POLY 288 |
| The structure of core-shell particles of polymethylmethacrylate (the core) and polyurethane (the shell) of various sizes (in a range of 25 – 90 nm) have been investigated by methods of small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). A set of SAXS patterns has been obtained for each sample using contrast variation method. An evolution of pair distance distribution functions (PDDF), extracted from SAXS using regularization method, for the latexes dissolved in various sucrose solutions has been used to obtain structural parameters of the particles such as core size, shell thickness, density of the polymers. It has been demonstrated that PDDF obtained for latex particles in sucrose solutions, in a range of electron densities matching the electron densities of the polymers composing the core-shell particles is sensitive to deviations in both geometrical parameters of the particles and electron density of the polymers. In this particular work this effect has been used to measure the electron density deviations within the particle's core and the particle's shell (Figure 2). The effect of phase separation, which could take place in the PU, on the PDDF is estimated using Monte-Carlo simulations where the phase-separated PU shell is represented by spherical caps surrounded by the rest of the shell simulating the location of hard and soft PU segments respectively. |
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Multicompartment Micelles: Higher Order Self-assembly of Block Copolymers
1:30 PM-5:00 PM, Monday, 11 September 2006 San Francisco Marriott -- Salon B2, Oral
Division of Polymer Chemistry |