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  • 51.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Ion specific differences in salt induced precipitation of kraft lignin2002Report (Other academic)
  • 52.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lignin: Recent advances and emerging applications2014In: Current Opinion in Colloid & Interface Science, ISSN 1359-0294, E-ISSN 1879-0399, Vol. 19, p. 409-416Article, review/survey (Refereed)
    Abstract [en]

    In this paper, we focus on the recent advances on the physical chemistry of lignin. Emerging trends of incorporating lignin in promising future applications such as controlled release, saccharification of lignocelluloses, bioplastics, composites, nanoparticles, adsorbents and dispersants, in electro-chemical applications and carbon fi bers, arealso reviewed. We briefl y describe the complexity of the lignin structure that influences the solution behavior, both as a macromolecule and a col loid, as well as the potential of being a renewable precursor in the development of high-value applications. Special attention is paid on summarizing the present knowledge on lignin colloidalstability and surface chemistry.

  • 53.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Stabilisation of Kraft Lignin Solutions by Surfactant Additions2001In: Colloids and Surfaces A, ISSN 0927-7757, Vol. 194, no 1-3, p. 239-248Article in journal (Refereed)
    Abstract [en]

    The colloidal stability of kraft lignin (KL) and some various KL-surfactant mixtures in aqueous alkaline solutions, pH 10.0-11.50, was tuned and investigated at high ionic strengths, 0.5-1.1 M, and elevated temperatures, 70 and 150°C. The main techniques used were Quasi-Elastic Light-Scattering (QELS) and turbidity measurements, together with sample inspection by the naked eye. Samples without surfactant additions and samples containing various alkyl sulfonates showed a comparably low colloidal stability, whereas in mixtures containing sodium salts of bile acids, the stability was found greatly improved. The efficiency of different bile salts was investigated and it was found that the overall best solution stability is obtained in mixtures of KL and sodium taurodeoxycholate (STDC). STDC showed a relatively good stabilising effect also at very high temperatures (150°C). Furthermore, in already aggregated KL solutions, additions of STDC were found to cause 'de-aggregation' and the number of formed aggregates was dramatically decreased. From the outcome of the investigation, it can be concluded that by introducing surfactants, and maybe other designed additives too, new possibilities in controlling the colloidal stability of KL at rough solution conditions are given.

  • 54.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nilvebrant, Nils-Olof
    Physiochemical differences between dissolved and precipitated Kraft lignin fragments as determined by PFG NMR, CZE and quantitative UV spectrophotometry2001In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 27, no 11, p. 359-363Article in journal (Refereed)
    Abstract [en]

    A combination of analytical techniques, specifically capillary zone electrophoresis, H-1 pulsed-field gradient nuclear magnetic resonance se (diffusion measurements and quantitative UV spectrophotometric measurements, was used to investigate physicochemical differences between dissolved and precipitated kraft lignin (KL)fragments, obtained from the same sample. Precipitation was induced by heating alkaline (pOH4)Indulin AT solutions, containing various concentrations of NaCl (0.20-1.0 mol/L), at 75 degreesC. Depending on the salt concentration in the samples, different amounts of KL were precipitated. The KL precipitated at the lowest NaCl concentrations was found to consist of the largest lignin fragments whereas, at high NaCl concentrations, the KL fragments in the supernatants were found to be of comparably lower mean molecular weights. From the outcome of the investigation, it was found that the combination of analytical techniques used provides the possibility of collecting important information about physicochemical characteristics related to the solution behaviour of industrial lignins.

  • 55.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wågberg, Lars
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Aggregation of Lignin Derivatives under Alkaline Conditions. Kinetics and Aggregate Structure2002In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, no 7, p. 2859-2865Article in journal (Refereed)
    Abstract [en]

    The kinetics of kraft lignin (KL) aggregation at alkaline conditions was studied by quasi-elastic light scattering (QELS) and turbidity measurements. Stability ratios (W) for KL were obtained at 70 °C and various concentrations of sodium chloride. By analyzing the early-time evolution data of aggregate growth obtained from QELS, fractal dimensions of flocs formed in both reaction-limited cluster-cluster aggregation regimes and diffusion-limited cluster-cluster aggregation regimes were determined. Correlations between the fractal dimension and the W-ratio were found in accordance to recent studies of a system containing monodisperse polystyrene colloids. By cryogenic transmission electron microscopy, the fractality of KL aggregate structures in the system was also shown. It was seen from stability studies of KL solutions that the effects of specific co- and counterions follow the Hofmeister series. From the outcome of the investigation, different modes of aggregation occurring in a KL system are proposed. Starting from the macromolecular state of KL and evolving through larger aggregates, the KL clusters finally exhibit a supramolecular structure similar to what earlier has been proposed for native softwood lignin.

