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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Preparation and morphological study of composite nano-particles made of homopolymers

Wang, Nan 27 August 2008 (has links)
Composite polymer particles were made of two or more polymers. If these polymers are incompatible, the particles after polymer phase segregation exhibit complex morphologies which determine their properties and applications. Such particles may have applications in both academia and industry. In this work, polystyrene (PS)/ poly(2-cinnamoyloxyethyl methacrylate) (PCEMA) and poly(acetyloxyethyl methacrylate) (PAEMA)/PCEMA composite polymer particles are prepared by the evaporation of toluene from PS/PCEMA/toluene and PAEMA/PCEMA/toluene droplets dispersed in an aqueous solution containing surfactants. The surfactants used for the two systems are poly(glyceryl methacrylate)100-block-poly(2-cinnamoyloxyethyl methacrylate)15 (PGMA100-b-PCEMA15) and poly(glyceryl methacrylate)300-block-poly(2-cinnamoyloxyethyl methacrylate-ran-acetyloxyethyl methacrylate)37 (PGMA300-b-P(CEMA-ran-AEMA)37), respectively, for the PS/PCEMA and the PAEMA/PCEMA systems. The morphologies of the PS/PCEMA and PAEMA/PCEMA composite particles are analyzed by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). The results indicate that the particles are polydisperse and of nanometer size. For the PAEMA/PCEMA particles, the preferred morphology is hemisphere, while for the PS/PCEMA system the morphology is a mixture of acorn and occluded core-shell. Based on Gibbs free energy theory, and knowing the corresponding surface tensions and interfacial tensions, the thermodynamic equilibrium morphologies for both kinds of composite particles were found. Due to the uncertainty during measurements and calculations, and the influence of kinetic factors, the theoretical predictions agreed only partially with the experimental observations. / Thesis (Master, Chemistry) -- Queen's University, 2008-08-27 12:16:37.142

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