Unravelling a Self-healing Thermo- and Hydrodynamic Mechanism of Transient Pore’s Late-stage Closing in Vesicles, and Related Soft-matter Systems, in Terms of Liaison Between Surface-tension and Bending Effects

摘要

This study is devoted to reveal a simple self-healing, diffusive–dissolution-like mechanism of transient pore’s closing in a model spherical vesicle.It is based on a novel thermodynamic mechanism invented in terms of structuralflux–force relations, with Onsager’s coefficients reflecting the mainandcross-effects of nearly one-micrometer-in-diameter pore formation (oflinear cross sectional size r) immersed within the membrane of a sphericalvesicle of at least several tens of micrometer in its radius (R). The closingnanoscopic limit is given by r ! 0. The pore’s formation is envisaged as akind of bending and excess-area bearing (randomly occurring) failure, contrastingwith a homogenizing action of the surface tension, trying to recoveran even distribution of the elastic energy accumulated in the membrane.The failure yields at random the subsequent transient pore of a certain characteristic length along which the solution leaks out, with some appreciable speed, until the passage is ultimately closed within a suitable time interval. Inside such a time span, the system relaxes back toward its local equilibrium and uncompressed state until which the pore dissolves, and the before mentioned excess area vanishes. The (slow and non-exponential) relaxation–dissolution behavior bears a diffusion fingerprint, and it can be related with varying osmotic-pressure conditions. Useful connotations with a qualitatively similar biolubrication mechanism in articulating (micellescontaining) systems, down to the nanoscale, have also been pointed out.