  • 56.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wågberg, Lars
    Annergren, Göran
    Fundamental Physical Aspects on Lignin Dissolution2002In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 17, no 4, p. 370-373Article in journal (Refereed)
    Abstract [en]

    The aggregation of diluted kraft lignin (KL) solutions was studied by turbidity measurements at elevated temperatures, various sodium chloride and sodium hydroxide concentrations. Since adsorptive processes usually precede self-aggregation in macromolecular systems as the solution conditions get worse, the interaction between KL and pulp fibres was also investigated. When treating samples of fully bleached softwood pulp fibres in KL solutions under various solution conditions, the light-absorption coefficient increased and the brightness was found to decrease rapidly above pOH 1, as the temperature was elevated. At pOH 2 and 175°C, the adsorption of KL was up to about 6 mg g-1. The results are also discussed theoretically in terms of lignin solubility and lignin coagulation.

  • 57.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Wågberg, Lars
    Lindström, Birger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Annergren, Göran
    Aggregation of Kraft Lignin Derivatives under Conditions Relevant to the Process. Part I. Phase Behaviour2001In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 194, no 1-3, p. 85-96Article in journal (Refereed)
    Abstract [en]

    Aggregation of a commercial, polydisperse softwood kraft lignin (Indulin AT) in diluted aqueous alkaline solutions was investigated experimentally, by means of turbidity measurements. The influence of temperature, salt concentration and pOH and the role of a divalent counterion on the aggregation behaviour were studied. When the temperature was increased, an increased tendency of aggregation in samples containing high concentrations of sodium chloride was found. Phase separation could be detected even at pOH=2 at 175°C and the effect was pronounced when the concentration of hydroxide ions decreased. The phase transition from soluble to precipitated lignin was found to be irreversible concerning temperature change. Small amounts of calcium ions were seen to induce dramatic effects on the system stability, even at relatively high hydroxide concentrations (pOH 1-2). At a given temperature and pOH, the coagulation was found to appear at a certain critical coagulation concentration (CCC) of the added electrolyte. Furthermore, calculations were carried out to compare with the outcome of the experimental observations. A theoretical model, based on the DLVO theory, was found to predict the kraft lignin solution behaviour well.

  • 58.
    Norgren, Magnus
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Mackin, S
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Different aggregations processes during kraft lignin aggregation.2004In: Eighth European Workshop on lignocellulosics and pulp : utilization of lignocellulosics and by-products of pulping ; August 22-25,2004 ; proceedings.: Workshop on Lignocellulosics and Pulp (EWLP) ; 8 (Riga) : 2004.08.22-25, Riga: Institute of Wood Chemistry , 2004, p. 562-Conference paper (Refereed)
    Abstract [en]

    This study is focused on the aggregation behaviour of kraft lignin (KL) in presence of different types of surfactants at elevated temperatures. Especially the initial part of the aggregation process, the nucleation and onset, is of interest. KL aggregation is induced either by adding surfactants or salt. The KL-surfactant interactions are found to be different depending on the type of surfactant. Starting with KL as a negatively charged polymeric fragment and adding a positively charged surfactant, the aggregation behaviour is significantly influenced. However, adding non-ionic surfactants without obvious head group interactions to the KL solutions, or surfactants with negatively charged head groups, completely different aggregation processes and particle structures are observed.

  • 59.
    Persson, Gerd
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Amenitsch, Hans
    Laggner, Peter
    Lindblom, Göran
    The 1-monooleoyl-rac-glycerol/n-octyl-beta-D-glucoside/water system: Phase diagram and phase structures determined by NMR and X-ray diffraction2003In: Langmuir, ISSN 0743-7463, Vol. 19, no 14, p. 5813-5822Article in journal (Refereed)
    Abstract [en]

    Using SAXD and NMR techniques as well as visual observations, a detailed study of the extension of the phase regions and their structures has been performed for the ternary system 1-monooleoyl-rac-glycerol (MO)/n-octyl-β-d-glucopyranoside (OG)/2H2O at 25 °C. OG in water forms a large region of a micellar solution phase, in which substantial amounts of MO can be dissolved. Increasing the MO concentration at constant water content results in the formation of two- and three-phase areas, consisting of liquid, lamellar, or cubic phases in equilibrium with a very dilute water/OG solution. Besides the different phases previously reported for the binary systems, an additional hexagonal phase occurs at high OG contents. Addition of minor amounts (≈1.5 wt %) of OG converts the cubic phases present in the MO/2H2O system to an Lα phase, while the cubic phase in the OG/2H2O system is able to dissolve as much as 15 wt % MO. Since a major part of the phase diagram consists of planar bilayers, it is concluded that for most MO/OG ratios the spontaneous curvature is close to zero. The reason for this is discussed in terms of the molecular packing of MO and OG.

