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MD AND SCF ON BILAYERS OF SOPC AND SDPC F.A.M. Leermakers 1) , N.K. Balabaev 2) , A.L. Rabinovich 3) 1) Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands 2) Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, 142292, Russia 3) Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Pushkinskaja str 11, Petrozavodsk, 185610, Russia ABSTRACT Structural features of two lipid bilayer membranes composed of mono-unsaturated 1-stearoyl-2-oleoyl-snglycero-3-phosphatidylcholine SOPC and 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphatidylchol SDPC have been evaluated by an all-atom Molecular Dynamics simulation and compared to results obtained from a detailed numerical SCF method. SCF is computationally approximately 10.000 times more efficient than MD. The two methods appear complementary. The MD gives more details. In SCF it is possible to vary parameters. It is found that unsaturated lipid tails are effectively shorter (end-to-end distance. They reduce the interdigitation of tails into opposite monolayers (they modify the coupling between the two monolayers). Both MD and SCF predict equilibrium area per molecule close to the experimental data.
SURFACE FORCES, SUPRAMOLECULAR POLYMERS, AND DIRECTIONALITY J. van der Gucht 1,2) , N.A.M. Besseling 1) , M.A. Cohen Stuart 1) 1) Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands 2) Dutch Polymer Institute, Postbus 902, 5600 AX Eindhoven, The Netherlands email: klaas@fenk.wau.nl ABSTRACT Interactions between surfaces, e.g. of dispersed colloidal particles are crucial in all heterogeneous soft matter.(1) Supramolecular equilibrium polymers (sometimes denoted as living polymers) are polymeric chains formed by reversible, non-covalent association of special small molecules.(2) The main purpose of this presentation is to point out the relevance of the symmetry of the monomers for their behaviour at surfaces. Monomers that are symmetric in the sense that their two binding sites are self-complementary form nondirectional chains, but monomers with mutually complementary binding sites, often denoted as donor and acceptors sites (or as host and guest, lock and key) form directional chains. In solution or in bulk this difference will not lead to any difference in behaviour. However, in the presence of surfaces, and especially when two surfaces approach each other, the directionality of the monomers and the ensuing chains may be crucial. Figure 1. Non-directional chains between two surfaces (a), and directional chains between two similar surfaces that bind preferentially to the acceptor binding sites of the monomers (b). Phenomenological Landau analysis indicates that non-directional equilibrium polymers always yield attractive surface forces, but that directional equilibrium polymers may yield repulsion between surfaces that binds preferentially either the donors or the acceptors. More detailed information is deduced from a lattice model analysed in a Bethe-Guggenheim approximation. The strength and the range of the surface force, and their concentration dependencies is predicted to be different for the directional and the non-directional cases. These principles may explain certain observations on heterogeneous systems, and might be used to manipulate the properties of such systems. References 1. J. Israelachvili, Intermolecular and Surface Forces, Academic Press, 1991. 2. A. Ciferri, Supramolecular Polymers, Marcel Dekker, 2000. 3. J. van der Gucht, N.A.M. Besseling, M.A. Cohen Stuart, 2002. Surface forces, supramolecular polymers, and inversion symmetry. J. Am. Chem. Soc. 124, 6202-6205.
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: COLLAPSE OF POLYMER BRUSHES GRAFTED
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 and 26: MODELING OF STATIONARY POLYMER DIFF
Page 27 and 28: THEORY AND SIMULATION OF BILAYER ME
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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