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Título: Novel self-assembly of an alternating copolymer into nanotubes : theoretical investigation and experimental characterisation
Autores: Malardier-Jugroot, Cécile
Fecha: 2004
Publicador: McGill University - MCGILL
Fuente:
Tipo: Electronic Thesis or Dissertation
Tema: Chemistry, Physical.
Descripción: This thesis is aimed at understanding and fully characterising the association mechanism of an alternating copolymer in water and the effect of the association in solution on the conformation of the polymer chains at the air/water interface.
Self-assembly is an elegant and efficient method to obtain well defined and usually defect-free nano-architectures. The association, variety of shapes and properties of block copolymers have been extensively studied. The present study led to a precise understanding of the complex behaviour of large molecules. The polymer studied is an alternating copolymer; poly(styrene- alt-maleic anhydride) (SMA). This polymer has various applications ranging from surface sizing of paper, to nanotechnology and pharmaceutical applications.
The detailed theoretical investigation of the SMA association led to the discovery of a novel way to self-assemble polymer chains, and the prediction and characterisation of a tubular structure formed by this association. The nanotubes are several micrometers long and their conformation shows that the hydrophobic groups are mainly located inside the tube and the hydrophilic groups are mainly on the exterior surface of the tube.
The predicted tubular structure of SMA in solution was also confirmed by neutron scattering experiments. This study showed that the tubes interact forming two-dimensional sheets of tubes and higher order structures. In addition, the SMA association has been shown to be thermally stable.
Furthermore, neutron reflectivity experiments were performed on the SMA solution to determine the influence of the association in solution on the conformation of the polymer at the air-water interface. This study revealed an equilibrium between the conformation of the polymer in solution and at the interface.
Using the knowledge of the association mechanism obtained from the complete theoretical and experimental characterisation of the association of poly(styrene-maleic anhydride) in water and at the air-water interface, a novel application for the polymer has been developed. This application uses the template formed by the nanotubes to form nanowires of intrinsically conducting polymers. Neutron scattering, neutron reflectivity, cryo-TEM and AFM experimental studies characterised the synthesis of the nanowires.
Idioma: en