  • 60.
    Persson, Gerd
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lindblom, Göran
    Phase Behavior of 1-Alkylpyridinium Octane-1-sulfonates: Effect of the 1-Alkylpyridinium Counterion Size2004In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, no 4, p. 1168-1179Article in journal (Refereed)
    Abstract [en]

    The temperature-versus-composition phase diagrams of eight different 1-alkylpyridinium octane-1-sulfonates (APOSs) in water were studied by 1H NMR, 2H NMR, pulsed gradient spin-echo NMR, small-angle X-ray diffraction, differential scanning calorimetry, surface tension and conductivity measurements, and polarizing microscopy. The number of carbons (nc) in the hydrocarbon chain of the pyridinium counterions was varied from nc = 1 to nc = 8 to study how the phase behavior of the APOS/2H2O systems was affected by a change in the chain length of the counterion. The sodium octane-1-sulfonate (NaOS)/water system was used as a reference. This system formed an isotropic micellar solution (L1) phase and a normal hexagonal (HI) phase. All APOSs were readily soluble in water and formed L1 phases. The surface tension above the critical micelle concentration for nc between 1 and 3 was higher than that for NaOS, and it decreased steadily for the different APOSs with increasing chain length. The area per molecule at the air/solution interfaces was rather constant at 68 Å2 for nc between 1 and 7. For 1-octylpyridinium octane-1-sulfonate (OPOS), it was about 5 Å2 smaller, which was just outside the estimated error. However, the smallest area was obtained for NaOS. At higher surfactant concentrations, liquid crystalline phases formed. Both cubic and HI phases were found for nc = 1 and 2, while for nc between 3 and 5 only an HI phase was observed. HI and lamellar liquid crystalline (L) phases formed for nc = 6 and 7. The only liquid crystalline phase found in the OPOS system was a L phase. The NaOS HI phase was the only liquid crystalline phase that showed a linear relation between the 2H2O NMR quadrupolar splitting (W) and Xsurf/XW, where Xsurf and XW are the mole fractions of surfactant and water. The OPOS lamellae were found to be much thinner than expected, indicating a defect lamellar structure. This was further supported by the behavior of the quadrupolar splitting of deuterated OPOS. The anomalous behaviors of the 2H2O NMR quadrupolar splitting observed in the L phases of 1-heptylpyridinium octane-1-sulfonate and OPOS were interpreted in terms of changes in the population of the water molecules residing in different sites combined with a continuous rearrangement of the lamellae surface with the possible development of holes. The appearances of the phase diagrams were discussed in terms of surfactant molecular geometry and the packing of the amphiphiles in the aggregates formed.

  • 61. Persson, Gerd
    et al.
    Edlund, Håkan
    Lindblom, G
    Phase behaviour of the 1-monooleoyl-rac-glycerol/n-octyl-beta-D-glucoside/water system2004In: TRENDS IN COLLOID AND INTERFACE SCIENCE XVI / [ed] Miguel, MG; Burrows, HD, Springer, 2004, Vol. 123, p. 36-39Conference paper (Refereed)
    Abstract [en]

    Obtaining high-quality crystals for X-ray diffraction from membrane proteins has proven to be a difficult task. One recently presented method utilises the cubic phases formed by 1-monooleoyl-rac-glycerol (MO). Removing the proteins from their native environment requires the use of surfactants. One commonly used surfactant is n-octyl-beta-D-glucopyranoside (OG). Using NMR techniques and visual observations, the ternary phase diagram of MO/OG/(H2O)-H-2 was outlined at 25 degreesC. The preliminary data show that all phases present in the binary systems at this temperature are also found in the ternary. Further, at the OG-rich side, an additional phase that appears to be hexagonal occurs. Addition of minor amounts (approximate to1.5 wt/wt %) of OG converts the cubic phases of MO to a lamellar structure, while the OG-rich cubic phase is able to dissolve about 15 wt/wt % MO. OG in water forms a large micellar solution phase;. Increasing the MO concentration at constant water content leads to a series of two- and three-phase areas in which one or two phases are in equilibrium with almost pure water.

