The bridging conformations of double-end anchored polymer-surfactants destabilize a hydrogel of lipid membranes

Double-end-anchored poly-ethylene-glycol-surfactants (DEA-PEG-surfactants) induce the gelation of lyotropic lamellar L-alpha phases stabilized by undu lation forces. The physical hydrogel (L-alpha ,L-g) derives its viscoelasti city from the proliferation of defects at a mesoscopic level. The DEA-PEG-s urfactants assume both looping and bridging conformations. The existence of novel bridging conformations is indicated by the coexistence of two lamell ar phases and the limited swelling of the L-alpha and L-alpha ,L-g phases. Modeling of the polymer decorated membranes demonstrates the existence of b ridging and yields a rapidly decreasing density of bridging conformations w ith increasing interlayer spacing. (C) 2001 American Institute of Physics.