The influence of gradient copolymerisation poly(oligo(propylene glycol) methacrylate) hydrogels with 2-hydroxyethyl methacrylate on thermoresponsive properties

Abstract

Gamma radiation was used to prepare copolymer libraries based on oligo(propylene glycol) methacrylate (OPGMA) and 2-hydroxyethyl methacrylate (HEMA); a complete screening in composition of P(OPGMA/HEMA) copolymers was elaborated from 0 to 100% of OPGMA. Determination of gel fraction was performed as a first step after radiation induced synthesis. Tuning of the volume phase transition temperature (VPTT) of P(OPGMA/HEMA) copolymeric hydrogels was investigated by swelling study; the swelling properties were preliminary investigated over the wide pH (2.2-9.0) and temperature (4-80°C) ranges. It has been observed that P(OPGMA/HEMA) hydrogels followed a simple rule in their thermoresponsive behaviour showing a linear increase in VPTT with a decreasing wt% of OPGMA in the copolymer composition. Additional characterisation of the structure and properties was conducted by FTIR, DSC and UV-Vis spectroscopy. All results indicate that new P(OPGMA/HEMA) copolymeric hydrogels have wide diversity in thermoresponsive properties which strongly depend on their composition.