INSTABILITY AND PEARLING STATES PRODUCED IN TUBULAR MEMBRANES BY COMPETITION OF CURVATURE AND TENSION

We investigate the stability of tubular fluid membranes by perturbing them with optical tweezers. A peristaltic instability appears, with wa velength on the order of the tube circumference, characterized by taut ness and suppression of curvature fluctuations in the membrane. We int erpret this in terms of a model that includes a surface tension term i n the elastic energy, and describes a transition to stable, finite amp litude peristaltic states. At high amplitudes the experiment reveals n ew dynamic states of ''pearls'' interconnected via thin tubes along wh ich they travel and aggregate.