Sum Frequency SpectroscopyManuskript (preprint) (Övrigt vetenskapligt)
  • 36.
    Okur, Halil I.
    et al.
    Ecole Polytech Fed Lausanne, Inst Bioengn IBI, Sch Engn STI, Lab Fundamental BioPhoton LBP, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Inst Mat Sci IMX, Sch Engn STI, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Lausanne Ctr Ultrafast Sci LACUS, CH-1015 Lausanne, Switzerland..
    Drexler, Chad I.
    Penn State Univ, Dept Chem, University Pk, PA 16802 USA..
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Ecole Polytech Fed Lausanne, Inst Bioengn IBI, Sch Engn STI, Lab Fundamental BioPhoton LBP, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Inst Mat Sci IMX, Sch Engn STI, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Lausanne Ctr Ultrafast Sci LACUS, CH-1015 Lausanne, Switzerland..
    Cremer, Paul S.
    Penn State Univ, Dept Chem, University Pk, PA 16802 USA.;Penn State Univ, Biochem & Mol Biol, University Pk, PA 16802 USA..
    Roke, Sylvie
    Ecole Polytech Fed Lausanne, Inst Bioengn IBI, Sch Engn STI, Lab Fundamental BioPhoton LBP, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Inst Mat Sci IMX, Sch Engn STI, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Lausanne Ctr Ultrafast Sci LACUS, CH-1015 Lausanne, Switzerland..
    The Jones-Ray Effect Is Not Caused by Surface-Active Impurities2018Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 9, nr 23, s. 6739-6743Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pure aqueous electrolyte solutions display a minimum in surface tension at concentrations of 2 +/- 1 mM. This effect has been a source of controversy since it was first reported by Jones and Ray in the 1930s. The Jones Ray effect has frequently been dismissed as an artifact linked to the presence of surface-active impurities. Herein we systematically consider the effect of surface-active impurities by purposely adding nanomolar concentrations of surfactants to dilute electrolyte solutions. Trace amounts of surfactant are indeed found to decrease the surface tension and influence the surface chemistry. However, surfactants can be removed by repeated aspiration and stirring cycles, which eventually deplete the surfactant from solution, creating a pristine surface. Upon following this cleaning procedure, a reduction in the surface tension by millimolar concentrations of salt is still observed. Consequently, we demonstrate that the Jones Ray effect is not caused by surface-active impurities.

  • 37.
    Piela, Katarzyna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Tyrode, Eric C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Furo, Istvan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Cryoporometry in Femtoliter Volumes by Confocal Raman Spectroscopy2019Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, nr 26, s. 8823-8828Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The properties of porous material are largely dependent on the size, shape, and connectivity of the pores. Here, we present a method based on confocal Raman spectroscopy to quantify porosity using a cryoporometric approach. We show that the phase transition of water imbibed in porous silica can be accurately determined using two different, but complementary methodologies. The first one relies on integrating the temperature-dependent spectral intensities across the whole OH (H2O) or OD (D2O) stretching region. The second, more quantitative approach, deconvolutes the spectral contributions within the pores in terms of liquid and solid fractions. The results show the expected reciprocal dependence of the average phase transition point with pore size, as well as the typical hysteresis between the freezing and melting transitions. One of the key advantages of the confocal Raman approach is its high spatial resolution, with sampling volumes starting from just a few femtoliters, opening the possibility of mapping the structure in heterogeneous porous materials.

  • 38.
    Rahm, Martin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Brinck, Tore
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    The Molecular Surface Structure of Ammonium and Potassium Dinitramide: A Vibrational Sum Frequency Spectroscopy and Quantum Chemical Study2011Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, nr 21, s. 10588-10596Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vibrational sum frequency spectroscopy (VSFS) and quantum chemical modeling have been employed to investigate the molecular surface structure of ammonium and potassium dinitramide (ADN and KDN) crystals. Identification of key vibrational modes was made possible by performing density functional theory calculations of molecular clusters. The surface of KDN was found to be partly covered with a thin layer of the decomposition product KNO3, which due to its low thickness was not detectable by infrared and Raman spectroscopy. In contrast, ADN exhibited an extremely inhomogeneous surface, on which polarized dinitramide anions were present, possibly together with a thin layer of NH4NO3. The intertwined use of theoretical and experimental tools proved indispensable in the analysis of these complex surfaces. The experimental verification of polarized and destabilized dinitramide anions stresses the importance of designing surface-active polymer support, stabilizers, and/or coating agents, in order to enable environmentally friendly ADN-based solid-rocket propulsion.

