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  • 151. Mollmann, SH
    et al.
    Bukrinsky, JT
    Frokjaer, S
    Elofsson, Ulla
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Adsorption of human insulin and AspB28 insulin on a PTFE-like surface2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 286, p. 28-35Article in journal (Refereed)
    Abstract [en]

    The interactions of human insulin, Zn-free human insulin, and AspB28 insulin with a hydrophobic surface were studied by ellipsometry. All three insulin types investigated adsorbed with high affinity onto the hydrophobic surface, as the plateau of the adsorption isotherm, represented by the irreversible bound fraction, was reached at concentrations >10-3 mg/ml. The plateau values for human insulin and Zn-free human insulin could not be distinguished with statistical significance, whereas the plateau value for AspB28 insulin was lower than those for the two others, with an adsorbed amount corresponding to a monolayer of insulin monomers. The results observed may be explained by differences in self-association patterns of the insulin types or by enhanced charge repulsion between the AspB28 analog and the negatively charged surface

  • 152. Mueller, H
    et al.
    Friberg, S
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Hellsten, M
    Investigations on the interaction between metal ions and alkyl phosphate monolayers at the air-water interface by means of surface pressure determination and infrared spectroscopy1970In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 32, p. 132-140Article in journal (Refereed)
  • 153. Muller, D
    et al.
    Carlsson, F
    Malmsten, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Adsorption of poly(ethylene oxide)-poly(lactide) copolymers. Effects of composition and degradation2001In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 236, p. 116-126Article in journal (Refereed)
    Abstract [en]

    The effect of chemical degradation of two diblock copolymers of poly(ethylene oxide) (E) and poly(lactide) (L), E39L5 and E39L20, on their adsorption at silica and methylated silica was investigated with in situ ellipsometry. Steric stablization of polystyrene dispersions was investigated in relation to degradation. Hydrolysis of the poly(lactide) block of the copolymers was followed at different temperatures and pH by using HPLC to measure the occurrence of lactic acid in solution. The block copolymers were quite stable in pH-unadjusted solution at low temperature, whereas degradation was facilitated by increasing temperature or lowering of the pH. Lower degradation rates of E39L20 where observed at low temperature in comparison with those of E39L5, whereas the degradation rates of the copolymers were quantitatively similar at high temperature. The adsorption of the copolymers at methylated silica substrates decreased with increasing degree of degradation due to the reduction in the ability of hydrophobic block to anchor the copolymer layer at the surface. At silica the adsorption initially increased with increasing degradation, particularly for E39L20 due to deposition of aggregates onto the surface. After extensive degradation the adsorption of the copolymers at both silica and methylated silica resembled that of the corresponding poly(ethylene oxide) homopolymer. Overall, it was found that the eventual reduction in adsorption occurred at a lower degree of degradation for E39L5 than for E39L20. Mean-field calculations showed a reduced anchoring for the block copolymers with decreasing poly(lactide) block length at hydrophobic surfaces. In accordance with this finding, it was observed that polystyrene dispersions were stabilized by E39L20 or E39L5 in a way that depended on both the lactide block length and the degree of degradation. Upon degradation of the hydrophobic block, stabilization of the polystyrene dispersions was maintained initially, but eventually degradation resulted in destabilization. The average residual copolymer concentration required for stabilization of the polystyrene dispersions was much higher than the corresponding concentration of intact copolymer required for stabilization.

  • 154. Muller, D
    et al.
    Malmsten, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tanodekaew, S
    Booth, C
    Adsorption of diblock copolymers of poly(ethylene oxide) and poly(lactide) at hydrophilic silica from aqueous solution2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 228, p. 317-325Article in journal (Refereed)
    Abstract [en]

    The adsorption of a series of amphiphilic poly(ethylene oxide)-poly(DL-lactide) (PEO-PL) diblock copolymers at the water/silica interface was investigated by ellipsometry and reflectometry. For all copolymers, a much higher saturation adsorption is found compared to that of the PEO homopolymers, indicating the importance of the PL block for the adsorption. The copolymers display a saturation adsorption that increases with increasing hydrophobic content of the polymer, and decreases with increasing hydrophilic content of the polymer. Despite this, however, the layer thickness observed is rather similar for all polymers, regardless of the length and composition of the copolymers. Moreover, the layer thicknesses were significantly higher than what would be expected for the unperturbered copolymer dimensions. The initial adsorption kinetics of the different copolymers are comparable. The initial adsorption rate increases cooperatively with concentration and is slower than that expected for diffusion-controlled adsorption. Moreover, the adsorption increases only slightly over a concentration the range from 20 to 50°C. Furthermore, pH titrations show that all polymers exhibit a critical desorption pH of 8-9, which is lower than the corresponding value of pH 10.5 observed for the PEO homopolymer. These results are discussed in terms of the adsorption mechanism and the adsorbed layer structure and formation.

