Thermoresponsive Gels: How do the structural parameters affect the gelation properties?

Thermoresponsive polymers are promising biomaterials in Tissue Engineering and in 3D printing. Therefore, this PhD thesis aims to synthesise polymers that form physical gels at body temperature (b.t.). Four different families of thermoresponsive polymers have been successfully synthesised via Group Transfer Polymerisation, and their properties have been investigated, with emphasis on their thermogelling behaviour. i) In the first study, the ionic, pH- and thermoresponsive 2-(dimethylamino) ethyl methacrylate (DMAEMA) has been combined with the hydrophilic tri(ethylene glycol) methyl ether methacrylate (TEGMA), and the hydrophobic n-butyl methacrylate (BuMA). The architecture of diblock terpolymers has been systematically varied for the first time, while statistical and triblock terpolymers have been investigated for comparison. ii) In the second study, penta(ethylene glycol) methyl ether methacrylate (PEGMA) has been used as the hydrophilic unit, whereas BuMA and DMAEMA have been kept the same as in the first study. Thermoresponsive tetrablock terpolymers of varying architectures and compositions have been systematically investigated for the first time. iii) The third study is focused on investigating polymers containing a non-ionic thermoresponsive unit, namely di(ethylene glycol) methyl ether methacrylate (DEGMA, C unit). ABC triblock terpolymers of various compositions have been synthesised, with A and B blocks being based on PEGMA and BuMA, respectively. iv) The fourth study focuses on mimicking Pluronic® F127, which is the commercially-available thermoresponsive polymer. ABA triblock bipolymers with different molar mass (MM) and composition have been produced (A is PEGMA, an B is the in-house synthesised hydrophobic monomer di(propylene glycol) methyl ether methacrylate (diPGMA). In conclusion, the following structural parameters have been identified as crucial for the thermogelling properties: i) architecture, ii) composition, iii) MM and iv) as expected, the chemistry. The best architecture is the ABC triblock architecture with the hydrophobic monomer as the B block, while the most promising chemistry seems to be the PEGMA-BuMA-DEGMA series.Open Acces