Amorphous magnesium carbonate nanomaterials : Synthesis, characterization and applications

Sammanfattning: High surface-to-volume ratio materials, including nanoparticles and mesoporous materials, have a number of applications due to their large surface area and special structures. Traditional approaches for synthesizing high surface-to-volume ratio nanomaterials are often complicated, expensive or environmentally unfriendly. Considering aspects such as availability and safety in terms of environmental or biological contact, magnesium carbonate-based nanomaterials are an interesting and potentially valuable candidate for novel applications. The overall aim of this thesis was to develop novel high surface-to-volume ratio amorphous magnesium carbonate nanomaterials and investigating their possible applications.Amorphous magnesium carbonate nanoparticles (AMN) were successfully synthesized via a simple and low-temperature pathway. The structure and resulting properties of the material can be tailored by changing the final steps in the synthesis process.The ability of AMN to stabilize ibuprofen (IBU) in the amorphous state was investigated. Nanocomposites with IBU:AMN mass ratios as high as to 5:1 were shown to enhance the release rate of IBU in vitro by as much as 83 times compared to IBU in crystalline form. A related nanostructured material, mesoporous magnesium carbonate (MMC), was evaluated as a drug carrier for stabilizing amorphous drugs through the incorporation of the drug within its pores. In this study, MMC was used to release and sustain two poorly soluble drugs (tolfenamic acid and rimonabant) in the supersaturated state with the assistance of hydroxypropyl methylcellulose.AMN was also used to synthesize a novel adhesive together with IBU without the addition of a polymer. This adhesive was transparent, self-healing, shapeable, stretchable and reusable. In addition, the adhesive was able to glue a variety of materials, including metals, glass, paper and plastics (even Teflon).Finally, AMN was used to prepare flexible, transparent and UV-shielding films when incorporated into a PMMA matrix. These films exhibited both UV-shielding properties and moisture absorbance and retention abilities. In addition, the UV- and thermo-stability of these films were enhanced by the addition of AMN.The work presented in this thesis show that the nanomaterials AMN and MMC possess great potential for an extremely broad range of applications, from pharmaceutical applications dealing with poorly soluble drugs to structural applications such as adhesives to applications in optics or electronics such as UV-shielding or moisture barrier films.