During the last decade, silica nanoparticles have found applications in catalysis, water_x000D_ purification, biomedical, agricultural and industrial fields… due to their unique chemical_x000D_ and physical characteristics, such as high surface area, excellent biocompatibility, good_x000D_ thermal, mechanical and chemical stability, adjustable pore size and shape, enriched_x000D_ surface silanol groups with easy surface modification. Our research in this thesis has_x000D_ been focused on the preparation and characterization of various types of novel_x000D_ functionalized silica nanoparticles, as well as their application in catalysis, biomedicine_x000D_ and rare earth elements recovery. Novel mesoporous silica nanoparticles derived from mono- and bis-silylated proline-valinol amides were prepared and used as recyclable catalysts for the asymmetric aldol reaction with high activity and selectivity. These nanomaterials can be successfully recovered and reused for up to six runs (Chapter 2). Conversely, our efforts in the preparation of recyclable organosilica nanoparticles as chiral catalysts or ligands for the enantioselective α-trifuoromethylation and α-fluorination of carbonyl compounds were not successful (Chapter 2). _x000D_ A series of mixed periodic mesoporous organosilica nanoparticles possessing Boc and tert-butyl ester groups were prepared as potential high intensity focused ultrasound (HIFU) responsive agents. These nanomaterials were expected to release CO2 and/or isobutene from the temperature-sensitive COOtBu group. However, Boc group was found to be quite stable and could not be removed under HIFU conditions at 80 ºC, requiring the addition of acid. The concept is nevertheless promising for future contrast agents for HIFU based therapies (Chapter 3)._x000D_ Non-steroidal anti-inflammatory drugs such as ibuprofen and diclofenac were grafted to silica nanoparticles through an amide functional group for potential application in ointment and cream topical formulations. Furthermore, coating of cotton fabrics with these functionalized silica nanoparticles provided hydrophobic fabrics for potential topical cutaneous applications in dressings intended to treat chronic wounds. The corresponding anti-inflammatory drug is released in situ by the selective enzymatic cleavage of the amide bond in the presence of proteases (Chapter 4). _x000D_ Two functionalized magnetic core-shell mesoporous silica nanoparticles containing cyclen moieties were prepared as novel adsorbents for the specific and selective recovery of different rare earth (REs) ions from wastewater (Chapter 5).
Functionalized Silica Nanoparticles for Catalysis, Nanomedicine and Rare Earth Metal Recycling
LI, H. (Author). 21 Jul 2020
Student thesis: Doctoral thesis
Student thesis: Doctoral thesis