Polymer ejection from strong spherical confinement

Joonas Piili, Riku P. Linna

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)
108 Downloads (Pure)


We examine the ejection of an initially strongly confined flexible polymer from a spherical capsid through a nanoscale pore. We use molecular dynamics for unprecedentedly high initial monomer densities. We show that the time for an individual monomer to eject grows exponentially with the number of ejected monomers. By measurements of the force at the pore we show this dependence to be a consequence of the excess free energy of the polymer due to confinement growing exponentially with the number of monomers initially inside the capsid. This growth relates closely to the divergence of mixing energy in the Flory-Huggins theory at large concentration. We show that the pressure inside the capsid driving the ejection dominates the process that is characterized by the ejection time growing linearly with the lengths of different polymers. Waiting time profiles would indicate that the superlinear dependence obtained for polymers amenable to computer simulations results from a finite-size effect due to the final retraction of polymers' tails from capsids.
Original languageEnglish
Article number062715
Pages (from-to)1-6
JournalPhysical Review E
Issue number6
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed


  • bacteriophage
  • capsid ejection
  • polymer physics
  • stochastic rotation dynamics
  • virus capsid

Fingerprint Dive into the research topics of 'Polymer ejection from strong spherical confinement'. Together they form a unique fingerprint.

  • Equipment


    Mikko Hakala (Manager)

    School of Science

    Facility/equipment: Facility

  • Cite this