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Supervisors: Dr.ssa Bertoldo Monica
Title: Synthesis and characterization of IPN multiresponsive microgels
Abstract:
Colloidal multiresponsive systems have been strongly studied either for theoretical implications and for technological application, as in pharmaceutics industries, tissue engineering and for sensors.
These “smart” materials are nanometre- or micrometre-sized hydrogel particles, which are able to respond to external stimuli such as temperature, pH, ionic strength or electric field, by undergoing a rapid but reversible volume phase transition, at critical values, from a swollen hydrophilic state to a collapsed hydrophobic state, changing their behaviour between hard-sphere and ultra-soft colloids. Therefore they are really interesting as models to analyse colloidal dynamic, especially the difference between hard and soft particles in the arrested states.
This PhD project will mainly investigate microgels consisting of interpenetrated polymer network (IPN) of poly(N-isopropylacrilamide) and polyacrylic acid, combining the thermo-responsivity of the former with the pH-responsivity of the latter and achieving a structure of the particles that allows the same independent response as the two components to external stimuli.
The main aim is a detailed study of a synthesis methodology that allows achieving an accurate control of composition, structure and size of the particles. Materials produced under the standard procedure currently proposed, based on two sequential radical polymerization steps in aqueous phase, will be investigated and compared with other synthesis route, as inverse emulsion polymerization and controlled radical polymerization (RAFT).
The prepared materials will be characterized by spectroscopic methods (FT-IR, NMR), elemental analysis, Dinamic Light Scattering, X-ray scattering, AFM, neutron and x-ray diffraction or scattering methods. Applications of these materials for sensors or active food packaging will be tested.