  • 155. Muller, D
    et al.
    Malmsten, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tanodekaew, S
    Booth, C
    Adsorption of diblock copolymers of poly(ethylene oxide) and poly(lactide) at hydrophobized silica from aqueous solution2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 228, p. 326-334Article in journal (Refereed)
    Abstract [en]

    The adsorption of a series of amphiphilic diblock copolymers of poly(ethylene oxide) (PEO) and poly(DL-lactide) (PL) at hydrophobized silica from aqueous solution was studied using time-resolved ellipsometry and reflectometry. The adsorbed amounts only display a weak dependence on the copolymer composition in both water and phosphate-buffered solution. For the short copolymers, the layer thickness decreases slightly with increasing length of the hydrophobic block. Furthermore, in comparison with the short copolymers, the layer thickness of the long copolymers is substantially higher. Upon degradation of the PL block, the adsorbed amount is found to decrease and approach that of the corresponding PEO homopolymer. Protein rejection studies indicate that the adsorption of fibrinogen is inhibited by copolymer preadsorption. The protein rejection is enhanced with increasing surface coverage of the preadsorbed copolymer, but largely independent of the length of the PL block and the PEO block. For all polymers investigated, essentially complete protein rejection is obtained above a critical surface coverage that is significantly lower than the saturation coverage of the copolymers. Removing the copolymer from bulk solution after preadsorption causes a partial desorption, resulting in reduced protein rejection. However, the protein rejection capacity with and without copolymer in the bulk solution is found to be similar at a given surface coverage. Contrary to the behavior of the intact copolymers, fibrinogen adsorption is found to be significant at surfaces pretreated with an extensively degraded copolymer and, in fact, quantitatively comparable to that at the hydrophobic surface in the absence of preadsorption. This finding, together with that of the effect of the copolymer composition on protein rejection, suggests that an efficient protein rejection is maintained until only a few L units remain in the copolymer, i.e., until nearly completed degradation.

  • 156. Naderi, A
    et al.
    Makuska, R
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Interactions between bottle-brush polyelectrolyte layers: Effects of ionic strength and oppositely charged surfactant2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 323, p. 191-202Article in journal (Refereed)
    Abstract [en]

    Interactions between cationic bottle-brush polyelectrolyte layers adsorbed on mica across salt and oppositely charged surfactant solutions were investigated with the interferometric surface force apparatus, and the results were compared with what is known for similarly charged linear polyelectrolytes. Ellipsometric measurements demonstrated that the bottle-brush polyelectrolytes, which contain 45 units long poly(ethylene oxide) side chains, are more readily desorbed than linear equivalents when the ionic strength of the solution is increased. It is argued that this is due to the steric repulsion between the poly(ethylene oxide) side chains that reduces the surface affinity. The preadsorbed bottle-brush polyelectrolyte layers were also exposed to sodium dodecyl sulfate (SDS) solutions. It was found that the presence of SDS affected the force profiles less than observed for similarly charged linear polyelectrolytes. This observation was attributed to excluded volume constraints imposed by the poly(ethylene oxide) side chains that reduces the accessibility of the charged polyelectrolyte segments and counteracts formation of large aggregates within the layer

  • 157. Naderi, Ali
    et al.
    Olanya, Geoffrey
    Makuska, Ricardas
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Desorption of bottle-brush polyelectrolytes from silica by addition of linear polyelectrolytes studied by QCM-D and reflectometry2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 323, p. 223-228Article in journal (Refereed)
    Abstract [en]

    The possibility of exchanging adsorbed layers of PEO(45)MEMA:METAC-X brush polyelectrolytes (with two different charge densities, 10 and 75 mol%, denoted by X), with poly(MAPTAC), a highly charged linear polyelectrolyte, was investigated by quartz crystal microbalance with dissipation and reflectometry. The studies were conducted on a silica substrate at pH 10, conditions under which only electrostatic interactions are effective in the adsorption process. Based on the results, it was concluded that PEO(45)MEMA:METAC-10 forms an inhomogeneous layer at the interface through which poly(MAPTAC) chains can easily diffuse to reach the surface. On the other hand, the PEO(45)MEMA:METAC-75 layer was not affected when exposed to a poly(MAPTAC) solution. We argue that the observed effect for PEO(45)MEMA: METAC-75 is due to the formation of a homogeneous protective brush layer, in combination with the small difference in surface affinity between the bottle-brush polyelectrolyte and poly(MAPTAC), together with the difficulty of displacing highly charged polyelectrolyte chains once they are adsorbed on the oppositely charged surface. We also use the combination of QCM-D and reflectometry data to calculate the Water content and layer thickness of the adsorbed layers

  • 158.
    Niga, Petru
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Hansson-Mille, Petra M.
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Swerin, Agne
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation. KTH Royal Institute of Technology, Sweden.
    Claesson, Per M.
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation. KTH Royal Institute of Technology, Sweden.
    Schoelkopf, Joachim
    Omya International AG, Switzerland.
    Gane, Patrick A. C.
    Omya International AG, Switzerland; Aalto University, Finland.
    Bergendal, Erik
    KTH Royal Institute of Technology, Sweden.
    Tummino, Andrea
    Institut Laue-Langevin, France; Eötvös Loránd University, Hungary.
    Campbell, Richard A.
    Institut Laue-Langevin, France.
    Johnson, C. Magnus
    KTH Royal Institute of Technology, Sweden.
    Interactions between model cell membranes and the neuroactive drug propofol2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 526, p. 230-243Article in journal (Refereed)
    Abstract [en]

    phospholipid, NR data reveal that propofol is located exclusively in the head group region, which is rationalized in the context of previous studies. The results imply a non-homogeneous distribution of propofol in the plane of real cell membranes, which is an inference that requires urgent testing and may help to explain why such low concentration of the drug are required to induce general anaesthesia.

