Charged Entities Interacting with Electronically Responsive Structures with Implications for the Modeling of Interactions between Carbon Nanotubes and DNA

• Author / Creator

  Malysheva, Oxana

• Understanding interactions between charged entities with electronically responsive
  structures embedded in an electrolytic environment is important because of the diverse
  range of practical applications. This study was motivated by the technique
  where single stranded DNA was used to separate carbon nanotubes (CNTs) with
  different electronic properties (metallic or semiconducting).
  The objective of this study was to create theoretical models which improve the
  understanding of the DNA-assisted separation technique for CNTs. In the course
  of this study four models with different levels of complexity at the continuum level
  were developed, with the electrostatic interaction being the main focus. In each of
  these models, with certain simplifications on geometry the boundary value problems
  for the electric potential were formulated using equations of electrostatics and
  in particular the Debye-Huckel theory for electrolyte. Using mathematical techniques,
  semi-analytical solutions for the electric potential were obtained and its implication
  for the DNA-CNT interaction and the property of the DNA-CNT hybrid
  were discussed. It was found that the electric potential due to a metallic CNT-DNA
  hybrid is weaker than that for a semiconducting CNT-DNA. In addition to that based
  on the proposed models, it was observed that the obtained results are applicable to
  a larger class of problems involving charged entities interacting with responsive
  structures. For example, it was studied how the phenomenon of counterion condensation
  on a polyelectrolyte (PE) is affected by the presence of a responsive cylinder.
  It was shown that counterions gradually release from the surface of the PE as it
  approaches a metallic cylinder, whereas more counterions are condensed on the PE
  as it approaches a dielectric cylinder where the dielectric constant of that cylinder
  ia smaller than that of the electrolyte solution.
  Results from this dissertation clearly demonstrate that in order to model the
  interaction between a charged entity and an electronically responsive structure, it is
  crucial to account for the response of the structure. Therefore, the models developed
  here have implications for modeling interactions between other charged entities
  near responsive structures. For example, cells adhering to an implant’s surface and
  biosensors detecting a specific DNA sequence.

• Subjects / Keywords

  • Responsive structure
  • Charged entity
  • Debye-Huckel theory
  • Polyelectrolyte
  • Carbon nanotubes

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3J406

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.