  • 39.
    Rutland, Mark W.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Tech Res Inst, Sweden.
    Liljeblad, Jonathan D. F.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Dublanchet, Ann-Claude
    Luengo, Gustavo
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Long chained fatty acid monolayers: Influence of methyl branching2014Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, s. 61-COLL-Artikel i tidskrift (Övrigt vetenskapligt)
  • 40.
    Sengupta, Sanghamitra
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Moberg, Daniel R.
    Univ Calif San Diego, Dept Chem & Biochem, Mat Sci & Engn, La Jolla, CA 92093 USA..
    Paesani, Francesco
    Univ Calif San Diego, Dept Chem & Biochem, Mat Sci & Engn, La Jolla, CA 92093 USA.;Univ Calif San Diego, San Diego Supercomp Ctr, La Jolla, CA 92093 USA..
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Neat Water-Vapor Interface: Proton Continuum and the Nonresonant Background2018Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 9, nr 23, s. 6744-6749Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Whether the surface of neat water is "acidic" or "basic" remains an active and controversial field of research. Most of the experimental evidence supporting the preferential adsorption of H3O+ ions stems from nonlinear optical spectroscopy methods typically carried out at extreme pH conditions (pH < 1). Here, we use vibrational sum frequency spectroscopy (VSFS) to target the "proton continuum", an unexplored frequency range characteristic of hydrated protons and hydroxide ions. The VSFS spectra of neat water show a broad and nonzero signal intensity between 1700 and 3000 cm-' in the three different polarization combinations examined. By comparing the SF response of water with that from dilute HCl and NaOH aqueous solutions, we conclude the intensity does not originate from either adsorbed H3O+ or OH- ions. Contributions from the nonresonant background are then critically considered by comparing the experimental results with many-body molecular dynamics (MB-MD) simulated spectra.

  • 41.
    Sthoer, Adrien
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. kth.
    Interactions of Na+ Cations with a Highly Charged Fatty Acid Langmuir Monolayer: Molecular Description of the Phase Transition2019Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Vibrational sum frequency spectroscopy has been used to study the molecular properties upon compression of a highly charged arachidic acid Langmuir monolayer, which displays a first-order phase transition plateau in the surface pressure - molecular area (π-A) isotherm. By targeting vibrational modes from the carboxylic acid headgroup, alkyl chain, and interfacial water molecules, information regarding the surface charge, surface potential, type of ion pair formed, and conformational order of the monolayer could be extracted. The monolayer was found to be fully charged before reaching the 2D-phase transition plateau, where partial reprotonation, as well as the formation of COO⎺ Na+ contact-ion pairs, started to take place. After the transition, three headgroup species, mainly hydrated COO⎺, COOH, and COO⎺ Na+ contact-ion pairs could be identified and their proportions quantified. Comparison with theoretical models shows that predictions from the Gouy Chapman model are only adequate for the lowest surface charge densities (<-0.1 C/m2). In contrast, a modified Poisson-Boltzmann (MPB) model that accounts for finite-size of the cation, captures many of the experimental observables, including the partial reprotonation, and surface potential changes upon compression. The experimental results provide a quantitative molecular insight that could be used to test potential extensions to the theory.