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  • 159. Nilsson Ekdahl, S
    et al.
    Nilsson, B
    Gölander, CG
    Elwing, H
    Lassen, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Nilsson, UR
    Complement activation on radio frequency plasma modified polystyrene surfaces1993In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 158, p. 121-128Article in journal (Refereed)
  • 160. Oh, S-G
    et al.
    Holmberg, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Ninham, BW
    Effect of hydrocarbon chain length on yield of lipase catalyzed triglyceride synthesis in microemulsion1996In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 181, p. 341-343Article in journal (Refereed)
    Abstract [en]

    Previous work on lipase catalyzed esterification of glycerol with fatty acids in w/o microemulsions gave monoglyceride as the main reaction product. Only traces of triglyceride were obtained. We show here that the reason triglycerides are not formed in these systems is that the diglyceride formed in the oil-water interfacial zone partitions into the continuous hydrocarbon domain. It is then inaccessible to the enzyme. The yield of triglyceride is increased by using longer hydrocarbons as the oil component. These have poorer solvency for mono- and diglycerides. When the hydrocarbon chain length exceeds that of the glyceride acyl groups, triglyceride is the main reaction product.

  • 161. Olofsson, G
    et al.
    Kizling, J
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Stenius, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Partial molar enthalpies of water and surfactant in solution of pentaethyleneoxide dodecyl ether and water in hexadecane1986In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 111, p. 213-222Article in journal (Refereed)
  • 162. Parker, JL
    et al.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Cho, DL
    Ahlberg, A
    Tidblad, Johan
    Blomberg, E
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Plasma modification of mica1990In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 134, p. 449-458Article in journal (Refereed)
    Abstract [en]

    When mica is exposed to a low temperature nonpolymer-forming plasma the surface structure is altered by a combination of sputtering and chemical reaction with reactive species in the plasma. The chemical composition of the surface is altered without a significant increase in surface roughness under optimal conditions. The effect of the plasma process parameters (exposure time, power, flow rate, and pressure) on the extent of surface modification has been investigated by means of ESCA and contact angle measurements. After exposure to water vapor plasma the mica surface becomes reactive to silanation with chlorosilanes in the gas phase. The durability of mica surfaces modified by plasma treatment and subsequent reaction with some chlorosilanes has been investigated. The forces between water plasmatreated surfaces after silanation have been measured using a surface force apparatus.

  • 163. Persson, CM
    et al.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Lunkenheimer, K
    Interfacial behavior of n-decyl-ß-D-maltopyranoside on hydrophobic interfaces and the effect of small amounts of surface-active impurities2002In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 251, p. 182-192Article in journal (Refereed)
    Abstract [en]

    The effect of small amounts of surface-active impurities on the interfacial properties of n-decylß-D-maltopyranoside was investigated using various methods. The n-Decylß-D-maltopyranoside was used both as received from Sigma (<98% by GC) and after being purified with the urfactant-purifying apparatus developed by Lunkenheimer, which removes impurities that are more surface active than the major component. Surface tension measurements demonstrate that the surface elasticity of the surfactant-loaded liquid-vapor interface increased after purification. Measurements of interactions across single foam films revealed that the purified solution formed considerably less charged and less stable films compared with the as-received sample. These results are consistent with the lower foam stability for the purified sample as determined by simple shaking experiments. The lower film stability for the purified solution was attributed to the lower double-layer force. The forces acting between spherical silanated glass surfaces across surfactant solutions were determined with the MASIF (measurement and analysis of surface interaction forces) technique. On approach, the same interactions were experienced in solutions of the as-received and purified surfactant. On the other hand, the adhesion force was lower after purification. Both for the as-received and the purified sample it was observed that the adhesion increased with increasing contact time up to a certain limit. This was explained in terms of partial pressure-induced desorption of surfactants from the disordered silane layers. Wetting experiments also indicated that the surfactants were difficult to remove completely from this surface

  • 164.
    Persson, M
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Jonsson, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Eriksson, JC
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Testing the Gouy-Chapman theory by means of surface tension measurements for SDS-NaCl mixtures2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 267, p. 151-154Article in journal (Refereed)
    Abstract [en]

    Surface tension isotherms were measured for sodium dodecyl sulfate (SDS) at different concentrations of added salt (NaCl). The free energy of the surfactant monolayer was assessed by invoking the Gouy–Chapman theory for the charged head groups, the hydrophobic (Tanford) free energy of transfer of the hydrocarbon chain, and the hydrocarbon chain configurational free energy according to Gruen's calculations and finally macroscopic contact terms. In particular, the effect of an increased salt concentration in bulk was examined. Theoretical predictions compare well with the experimental findings, and good agreement was found with respect to both the variation of free energy of the monolayer and the surface pressure behavior. Thus, at least for a liquid-expanded monolayer of SDS, the Gouy–Chapman model yields a satisfactory account of the electrostatic contribution to the thermodynamic properties at different salt concentrations of NaCl

  • 165. Persson, P
    et al.
    Stenius, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Phase equilibria in the 1-O-decylglycerol-water system1984In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 102, p. 527-532Article in journal (Refereed)
  • 166. Pettersson, T
    et al.
    Dedinaite, A
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Normal and friction forces between mucin and mucin–chitosan layers in absence and presence of SDS2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 324, p. 246-256Article in journal (Refereed)
  • 167. Pettersson, T
    et al.
    Fogden, A
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Spreading of individual toner particles studied using in situ optical microscopy2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 287, p. 249-260Article in journal (Refereed)
    Abstract [en]