  • 62.
    Persson, Gerd
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lindblom, Göran
    Thermal Behaviour of Cubic Phases Rich in 1-monooleoyl-rac-glycerol in the ternary system 1-monooleoyl-rac-glycerol / n-octyl-b-D-glucoside / Water.2003In: European Journal of Biochemistry, ISSN 0014-2956, Vol. 270, no 1, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Using synchrotron X-ray diffraction the thermal behaviour was studied of the cubic phases in the 1-monooleoyl-rac -glycerol (MO)/n-octyl-beta-d-glucopyranoside (OG)/(2) H-2 O system with 58 or 45 wt % MO concentration and varying OG/(H2O)-H-2 contents. These MO contents correspond to a Pn3m cubic single-phase or a Pn3m cubic phase in excess water on the binary MO/water axis of the ternary phase diagram. The cubic liquid crystalline phases are stable with small fractions of OG, while higher OG concentrations trigger a cubic-to-lamellar phase transition. Moreover, with increasing OG concentration the initial Pn3m structure is completely converted to an Ia3d structure prior to the L-alpha phase being formed. Upon heating this effect is reversed, resulting in an Ia3d -to-Pn3m phase transition. For some samples additional peaks were observed in the diffractograms upon heating, resulting from the metastability notoriously shown by bicontinuous cubic phases. This judgement is supported by the fact that upon cooling these peaks were absent. Remarkably, both the Ia3d and the Pn3m cubic structures could be in equilibrium with excess water in this ternary system. A comparison is made with previous results on n -dodecyl-beta-d-maltoside (DM), showing that cubic phases with OG have higher thermal and compositional stability than with DM

  • 63. Raghavan, Srinivasa
    et al.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Kaler, Eric
    Cloud-Point Phenomena in Wormlike Micellar Systems Containing Catanionic Surfactant and Salt2002In: Langmuir, ISSN 0743-7463, Vol. 18, no 4, p. 1056-1064Article in journal (Refereed)
  • 64.
    Svanedal, Ida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Satija, Sushil K.
    NIST, Ctr Neutron Res, 100 Bur Dr,MS 6100, Gaithersburg, MD 20899 USA.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Univ Coimbra, Dept Chem, Rua Larga, P-3004535 Coimbra, Portugal.
    Rennie, Adrian R.
    Uppsala Univ, Mat Phys, Uppsala, Sweden; Uppsala Univ, Ctr Neutron Scattering, Angstrom Lab, Uppsala, Sweden.
    Molecular Organization of an Adsorbed Layer: A Zwitterionic, pH-Sensitive Surfactant at the Air/Water Interface2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 42, p. 10936-10945Article in journal (Refereed)
    Abstract [en]

    Neutron and X-ray reflection measurements have been used to study the structure of the adsorbed layer of a chelating surfactant at the air/liquid interface. The chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (C-12-DTPA) has a large headgroup containing eight donor atoms that can participate in the coordination of metal ions. The donor atoms are also titrating, resulting in an amphoteric surfactant that can adopt a number of differently charged species depending on the pH. Very strong coordination complexes are formed with metal ions, where the metal ion can be considered as part of the surfactant structure, in contrast to monovalent cations that act as regular counterions to the negative net charge. Adsorption was investigated over a large concentration interval, from well below the critical micelle concentration (cmc) to five times the cmc. The most striking result is the maximum in the surface excess found around the cmc, winch is consistent with previous indications from surface tension measurements. Adding divalent metal ions has a limited effect on the adsorption at the air/liquid interface. The reason is the coordination of the metal ion, resulting in compensating deprotonation of the complex. Small variations in the headgroup area of different metal complexes are found, correlating to the conditional stability constants. Adding sodium chloride has a significant effect on the adsorption behavior, and the results indicate that the protonation equilibrium is more important than the ionic strength effects. From combined fits of the neutron and X-ray data, a model that consists of a thick headgroup region and a relatively thin dehydrated tail region is found, and it indicates that the tails are not fully extended and that the limiting area per molecule is determined by the bulky headgroup.

  • 65.
    Svanedal, Ida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Boija, Susanne
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Almesåker, Ann
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Gerd
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Bylund, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Metal Ion Coordination, Conditional Stability Constants and Solution Behavior of Chelating Surfactant Metal Complexes2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 16, p. 4605-4612Article in journal (Refereed)
    Abstract [en]

