Authors: A.S.W. Chan, M. Groves, C. Malardier-Jugroot
Affilation: Royal Military College of Canada, Canada
Pages: 41 - 44
Keywords: characterization, poly(isobutyl-alt-maleic anhydride), alternating copolymer, SANS, TEM, DLS, pH responsive
Our research focuses on the characterization of the association and the properties in aqueous solution of nanostructures composed of amphiphilic alternating copolymers. These copolymers are composed of a pH sensitive hydrophilic group, maleic anhydride alternating with a hydrophobic group. An experimental approach was chosen to investigate and characterize the association of IMA chains at different pH values. A change in structure at different environments was observed using Dynamic Light Scattering (DLS), Small Angle Neutron Scattering (SANS) and Transmission Electron Microscopy (TEM). DLS results reveal an association occurring at neutral pH whereas the copolymer was unable to from any observable structure at low and high pH. From the fitting of SANS pattern, it is suggested that IMA copolymer at pH 7 forms double layer sheets in which the outer surfaces are hydrophilic and the center gap is hydrophobic. In addition, TEM images of a dried sample showed sheet-like structures associated in layers. It was also observed that an addition of salt would influence the assembly of the copolymer; the formation of IMA spheres was possible at low pH with an increase of salt. This was confirmed using DLS, SANS and TEM.