    This study develops and tests an experimental method to monitor in situ the dynamic spreading of individual toner particles on model substrates during heating, to simulate on laboratory scale the fusing sub-processes occurring in electrophotographic printing of paper. Real toner particles of cyan, magenta, yellow and black are transformed to perfect spheres by a temperature pre-treatment, then applied to the substrate, either high-energy clean glass or low-energy hydrophobised glass, and heated at rates up to 50 •C/min. The subsequent spreading as a function of time (and temperature) is recorded by an optical microscope and CCD camera mounted above the substrate, with the measured drop covering area used to calculate the corresponding toner–substrate–air contact angle. On the hydrophobic substrate the spreading is limited and equal for all four colours, while the substantially greater spreading on the hydrophilic substrate is accompanied by significant differences between the toner colours. In particular, the cyan and black toners are found to spread to almost twice the extent of the yellow particles. The dynamic spreading behaviour is interpreted in terms of complementary measurements of substrate and toner surface energy components and bulk toner rheology, and a simple empirical relation is proposed that fits very well the measurements for all toner and substrate types tested. In particular, the spreading relation is found to be determined only by the toner surface energy and its equilibrium contact angle, with no explicit dependence on toner viscosity

  • 168. Pezron, E
    et al.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Berg, JM
    Vollhardt, D
    Stability of arachidic and acid monolayers on aqueous salt solutions1990In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 138, p. 245-254Article in journal (Refereed)
    Abstract [en]

    The stability of arachidic acid monolayers on water at different pH values and on aqueous solutions of 10 mM monovalent (NaCl and LiCl) or divalent (CaCl2 and MgCl2) salts has been studied. Relaxation measurements of the monolayer kept at a constant surface pressure (from Π=10 to Π=50 mN/m) reveal that the presence and the nature of the cation dramatically influence the rate of collapse. The order of increasing stability is H+ < Li+ < Na+ < Ca2+ < Mg2+ . The determination of equilibrium spreading pressures shows that in all cases the monolayer is thermodynamically unstable at surface pressures above 0.25mN/m. The correlation between the order of stability and the calculated degree of dissociation of the monolayer suggests that electrostatic forces within or between nuclei formed in the film may create an important stabilizing effect for monolayers on aqueos subphases containing monovalent electrolyte. The much greater stability induced by divalent counterions can, however, hardly be rationalized in terms of the ionization of the monolayer.

  • 169. Pezron, I
    et al.
    Pezron, E
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergenståhl, BA
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Monoglyceride surface films; Stability and interlayer interactions1991In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 144, p. 449-457Article in journal (Refereed)
    Abstract [en]

    Interactions between surfaces coated with monolayers of monoglycerides immersed in water have been studied using the surface force apparatus. The monolayers were deposited onto hydrophobized mica surfaces by means of the Langmuir-Blodgett techniqe. The measured forces beteween monopalmitin monolayers in the gel state show the existence of an adhesive minimum at a seperation of about 10 Å; this atttaction decreases when the temperature increases. At even shorter seperations a strong repulsion dominates the interaction. The forces between monoolein monolayers deposited in the liquid expanded state are repulsive at all separations and the range of the hydration/steric force is 10-15 Å. Deposited monolayers of monopalmitin in the gel state exhibit a good stability and remarkeble rehealing properties. In contrast, deposited monolayers of monoolein are unstable and readily transform into different structure.

  • 170.
    Pugh, RJ
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Surface chemical analysis of oxidized α-SiC powders by electron spectroscopy1990In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 138, p. 16-20Article in journal (Refereed)
    Abstract [en]

    The oxidation behavior of ultrafine α-SiC powder was studied in air at temperatures up to 1100°C. The thickness of the oxidized film that formed was determined by electron spectroscopy for chemical analysis at a range of oxidation times and from this data the oxidation rates were calculated. From an Arrhenius plot a relatively low value (≈45 kJ/mol) for the apparent activation energy was obtained for the initial stages of the oxidation process. This value appears to support the mechanism involving the diffusion of oxidant species through the surface film.

  • 171.
    Pugh, RJ
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    The uptake of mg(II) on ultrafine alfa-silicon carbide and alfa-alumina1988In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 124, p. 570-580Article in journal (Refereed)
  • 172.
    Pugh, RJ
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Manev, ED
    Froth stability in aqueous solutions of non-ionic surfactant and inorganic electrolyte1992In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 152, p. 582-584Article in journal (Refereed)
    Abstract [en]

    The froth stability of aqueous solutions of non-ionic surfactant was found to decrease on addition of low concentrations of KCl but increase at higher concentrations. From earlier reported studies on free aqueous films, it could be suggested that two different types of stabilizing mechanisms were operating in the froth system. At low electrolyte, the decrease in froth stability was explained by the decrease in interfacial electrostatic repulsion force while at high electrolyte, the enhanced stability was accounted for by steric forces.