    Coordination complexes of some divalent metal ions with the DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) have been examined in terms of chelation and solution behavior. The headgroup of 4-C 12-DTPA contains eight donor atoms that can participate in the coordination of a metal ion. Conditional stability constants for five transition metal complexes with 4-C12-DTPA were determined by competition measurements between 4-C12-DTPA and DTPA, using electrospray ionization mass spectrometry (ESI-MS). Small differences in the relative strength between the coordination complexes of DTPA and 4-C12-DTPA indicated that the hydrocarbon tail only affected the chelating ability of the headgroup to a limited extent. The coordination of Cu2+ ions was investigated in particular, using UV-visible spectroscopy. By constructing Job's plots, it was found that 4-C12-DTPA could coordinate up to two Cu2+ ions. Surface tension measurements and NMR diffusometry showed that the coordination of metal ions affected the solution behavior of 4-C 12-DTPA, but there were no specific trends between the studied divalent metal complexes. Generally, the effects of the metal ion coordination could be linked to the neutralization of the headgroup charge of 4-C 12-DTPA, and the resulting reduced electrostatic repulsions between adjacent surfactants in micelles and monolayers. The pH vs concentration plots, on the other hand, showed a distinct difference between 4-C12-DTPA complexes of the alkaline earth metals and the transition metals. This was explained by the difference in coordination between the two groups of metal ions, as predicted by the hard and soft acid and base (HSAB) theory.

  • 66.
    Svanedal, Ida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Boija, Susanne
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Headgroup interactions and ion flotation efficiency in mixtures of a chelating surfactant, different foaming agents and divalent metal ions2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 22, p. 6331-6338Article in journal (Refereed)
    Abstract [en]

    The correlation between interaction parameters and ion flotation efficiency in mixtures of chelating surfactant metal complexes and different foaming agents was investigated. We have recently shown that chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C-12-DTPA) forms strong coordination complexes with divalent metal ions, and this can be utilized in ion flotation. Interaction parameters for mixed micelles and mixed monolayer formation for Mg2+ and Ni2+ complexes with the chelating surfactant 4-C-12-DTPA and different foaming agents were calculated by Rubingh's regular solution theory. Parameters for the calculations were extracted from surface tension measurements and NMR diffusometry. The effects of metal ion coordination on the interactions between 4-C-12-DTPA and the foaming agents could be linked to a previously established difference in coordination chemistry between the examined metal ions. As can be expected from mixtures of amphoteric surfactants, the interactions were strongly pH-dependent. Strong correlation was found between interaction parameter beta(sigma)for mixed monolayer formation and the phase-transfer efficiency of Ni2+ complexes with 4-C-12-DTPA during flotation in a customized flotation cell. In a mixture of Cu(2+)and Zn2+, the significant difference in conditional stability constants (log K) between the metal complexes was utilized to selectively recover the metal complex with the highest log K (Cu2+) by ion flotation. Flotation experiments in an excess concentration of metal ions confirmed the coordination of more than one metal ion to the headgroup of 4-C-12-DTPA.

  • 67.
    Svanedal, Ida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Gerd
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Anomalies in Solution Behavior of an Alkyl Aminopolycarboxylic Chelating Surfactant2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 45, p. 13708-13716Article in journal (Refereed)
    Abstract [en]

    The solution behavior of a DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant, 4-C12-DTPA, has beenstudied by tensiometry and NMR diffusometry. In the absence of metalions, the eight donor atoms in the headgroup are titrating, and thecharge of the headgroup can thus be tuned by altering the pH. 4-C12-DTPA changes from cationic at very low pH, over a number ofzwitterionic species as the pH is increased, and eventually becomesanionic at high pH. Around the isoelectric point, the chelatingsurfactant precipitated. The solution properties, studied above thesolubility gap, were found strongly pH dependent. When increasing theamount of negative charges in the headgroup, by increasing the pH, theadsorption efficiency was reduced and the cmc was increased. Anoptimum in surface tension reduction was found at pH 5, due to aproper balance between protonated and dissociated groups. Anomaliesbetween surface tension measurements and NMR diffusometry in determination of cmc revealed a more complex relationbetween surface tension, surface coverage, and cmc than usually considered, which is not in line with the common interpretationof the Gibbs adsorption equation. At some of the investigated pH levels, measurements of bulk pH could confirm the location ofcmc, due to the increased protonation of micelles compared to monomers in solution. The adsorption of monomers to the air−water interface showed unusually slow time dependence, evident from decreasing surface tension for several hours. This isexplained by rearrangements of the large head groups to reduce the headgroup area and increase the packing parameter.

