Extension of a Flexible Polymer Confined inside a Nano-Channel

چکیده مقاله

Half a century passes from the development of theories for polymers in cylindrical channels by de Gennes. It predicts the relation (b/D)^(2/3) Nb for the polymer extension along the channel. This result is derived in the thermodynamic limit that: (1) the channel diameter is orders larger than the monomer’s size, (2) the polymer extension along the channel is much larger than the channel diameter. New methods in nano-technology have made the study of polymers confined in the nano-channel possible. The extensive experimental and simulation works on this subject use the old de Gennes’s theory to explain their results. For narrow nano-channels with few nano-meters wide or shorter polymers, this is in contrast to the condition of thermodynamic limit assumed in this theory. In this paper, we study the extension of a polymer confined inside a nano-channel, using Molecular Dynamics (MD) simulations. The simulations are performed for nano-channels with diameter of the order of monomers size and polymers with several hundreds of monomers. We compare the MD results with the de Gennes theory. We show that this theory can explain the MD results, completely well. It shows that despite the existing controversies, the de Gennes theory is valid in for polymers confined in the nano-channels.