  • 173.
    Pugh, RJ
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Ralston, J
    Alfred Kitchener (1916–2009) In memoriam2009In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 338, no 1, p. 326-327Article in journal (Refereed)
  • 174.
    Pugh, RJ
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tjus, K
    Electrokinetic studies on Cu(II) hydroxy coated zinc sulfide particles1987In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 117, p. 231-241Article in journal (Refereed)
  • 175.
    Pugh, RJ
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Yoon, RH
    Hydrophobicity and rupture of thin aqueous films1994In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 163, p. 169-176Article in journal (Refereed)
    Abstract [en]

    In the present study, the magnitude and range of the hydrophobic interaction (which is the predominating force causing the coalescence of air-bubbles in pure water) was calculated from the critical thickness of rupture of a free metastable horizontal water film in air. Application of a modified DLVO theory enabled values of the pre-exponential hydrophobic interaction parameter (C) and the decay length (Do) to be estimated. The experimental data confirmed the long range nature of the hydrophobic force. In addition, it was found that the decay length and interaction parameter was reduced in KCl and this appears to be consistent with the fact that salts act to prevent the coalescence of airbubbles in water.

  • 176.
    Raj, Akanksha
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wang, Min
    KTH Royal Institute of Technology, Sweden.
    Liu, Chao
    KTH Royal Institute of Technology, Sweden.
    Ali, Liaquat
    University of Gothenburg, Sweden.
    Karlsson, Niclas G.
    University of Gothenburg, Sweden.
    Claesson, Per M.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces. KTH Royal Institute of Technology, Sweden.
    Dėdinaitė, Andra
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces. KTH Royal Institute of Technology, Sweden.
    Molecular synergy in biolubrication: The role of cartilage oligomeric matrix protein (COMP) in surface-structuring of lubricin2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 495, p. 200-206Article in journal (Refereed)
    Abstract [en]

    Hypothesis Synovial surfaces are lubricated by biomolecular aggregates that act in synergy, and lubricin is one key biolubricant. Its molecular structure allows extensive hydration and this is conducive to its lubrication performance. However, in order to fullfil its lubrication function it needs to be anchored and oriented on the surface in a proper way. We suggest that cartilage oligomeric matrix protein (COMP) is one of the biomolecules that promotes anchoring of lubricin in a fashion that facilitates lubrication. Experiments Weakly hydrophobic poly(methyl methacrylate) (PMMA) surfaces were coated by COMP and lubricin, individually and in combinations. Adsorption was investigated using a quartz crystal microbalance, and friction between the biopolymer-coated surfaces was determined by employing the atomic force microscope-colloidal probe technique. Findings It was found that COMP facilitated firm directed attachment of lubricin in a manner that resulted in low friction forces, significantly lower than what was achieved when lubricin was directly adsorbed to PMMA. Evidently, COMP provides means for lubricin to attach strongly and in a favourable conformation for efficient lubrication of this surface. We suggest that our findings can be extrapolated to cartilage surfaces, where co-localization of COMP and lubricin has been demonstrated.

  • 177.
    Raj, Akanksha
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wang, Min
    KTH Royal Institute of Technology, Sweden.
    Zander, Thomas
    Institute for Materials Research, Germany.
    Wieland, D. C. Florian
    Institute for Materials Research, Germany.
    Liu, Xiaoyan
    KTH Royal Institute of Technology, Sweden.
    An, Junxue
    KTH Royal Institute of Technology, Sweden.
    Garamus, Vasil M.
    Institute for Materials Research, Germany.
    Willumeit-Römer, Regine
    Institute for Materials Research, Germany.
    Fielden, Matthew
    KTH Royal Institute of Technology, Sweden.
    Claesson, Per M.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces. KTH Royal Institute of Technology, Sweden.
    Dėdinaitė, Andra
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces. KTH Royal Institute of Technology, Sweden.
    Lubrication synergy: Mixture of hyaluronan and dipalmitoylphosphatidylcholine (DPPC) vesicles2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 488, p. 225-233Article in journal (Refereed)
    Abstract [en]

    Phospholipids and hyaluronan have been implied to fulfil important roles in synovial joint lubrication. Since both components are present in synovial fluid, self-assembly structures formed by them should also be present. We demonstrate by small angle X-ray scattering that hyaluronan associates with the outer shell of dipalmitoylphophatidylcholine (DPPC) vesicles in bulk solution. Further, we follow adsorption to silica from mixed hyaluronan/DPPC vesicle solution by Quartz Crystal Microbalance with Dissipation measurements. Atomic Force Microscope imaging visualises the adsorbed layer structure consisting of non-homogeneous phospholipid bilayer with hyaluronan/DPPC aggregates on top. The presence of these aggregates generates a long-range repulsive surface force as two such surfaces are brought together. However, the aggregates are easily deformed, partly rearranged into multilayer structures and partly removed from between the surfaces under high loads. These layers offer very low friction coefficient (<0.01), high load bearing capacity (≈23 MPa), and self-healing ability. Surface bound DPPC/hyaluronan aggregates provide a means for accumulation of lubricating DPPC molecules on sliding surfaces.