  • 42.
    Sthoer, Adrien
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Adams, Ellen
    Ohio State University.
    Sengupta, Sanghamitra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Corkery, Robert
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Allen, Heather
    Tyrode, Eric
    KTH.
    La3+ and Y3+ interactions with the carboxylic acid moiety at theliquid/vapor interface: identification of binding complexes, chargereversal, and detection limits.Manuskript (preprint) (Övrigt vetenskapligt)
  • 43.
    Sthoer, Adrien
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Hladilkova, Jana
    Lund Univ, Sweden.
    Lund, Mikael
    Lund Univ Sweden.
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Molecular insight into carboxylic acid-alkali metal cations interactions: reversed affinities and ion-pair formation revealed by non-linear optics and simulations2019Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, nr 21, s. 11329-11344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Specific interactions between the carboxylic acid moiety and the monovalent salts CsCl, NaCl, and LiCl, have been investigated in Langmuir monolayers using vibrational sum frequency spectroscopy (VSFS) and complemented with coarse grained and all-atom molecular dynamics simulations. By exploiting VSFS's intrinsic surface specificity, an emphasis was made on targeting headgroup vibrations of both its charged and uncharged forms as well as water molecules in the interfacial layer. The degree of deprotonation of the monolayer as a function of cation concentration and pH was experimentally determined and theoretically rationalized. Starting from 100 mM, the surface charge was overestimated by the Gouy-Chapman model and varied depending on the identity of the cation, highlighting the appearance of ion specific effects. Agreement could be found using a modified Poisson-Boltzmann model that takes into account steric effects, with a fitted effective ion-size compatible with the hydrated ion diameters. The relative affinity of the cations to the carboxylic acid moiety was pH dependent: at pH 4.5 they arranged in the order Cs+ 4 Na+ 4 Li+, but fully reversed (Li+ 4 Na+ 4 Cs+) at pH 9. Simulations yielded microscopic insight into the origin of this behavior, with the cations showing contrasting interaction preferences for either the uncharged carboxylic acid or the charged carboxylate. Sum frequency spectra also provided evidence that all cations remained hydrated when interacting with the charged headgroup, forming solvent-separated or solvent-shared ion pairs. However, for the specific case of 1 M Li+ at pH 9, contact ion pairs were formed. Finally, the remarkable effect of trace metal multivalent cations in the interpretation of experiments is briefly discussed. The results provide exciting new insights into the complex interactions of alkali metal cations with the biophysically relevant carboxylic acid moiety.

  • 44.
    Sthoer, Adrien
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Hladilkova, Jana
    Lund Univ, Theoret Chem, Lund, Sweden..
    Lund, Mikael
    Lund Univ, Theoret Chem, Lund, Sweden..
    Tyrode, Eric
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Molecular insight into the carboxylic acid - alkali metal cations interactions: Reversed affinity and ion pair formation2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 45. Tong, Yujin
    et al.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Osawa, Masatoshi
    Yoshida, Naoya
    Watanabe, Toshiya
    Nakajima, Akira
    Ye, Shen
    Preferential Adsorption of Amino-Terminated Silane in a Binary Mixed Self-Assembled Monolayer2011Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, nr 9, s. 5420-5426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The composition and structure of a binary mixed self-assembled monolayer (SAM) of 3-aminopropyltiethoxysilane (APS, NH2(CH2)(3)Si-(OCH2CH3)(3)) and octadecyltrimethoxysilane (ODS, CH3(CH2)(17)Si(OCH3)(3)) on a silicon oxide surface have been characterized by water contact-angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and sum frequency generation (SFG) vibrational spectroscopy. XPS demonstrated that APS in the mixed SAM is significantly enriched in comparison to that in solution, indicating the preferential adsorption of APS during the SAM formation. AFM observations showed that the mixed SAM becomes rougher. SFG revealed that the coadsorption of APS induced a conformation disordering in the ODS molecules present in the mixed SAM. The surface enrichment of APS has been explained in terms of differences in the surface adsorption rates of the two components as well as in the self-congregation states of APS molecules in the bulk solution. Furthermore, the structure of the water molecules on the mixed SAM surface in contact with the aqueous solutions at different pH's has also been studied. The results indicate that the mixed-SAM modified surface is positively charged at pH < 5 and negatively charged at pH > 7.

