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A SCF STUDY OF INHOMOGENEOUS ADSORPTION OF NON-IONIC SURFACTANTS ON HYDROPHOBIC SURFACES A.B. Jódar-Reyes, J.L. Ortega-Vinuesa, A. Martín-Rodríguez, F.A.M. Leermakers University of Granada, Dpto. Fisica Aplicada, Facultad de Ciencias, Fuent, Granada, 18071, Spain email: ajodar@ugr.es ABSTRACT The structure of non-ionic surfactant layer adsorbed on a hydrophobic surface is studied by means the SCF-A. The possibility of formation of surface aggregates instead of homogeneous layers is included. Applying the one-gradient version of this theory in combination with the two-gradient one, we could follow the evolution of the adsorption process for several lengths of the PEO head. A branched hydrocarbon tail model that has an important effect on micellisation and adsorption results is also used. Theoretical results are compared to the experimental adsorption isotherms of Triton X-100 and Triton X-405 onto a polystyrene Latex dispersion. The process including inhomogeneous adsorption is closer to the experimental results than the homogeneous one.
THEORY AND SIMULATION OF BILAYER MEMBRANE FUSION: FREE ENERGY AND STRUCTURE OF INTERMEDIATES K. Katsov 1) , M. Schick 1) , M. Mueller 2) 1) Department of Physics, University of Washington, U.S.A. 2) Institut für Physik, Johannes-Gutenberg-Universität, Mainz, Germany email: schick@mahler.phys.washington.edu ABSTRACT We combine Monte Carlo simulations and SCF theory to study the microscopic mechanism of bilayer membrane fusion. Bilayers are composed of single chain amphiphiles in an excess homopolymer solvent. The fusion mechanism we observe in simulations is very different from a widely accepted "stalk" hypothesis. Instead of the radial stalk expansion into a hemifusion diaphragm with subsequent fusion pore formation, we observe very strong bilayer destabilization after the first local connections (stalks) are formed. This destabilization leads to a local rupture of the membranes in the vicinity of the stalk with a following sealing off of the formed microscopic holes by propagation of the initial connection (stalk). The observed mechanism is supported by our SCFT calculations of the structure and free energy of different intermediates that could be involved in the fusion process. The structures that we are able to study within the SCFT include bilayer edge, 3- and 4-junctions, point and linear stalks and some transition states. We calculate both relative stability of the intermediates and barriers encountered along the alternative fusion reaction paths. We also address the problem of mixed bilayers and find relatively strong deviations from the ideal mixing. The obtained results allow us to make very definite predictions that can be checked experimentally. This includes, e.g. the effect of tension and amphiphile architecture on the fusion rate, and the fact that the membrane fusion is a leaky process.
Page 1 and 2: Frontis - Wageningen International
Page 3 and 4: Prof. dr. Hans Fraaije Leiden Unive
Page 5 and 6: Prof. Ullrich Steiner University of
Page 7 and 8: Preface Self-consistent field model
Page 9 and 10: covered by polymers), and R. Rajago
Page 11 and 12: FIRST-ORDER WETTING TRANSITION AT F
Page 13 and 14: MOLECULAR SCF MODELLING OF PORES IN
Page 15 and 16: COLLAPSE OF POLYMER BRUSHES GRAFTED
Page 17 and 18: SURFACE FORCES, SUPRAMOLECULAR POLY
Page 19 and 20: SWEET BRUSHES: SYNTHESIS AND INTERF
Page 21 and 22: EFFECT OF MIXING OF TWO CHARGED PHO
Page 23 and 24: Figure 2 show a semi-log comparison
Page 25: MODELING OF STATIONARY POLYMER DIFF
Page 29 and 30: Figure 1. Time evolution of the she
Page 31 and 32: SALT EFFECT TO RAYLEIGH DROPLETS OF
Page 33 and 34: MACROMOLECULES AT INTERFACES, A FLE
Page 35 and 36: APPLICATION OF HETEROGENEOUS LATTIC
Page 37 and 38: 8. Linse, P., 1993b. Phase behavior
Page 39 and 40: MODELING INTERFACIAL EFFECTS ON THE
Page 41 and 42: Using this patterned electrode, we
Page 43 and 44: span the gap between the electrodes
Page 45 and 46: desirable to use a probe with a muc
Page 47 and 48: span the gap between the electrodes
Page 49 and 50: MEMBRANE FUSION: RESULTS FROM SIMUL
Page 51 and 52: the transition temperature T * when
Page 53 and 54: PROTEIN ADSORPTION ON SURFACES WITH
Page 55 and 56: MODELLING STRUCTURE AND ADHESION AT
Page 57 and 58: References 1. Fischel, L.B. and The
Page 59 and 60: MULTIDOMAIN CONFORMATIONS OF RANDOM
Page 61 and 62: SUPRAMOLECULAR COORDINATION POLYMER
Page 63 and 64: INFLUENCE OF POLYMERS ON THE BENDIN
Page 65 and 66: SPINODAL DECOMPOSITION IN BINARY PO
Page 67 and 68: PERSISTENCE LENGTH OF WORM-LIKE MIC
Page 69 and 70: For small particles with radius R <
Page 71: MEAN-FIELD THEORY FOR THE ADSORPTIO

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