  • 178. Rance, DG
    et al.
    Friberg, S
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Micellar solutions versus microemulsions1977In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 60, p. 207-209Article in journal (Refereed)
  • 179.
    Roberts, K
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Axberg, C
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Österlund, R
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    The effect of spontaneous emulsification of defoamer on foam prevention1977In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 62, p. 264-271Article in journal (Refereed)
  • 180.
    Roberts, K
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Barla, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    The influence of lignin sulphonate and xylan on the microflotation of microcrystalline cellulose1974In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 49, p. 75-81Article in journal (Refereed)
  • 181. Roberts, K
    et al.
    Kowalewska, J
    Friberg, S
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    The influence of interactions between hydrolyzed aluminium ions and polyacrylamides on the sedimentation of kaolin suspensions1974In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 48, p. 361-367Article in journal (Refereed)
  • 182.
    Roberts, K
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Österlund, R
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Axberg, C
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Interactions between fatty acids and aliphatic alcohols in organic solutionand monolayers and their implications for prevention of particle-stabilizedfoams1976In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 55, p. 563-570Article in journal (Refereed)
  • 183. Rojas, OJ
    et al.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Muller, D
    Neuman, RD
    The effect of salt concentration on adsorption of low-charge-density polyelectrolytes and interactions between polyelectrolyte-coated surfaces1998In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 205, p. 77-88Article in journal (Refereed)
    Abstract [en]

    In this investigation surface force, X-ray photoelectron spectroscopy and ellipsometry techniques have been used to study the adsorption of a low-charge-density cationic polyelectrolyte on negatively charged surfaces. It is shown that the low cationicity of this polyelectrolyte induces an adsorption behavior which is limited by steric factors rather than by the substrate surface charge or potential. It is also established that an increase in ionic strength of the solution results in desorption of the polyelectrolyte accompanied by an increase in layer thickness. This phenomenon is typical of a screening-reduced adsorption regime where electrostatic interactions predominate in the adsorption process. An increase in layer thickness most often occurs as a result of an increased adsorbed amount. Here, however, the increase in layer thickness occurs despite a reduction in the adsorbed amount. This can be understood as resulting from a reduced polyelectrolyte-surface affinity and a swelling of the adsorbed layer. Finally, it is demonstrated that the employed techniques complement each other and reveal new information on the interaction forces and conformation of polyelectrolytes at the solid-liquid interface.

  • 184. Rojas, OJ
    et al.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Neuman, RD
    Desorption of low-charge-density polyelectrolyte adlayers in aqueous sodium n-dodecyl sulfate solution2001In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 237, p. 104-111Article in journal (Refereed)
    Abstract [en]

    The association between low-charge-density polyelectrolytes adsorbed onto negatively charged surfaces (mica and silica) and an anionic surfactant, sodium dodecyl sulfate (SDS), has been investigated using surface force measurements, ellipsometry, and XPS. All three techniques show that the polyelectrolyte desorbs when the SDS concentration is high enough. The XPS study indicates that desorption starts at a SDS concentration of ca. 0.1 unit of cmc (8?10-4 M) and that the desorption proceeds progressively as the SDS concentration is increased. Surface force measurements show that for the polyelectrolyte studied here, having 1% of the segments charged, the desorption proceeds without any swelling of the adsorbed layer. This behavior differs from that observed when polyelectrolytes of greater charge density are used.

  • 185. Rundlöf, M
    et al.
    Karlsson, M
    Wågberg, L
    Poptoshev, E
    Rutland, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Claesson, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Application of the JKR method to the measurement of adhesion to Langmuir-Blodgett cellulose surfaces2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 230, p. 441-447Article in journal (Refereed)
    Abstract [en]

    The JKR method has been applied for studying adhesion between poly(dimethylsiloxane) (PDMS) caps and Langmuir-Blodgett cellulose surfaces including the substrate, hydrophobized mica, and two flat mineral surfaces, bare mica and glass. The self-adhesion of PDMS caps and oxidized PDMS caps are included as a reference to compare with literature data. The results of the measurements have been compared with previous studies using the surface force apparatus and similar systems. A satisfactory agreement is obtained for simple systems showing no, or very limited, hysteresis between loading and unloading curves. In several cases, however, a large hysteresis is found between loading and unloading curves, with a larger adhesion measured from the pull-off force than from the JKR-curve determined on loading. This is, for instance, the case for PDMS against cellulose. The situation is analogous to that found in wetting studies showing a large hysteresis between advancing and receding contact angles

  • 186. Rydhag, L
    et al.
    Stenius, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Ödberg, L
    Phase equilibria and vesicle stability in dimyristoyl phosphatidylcholine-cetyltrimethylammonium bromide systems1982In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 86, p. 274-276Article in journal (Refereed)
  • 187.
    Rödner, S
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Effect of crystallisation rate and colloidal stability on structural rearrangements during growth of colloidal monolayers2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 265, p. 29-35Article in journal (Refereed)
    Abstract [en]

    The structural rearrangements during growth of colloidal crystals were investigated using a combination of light microscopy and image analysis based on a Delaunay triangulation procedure. We followed the creation and disappearance of square lattice domains during the convection-promoted formation of colloidal monolayers by drying. We found that the concentration of square lattice domains increased with the crystal growth rate and that there is a direct relation between the concentration of square lattice domains formed at the crystal-suspension interface and the lower concentration of these domains in the colloidal monolayer; hence, the degree of rearrangement from square lattice domains to a close-packed triangular structure is not significantly affected by the crystal growth rate for colloidally stable suspensions. The colloidal stability, manipulated by the addition of salt, has a profound influence on the structural features of the growing monolayers. Particles that adhere strongly to each other, and to the substrate, tend to resist rearrangement; hence, the defect density is high in the colloidal monolayers and the structural reorganization of the square lattice domains to the more stable close-packed triangular structure occurred gradually over large distances from the crystal-suspension interface.

