Fluctuations of bare membranes and their modification on incorporation of polymers having equally spaced anchors

Membrane undulations of highly ordered bare nonionic surfactant penta(ethyleneglycol) dodecyl ether (C₁₂E₅) multilayers were studied by neutron spin echo spectroscopy (NSE). The membrane relaxations profiles were fitted by a stretched exponential law S(q,t) = S(q)exp(Γ_qt)^3/2, where S(q) is the static structure factor and Γ_q is the relaxation rate. The universal scaling law Γ_q∼q³ for qd/2π>1, where d is the inter-lamellar spacing was observed. From the dependence of Γ_q on d as obtained for different surfactant volume fractions, shows that intermembrane contributions are still important at these q values. A model comb-graft polymer with monodisperse Polyethylene glycol (PEG) blocks of 6kg/mol connecting C₁₈ stearylamide hydrophobes, which serve as anchors, was introduced in the lamellar phase at increasing polymer concentration at two membrane volume fraction of 20% and 30% (Langmuir 18 (2002) 6).