INJECTION THRESHOLD FOR A STATISTICALLY BRANCHED POLYMER INSIDE A NANOPORE

A nonadsorbing, flexible polymer (in dilute solution with a good solve nt) enters a pore (of diameter D smaller than its natural size, R) onl y when it is sucked in by a solvent flux, J, higher than a threshold v alue, J(c). For linear polymers J(c) similar to kT/eta (where T is the temperature and eta the solvent viscosity). We discuss here the case of statistically branched polymers, with an average number, b, of mono mers between branch points. We find that there are two regimes, ''weak confinement'' and ''strong confinement'', depending on the tube diame ter. By measuring J(c) in both regimes, we should determine both the m olecular weight and the number b.