  • 188. Scherlund, M
    et al.
    Brodin, A
    Malmsten, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Nonionic cellulose ethers as potential drug delivery systems for periodontal anesthesia2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 229, p. 365-374Article in journal (Refereed)
    Abstract [en]

    Nonionic cellulose ethers displaying a lower consolute temperature, or cloud-point, close to body temperature were investigated as potential carrier systems for the delivery of local anesthetic agents to the periodontal pocket. The interaction between the polymers, i.e., ethyl(hydroxyethyl)cellulose (EHEC) and hydrophobically modified EHEC (HM-EHEC), and ionic surfactants was determined in the absence and in the presence of the local anesthetic agents lidocaine and prilocaine. The cloud-point and rheology data indicate interactions between the polymer and both anionic and cationic surfactants. More precisely, a number of ionic surfactants were found to result in an increase in cloud-point at higher surfactant concentrations, a surfactant-concentration-dependent thickening, and a temperature-induced gelation upon heating. Upon addition of the local anesthetic agents lidocaine and prilocaine in their uncharged form to EHEC and HM-EHEC, in the absence of surfactants, only minor interaction with the polymer could be inferred. However, these substances were found to affect the polymer-surfactant interaction. In particular, the drug release rate in vitro as well as the stability and temperature-dependent viscosity were followed for an EHEC/SDS system and EHEC/myristoylcholine bromide system upon addition of lidocaine and prilocaine. The data indicate a possibility of formulating a local anesthetic drug delivery system suitable for administration into the periodontal pocket where at least small amounts of active ingredients can be incorporated into the system without severely affecting the gelation behavior. The results found for the cationic myristoylcholine bromide system are particularly interesting for the application in focus here since this surfactant is antibacterial and readily biodegradable.

  • 189.
    Sennerfors, T
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Fröberg, J
    Tiberg, F
    Adsorption of polyelectrolyte-nanoparticle systems on silica: Influence on interaction forces2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 228, p. 127-134Article in journal (Refereed)
    Abstract [en]

    In this work, we have studied the interfacial properties of cationic polyelectrolyte (PE) and silica nanoparticle (NP) systems at macroscopic silica surfaces by means of ellipsometry. The influence of adsorbed layers on the interactions between silica surfaces was also investigated using the bimorph surface force apparatus. Added nanoparticles were observed to strongly swell the interfacial polyelectrolyte layers, an effect partly related to neutralisation of charged polyelectrolyte groups. The effect was more pronounced for low than highly charged polyelectrolytes. Overall, the presence of nanoparticles seemed to increase the repulsive interaction measured between silica surfaces. The force measured on approach was long-range and quite strongly repulsive. On separation, an attractive bridging interaction was measured for polyelectrolyte covered surfaces. For the low charged polyelectrolyte used in the study, the force turned repulsive on addition of nanoparticles. For the highly charged polyelectrolyte used, a change from a very strong attraction (involving a jump of the surfaces out of contact) to a very long-range elastic attractive force was observed on adding nanoparticles. The long-range elastic force indicates that polymer chains and nanoparticles form a transient network in the gap between the surfaces. The observed difference in the outward force curves may explain why the addition of nanoparticles appears to improve e.g., shear-resistance and re-flocculation characteristics of polymeric flocculants.

  • 190. Sennerfors, T
    et al.
    Solberg, D
    Tiberg, F
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Adsorption of polyelectrolyte-nanoparticle systems on silica: Influence of ionic strength2002In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 254, p. 222-226Article in journal (Refereed)
    Abstract [en]

    In this work the effect of ionic strength on the adsorption behavior of cationic polyelectrolyte (acrylamide-acrylamidopropyltrimethylammonium chloride) and negatively charged silica particles has been studied by means of ellipsometry. The adsorption of the polyelectrolyte was observed to increase with increasing salt concentration, a behavior typical for polyelectrolytes with a screening-reduced solvency and a nonelectrostatic affinity for the surface. A similar dependence on the ionic strength was observed when studying the electrolyte effect on the nanoparticle adsorption to the preadsorbed polyelectrolyte film, suggesting that the polyelectrolyte surface conformations largely govern the binding capacity of the particles to the surface

  • 191.
    Sennerfors, T
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, F
    Adsorption of polyelectrolyte and nanoparticles at the silica-aqueous solution interface: Influence of the history of additions of the two components2001In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 237, p. 129-135Article in journal (Refereed)
    Abstract [en]

    The interfacial properties of a mixed system of low-charged cationic polyelectrolyte and silica nanoparticles has been studied by means of ellipsometry. Special attention was devoted to the effect that the order of addition of the two components has on the adsorption behavior of the mixed system. Adsorption on silica was in one case studied after simultaneous addition of the components to the aqueous solution. The measured adsorption rates were then much slower than expected for a mass-transfer limited process. This behavior signifies the presence of an electrosteric barrier arising due to preadsorbed polymer-particle complexes. Interfacial layers containing particles were at plateau conditions shown to be highly swollen, whereas the cationic polymer in the particle-free systems adopted a more flat surface conformation. The layer thickness was observed to monotonously increase with an increasing presence of nanoparticles in solution, while the surface excess showed a maximum at intermediate values. The finding was rationalized by the competition between particles and the surface for polymer charges leading to swelling and a decreased effective interaction between polymer and surface. In the other case studied, when polyelectrolyte and nanoparticles were added sequentially, a much more rapid concentration-dependent adsorption was observed. The kinetic adsorption barrier for nonassociated particles was clearly negligible compared with that for the polymer-particle complex. The surface excess did not exhibit an adsorption maximum as a function of added nanoparticles in this situation, indicating that the polymer layer to some degree is irreversibly anchored at the silica surface. Some implications of the above findings for practical papermaking using multicomponent retention systems are put forward