  • 68.
    Svanedal, Ida
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Gerd
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Interactions in Mixed Micellar Systems of an Amphoteric Chelating Surfactant and Ionic Surfactants2014In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, no 5, p. 1250-1256Article in journal (Refereed)
    Abstract [en]

    Mixtures of ionic surfactants and the chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) have been examined in terms of interactions in mixed micellar systems. The amphoteric 4-C12-DTPA is zwitterionic with a negative net charge at the studied pH levels. The investigated ionic surfactants were the cationic dodecyltrimethylammonium chloride (DoTAC), the anionic sodium dodecyl sulfate (SDS), and the zwitterionic dimethyldodecylamine-N-oxide (DDAO). The surfactants all have the same hydrophobic chain lengths, and the results are evaluated in terms of headgroup interactions. 4-C12-DTPA interacts with different ionic surfactants by accepting or donating protons to the aqueous solution to increase the attractive interactions between the two surfactants; i.e., the protonation equilibrium of 4-C12-DTPA is shifted in different directions depending on whether there are predominant repulsions between positively or negatively charged groups in the mixed micelles. This was monitored by measuring pH vs concentration in the mixed systems. By measuring the pH, it was also possible to study the shift in the protonation equilibrium at increasing concentration, as the composition in the micelles approaches the composition in the total solution. Following the approach of Rubingh's regular solution theory, the interaction parameter β for mixed micelle formation was calculated from the cmc values determined by NMR diffusometry. Synergism in mixed micelle formation and negative β parameters were found in all of the investigated systems. As expected, the most negative β parameter was found in the mixture with DoTAC, followed by DDAO and SDS. The self-diffusion in the 4-C12-DTPA/DoTAC system was also discussed. The self-diffusion coefficient vs concentration plots show two distinctly different curves, depending on the surfactant that is present in excess.

  • 69.
    Yang, Jiayi
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    pH-responsive cellulose–chitosan nanocomposite films with slow release of chitosan2019In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 6, p. 3763-3776Article in journal (Refereed)
    Abstract [en]

    Cellulose–chitosan films were preparedusing a physical method in which cellulose andchitosan were separately dissolved via freeze thawingin LiOH/urea and mixed in different proportions, theresulting films being cast and regenerated in water/ethanol. X-ray diffraction and Fourier transforminfrared spectroscopy (FT-IR) spectroscopy verifiedthe composition changes in the nanocomposites due todifferent mixing ratios between the polymers. Tensilestress–strain measurements indicated that the mechan-ical performance of the cellulose–chitosan nanocom-posites slightly worsened with increasing chitosancontent compared with that of films comprisingcellulose alone. Field emission scanning electronmicroscopy revealed the spontaneous formation ofnanofibers in the films; these nanofibers were subse-quently ordered into lamellar structures. Water uptakeand microscopy analysis of film thickness changesindicated that the swelling dramatically increased atlower pH and with increasing chitosan content, thisbeing ascribed to the Gibbs–Donnan effect. Slowmaterial loss appeared at acidic pH, as indicated by aloss of weight, and quantitative FT-IR analysisconfirmed that chitosan was the main componentreleased.Asample containing 75% chitosan reached amaximum swelling ratio and weight loss of 1500%and 55 wt%, respectively, after 12 h at pH 3. Thestudy presents a novel way of preparing pH-responsivecellulose–chitosan nanocomposites with slow-releasecharacteristics using an environmentally friendlyprocedure and without any chemical reactions.

  • 70.
    Yang, Jiayi
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Duan, Jiangjiang
    Wuhan University, China.
    Zhang, Lina
    Wuhan University, China.
    Lindman, Björn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Spherical nanocomposite particles prepared from mixed cellulose–chitosan solutions2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 5, p. 3105-3115Article in journal (Refereed)
    Abstract [en]

    Novel cellulose–chitosan nanocomposite particles with spherical shape were successfully prepared via mixing of aqueous biopolymer solutions in three different ways. Macroparticles with diameters in the millimeter range were produced by dripping cellulose dissolved in cold LiOH/urea into acidic chitosan solutions, inducing instant co-regeneration of the biopolymers. Two types of microspheres, chemically crosslinked and non-crosslinked, were prepared by first mixing cellulose and chitosan solutions obtained from freeze thawing in LiOH/KOH/urea. Thereafter epichlorohydrin was applied as crosslinking agent for one of the samples, followed by water-in-oil (W/O) emulsification, heat induced sol–gel transition, solvent exchange, washing and freeze-drying. Characterization by X-ray photoelectron spectroscopy, total elemental analysis, and Fourier transform infrared spectroscopy confirmed the prepared particles as being true cellulose–chitosan nanocomposites with different distribution of chitosan from the surface to the core of the particles depending on the preparation method. Field emission scanning electron microscopy and laser diffraction was performed to study the morphology and size distribution of the prepared particles. The morphology was found to vary due to different preparation routes, revealing a core shell structure for macroparticles prepared by dripping, and homogenous nanoporous structure for the microspheres. The non-crosslinked microparticles exhibited a somewhat denser structure than the crosslinked ones, which indicated that crosslinking restricts packing of the chains before and under regeneration. From the obtained volume-weighted size distributions it was found that the crosslinked microspheres had the highest median diameter. The results demonstrate that not only the mixing ratio and distribution of the two biopolymers, but also the morphology and nanocomposite particle diameters are tunable by choosing between the different routes of preparation.