  • 46.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Insights into the effect of unsaturations in the surface structure of fatty acids monolayers and its interfacial aqueous subphase: A vibrational sum frequency spectroscopy study2011Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241Artikel i tidskrift (Övrigt vetenskapligt)
  • 47.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Vibrational Sum Frequency Spectroscopy Studies at the Air-Liquid Interface2005Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis the structure and hydration of small organic and amphipilic compounds adsorbed at the air-liquid interface, have been studied using the nonlinear optical technique Vibrational Sum Frequency Spectroscopy (VSFS). The second order nature of the sum frequency process makes this technique particularly surface sensitive and very suitable for interfacial studies, as molecules at the surface can be distinguished even in the presence of a vast excess of the same molecules in the bulk. Particular emphasis was given to the surface water structure and how it is affected by the presence of small model compounds such as acetic acid and formic acid, and also non-ionic surfactants with sugar based and ethylene oxide based polar headgroups. Understanding the structure of water at these interfaces is of considerable fundamental importance, and here VSFS provided unique information. Upon addition of tiny amounts of these surface active compounds, the ordered surface structure of water was found to be significantly perturbed, as revealed by the changes observed in the characteristic spectroscopic signature of the dangling OH bond of water molecules, which vibrate free in air and are present in the top monolayer. Dramatic differences between the different compounds were also observed in the bonded OH region, providing a valuable insight into the hydration of polar groups at interfaces. Additionally, by employing different polarization combinations of the laser beams involved in the sum frequency process, information about the different water species present at the surface and their average orientation were extracted. In particular an unusual state of water was found with a preferred orientation in a non-donor configuration in close proximity to the hydrophobic region formed by the hydrocarbon tails of the surfactant molecules.

    The conformation and orientation of the different adsorbates were also characterized, targeting their specific vibrational frequencies. Noteworthy is the orientation of the fluorocarbon chain of ammonium perfluorononanoate (APFN), which in contrast to the hydrocarbon chains of the other surfactant molecules studied, remained constant over a wide range of surface densities. This behaviour was also observed for the anionic headgroup of sodium dodecyl sulphate (SDS). Other interesting findings were the formation of a cyclic dimer bilayer at the surface of concentrated aqueous solutions of acetic acid and the water structuring effect induced by poly(ethylene-oxide) headgroups, in spite of being themselves disordered at the air-liquid interface.

  • 48.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Water structure close to ordered and disordered hydrophobic surfaces studied by linear and nonlinear vibrational spectroscopies2011Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241Artikel i tidskrift (Övrigt vetenskapligt)
  • 49.
    Tyrode, Eric
    et al.
    Laboratorio FIRP, Ingeniería Química, Universidad de Los Andes, Mérida, Venezuela.
    Allouche, Joachim
    Choplin, Lionel
    Salager, Jean-Louis
    Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 4. Following the Emulsion Viscosity during Three Inversion Protocols and Extending the Critical Dispersed-Phase Concept2005Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 44, nr 1, s. 67-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three protocols are tested to invert an abnormal emulsion into a normal one: a dynamic process with continuous addn. of an internal phase, continuous stirring of a given emulsion with no addn. of an internal phase, and the combination of the previous ones, i.e., a standstill dynamic process in which the addn. of an internal phase is interrupted at some time and then followed by continued stirring. In situ follow-up of both cond. and viscosity data in a rheomixer vessel provides complementary information to corroborate the crit. dispersed-phase concept as a condition for the inversion to take place in all cases. Some applications are discussed. [on SciFinder (R)]

  • 50.
    Tyrode, Eric
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Corkery, Robert
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Charging of Carboxylic Acid Monolayers with Monovalent Ions at Low Ionic Strengths: Molecular Insight Revealed by Vibrational Sum Frequency Spectroscopy2018Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 50, s. 28775-28786Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The charging of arachidic acid Langmuir monolayers as a function of subphase pH and monovalent ion concentration below 100 mM was investigated using vibrational sum frequency spectroscopy. Molecular information was obtained by targeting the vibrational modes of the carboxylic acid headgroups, alkyl chains, and water molecules in the immediate surface and diffuse double layers. The surface charge in the monolayer was experimentally determined by monitoring the hydrated carboxylate stretching modes. The charging behavior was found to be in excellent agreement with that predicted by Gouy-Chapman theory using a thermodynamic pK(a) of 5.1 +/- 0.2. This resulted in an apparent pK(a) of similar to 10.8 when the only ions present in solution were those associated with adjusting the pH. Water molecules with a preferred orientation in the immediate surface region were found to primarily interact with the uncharged carboxylic acid moiety, decreasing in number as the monolayer further deprotonated. Contributions from water molecules in the diffuse double layer, partly aligned by the exponentially decaying surface electric field, closely followed the predictions of a recently proposed theoretical framework that accounts for interference and screening effects. Finally, the charging of the monolayer was experimentally found to be independent of the identity of either the monovalent cation (i.e., Li+, Na+, Rb+) or anion (i.e., F-, Cl-, I-) at low salt concentrations.

12 1 - 50 av 63
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf