Abstract
Background: Polymeric materials self-assembled into three-dimensional opal structures may be considered an interesting class of materials intended for photonic, chemical and biochemical applications.
Objective: The present work focuses on the synthesis of iridescent copolymers with the basis of methyl methacrylate and methacrylic acid, exhibiting enhanced thermal properties due to the incorporation of methacrylic acid comonomer into the copolymer chains. Method: Methyl methacrylate / methacrylic acid copolymer was synthesized through batch emulsion polymerization process. The morphology of iridescent copolymer particles has been evaluated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the thermal features have been evaluated by thermogravimetric measurements, differential scanning and calorimetry, and nuclear magnetic resonance (NMR) was been employed for the structural evaluation of (co)polymeric materials. Results: The copolymer presented iridescent characteristics, and as a result of particle self-assembly in three-dimensional ordered structures, that led to the formation of macrocrystals, which is responsible for optical effects, resulting in changes in polymeric material coloration. Microscopy analyses revealed spherical morphology of the polymeric particles, which exhibit monodisperse particle size, with 180 nm mean diameter. The particles were rigid at room temperature, and did not coalesce upon drying. Dried polymer particles portrayed a hexagonal ordered structure of close packing of the smaller particles. Conclusion: Monodisperse poly(methyl methacrylate-co-methacrylic acid) nanoparticles exhibiting iridescent behavior have been successfully synthesized. Due to the methacrylic acid incorporation, the resulting copolymer material has been obtained with improved glass transition temperature and thermal stability.Keywords: Iridescent effect, ordered structure, self-assembly, vinylic monomers, emulsion polymerization, macrocrystals.
Graphical Abstract