  • 71.
    Yang, Jiayi
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Selective separation of wood substances from TMP mill process water by flotation. Analysis of the foam fraction.2013Conference paper (Refereed)
  • 72.
    Yang, Jiayi
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Zasadowski, Dariusz
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Biorefining of Spruce TMP Process Water: Selective Fractionation of Lipophilic Extractives with Induced Air Flotation and Surface Active Additive2019In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 2, p. 4124-4135Article in journal (Refereed)
    Abstract [en]

    Lignocellulose biomass plays an important role in reducing thedependency on fossil fuels and ameliorating the dire consequences ofclimate change. It is therefore important that all the components oflignocellulose biomass are exploited. These components includehemicelluloses and extractives that are liberated and sterically stabilizedduring the thermomechanical pulping and that form the dissolved andcolloidal substance (DCS) in the process water. Biorefining of this processwater can extract these substances, which have a number of promisingapplications and can contribute to the full exploitation of lignocellulosebiomass. This paper presents a simple treatment of unbleached Norwayspruce (Picea abies) process water from TMP (thermomechanical pulping)production using induced air flotation (IAF) and cationic surfactant,dodecyl trimethylammonium chloride (DoTAC) to refine the extractivesand prepare the waters so that hemicellulose could be easily harvested ata later stage. By applying 80 ppm of DoTAC at a pH of 3.5 and 50 °Cbefore induced air flotation, 94% of the lipophilic extractives wererecovered from process water. Dissolved hemicellulose polysaccharideswere cleansed and left in the treated process water. The process enabledefficient biorefining of lipophilic extractives and purification of the processwater to enable more selective harvesting of hemicelluloses in subsequentsteps.

  • 73.
    Zasadowski, Darius
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Strand, Anders
    Laboratory of Wood and Paper Chemistry, Åbo Academy University, Porthansgatan 3, 20500 Turku, Finland .
    Sundberg, Anna
    Laboratory of Wood and Paper Chemistry, Åbo Academy University, Porthansgatan 3, 20500 Turku, Finland .
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Selective purification of bleached spruce TMP process water by induced air flotation (IAF)2014In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 68, no 2, p. 157-165Article in journal (Refereed)
    Abstract [en]

    The environmentally benign closure of water systems in paper mills leads to the problem of accumulation of dissolved and colloidal wood substances (DCS) in process water. Notably, pitch affects the pulp and paper production negatively and increases the demand for additional treatment of the process water. In the present article, the purification of thermomechanical pulping process water from the alkaline peroxide bleaching stage has been investigated, with the induced air flotation (IAF) in focus. The following parameters were considered concerning the IAF efficiency to remove detrimental substances: concentration of cationic foaming agent, pH value, calcium concentration, and temperature. The amounts and characteristics of residual DCS were determined by gas chromatography and turbidity measurements. Residual concentrations of the foaming agent dodecyltrimetylammonium chloride were determined by electrospray ionization mass spectrometry. Up to 90% of pitch was removed, whereas hemicelluloses, which are important in preventing pitch problems, remained in the waters. Up to 70% of the pectic acids accounted for the high cationic demand of the process waters were removed by optimization of the IAF parameters. The presented separation process gives new opportunities to a selective purification of the process waters.

  • 74.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Almesåker, Ann
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Removal of dissolved and colloidal substances from mechanical pulping white waters by flotation2011In: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC / [ed] Wang, L. et al., Tianjin: China Light Industry Press , 2011, p. 1238-1242Conference paper (Other academic)
    Abstract [en]

    Various sorts of process water, foaming agents and a new chelating surfactant have been investigated in the chemical optimization of flotation ofwaters generated at laboratory and white water from mechanical pulping. Turbidity measurements, the Orcinol method for quantitative carbohydrate analysis and total organic carbon (TOC) as well as gas chromatography (GC) of extractives, have been carried out to determine theremoval and characteristics of Dissolved and Colloidal substances (DisCo). The tests have been realized under different conditions, such as using different flotation cells, foaming agents and complexing agents at different temperatures and pH values. It was found that a reduction of thewhite water turbidity of 70% and a 50% removal of the lipophilic substances from the white water can be obtained in a single-stage flotationunit, and that the selection of suitable flotation equipment, foaming agents and solution conditions plays a very important role in the removalcapacity of the unwished substances.

