The objectives of this work are (i) to prepare silver and TiO2 nanoparticles
functionalized with polymers or alkoxysilanes as capping agents with specific
control of morphology, size, and chemical reactivity and (ii) their attachment to
the surface and pore wall of ultrafiltration membranes. These particles are
interesting due to their known antibacterial, anti-biofouling efficiency, besides the
photocatytic activity exhibited by TiO2.
The first chapter focuses on the synthesis and characterization of silver
nanoparticles. Their performance depends on the shape, size and other colloidal
characteristics. A complete analysis of the effect of the stabilizer and pH
conditions on particle size and shape was conducted by using polyethyleneimine
and polyvinylpyrrolidone. Opposite trends and different morphologies were
observed for both stabilizers.
The second chapter describes the surface attachment of TiO2 nanoparticles onto
polyetherimide ultrafiltration membrane with pore size around 134nm by using
organoalkylsilanes. Excellent hydrophilicity (contact angle 39 2) and high and
thermal stability (260oC) was achieved. Particles and membranes samples were
characterized by microscopy, chemical and surface analysis.
|Date of Award
- Physical Sciences and Engineering
|Suzana Nunes (Supervisor)