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Cascades of unfolding transitions in amphiphilic molecular brushes.

Anna S IvanovaIvan V MikhailovAlexey A PolotskyAnatoly A DarinskiiTatiana M BirshteinOleg V Borisov
Published in: The Journal of chemical physics (2020)
Using a combination of self-consistent field theory with coarse-grained Brownian dynamics simulations, we studied mechanical unfolding of an amphiphilic molecular brush in a solvent that was poor for the side chains but good for the main chain of the brush. In striking contrast to earlier theoretical predictions [O. V. Borisov and A. Halperin, Europhys. Lett. 34, 657 (1996)] made for amphiphilic graft copolymers, we discovered that in a partially unfolded molecular brush, a globular core co-exists, at equilibrium, with a necklace of smaller sized intra-molecular micelles, each comprising a few side chains connected by stretched main chain strands (bridges). A progressive increase in the main chain end-to-end distance of the brush triggers a sequence of discrete events of generation of new intramolecular micelles, giving rise to a sawtooth pattern in the restoring force-deformation curve.
Keyphrases
  • molecular dynamics
  • single molecule
  • drug delivery
  • molecular dynamics simulations
  • cancer therapy
  • computed tomography