  • 75.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Removal of lipophilic extractives and manganese ions from spruce TMP waters in a customized flotation cell2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 2, p. 2376-2392Article in journal (Refereed)
    Abstract [en]

    The influence of a chelating surfactant, different foaming agents, cationic polyelectrolytes, pH value, and temperature on the purification efficiency of process waters from a mechanical pulp mill has been studied by flotation in a 1 L customized unit. Turbidity measurements and gas chromatography (GC) were carried out to determine the removal and characteristics of dissolved and colloidal substances (DisCo). The manganese ion content in the process waters before flotation and the metal chelate removal capacity by flotation were determined by Inductively Coupled Plasma (ICP) and Atomic Absorption Spectrometry (AAS) measurements. It was found that a 99% removal of complex bound manganese ions and a 94% decrease in turbidity of the TMP water produced at the laboratory can be achieved in a single-stage flotation with a chelating surfactant and a foaming agent. Furthermore, a 91% decrease in turbidity, the removal of up to 96% of resin and fatty acids, and 93% of triglycerides from TMP water can be obtained after application of a foaming agent.

  • 76.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Use of a Voith flotation cell for removal of lipophilic extractives and Mn ions from spruce thermomechanical pulping process waters2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 3, p. 2784-2126Article in journal (Refereed)
    Abstract [en]

    The effects of a chelating surfactant and different foaming agents on the efficiency of cleaning process waters from a thermomechanical pulp (TMP) mill were studied in a Voith flotation cell. Turbidity measurements and gas chromatography were used to determine the removal extent and characteristics of dissolved and colloidal substances (DisCo). The metal ion content in the process waters before flotation and the metal chelate removal after flotation were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). FiberLab (TM) equipment was used to characterize changes in the size of fibers present in the process waters. The results indicate that a decrease in turbidity of up to 91% and the removal of 80% of lipophilic extractives in the TMP water could be obtained using a single-stage flotation unit. Furthermore, the foam fraction was within 5% of the initial volume, and 100% of the Mn2+/chelating surfactant complex added to the TMP water was removed.

  • 77.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Recovery of water-soluble hemicelluloses from TMP process water after selective flotation.2013In: The 17th International Symposiumon on Wood, Fiber and Pulping Chemistry, 2013Conference paper (Refereed)
  • 78.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Yang, Jiayi
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Antisolvent precipitation of water-soluble hemicelluloses from TMP process water2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 113, p. 411-419Article in journal (Refereed)
    Abstract [en]

    During the thermomechanical pulping (TMP) of spruce, hemicelluloses (mainly galactoglucomannans, GGMs) are released into the process water at relatively low concentrations that are currently impossible to efficiently recover. This paper examines the recovery of hemicelluloses precipitated from TMP process water via solubility reduction by adding antisolvents such as methanol, ethanol, and acetone. The phase separation was monitored by turbidity measurements. Gravimetric analysis, FTIR, GC–MS, UV spectroscopy, and ICP-OES were used to determine the yield, purity, and composition of the precipitates. Gel permeation chromatography and pulsed field-gradient self-diffusion NMR were used to measure the molecular mass distribution of the precipitates. Acetone was found to be the most efficient antisolvent, giving the highest yield at the lowest addition. The contents of lipophilic extractives and lignin impurities were below 0.5% and 1.6%, respectively, and the metal content was approximately 2% in the precipitates obtained with acetone.

  • 79.
    Zhang, Renyun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andersson, Henrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Andersson, Mattias
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edvardsson, Sverker
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Hummelgård, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Johansson, Niklas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Karlsson, Kristoffer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olsen, Martin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Uesaka, Tetsu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Öhlund, Thomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Soap-film coating: High-speed deposition of multilayer nanofilms2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. Art. no. 1477-Article in journal (Refereed)
    Abstract [en]

    The coating of thin films is applied in numerous fields and many methods are employed for the deposition of these films. Some coating techniques may deposit films at high speed; for example, ordinary printing paper is coated with micrometre-thick layers of clay at a speed of tens of meters per second. However, to coat nanometre thin films at high speed, vacuum techniques are typically required, which increases the complexity of the process. Here, we report a simple wet chemical method for the high-speed coating of films with thicknesses at the nanometre level. This soap-film coating technique is based on forcing a substrate through a soap film that contains nanomaterials. Molecules and nanomaterials can be deposited at a thickness ranging from less than a monolayer to several layers at speeds up to meters per second. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.

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