Pore stability and dynamics in polymer membranes

¹ Department of Chemical and Biomolecular Engineering, University of Pennsylvania Philadelphia, PA 19104, USA
² Institute for Medicine and Engineering, University of Pennsylvania Philadelphia, PA 19104, USA

Received: 27 June 2003
Accepted: 29 August 2003

Abstract

Vesicles self-assembled from amphiphilic diblock copolymers exhibit a wide diversity of behavior upon poration, due to competitions between edge, surface and bending energies, while viscous dissipation mechanisms determine the time scales. The copolymers are essentially chemically identical, only varying in chain length (related to the membrane thickness d). For small d, we find large unstable pores and the resulting membrane fragments reassemble into vesicles within minutes. For large d, however, submicron pores form and are extremely long-lived. The results show that pore behavior depends strongly on d, suggesting that the relevant energies depend on d and pore size r in a more complex manner than what is generally assumed. Further control over these systems would make them useful for numerous applications.