  • 192. Sjöblom, E
    et al.
    Friberg, S
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Light-scattering and electron microscopy determinations of association structures in W/O microemulsions1978In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 67, p. 16-30Article in journal (Refereed)
  • 193.
    Sjöblom, J
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Gestblom, B
    A dielectric spectroscopic study of some ionic and nonionic microemulsions1987In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 115, p. 535-544Article in journal (Refereed)
  • 194.
    Sjöblom, J
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Gestblom, B
    Relaxation and aggregate structure in the system trioxyethylene dodecylether/water as studied by dielectric time domain spectroscopy1989In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 127, p. 141-146Article in journal (Refereed)
  • 195.
    Sjöblom, J
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Jönsson, B
    Nylander, C
    Lundström, I
    Dielectric constants related to changes in shape of reversed micelles1984In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 100, p. 27-32Article in journal (Refereed)
  • 196.
    Sjöblom, J
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Jönsson, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Nylander, C
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Lundström, I
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Some dielectric properties of reversed micellar systems with different alkalicarboxylates and n-alcohols1983In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 96, p. 504-516Article in journal (Refereed)
  • 197. Sonesson, AW
    et al.
    Blom, H
    Hassler, K
    Elofsson, Ulla
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Callisen, TH
    Widengren, J
    Protein-surfactant interactions at hydrophobic interfaces studied with total internal reflection fluorescence correlation spectroscopy (TIR-FCS)2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 317, no 2, p. 449-457Article in journal (Refereed)
  • 198.
    Sott, Kristin
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik. Chalmers University of Technology, Sweden.
    Gebäck, Tobias
    Chalmers University of Technology, Sweden.
    Pihl, Maria
    Chalmers University of Technology, Sweden.
    Loren, Niklas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik.
    Hermansson, Ann-Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SIK – Institutet för livsmedel och bioteknik. Chalmers University of Technology, Sweden.
    Heintz, Alexei G.
    Chalmers University of Technology, Sweden.
    Rasmuson, Anders
    Chalmers University of Technology, Sweden.
    μPIV methodology using model systems for flow studies in heterogeneous biopolymer gel microstructures2013In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 398, p. 262-269Article in journal (Refereed)
    Abstract [en]

    A methodology for studying flow in heterogeneous soft microstructures has been developed. The methodology includes: (1) model fractal or random heterogeneous microstructures fabricated in PDMS and characterised using CLSM; (2) ?PIV measurements; (3) Lattice-Boltzmann simulations of flow. It has been found that the flow behaviour in these model materials is highly dependent on pore size as well as on the connectivity and occurrence of dead ends. The experimental flow results show good agreement with predictions from the Lattice-Boltzmann modelling. These simulations were performed in geometries constructed from 3D CLSM images of the actual PDMS structures. Given these results, mass transport behaviour may be predicted for even more complex structures, like gels or composite material in, e.g., food or biomaterials. This is a step in the direction towards predictive science with regards to tailoring soft biomaterials for specific mass transport properties.

  • 199.
    Steinby, K
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Silveston, R
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Kronberg, R
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    The effect of temperature on the adsorption of a nonionic surfactant on a PMMA latex1993In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 155, p. 70-78Article in journal (Refereed)
    Abstract [en]

    Adsorption isotherms of a nonionic surfactant, viz. a nonylphenol-polyethylene oxide with 20 ethylene oxide units in the chain, NP-EO20, on poly(methyl methacrylate), PMMA, latex have been determined at 10, 25, 40, 60 and 80°C. At all temperatures the isotherms are of high affinity type, i.e. strong adsorption at low solution concentration reaching a limiting value at higher concentration. The adsorption is strongly temperature dependent and increasing with the temperature. Thermo--dynamic analysis reveals that the only factor significantly affecting the temperature dependence of the adsorption of nonionic surfactants of NP-EOn type is the polyethylene oxide - water interaction. Adsorption measurements can therefore be used as a sensitive probe for this interaction. Two explanations are given for the temperature dependence of the polyethylene oxide - water interaction. The first is that the temperature dependence of this interaction is dominated by the water structuring, normally occuring around hydrophobic molecules. The increase in adsorption with temperature is a result of the decreasing water structuring. The second explanation is that the polymer has a higher probability of occupying less favorable conformations as the temperature is increased, thus rendering the polymer less soluble in the water phase, which in turn increases the adsorption.

  • 200. Stiernstedt, J
    et al.
    Nordgren, N
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Wågberg, L
    Brumer, H
    Gray, DG
    Rutland, MW
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Friction and forces between cellulose model surfaces: A comparison2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 303, p. 117-123Article in journal (Refereed)
    Abstract [en]

    Four different cellulose model surfaces, and one silica surface, have been studied by means of atomic force microscopy (AFM). The normal interactions have been found to consist of a longer range double layer force with a short range steric interaction, the nature of which is extensively discussed. Both the surface charge and range of the steric force depend on the type of cellulose substrate used, as does the magnitude of the adhesion. Studies of friction reveal that surface roughness is the determining factor for the friction coefficient, with which it increases monotonically. The absolute value, however, is determined by the surface chemistry. All studied cellulose surfaces show similar behavior in response to xyloglucan addition.

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